neovim/src/nvim/spell.c

// VIM - Vi IMproved    by Bram Moolenaar
//
// Do ":help uganda"  in Vim to read copying and usage conditions.
// Do ":help credits" in Vim to see a list of people who contributed.
// See README.txt for an overview of the Vim source code.

// spell.c: code for spell checking
//
// The spell checking mechanism uses a tree (aka trie).  Each node in the tree
// has a list of bytes that can appear (siblings).  For each byte there is a
// pointer to the node with the byte that follows in the word (child).
//
// A NUL byte is used where the word may end.  The bytes are sorted, so that
// binary searching can be used and the NUL bytes are at the start.  The
// number of possible bytes is stored before the list of bytes.
//
// The tree uses two arrays: "byts" stores the characters, "idxs" stores
// either the next index or flags.  The tree starts at index 0.  For example,
// to lookup "vi" this sequence is followed:
//      i = 0
//      len = byts[i]
//      n = where "v" appears in byts[i + 1] to byts[i + len]
//      i = idxs[n]
//      len = byts[i]
//      n = where "i" appears in byts[i + 1] to byts[i + len]
//      i = idxs[n]
//      len = byts[i]
//      find that byts[i + 1] is 0, idxs[i + 1] has flags for "vi".
//
// There are two word trees: one with case-folded words and one with words in
// original case.  The second one is only used for keep-case words and is
// usually small.
//
// There is one additional tree for when not all prefixes are applied when
// generating the .spl file.  This tree stores all the possible prefixes, as
// if they were words.  At each word (prefix) end the prefix nr is stored, the
// following word must support this prefix nr.  And the condition nr is
// stored, used to lookup the condition that the word must match with.
//
// Thanks to Olaf Seibert for providing an example implementation of this tree
// and the compression mechanism.
// LZ trie ideas:
//      http://www.irb.hr/hr/home/ristov/papers/RistovLZtrieRevision1.pdf
// More papers: http://www-igm.univ-mlv.fr/~laporte/publi_en.html
//
// Matching involves checking the caps type: Onecap ALLCAP KeepCap.
//
// Why doesn't Vim use aspell/ispell/myspell/etc.?
// See ":help develop-spell".

// Use SPELL_PRINTTREE for debugging: dump the word tree after adding a word.
// Only use it for small word lists!

// Use DEBUG_TRIEWALK to print the changes made in suggest_trie_walk() for a
// specific word.

// Use this to adjust the score after finding suggestions, based on the
// suggested word sounding like the bad word.  This is much faster than doing
// it for every possible suggestion.
// Disadvantage: When "the" is typed as "hte" it sounds quite different ("@"
// vs "ht") and goes down in the list.
// Used when 'spellsuggest' is set to "best".
#define RESCORE(word_score, sound_score) ((3 * word_score + sound_score) / 4)

// Do the opposite: based on a maximum end score and a known sound score,
// compute the maximum word score that can be used.
#define MAXSCORE(word_score, sound_score) ((4 * word_score - sound_score) / 3)

// Vim spell file format: <HEADER>
//                        <SECTIONS>
//                        <LWORDTREE>
//                        <KWORDTREE>
//                        <PREFIXTREE>
//
// <HEADER>: <fileID> <versionnr>
//
// <fileID>     8 bytes    "VIMspell"
// <versionnr>  1 byte      VIMSPELLVERSION
//
//
// Sections make it possible to add information to the .spl file without
// making it incompatible with previous versions.  There are two kinds of
// sections:
// 1. Not essential for correct spell checking.  E.g. for making suggestions.
//    These are skipped when not supported.
// 2. Optional information, but essential for spell checking when present.
//    E.g. conditions for affixes.  When this section is present but not
//    supported an error message is given.
//
// <SECTIONS>: <section> ... <sectionend>
//
// <section>: <sectionID> <sectionflags> <sectionlen> (section contents)
//
// <sectionID>    1 byte    number from 0 to 254 identifying the section
//
// <sectionflags> 1 byte    SNF_REQUIRED: this section is required for correct
//                                          spell checking
//
// <sectionlen>   4 bytes   length of section contents, MSB first
//
// <sectionend>   1 byte    SN_END
//
//
// sectionID == SN_INFO: <infotext>
// <infotext>    N bytes    free format text with spell file info (version,
//                          website, etc)
//
// sectionID == SN_REGION: <regionname> ...
// <regionname>  2 bytes    Up to 8 region names: ca, au, etc.  Lower case.
//                          First <regionname> is region 1.
//
// sectionID == SN_CHARFLAGS: <charflagslen> <charflags>
//                              <folcharslen> <folchars>
// <charflagslen> 1 byte    Number of bytes in <charflags> (should be 128).
// <charflags>  N bytes     List of flags (first one is for character 128):
//                          0x01  word character        CF_WORD
//                          0x02  upper-case character  CF_UPPER
// <folcharslen>  2 bytes   Number of bytes in <folchars>.
// <folchars>     N bytes   Folded characters, first one is for character 128.
//
// sectionID == SN_MIDWORD: <midword>
// <midword>     N bytes    Characters that are word characters only when used
//                          in the middle of a word.
//
// sectionID == SN_PREFCOND: <prefcondcnt> <prefcond> ...
// <prefcondcnt> 2 bytes    Number of <prefcond> items following.
// <prefcond> : <condlen> <condstr>
// <condlen>    1 byte      Length of <condstr>.
// <condstr>    N bytes     Condition for the prefix.
//
// sectionID == SN_REP: <repcount> <rep> ...
// <repcount>    2 bytes    number of <rep> items, MSB first.
// <rep> : <repfromlen> <repfrom> <reptolen> <repto>
// <repfromlen>  1 byte     length of <repfrom>
// <repfrom>     N bytes    "from" part of replacement
// <reptolen>    1 byte     length of <repto>
// <repto>       N bytes    "to" part of replacement
//
// sectionID == SN_REPSAL: <repcount> <rep> ...
//   just like SN_REP but for soundfolded words
//
// sectionID == SN_SAL: <salflags> <salcount> <sal> ...
// <salflags>    1 byte     flags for soundsalike conversion:
//                          SAL_F0LLOWUP
//                          SAL_COLLAPSE
//                          SAL_REM_ACCENTS
// <salcount>    2 bytes    number of <sal> items following
// <sal> : <salfromlen> <salfrom> <saltolen> <salto>
// <salfromlen>  1 byte     length of <salfrom>
// <salfrom>     N bytes    "from" part of soundsalike
// <saltolen>    1 byte     length of <salto>
// <salto>       N bytes    "to" part of soundsalike
//
// sectionID == SN_SOFO: <sofofromlen> <sofofrom> <sofotolen> <sofoto>
// <sofofromlen> 2 bytes    length of <sofofrom>
// <sofofrom>    N bytes    "from" part of soundfold
// <sofotolen>   2 bytes    length of <sofoto>
// <sofoto>      N bytes    "to" part of soundfold
//
// sectionID == SN_SUGFILE: <timestamp>
// <timestamp>   8 bytes    time in seconds that must match with .sug file
//
// sectionID == SN_NOSPLITSUGS: nothing
//
// sectionID == SN_WORDS: <word> ...
// <word>        N bytes    NUL terminated common word
//
// sectionID == SN_MAP: <mapstr>
// <mapstr>      N bytes    String with sequences of similar characters,
//                          separated by slashes.
//
// sectionID == SN_COMPOUND: <compmax> <compminlen> <compsylmax> <compoptions>
//                              <comppatcount> <comppattern> ... <compflags>
// <compmax>     1 byte     Maximum nr of words in compound word.
// <compminlen>  1 byte     Minimal word length for compounding.
// <compsylmax>  1 byte     Maximum nr of syllables in compound word.
// <compoptions> 2 bytes    COMP_ flags.
// <comppatcount> 2 bytes   number of <comppattern> following
// <compflags>   N bytes    Flags from COMPOUNDRULE items, separated by
//                          slashes.
//
// <comppattern>: <comppatlen> <comppattext>
// <comppatlen>  1 byte     length of <comppattext>
// <comppattext> N bytes    end or begin chars from CHECKCOMPOUNDPATTERN
//
// sectionID == SN_NOBREAK: (empty, its presence is what matters)
//
// sectionID == SN_SYLLABLE: <syllable>
// <syllable>    N bytes    String from SYLLABLE item.
//
// <LWORDTREE>: <wordtree>
//
// <KWORDTREE>: <wordtree>
//
// <PREFIXTREE>: <wordtree>
//
//
// <wordtree>: <nodecount> <nodedata> ...
//
// <nodecount>  4 bytes     Number of nodes following.  MSB first.
//
// <nodedata>: <siblingcount> <sibling> ...
//
// <siblingcount> 1 byte    Number of siblings in this node.  The siblings
//                          follow in sorted order.
//
// <sibling>: <byte> [ <nodeidx> <xbyte>
//                    | <flags> [<flags2>] [<region>] [<affixID>]
//                    | [<pflags>] <affixID> <prefcondnr> ]
//
// <byte>       1 byte      Byte value of the sibling.  Special cases:
//                          BY_NOFLAGS: End of word without flags and for all
//                                      regions.
//                                      For PREFIXTREE <affixID> and
//                                      <prefcondnr> follow.
//                          BY_FLAGS:   End of word, <flags> follow.
//                                      For PREFIXTREE <pflags>, <affixID>
//                                      and <prefcondnr> follow.
//                          BY_FLAGS2:  End of word, <flags> and <flags2>
//                                      follow.  Not used in PREFIXTREE.
//                          BY_INDEX:   Child of sibling is shared, <nodeidx>
//                                      and <xbyte> follow.
//
// <nodeidx>    3 bytes     Index of child for this sibling, MSB first.
//
// <xbyte>      1 byte      Byte value of the sibling.
//
// <flags>      1 byte      Bitmask of:
//                          WF_ALLCAP   word must have only capitals
//                          WF_ONECAP   first char of word must be capital
//                          WF_KEEPCAP  keep-case word
//                          WF_FIXCAP   keep-case word, all caps not allowed
//                          WF_RARE     rare word
//                          WF_BANNED   bad word
//                          WF_REGION   <region> follows
//                          WF_AFX      <affixID> follows
//
// <flags2>     1 byte      Bitmask of:
//                          WF_HAS_AFF >> 8   word includes affix
//                          WF_NEEDCOMP >> 8  word only valid in compound
//                          WF_NOSUGGEST >> 8  word not used for suggestions
//                          WF_COMPROOT >> 8  word already a compound
//                          WF_NOCOMPBEF >> 8 no compounding before this word
//                          WF_NOCOMPAFT >> 8 no compounding after this word
//
// <pflags>     1 byte      Bitmask of:
//                          WFP_RARE    rare prefix
//                          WFP_NC      non-combining prefix
//                          WFP_UP      letter after prefix made upper case
//
// <region>     1 byte      Bitmask for regions in which word is valid.  When
//                          omitted it's valid in all regions.
//                          Lowest bit is for region 1.
//
// <affixID>    1 byte      ID of affix that can be used with this word.  In
//                          PREFIXTREE used for the required prefix ID.
//
// <prefcondnr> 2 bytes     Prefix condition number, index in <prefcond> list
//                          from HEADER.
//
// All text characters are in 'encoding', but stored as single bytes.

// Vim .sug file format:  <SUGHEADER>
//                        <SUGWORDTREE>
//                        <SUGTABLE>
//
// <SUGHEADER>: <fileID> <versionnr> <timestamp>
//
// <fileID>     6 bytes     "VIMsug"
// <versionnr>  1 byte      VIMSUGVERSION
// <timestamp>  8 bytes     timestamp that must match with .spl file
//
//
// <SUGWORDTREE>: <wordtree>  (see above, no flags or region used)
//
//
// <SUGTABLE>: <sugwcount> <sugline> ...
//
// <sugwcount>  4 bytes     number of <sugline> following
//
// <sugline>: <sugnr> ... NUL
//
// <sugnr>:     X bytes     word number that results in this soundfolded word,
//                          stored as an offset to the previous number in as
//                          few bytes as possible, see offset2bytes())

#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <wctype.h>

#include "nvim/vim.h"
#include "nvim/ascii.h"
#include "nvim/spell.h"
#include "nvim/buffer.h"
#include "nvim/charset.h"
#include "nvim/cursor.h"
#include "nvim/edit.h"
#include "nvim/eval.h"
#include "nvim/ex_cmds.h"
#include "nvim/ex_cmds2.h"
#include "nvim/ex_docmd.h"
#include "nvim/fileio.h"
#include "nvim/func_attr.h"
#include "nvim/getchar.h"
#include "nvim/hashtab.h"
#include "nvim/mbyte.h"
#include "nvim/memline.h"
#include "nvim/memory.h"
#include "nvim/message.h"
#include "nvim/misc1.h"
#include "nvim/misc2.h"
#include "nvim/garray.h"
#include "nvim/normal.h"
#include "nvim/option.h"
#include "nvim/os_unix.h"
#include "nvim/path.h"
#include "nvim/regexp.h"
#include "nvim/screen.h"
#include "nvim/search.h"
#include "nvim/strings.h"
#include "nvim/syntax.h"
#include "nvim/term.h"
#include "nvim/tempfile.h"
#include "nvim/undo.h"
#include "nvim/os/os.h"
#include "nvim/os/input.h"

#ifndef UNIX            // it's in os_unix_defs.h for Unix
# include <time.h>      // for time_t
#endif

#define MAXWLEN 250             // Assume max. word len is this many bytes.
                                // Some places assume a word length fits in a
                                // byte, thus it can't be above 255.

// Type used for indexes in the word tree need to be at least 4 bytes.  If int
// is 8 bytes we could use something smaller, but what?
typedef int idx_T;

# define SPL_FNAME_TMPL  "%s.%s.spl"
# define SPL_FNAME_ADD   ".add."
# define SPL_FNAME_ASCII ".ascii."

// Flags used for a word.  Only the lowest byte can be used, the region byte
// comes above it.
#define WF_REGION   0x01        // region byte follows
#define WF_ONECAP   0x02        // word with one capital (or all capitals)
#define WF_ALLCAP   0x04        // word must be all capitals
#define WF_RARE     0x08        // rare word
#define WF_BANNED   0x10        // bad word
#define WF_AFX      0x20        // affix ID follows
#define WF_FIXCAP   0x40        // keep-case word, allcap not allowed
#define WF_KEEPCAP  0x80        // keep-case word

// for <flags2>, shifted up one byte to be used in wn_flags
#define WF_HAS_AFF  0x0100      // word includes affix
#define WF_NEEDCOMP 0x0200      // word only valid in compound
#define WF_NOSUGGEST 0x0400     // word not to be suggested
#define WF_COMPROOT 0x0800      // already compounded word, COMPOUNDROOT
#define WF_NOCOMPBEF 0x1000     // no compounding before this word
#define WF_NOCOMPAFT 0x2000     // no compounding after this word

// only used for su_badflags
#define WF_MIXCAP   0x20        // mix of upper and lower case: macaRONI

#define WF_CAPMASK (WF_ONECAP | WF_ALLCAP | WF_KEEPCAP | WF_FIXCAP)

// flags for <pflags>
#define WFP_RARE            0x01        // rare prefix
#define WFP_NC              0x02        // prefix is not combining
#define WFP_UP              0x04        // to-upper prefix
#define WFP_COMPPERMIT      0x08        // prefix with COMPOUNDPERMITFLAG
#define WFP_COMPFORBID      0x10        // prefix with COMPOUNDFORBIDFLAG

// Flags for postponed prefixes in "sl_pidxs".  Must be above affixID (one
// byte) and prefcondnr (two bytes).
#define WF_RAREPFX  (WFP_RARE << 24)    // rare postponed prefix
#define WF_PFX_NC   (WFP_NC << 24)      // non-combining postponed prefix
#define WF_PFX_UP   (WFP_UP << 24)      // to-upper postponed prefix
#define WF_PFX_COMPPERMIT (WFP_COMPPERMIT << 24) // postponed prefix with
                                                 // COMPOUNDPERMITFLAG
#define WF_PFX_COMPFORBID (WFP_COMPFORBID << 24) // postponed prefix with
                                                 // COMPOUNDFORBIDFLAG


// flags for <compoptions>
#define COMP_CHECKDUP           1       // CHECKCOMPOUNDDUP
#define COMP_CHECKREP           2       // CHECKCOMPOUNDREP
#define COMP_CHECKCASE          4       // CHECKCOMPOUNDCASE
#define COMP_CHECKTRIPLE        8       // CHECKCOMPOUNDTRIPLE

// Special byte values for <byte>.  Some are only used in the tree for
// postponed prefixes, some only in the other trees.  This is a bit messy...
#define BY_NOFLAGS      0       // end of word without flags or region; for
                                // postponed prefix: no <pflags>
#define BY_INDEX        1       // child is shared, index follows
#define BY_FLAGS        2       // end of word, <flags> byte follows; for
                                // postponed prefix: <pflags> follows
#define BY_FLAGS2       3       // end of word, <flags> and <flags2> bytes
                                // follow; never used in prefix tree
#define BY_SPECIAL  BY_FLAGS2   // highest special byte value

// Info from "REP", "REPSAL" and "SAL" entries in ".aff" file used in si_rep,
// si_repsal, sl_rep, and si_sal.  Not for sl_sal!
// One replacement: from "ft_from" to "ft_to".
typedef struct fromto_S {
  char_u      *ft_from;
  char_u      *ft_to;
} fromto_T;

// Info from "SAL" entries in ".aff" file used in sl_sal.
// The info is split for quick processing by spell_soundfold().
// Note that "sm_oneof" and "sm_rules" point into sm_lead.
typedef struct salitem_S {
  char_u      *sm_lead;         // leading letters
  int sm_leadlen;               // length of "sm_lead"
  char_u      *sm_oneof;        // letters from () or NULL
  char_u      *sm_rules;        // rules like ^, $, priority
  char_u      *sm_to;           // replacement.
  int         *sm_lead_w;       // wide character copy of "sm_lead"
  int         *sm_oneof_w;      // wide character copy of "sm_oneof"
  int         *sm_to_w;         // wide character copy of "sm_to"
} salitem_T;

typedef int salfirst_T;

// Values for SP_*ERROR are negative, positive values are used by
// read_cnt_string().
#define SP_TRUNCERROR   -1      // spell file truncated error
#define SP_FORMERROR    -2      // format error in spell file
#define SP_OTHERERROR   -3      // other error while reading spell file

// Structure used to store words and other info for one language, loaded from
// a .spl file.
// The main access is through the tree in "sl_fbyts/sl_fidxs", storing the
// case-folded words.  "sl_kbyts/sl_kidxs" is for keep-case words.
//
// The "byts" array stores the possible bytes in each tree node, preceded by
// the number of possible bytes, sorted on byte value:
//      <len> <byte1> <byte2> ...
// The "idxs" array stores the index of the child node corresponding to the
// byte in "byts".
// Exception: when the byte is zero, the word may end here and "idxs" holds
// the flags, region mask and affixID for the word.  There may be several
// zeros in sequence for alternative flag/region/affixID combinations.
typedef struct slang_S slang_T;

struct slang_S {
  slang_T     *sl_next;         // next language
  char_u      *sl_name;         // language name "en", "en.rare", "nl", etc.
  char_u      *sl_fname;        // name of .spl file
  bool sl_add;                  // true if it's a .add file.

  char_u      *sl_fbyts;        // case-folded word bytes
  idx_T       *sl_fidxs;        // case-folded word indexes
  char_u      *sl_kbyts;        // keep-case word bytes
  idx_T       *sl_kidxs;        // keep-case word indexes
  char_u      *sl_pbyts;        // prefix tree word bytes
  idx_T       *sl_pidxs;        // prefix tree word indexes

  char_u      *sl_info;         // infotext string or NULL

  char_u sl_regions[17];        // table with up to 8 region names plus NUL

  char_u      *sl_midword;      // MIDWORD string or NULL

  hashtab_T sl_wordcount;       // hashtable with word count, wordcount_T

  int sl_compmax;               // COMPOUNDWORDMAX (default: MAXWLEN)
  int sl_compminlen;            // COMPOUNDMIN (default: 0)
  int sl_compsylmax;            // COMPOUNDSYLMAX (default: MAXWLEN)
  int sl_compoptions;           // COMP_* flags
  garray_T sl_comppat;          // CHECKCOMPOUNDPATTERN items
  regprog_T   *sl_compprog;     // COMPOUNDRULE turned into a regexp progrm
                                // (NULL when no compounding)
  char_u      *sl_comprules;    // all COMPOUNDRULE concatenated (or NULL)
  char_u      *sl_compstartflags;   // flags for first compound word
  char_u      *sl_compallflags;   // all flags for compound words
  bool sl_nobreak;              // When true: no spaces between words
  char_u      *sl_syllable;     // SYLLABLE repeatable chars or NULL
  garray_T sl_syl_items;        // syllable items

  int sl_prefixcnt;             // number of items in "sl_prefprog"
  regprog_T   **sl_prefprog;    // table with regprogs for prefixes

  garray_T sl_rep;              // list of fromto_T entries from REP lines
  short sl_rep_first[256];          // indexes where byte first appears, -1 if
                                    // there is none
  garray_T sl_sal;              // list of salitem_T entries from SAL lines
  salfirst_T sl_sal_first[256];     // indexes where byte first appears, -1 if
                                    // there is none
  bool sl_followup;             // SAL followup
  bool sl_collapse;             // SAL collapse_result
  bool sl_rem_accents;          // SAL remove_accents
  bool sl_sofo;                 // SOFOFROM and SOFOTO instead of SAL items:
                                // "sl_sal_first" maps chars, when has_mbyte
                                // "sl_sal" is a list of wide char lists.
  garray_T sl_repsal;           // list of fromto_T entries from REPSAL lines
  short sl_repsal_first[256];   // sl_rep_first for REPSAL lines
  bool sl_nosplitsugs;           // don't suggest splitting a word

  // Info from the .sug file.  Loaded on demand.
  time_t sl_sugtime;            // timestamp for .sug file
  char_u      *sl_sbyts;        // soundfolded word bytes
  idx_T       *sl_sidxs;        // soundfolded word indexes
  buf_T       *sl_sugbuf;       // buffer with word number table
  bool sl_sugloaded;            // true when .sug file was loaded or failed to
                                // load

  bool sl_has_map;              // true, if there is a MAP line
  hashtab_T sl_map_hash;        // MAP for multi-byte chars
  int sl_map_array[256];        // MAP for first 256 chars
  hashtab_T sl_sounddone;       // table with soundfolded words that have
                                // handled, see add_sound_suggest()
};

// First language that is loaded, start of the linked list of loaded
// languages.
static slang_T *first_lang = NULL;

// Flags used in .spl file for soundsalike flags.
#define SAL_F0LLOWUP            1
#define SAL_COLLAPSE            2
#define SAL_REM_ACCENTS         4

// Structure used in "b_langp", filled from 'spelllang'.
typedef struct langp_S {
  slang_T     *lp_slang;        // info for this language
  slang_T     *lp_sallang;      // language used for sound folding or NULL
  slang_T     *lp_replang;      // language used for REP items or NULL
  int lp_region;                // bitmask for region or REGION_ALL
} langp_T;

#define LANGP_ENTRY(ga, i)      (((langp_T *)(ga).ga_data) + (i))

#define REGION_ALL 0xff         // word valid in all regions

#define VIMSPELLMAGIC "VIMspell"  // string at start of Vim spell file
#define VIMSPELLMAGICL 8
#define VIMSPELLVERSION 50

#define VIMSUGMAGIC "VIMsug"    // string at start of Vim .sug file
#define VIMSUGMAGICL 6
#define VIMSUGVERSION 1

// Section IDs.  Only renumber them when VIMSPELLVERSION changes!
#define SN_REGION       0       // <regionname> section
#define SN_CHARFLAGS    1       // charflags section
#define SN_MIDWORD      2       // <midword> section
#define SN_PREFCOND     3       // <prefcond> section
#define SN_REP          4       // REP items section
#define SN_SAL          5       // SAL items section
#define SN_SOFO         6       // soundfolding section
#define SN_MAP          7       // MAP items section
#define SN_COMPOUND     8       // compound words section
#define SN_SYLLABLE     9       // syllable section
#define SN_NOBREAK      10      // NOBREAK section
#define SN_SUGFILE      11      // timestamp for .sug file
#define SN_REPSAL       12      // REPSAL items section
#define SN_WORDS        13      // common words
#define SN_NOSPLITSUGS  14      // don't split word for suggestions
#define SN_INFO         15      // info section
#define SN_END          255     // end of sections

#define SNF_REQUIRED    1       // <sectionflags>: required section

// Result values.  Lower number is accepted over higher one.
#define SP_BANNED       -1
#define SP_OK           0
#define SP_RARE         1
#define SP_LOCAL        2
#define SP_BAD          3

// file used for "zG" and "zW"
static char_u   *int_wordlist = NULL;

typedef struct wordcount_S {
  uint16_t wc_count;                // nr of times word was seen
  char_u wc_word[1];                // word, actually longer
} wordcount_T;

static wordcount_T dumwc;
#define WC_KEY_OFF  (unsigned)(dumwc.wc_word - (char_u *)&dumwc)
#define HI2WC(hi)     ((wordcount_T *)((hi)->hi_key - WC_KEY_OFF))
#define MAXWORDCOUNT 0xffff

// Information used when looking for suggestions.
typedef struct suginfo_S {
  garray_T su_ga;                   // suggestions, contains "suggest_T"
  int su_maxcount;                  // max. number of suggestions displayed
  int su_maxscore;                  // maximum score for adding to su_ga
  int su_sfmaxscore;                // idem, for when doing soundfold words
  garray_T su_sga;                  // like su_ga, sound-folded scoring
  char_u      *su_badptr;           // start of bad word in line
  int su_badlen;                    // length of detected bad word in line
  int su_badflags;                  // caps flags for bad word
  char_u su_badword[MAXWLEN];       // bad word truncated at su_badlen
  char_u su_fbadword[MAXWLEN];      // su_badword case-folded
  char_u su_sal_badword[MAXWLEN];   // su_badword soundfolded
  hashtab_T su_banned;              // table with banned words
  slang_T     *su_sallang;          // default language for sound folding
} suginfo_T;

// One word suggestion.  Used in "si_ga".
typedef struct {
  char_u      *st_word;         // suggested word, allocated string
  int st_wordlen;               // STRLEN(st_word)
  int st_orglen;                // length of replaced text
  int st_score;                 // lower is better
  int st_altscore;              // used when st_score compares equal
  bool st_salscore;             // st_score is for soundalike
  bool st_had_bonus;            // bonus already included in score
  slang_T     *st_slang;        // language used for sound folding
} suggest_T;

#define SUG(ga, i) (((suggest_T *)(ga).ga_data)[i])

// True if a word appears in the list of banned words.
#define WAS_BANNED(su, word) (!HASHITEM_EMPTY(hash_find(&su->su_banned, word)))

// Number of suggestions kept when cleaning up.  We need to keep more than
// what is displayed, because when rescore_suggestions() is called the score
// may change and wrong suggestions may be removed later.
#define SUG_CLEAN_COUNT(su)    ((su)->su_maxcount < \
                                130 ? 150 : (su)->su_maxcount + 20)

// Threshold for sorting and cleaning up suggestions.  Don't want to keep lots
// of suggestions that are not going to be displayed.
#define SUG_MAX_COUNT(su)       (SUG_CLEAN_COUNT(su) + 50)

// score for various changes
#define SCORE_SPLIT     149     // split bad word
#define SCORE_SPLIT_NO  249     // split bad word with NOSPLITSUGS
#define SCORE_ICASE     52      // slightly different case
#define SCORE_REGION    200     // word is for different region
#define SCORE_RARE      180     // rare word
#define SCORE_SWAP      75      // swap two characters
#define SCORE_SWAP3     110     // swap two characters in three
#define SCORE_REP       65      // REP replacement
#define SCORE_SUBST     93      // substitute a character
#define SCORE_SIMILAR   33      // substitute a similar character
#define SCORE_SUBCOMP   33      // substitute a composing character
#define SCORE_DEL       94      // delete a character
#define SCORE_DELDUP    66      // delete a duplicated character
#define SCORE_DELCOMP   28      // delete a composing character
#define SCORE_INS       96      // insert a character
#define SCORE_INSDUP    67      // insert a duplicate character
#define SCORE_INSCOMP   30      // insert a composing character
#define SCORE_NONWORD   103     // change non-word to word char

#define SCORE_FILE      30      // suggestion from a file
#define SCORE_MAXINIT   350     // Initial maximum score: higher == slower.
                                // 350 allows for about three changes.

#define SCORE_COMMON1   30      // subtracted for words seen before
#define SCORE_COMMON2   40      // subtracted for words often seen
#define SCORE_COMMON3   50      // subtracted for words very often seen
#define SCORE_THRES2    10      // word count threshold for COMMON2
#define SCORE_THRES3    100     // word count threshold for COMMON3

// When trying changed soundfold words it becomes slow when trying more than
// two changes.  With less then two changes it's slightly faster but we miss a
// few good suggestions.  In rare cases we need to try three of four changes.
#define SCORE_SFMAX1    200     // maximum score for first try
#define SCORE_SFMAX2    300     // maximum score for second try
#define SCORE_SFMAX3    400     // maximum score for third try

#define SCORE_BIG       SCORE_INS * 3   // big difference
#define SCORE_MAXMAX    999999          // accept any score
#define SCORE_LIMITMAX  350             // for spell_edit_score_limit()

// for spell_edit_score_limit() we need to know the minimum value of
// SCORE_ICASE, SCORE_SWAP, SCORE_DEL, SCORE_SIMILAR and SCORE_INS
#define SCORE_EDIT_MIN  SCORE_SIMILAR

// Structure to store info for word matching.
typedef struct matchinf_S {
  langp_T     *mi_lp;                   // info for language and region

  // pointers to original text to be checked
  char_u      *mi_word;                 // start of word being checked
  char_u      *mi_end;                  // end of matching word so far
  char_u      *mi_fend;                 // next char to be added to mi_fword
  char_u      *mi_cend;                 // char after what was used for
                                        // mi_capflags

  // case-folded text
  char_u mi_fword[MAXWLEN + 1];         // mi_word case-folded
  int mi_fwordlen;                      // nr of valid bytes in mi_fword

  // for when checking word after a prefix
  int mi_prefarridx;                    // index in sl_pidxs with list of
                                        // affixID/condition
  int mi_prefcnt;                       // number of entries at mi_prefarridx
  int mi_prefixlen;                     // byte length of prefix
  int mi_cprefixlen;                    // byte length of prefix in original
                                        // case

  // for when checking a compound word
  int mi_compoff;                       // start of following word offset
  char_u mi_compflags[MAXWLEN];         // flags for compound words used
  int mi_complen;                       // nr of compound words used
  int mi_compextra;                     // nr of COMPOUNDROOT words

  // others
  int mi_result;                        // result so far: SP_BAD, SP_OK, etc.
  int mi_capflags;                      // WF_ONECAP WF_ALLCAP WF_KEEPCAP
  win_T       *mi_win;                  // buffer being checked

  // for NOBREAK
  int mi_result2;                       // "mi_resul" without following word
  char_u      *mi_end2;                 // "mi_end" without following word
} matchinf_T;

// The tables used for recognizing word characters according to spelling.
// These are only used for the first 256 characters of 'encoding'.
typedef struct {
  bool st_isw[256];           // flags: is word char
  bool st_isu[256];           // flags: is uppercase char
  char_u st_fold[256];        // chars: folded case
  char_u st_upper[256];       // chars: upper case
} spelltab_T;

// For finding suggestions: At each node in the tree these states are tried:
typedef enum {
  STATE_START = 0,      // At start of node check for NUL bytes (goodword
                        // ends); if badword ends there is a match, otherwise
                        // try splitting word.
  STATE_NOPREFIX,       // try without prefix
  STATE_SPLITUNDO,      // Undo splitting.
  STATE_ENDNUL,         // Past NUL bytes at start of the node.
  STATE_PLAIN,          // Use each byte of the node.
  STATE_DEL,            // Delete a byte from the bad word.
  STATE_INS_PREP,       // Prepare for inserting bytes.
  STATE_INS,            // Insert a byte in the bad word.
  STATE_SWAP,           // Swap two bytes.
  STATE_UNSWAP,         // Undo swap two characters.
  STATE_SWAP3,          // Swap two characters over three.
  STATE_UNSWAP3,        // Undo Swap two characters over three.
  STATE_UNROT3L,        // Undo rotate three characters left
  STATE_UNROT3R,        // Undo rotate three characters right
  STATE_REP_INI,        // Prepare for using REP items.
  STATE_REP,            // Use matching REP items from the .aff file.
  STATE_REP_UNDO,       // Undo a REP item replacement.
  STATE_FINAL           // End of this node.
} state_T;

// Struct to keep the state at each level in suggest_try_change().
typedef struct trystate_S {
  state_T ts_state;             // state at this level, STATE_
  int ts_score;                 // score
  idx_T ts_arridx;              // index in tree array, start of node
  short ts_curi;                // index in list of child nodes
  char_u ts_fidx;               // index in fword[], case-folded bad word
  char_u ts_fidxtry;            // ts_fidx at which bytes may be changed
  char_u ts_twordlen;           // valid length of tword[]
  char_u ts_prefixdepth;        // stack depth for end of prefix or
                                // PFD_PREFIXTREE or PFD_NOPREFIX
  char_u ts_flags;              // TSF_ flags
  char_u ts_tcharlen;           // number of bytes in tword character
  char_u ts_tcharidx;           // current byte index in tword character
  char_u ts_isdiff;             // DIFF_ values
  char_u ts_fcharstart;         // index in fword where badword char started
  char_u ts_prewordlen;         // length of word in "preword[]"
  char_u ts_splitoff;           // index in "tword" after last split
  char_u ts_splitfidx;          // "ts_fidx" at word split
  char_u ts_complen;            // nr of compound words used
  char_u ts_compsplit;          // index for "compflags" where word was spit
  char_u ts_save_badflags;      // su_badflags saved here
  char_u ts_delidx;             // index in fword for char that was deleted,
                                // valid when "ts_flags" has TSF_DIDDEL
} trystate_T;

// Structure used for the cookie argument of do_in_runtimepath().
typedef struct spelload_S {
  char_u sl_lang[MAXWLEN + 1];          // language name
  slang_T *sl_slang;                    // resulting slang_T struct
  int sl_nobreak;                       // NOBREAK language found
} spelload_T;

#define SY_MAXLEN   30
typedef struct syl_item_S {
  char_u sy_chars[SY_MAXLEN];               // the sequence of chars
  int sy_len;
} syl_item_T;

#define MAXLINELEN  500         // Maximum length in bytes of a line in a .aff
                                // and .dic file.
// Main structure to store the contents of a ".aff" file.
typedef struct afffile_S {
  char_u      *af_enc;          // "SET", normalized, alloc'ed string or NULL
  int af_flagtype;              // AFT_CHAR, AFT_LONG, AFT_NUM or AFT_CAPLONG
  unsigned af_rare;             // RARE ID for rare word
  unsigned af_keepcase;         // KEEPCASE ID for keep-case word
  unsigned af_bad;              // BAD ID for banned word
  unsigned af_needaffix;        // NEEDAFFIX ID
  unsigned af_circumfix;        // CIRCUMFIX ID
  unsigned af_needcomp;         // NEEDCOMPOUND ID
  unsigned af_comproot;         // COMPOUNDROOT ID
  unsigned af_compforbid;       // COMPOUNDFORBIDFLAG ID
  unsigned af_comppermit;       // COMPOUNDPERMITFLAG ID
  unsigned af_nosuggest;        // NOSUGGEST ID
  int af_pfxpostpone;           // postpone prefixes without chop string and
                                // without flags
  hashtab_T af_pref;            // hashtable for prefixes, affheader_T
  hashtab_T af_suff;            // hashtable for suffixes, affheader_T
  hashtab_T af_comp;            // hashtable for compound flags, compitem_T
} afffile_T;

#define AFT_CHAR        0       // flags are one character
#define AFT_LONG        1       // flags are two characters
#define AFT_CAPLONG     2       // flags are one or two characters
#define AFT_NUM         3       // flags are numbers, comma separated

typedef struct affentry_S affentry_T;
// Affix entry from ".aff" file.  Used for prefixes and suffixes.
struct affentry_S {
  affentry_T  *ae_next;         // next affix with same name/number
  char_u      *ae_chop;         // text to chop off basic word (can be NULL)
  char_u      *ae_add;          // text to add to basic word (can be NULL)
  char_u      *ae_flags;        // flags on the affix (can be NULL)
  char_u      *ae_cond;         // condition (NULL for ".")
  regprog_T   *ae_prog;         // regexp program for ae_cond or NULL
  char ae_compforbid;           // COMPOUNDFORBIDFLAG found
  char ae_comppermit;           // COMPOUNDPERMITFLAG found
};

# define AH_KEY_LEN 17          // 2 x 8 bytes + NUL

// Affix header from ".aff" file.  Used for af_pref and af_suff.
typedef struct affheader_S {
  char_u ah_key[AH_KEY_LEN];    // key for hashtab == name of affix
  unsigned ah_flag;             // affix name as number, uses "af_flagtype"
  int ah_newID;                 // prefix ID after renumbering; 0 if not used
  int ah_combine;               // suffix may combine with prefix
  int ah_follows;               // another affix block should be following
  affentry_T  *ah_first;        // first affix entry
} affheader_T;

#define HI2AH(hi)   ((affheader_T *)(hi)->hi_key)

// Flag used in compound items.
typedef struct compitem_S {
  char_u ci_key[AH_KEY_LEN];    // key for hashtab == name of compound
  unsigned ci_flag;             // affix name as number, uses "af_flagtype"
  int ci_newID;                 // affix ID after renumbering.
} compitem_T;

#define HI2CI(hi)   ((compitem_T *)(hi)->hi_key)

// Structure that is used to store the items in the word tree.  This avoids
// the need to keep track of each allocated thing, everything is freed all at
// once after ":mkspell" is done.
// Note: "sb_next" must be just before "sb_data" to make sure the alignment of
// "sb_data" is correct for systems where pointers must be aligned on
// pointer-size boundaries and sizeof(pointer) > sizeof(int) (e.g., Sparc).
#define  SBLOCKSIZE 16000       // size of sb_data
typedef struct sblock_S sblock_T;
struct sblock_S {
  int sb_used;                  // nr of bytes already in use
  sblock_T    *sb_next;         // next block in list
  char_u sb_data[1];            // data, actually longer
};

// A node in the tree.
typedef struct wordnode_S wordnode_T;
struct wordnode_S {
  union     // shared to save space
  {
    char_u hashkey[6];          // the hash key, only used while compressing
    int index;                  // index in written nodes (valid after first
                                // round)
  } wn_u1;
  union     // shared to save space
  {
    wordnode_T *next;           // next node with same hash key
    wordnode_T *wnode;          // parent node that will write this node
  } wn_u2;
  wordnode_T  *wn_child;        // child (next byte in word)
  wordnode_T  *wn_sibling;      // next sibling (alternate byte in word,
                                //   always sorted)
  int wn_refs;                  // Nr. of references to this node.  Only
                                //   relevant for first node in a list of
                                //   siblings, in following siblings it is
                                //   always one.
  char_u wn_byte;               // Byte for this node. NUL for word end

  // Info for when "wn_byte" is NUL.
  // In PREFIXTREE "wn_region" is used for the prefcondnr.
  // In the soundfolded word tree "wn_flags" has the MSW of the wordnr and
  // "wn_region" the LSW of the wordnr.
  char_u wn_affixID;            // supported/required prefix ID or 0
  uint16_t wn_flags;            // WF_ flags
  short wn_region;              // region mask

#ifdef SPELL_PRINTTREE
  int wn_nr;                    // sequence nr for printing
#endif
};

#define WN_MASK  0xffff         // mask relevant bits of "wn_flags"

#define HI2WN(hi)    (wordnode_T *)((hi)->hi_key)

// Info used while reading the spell files.
typedef struct spellinfo_S {
  wordnode_T  *si_foldroot;     // tree with case-folded words
  long si_foldwcount;           // nr of words in si_foldroot

  wordnode_T  *si_keeproot;     // tree with keep-case words
  long si_keepwcount;           // nr of words in si_keeproot

  wordnode_T  *si_prefroot;     // tree with postponed prefixes

  long si_sugtree;              // creating the soundfolding trie

  sblock_T    *si_blocks;       // memory blocks used
  long si_blocks_cnt;           // memory blocks allocated
  int si_did_emsg;              // TRUE when ran out of memory

  long si_compress_cnt;         // words to add before lowering
                                // compression limit
  wordnode_T  *si_first_free;   // List of nodes that have been freed during
                                // compression, linked by "wn_child" field.
  long si_free_count;           // number of nodes in si_first_free
#ifdef SPELL_PRINTTREE
  int si_wordnode_nr;           // sequence nr for nodes
#endif
  buf_T       *si_spellbuf;     // buffer used to store soundfold word table

  int si_ascii;                 // handling only ASCII words
  int si_add;                   // addition file
  int si_clear_chartab;             // when TRUE clear char tables
  int si_region;                // region mask
  vimconv_T si_conv;            // for conversion to 'encoding'
  int si_memtot;                // runtime memory used
  int si_verbose;               // verbose messages
  int si_msg_count;             // number of words added since last message
  char_u      *si_info;         // info text chars or NULL
  int si_region_count;          // number of regions supported (1 when there
                                // are no regions)
  char_u si_region_name[17];    // region names; used only if
                                // si_region_count > 1)

  garray_T si_rep;              // list of fromto_T entries from REP lines
  garray_T si_repsal;           // list of fromto_T entries from REPSAL lines
  garray_T si_sal;              // list of fromto_T entries from SAL lines
  char_u      *si_sofofr;       // SOFOFROM text
  char_u      *si_sofoto;       // SOFOTO text
  int si_nosugfile;             // NOSUGFILE item found
  int si_nosplitsugs;           // NOSPLITSUGS item found
  int si_followup;              // soundsalike: ?
  int si_collapse;              // soundsalike: ?
  hashtab_T si_commonwords;     // hashtable for common words
  time_t si_sugtime;            // timestamp for .sug file
  int si_rem_accents;           // soundsalike: remove accents
  garray_T si_map;              // MAP info concatenated
  char_u      *si_midword;      // MIDWORD chars or NULL
  int si_compmax;               // max nr of words for compounding
  int si_compminlen;            // minimal length for compounding
  int si_compsylmax;            // max nr of syllables for compounding
  int si_compoptions;           // COMP_ flags
  garray_T si_comppat;          // CHECKCOMPOUNDPATTERN items, each stored as
                                // a string
  char_u      *si_compflags;    // flags used for compounding
  char_u si_nobreak;            // NOBREAK
  char_u      *si_syllable;     // syllable string
  garray_T si_prefcond;         // table with conditions for postponed
                                // prefixes, each stored as a string
  int si_newprefID;             // current value for ah_newID
  int si_newcompID;             // current value for compound ID
} spellinfo_T;

static spelltab_T spelltab;
static int did_set_spelltab;

#define CF_WORD         0x01
#define CF_UPPER        0x02

// structure used to store soundfolded words that add_sound_suggest() has
// handled already.
typedef struct {
  short sft_score;              // lowest score used
  char_u sft_word[1];           // soundfolded word, actually longer
} sftword_T;

typedef struct {
  int badi;
  int goodi;
  int score;
} limitscore_T;


#ifdef INCLUDE_GENERATED_DECLARATIONS
# include "spell.c.generated.h"
#endif

// values for ts_isdiff
#define DIFF_NONE       0       // no different byte (yet)
#define DIFF_YES        1       // different byte found
#define DIFF_INSERT     2       // inserting character

// values for ts_flags
#define TSF_PREFIXOK    1       // already checked that prefix is OK
#define TSF_DIDSPLIT    2       // tried split at this point
#define TSF_DIDDEL      4       // did a delete, "ts_delidx" has index

// special values ts_prefixdepth
#define PFD_NOPREFIX    0xff    // not using prefixes
#define PFD_PREFIXTREE  0xfe    // walking through the prefix tree
#define PFD_NOTSPECIAL  0xfd    // highest value that's not special

// mode values for find_word
#define FIND_FOLDWORD       0   // find word case-folded
#define FIND_KEEPWORD       1   // find keep-case word
#define FIND_PREFIX         2   // find word after prefix
#define FIND_COMPOUND       3   // find case-folded compound word
#define FIND_KEEPCOMPOUND   4   // find keep-case compound word


// Use our own character-case definitions, because the current locale may
// differ from what the .spl file uses.
// These must not be called with negative number!
#include <wchar.h>        // for towupper() and towlower()
// Multi-byte implementation.  For Unicode we can call utf_*(), but don't do
// that for ASCII, because we don't want to use 'casemap' here.  Otherwise use
// the "w" library function for characters above 255.
#define SPELL_TOFOLD(c) (enc_utf8 && (c) >= 128 ? utf_fold(c) \
                         : (c) < \
                         256 ? (int)spelltab.st_fold[c] : (int)towlower(c))

#define SPELL_TOUPPER(c) (enc_utf8 && (c) >= 128 ? utf_toupper(c) \
                          : (c) < \
                          256 ? (int)spelltab.st_upper[c] : (int)towupper(c))

#define SPELL_ISUPPER(c) (enc_utf8 && (c) >= 128 ? utf_isupper(c) \
                          : (c) < 256 ? spelltab.st_isu[c] : iswupper(c))


static char *e_format = N_("E759: Format error in spell file");
static char *e_spell_trunc = N_("E758: Truncated spell file");
static char *e_afftrailing = N_("Trailing text in %s line %d: %s");
static char *e_affname = N_("Affix name too long in %s line %d: %s");
static char *e_affform = N_("E761: Format error in affix file FOL, LOW or UPP");
static char *e_affrange = N_(
    "E762: Character in FOL, LOW or UPP is out of range");
static char *msg_compressing = N_("Compressing word tree...");

// Remember what "z?" replaced.
static char_u *repl_from = NULL;
static char_u *repl_to = NULL;

// Main spell-checking function.
// "ptr" points to a character that could be the start of a word.
// "*attrp" is set to the highlight index for a badly spelled word.  For a
// non-word or when it's OK it remains unchanged.
// This must only be called when 'spelllang' is not empty.
//
// "capcol" is used to check for a Capitalised word after the end of a
// sentence.  If it's zero then perform the check.  Return the column where to
// check next, or -1 when no sentence end was found.  If it's NULL then don't
// worry.
//
// Returns the length of the word in bytes, also when it's OK, so that the
// caller can skip over the word.
int
spell_check (
    win_T *wp,                // current window
    char_u *ptr,
    hlf_T *attrp,
    int *capcol,              // column to check for Capital
    bool docount              // count good words
)
{
  matchinf_T mi;              // Most things are put in "mi" so that it can
                              // be passed to functions quickly.
  int nrlen = 0;              // found a number first
  int c;
  int wrongcaplen = 0;
  int lpi;
  bool count_word = docount;

  // A word never starts at a space or a control character. Return quickly
  // then, skipping over the character.
  if (*ptr <= ' ')
    return 1;

  // Return here when loading language files failed.
  if (GA_EMPTY(&wp->w_s->b_langp))
    return 1;

  memset(&mi, 0, sizeof(matchinf_T));

  // A number is always OK.  Also skip hexadecimal numbers 0xFF99 and
  // 0X99FF.  But always do check spelling to find "3GPP" and "11
  // julifeest".
  if (*ptr >= '0' && *ptr <= '9') {
    if (*ptr == '0' && (ptr[1] == 'x' || ptr[1] == 'X'))
      mi.mi_end = skiphex(ptr + 2);
    else
      mi.mi_end = skipdigits(ptr);
    nrlen = (int)(mi.mi_end - ptr);
  }

  // Find the normal end of the word (until the next non-word character).
  mi.mi_word = ptr;
  mi.mi_fend = ptr;
  if (spell_iswordp(mi.mi_fend, wp)) {
    do {
      mb_ptr_adv(mi.mi_fend);
    } while (*mi.mi_fend != NUL && spell_iswordp(mi.mi_fend, wp));

    if (capcol != NULL && *capcol == 0 && wp->w_s->b_cap_prog != NULL) {
      // Check word starting with capital letter.
      c = PTR2CHAR(ptr);
      if (!SPELL_ISUPPER(c))
        wrongcaplen = (int)(mi.mi_fend - ptr);
    }
  }
  if (capcol != NULL)
    *capcol = -1;

  // We always use the characters up to the next non-word character,
  // also for bad words.
  mi.mi_end = mi.mi_fend;

  // Check caps type later.
  mi.mi_capflags = 0;
  mi.mi_cend = NULL;
  mi.mi_win = wp;

  // case-fold the word with one non-word character, so that we can check
  // for the word end.
  if (*mi.mi_fend != NUL)
    mb_ptr_adv(mi.mi_fend);

  (void)spell_casefold(ptr, (int)(mi.mi_fend - ptr), mi.mi_fword,
      MAXWLEN + 1);
  mi.mi_fwordlen = (int)STRLEN(mi.mi_fword);

  // The word is bad unless we recognize it.
  mi.mi_result = SP_BAD;
  mi.mi_result2 = SP_BAD;

  // Loop over the languages specified in 'spelllang'.
  // We check them all, because a word may be matched longer in another
  // language.
  for (lpi = 0; lpi < wp->w_s->b_langp.ga_len; ++lpi) {
    mi.mi_lp = LANGP_ENTRY(wp->w_s->b_langp, lpi);

    // If reloading fails the language is still in the list but everything
    // has been cleared.
    if (mi.mi_lp->lp_slang->sl_fidxs == NULL)
      continue;

    // Check for a matching word in case-folded words.
    find_word(&mi, FIND_FOLDWORD);

    // Check for a matching word in keep-case words.
    find_word(&mi, FIND_KEEPWORD);

    // Check for matching prefixes.
    find_prefix(&mi, FIND_FOLDWORD);

    // For a NOBREAK language, may want to use a word without a following
    // word as a backup.
    if (mi.mi_lp->lp_slang->sl_nobreak && mi.mi_result == SP_BAD
        && mi.mi_result2 != SP_BAD) {
      mi.mi_result = mi.mi_result2;
      mi.mi_end = mi.mi_end2;
    }

    // Count the word in the first language where it's found to be OK.
    if (count_word && mi.mi_result == SP_OK) {
      count_common_word(mi.mi_lp->lp_slang, ptr,
          (int)(mi.mi_end - ptr), 1);
      count_word = false;
    }
  }

  if (mi.mi_result != SP_OK) {
    // If we found a number skip over it.  Allows for "42nd".  Do flag
    // rare and local words, e.g., "3GPP".
    if (nrlen > 0) {
      if (mi.mi_result == SP_BAD || mi.mi_result == SP_BANNED)
        return nrlen;
    }
    // When we are at a non-word character there is no error, just
    // skip over the character (try looking for a word after it).
    else if (!spell_iswordp_nmw(ptr, wp)) {
      if (capcol != NULL && wp->w_s->b_cap_prog != NULL) {
        regmatch_T regmatch;

        // Check for end of sentence.
        regmatch.regprog = wp->w_s->b_cap_prog;
        regmatch.rm_ic = FALSE;
        if (vim_regexec(&regmatch, ptr, 0))
          *capcol = (int)(regmatch.endp[0] - ptr);
      }

      if (has_mbyte) {
        return (*mb_ptr2len)(ptr);
      }
      return 1;
    } else if (mi.mi_end == ptr)
      // Always include at least one character.  Required for when there
      // is a mixup in "midword".
      mb_ptr_adv(mi.mi_end);
    else if (mi.mi_result == SP_BAD
             && LANGP_ENTRY(wp->w_s->b_langp, 0)->lp_slang->sl_nobreak) {
      char_u      *p, *fp;
      int save_result = mi.mi_result;

      // First language in 'spelllang' is NOBREAK.  Find first position
      // at which any word would be valid.
      mi.mi_lp = LANGP_ENTRY(wp->w_s->b_langp, 0);
      if (mi.mi_lp->lp_slang->sl_fidxs != NULL) {
        p = mi.mi_word;
        fp = mi.mi_fword;
        for (;; ) {
          mb_ptr_adv(p);
          mb_ptr_adv(fp);
          if (p >= mi.mi_end)
            break;
          mi.mi_compoff = (int)(fp - mi.mi_fword);
          find_word(&mi, FIND_COMPOUND);
          if (mi.mi_result != SP_BAD) {
            mi.mi_end = p;
            break;
          }
        }
        mi.mi_result = save_result;
      }
    }

    if (mi.mi_result == SP_BAD || mi.mi_result == SP_BANNED)
      *attrp = HLF_SPB;
    else if (mi.mi_result == SP_RARE)
      *attrp = HLF_SPR;
    else
      *attrp = HLF_SPL;
  }

  if (wrongcaplen > 0 && (mi.mi_result == SP_OK || mi.mi_result == SP_RARE)) {
    // Report SpellCap only when the word isn't badly spelled.
    *attrp = HLF_SPC;
    return wrongcaplen;
  }

  return (int)(mi.mi_end - ptr);
}

// Check if the word at "mip->mi_word" is in the tree.
// When "mode" is FIND_FOLDWORD check in fold-case word tree.
// When "mode" is FIND_KEEPWORD check in keep-case word tree.
// When "mode" is FIND_PREFIX check for word after prefix in fold-case word
// tree.
//
// For a match mip->mi_result is updated.
static void find_word(matchinf_T *mip, int mode)
{
  int wlen = 0;
  int flen;
  char_u      *ptr;
  slang_T     *slang = mip->mi_lp->lp_slang;
  char_u      *byts;
  idx_T       *idxs;

  if (mode == FIND_KEEPWORD || mode == FIND_KEEPCOMPOUND) {
    // Check for word with matching case in keep-case tree.
    ptr = mip->mi_word;
    flen = 9999;                    // no case folding, always enough bytes
    byts = slang->sl_kbyts;
    idxs = slang->sl_kidxs;

    if (mode == FIND_KEEPCOMPOUND)
      // Skip over the previously found word(s).
      wlen += mip->mi_compoff;
  } else {
    // Check for case-folded in case-folded tree.
    ptr = mip->mi_fword;
    flen = mip->mi_fwordlen;        // available case-folded bytes
    byts = slang->sl_fbyts;
    idxs = slang->sl_fidxs;

    if (mode == FIND_PREFIX) {
      // Skip over the prefix.
      wlen = mip->mi_prefixlen;
      flen -= mip->mi_prefixlen;
    } else if (mode == FIND_COMPOUND) {
      // Skip over the previously found word(s).
      wlen = mip->mi_compoff;
      flen -= mip->mi_compoff;
    }

  }

  if (byts == NULL)
    return;                     // array is empty

  idx_T arridx = 0;
  int endlen[MAXWLEN];              // length at possible word endings
  idx_T endidx[MAXWLEN];            // possible word endings
  int endidxcnt = 0;
  int len;
  int c;

  // Repeat advancing in the tree until:
  // - there is a byte that doesn't match,
  // - we reach the end of the tree,
  // - or we reach the end of the line.
  for (;; ) {
    if (flen <= 0 && *mip->mi_fend != NUL)
      flen = fold_more(mip);

    len = byts[arridx++];

    // If the first possible byte is a zero the word could end here.
    // Remember this index, we first check for the longest word.
    if (byts[arridx] == 0) {
      if (endidxcnt == MAXWLEN) {
        // Must be a corrupted spell file.
        EMSG(_(e_format));
        return;
      }
      endlen[endidxcnt] = wlen;
      endidx[endidxcnt++] = arridx++;
      --len;

      // Skip over the zeros, there can be several flag/region
      // combinations.
      while (len > 0 && byts[arridx] == 0) {
        ++arridx;
        --len;
      }
      if (len == 0)
        break;              // no children, word must end here
    }

    // Stop looking at end of the line.
    if (ptr[wlen] == NUL)
      break;

    // Perform a binary search in the list of accepted bytes.
    c = ptr[wlen];
    if (c == TAB)           // <Tab> is handled like <Space>
      c = ' ';
    idx_T lo = arridx;
    idx_T hi = arridx + len - 1;
    while (lo < hi) {
      idx_T m = (lo + hi) / 2;
      if (byts[m] > c)
        hi = m - 1;
      else if (byts[m] < c)
        lo = m + 1;
      else {
        lo = hi = m;
        break;
      }
    }

    // Stop if there is no matching byte.
    if (hi < lo || byts[lo] != c)
      break;

    // Continue at the child (if there is one).
    arridx = idxs[lo];
    ++wlen;
    --flen;

    // One space in the good word may stand for several spaces in the
    // checked word.
    if (c == ' ') {
      for (;; ) {
        if (flen <= 0 && *mip->mi_fend != NUL)
          flen = fold_more(mip);
        if (ptr[wlen] != ' ' && ptr[wlen] != TAB)
          break;
        ++wlen;
        --flen;
      }
    }
  }

  char_u *p;
  bool word_ends;

  // Verify that one of the possible endings is valid.  Try the longest
  // first.
  while (endidxcnt > 0) {
    --endidxcnt;
    arridx = endidx[endidxcnt];
    wlen = endlen[endidxcnt];

    if ((*mb_head_off)(ptr, ptr + wlen) > 0)
      continue;             // not at first byte of character
    if (spell_iswordp(ptr + wlen, mip->mi_win)) {
      if (slang->sl_compprog == NULL && !slang->sl_nobreak)
        continue;                   // next char is a word character
      word_ends = false;
    } else
      word_ends = true;
    // The prefix flag is before compound flags.  Once a valid prefix flag
    // has been found we try compound flags.
    bool prefix_found = false;

    if (mode != FIND_KEEPWORD && has_mbyte) {
      // Compute byte length in original word, length may change
      // when folding case.  This can be slow, take a shortcut when the
      // case-folded word is equal to the keep-case word.
      p = mip->mi_word;
      if (STRNCMP(ptr, p, wlen) != 0) {
        for (char_u *s = ptr; s < ptr + wlen; mb_ptr_adv(s))
          mb_ptr_adv(p);
        wlen = (int)(p - mip->mi_word);
      }
    }

    // Check flags and region.  For FIND_PREFIX check the condition and
    // prefix ID.
    // Repeat this if there are more flags/region alternatives until there
    // is a match.
    for (len = byts[arridx - 1]; len > 0 && byts[arridx] == 0;
         --len, ++arridx) {
      uint32_t flags = idxs[arridx];

      // For the fold-case tree check that the case of the checked word
      // matches with what the word in the tree requires.
      // For keep-case tree the case is always right.  For prefixes we
      // don't bother to check.
      if (mode == FIND_FOLDWORD) {
        if (mip->mi_cend != mip->mi_word + wlen) {
          // mi_capflags was set for a different word length, need
          // to do it again.
          mip->mi_cend = mip->mi_word + wlen;
          mip->mi_capflags = captype(mip->mi_word, mip->mi_cend);
        }

        if (mip->mi_capflags == WF_KEEPCAP
            || !spell_valid_case(mip->mi_capflags, flags))
          continue;
      }
      // When mode is FIND_PREFIX the word must support the prefix:
      // check the prefix ID and the condition.  Do that for the list at
      // mip->mi_prefarridx that find_prefix() filled.
      else if (mode == FIND_PREFIX && !prefix_found) {
        c = valid_word_prefix(mip->mi_prefcnt, mip->mi_prefarridx,
            flags,
            mip->mi_word + mip->mi_cprefixlen, slang,
            false);
        if (c == 0)
          continue;

        // Use the WF_RARE flag for a rare prefix.
        if (c & WF_RAREPFX)
          flags |= WF_RARE;
        prefix_found = true;
      }

      if (slang->sl_nobreak) {
        if ((mode == FIND_COMPOUND || mode == FIND_KEEPCOMPOUND)
            && (flags & WF_BANNED) == 0) {
          // NOBREAK: found a valid following word.  That's all we
          // need to know, so return.
          mip->mi_result = SP_OK;
          break;
        }
      } else if ((mode == FIND_COMPOUND || mode == FIND_KEEPCOMPOUND
                  || !word_ends)) {
        // If there is no compound flag or the word is shorter than
        // COMPOUNDMIN reject it quickly.
        // Makes you wonder why someone puts a compound flag on a word
        // that's too short...  Myspell compatibility requires this
        // anyway.
        if (((unsigned)flags >> 24) == 0
            || wlen - mip->mi_compoff < slang->sl_compminlen)
          continue;
        // For multi-byte chars check character length against
        // COMPOUNDMIN.
        if (has_mbyte
            && slang->sl_compminlen > 0
            && mb_charlen_len(mip->mi_word + mip->mi_compoff,
                wlen - mip->mi_compoff) < slang->sl_compminlen)
          continue;

        // Limit the number of compound words to COMPOUNDWORDMAX if no
        // maximum for syllables is specified.
        if (!word_ends && mip->mi_complen + mip->mi_compextra + 2
            > slang->sl_compmax
            && slang->sl_compsylmax == MAXWLEN)
          continue;

        // Don't allow compounding on a side where an affix was added,
        // unless COMPOUNDPERMITFLAG was used.
        if (mip->mi_complen > 0 && (flags & WF_NOCOMPBEF))
          continue;
        if (!word_ends && (flags & WF_NOCOMPAFT))
          continue;

        // Quickly check if compounding is possible with this flag.
        if (!byte_in_str(mip->mi_complen == 0
                ? slang->sl_compstartflags
                : slang->sl_compallflags,
                ((unsigned)flags >> 24)))
          continue;

        // If there is a match with a CHECKCOMPOUNDPATTERN rule
        // discard the compound word.
        if (match_checkcompoundpattern(ptr, wlen, &slang->sl_comppat))
          continue;

        if (mode == FIND_COMPOUND) {
          int capflags;

          // Need to check the caps type of the appended compound
          // word.
          if (has_mbyte && STRNCMP(ptr, mip->mi_word,
                  mip->mi_compoff) != 0) {
            // case folding may have changed the length
            p = mip->mi_word;
            for (char_u *s = ptr; s < ptr + mip->mi_compoff; mb_ptr_adv(s))
              mb_ptr_adv(p);
          } else
            p = mip->mi_word + mip->mi_compoff;
          capflags = captype(p, mip->mi_word + wlen);
          if (capflags == WF_KEEPCAP || (capflags == WF_ALLCAP
                                         && (flags & WF_FIXCAP) != 0))
            continue;

          if (capflags != WF_ALLCAP) {
            // When the character before the word is a word
            // character we do not accept a Onecap word.  We do
            // accept a no-caps word, even when the dictionary
            // word specifies ONECAP.
            mb_ptr_back(mip->mi_word, p);
            if (spell_iswordp_nmw(p, mip->mi_win)
                ? capflags == WF_ONECAP
                : (flags & WF_ONECAP) != 0
                && capflags != WF_ONECAP)
              continue;
          }
        }

        // If the word ends the sequence of compound flags of the
        // words must match with one of the COMPOUNDRULE items and
        // the number of syllables must not be too large.
        mip->mi_compflags[mip->mi_complen] = ((unsigned)flags >> 24);
        mip->mi_compflags[mip->mi_complen + 1] = NUL;
        if (word_ends) {
          char_u fword[MAXWLEN];

          if (slang->sl_compsylmax < MAXWLEN) {
            // "fword" is only needed for checking syllables.
            if (ptr == mip->mi_word)
              (void)spell_casefold(ptr, wlen, fword, MAXWLEN);
            else
              STRLCPY(fword, ptr, endlen[endidxcnt] + 1);
          }
          if (!can_compound(slang, fword, mip->mi_compflags))
            continue;
        } else if (slang->sl_comprules != NULL
                   && !match_compoundrule(slang, mip->mi_compflags))
          // The compound flags collected so far do not match any
          // COMPOUNDRULE, discard the compounded word.
          continue;
      }
      // Check NEEDCOMPOUND: can't use word without compounding.
      else if (flags & WF_NEEDCOMP)
        continue;

      int nobreak_result = SP_OK;

      if (!word_ends) {
        int save_result = mip->mi_result;
        char_u  *save_end = mip->mi_end;
        langp_T *save_lp = mip->mi_lp;

        // Check that a valid word follows.  If there is one and we
        // are compounding, it will set "mi_result", thus we are
        // always finished here.  For NOBREAK we only check that a
        // valid word follows.
        // Recursive!
        if (slang->sl_nobreak)
          mip->mi_result = SP_BAD;

        // Find following word in case-folded tree.
        mip->mi_compoff = endlen[endidxcnt];
        if (has_mbyte && mode == FIND_KEEPWORD) {
          // Compute byte length in case-folded word from "wlen":
          // byte length in keep-case word.  Length may change when
          // folding case.  This can be slow, take a shortcut when
          // the case-folded word is equal to the keep-case word.
          p = mip->mi_fword;
          if (STRNCMP(ptr, p, wlen) != 0) {
            for (char_u *s = ptr; s < ptr + wlen; mb_ptr_adv(s))
              mb_ptr_adv(p);
            mip->mi_compoff = (int)(p - mip->mi_fword);
          }
        }
#if 0
        c = mip->mi_compoff;
#endif
        ++mip->mi_complen;
        if (flags & WF_COMPROOT)
          ++mip->mi_compextra;

        // For NOBREAK we need to try all NOBREAK languages, at least
        // to find the ".add" file(s).
        for (int lpi = 0; lpi < mip->mi_win->w_s->b_langp.ga_len; ++lpi) {
          if (slang->sl_nobreak) {
            mip->mi_lp = LANGP_ENTRY(mip->mi_win->w_s->b_langp, lpi);
            if (mip->mi_lp->lp_slang->sl_fidxs == NULL
                || !mip->mi_lp->lp_slang->sl_nobreak)
              continue;
          }

          find_word(mip, FIND_COMPOUND);

          // When NOBREAK any word that matches is OK.  Otherwise we
          // need to find the longest match, thus try with keep-case
          // and prefix too.
          if (!slang->sl_nobreak || mip->mi_result == SP_BAD) {
            // Find following word in keep-case tree.
            mip->mi_compoff = wlen;
            find_word(mip, FIND_KEEPCOMPOUND);

#if 0       // Disabled, a prefix must not appear halfway a compound word,
            // unless the COMPOUNDPERMITFLAG is used and then it can't be a
            // postponed prefix.
            if (!slang->sl_nobreak || mip->mi_result == SP_BAD) {
              // Check for following word with prefix.
              mip->mi_compoff = c;
              find_prefix(mip, FIND_COMPOUND);
            }
#endif
          }

          if (!slang->sl_nobreak)
            break;
        }
        --mip->mi_complen;
        if (flags & WF_COMPROOT)
          --mip->mi_compextra;
        mip->mi_lp = save_lp;

        if (slang->sl_nobreak) {
          nobreak_result = mip->mi_result;
          mip->mi_result = save_result;
          mip->mi_end = save_end;
        } else {
          if (mip->mi_result == SP_OK)
            break;
          continue;
        }
      }

      int res = SP_BAD;
      if (flags & WF_BANNED)
        res = SP_BANNED;
      else if (flags & WF_REGION) {
        // Check region.
        if ((mip->mi_lp->lp_region & (flags >> 16)) != 0)
          res = SP_OK;
        else
          res = SP_LOCAL;
      } else if (flags & WF_RARE)
        res = SP_RARE;
      else
        res = SP_OK;

      // Always use the longest match and the best result.  For NOBREAK
      // we separately keep the longest match without a following good
      // word as a fall-back.
      if (nobreak_result == SP_BAD) {
        if (mip->mi_result2 > res) {
          mip->mi_result2 = res;
          mip->mi_end2 = mip->mi_word + wlen;
        } else if (mip->mi_result2 == res
                   && mip->mi_end2 < mip->mi_word + wlen)
          mip->mi_end2 = mip->mi_word + wlen;
      } else if (mip->mi_result > res) {
        mip->mi_result = res;
        mip->mi_end = mip->mi_word + wlen;
      } else if (mip->mi_result == res && mip->mi_end < mip->mi_word + wlen)
        mip->mi_end = mip->mi_word + wlen;

      if (mip->mi_result == SP_OK)
        break;
    }

    if (mip->mi_result == SP_OK)
      break;
  }
}

// Returns true if there is a match between the word ptr[wlen] and
// CHECKCOMPOUNDPATTERN rules, assuming that we will concatenate with another
// word.
// A match means that the first part of CHECKCOMPOUNDPATTERN matches at the
// end of ptr[wlen] and the second part matches after it.
static bool
match_checkcompoundpattern (
    char_u *ptr,
    int wlen,
    garray_T *gap      // &sl_comppat
)
{
  char_u      *p;
  int len;

  for (int i = 0; i + 1 < gap->ga_len; i += 2) {
    p = ((char_u **)gap->ga_data)[i + 1];
    if (STRNCMP(ptr + wlen, p, STRLEN(p)) == 0) {
      // Second part matches at start of following compound word, now
      // check if first part matches at end of previous word.
      p = ((char_u **)gap->ga_data)[i];
      len = (int)STRLEN(p);
      if (len <= wlen && STRNCMP(ptr + wlen - len, p, len) == 0)
        return true;
    }
  }
  return false;
}

// Returns true if "flags" is a valid sequence of compound flags and "word"
// does not have too many syllables.
static bool can_compound(slang_T *slang, char_u *word, char_u *flags)
{
  regmatch_T regmatch;
  char_u uflags[MAXWLEN * 2];
  int i;
  char_u      *p;

  if (slang->sl_compprog == NULL)
    return false;
  if (enc_utf8) {
    // Need to convert the single byte flags to utf8 characters.
    p = uflags;
    for (i = 0; flags[i] != NUL; ++i)
      p += mb_char2bytes(flags[i], p);
    *p = NUL;
    p = uflags;
  } else
    p = flags;
  regmatch.regprog = slang->sl_compprog;
  regmatch.rm_ic = FALSE;
  if (!vim_regexec(&regmatch, p, 0))
    return false;

  // Count the number of syllables.  This may be slow, do it last.  If there
  // are too many syllables AND the number of compound words is above
  // COMPOUNDWORDMAX then compounding is not allowed.
  if (slang->sl_compsylmax < MAXWLEN
      && count_syllables(slang, word) > slang->sl_compsylmax)
    return (int)STRLEN(flags) < slang->sl_compmax;
  return true;
}

// Returns true when the sequence of flags in "compflags" plus "flag" can
// possibly form a valid compounded word.  This also checks the COMPOUNDRULE
// lines if they don't contain wildcards.
static bool can_be_compound(trystate_T *sp, slang_T *slang, char_u *compflags, int flag)
{
  // If the flag doesn't appear in sl_compstartflags or sl_compallflags
  // then it can't possibly compound.
  if (!byte_in_str(sp->ts_complen == sp->ts_compsplit
          ? slang->sl_compstartflags : slang->sl_compallflags, flag))
    return false;

  // If there are no wildcards, we can check if the flags collected so far
  // possibly can form a match with COMPOUNDRULE patterns.  This only
  // makes sense when we have two or more words.
  if (slang->sl_comprules != NULL && sp->ts_complen > sp->ts_compsplit) {
    compflags[sp->ts_complen] = flag;
    compflags[sp->ts_complen + 1] = NUL;
    bool v = match_compoundrule(slang, compflags + sp->ts_compsplit);
    compflags[sp->ts_complen] = NUL;
    return v;
  }

  return true;
}

// Returns true if the compound flags in compflags[] match the start of any
// compound rule.  This is used to stop trying a compound if the flags
// collected so far can't possibly match any compound rule.
// Caller must check that slang->sl_comprules is not NULL.
static bool match_compoundrule(slang_T *slang, char_u *compflags)
{
  char_u      *p;
  int i;
  int c;

  // loop over all the COMPOUNDRULE entries
  for (p = slang->sl_comprules; *p != NUL; ++p) {
    // loop over the flags in the compound word we have made, match
    // them against the current rule entry
    for (i = 0;; ++i) {
      c = compflags[i];
      if (c == NUL)
        // found a rule that matches for the flags we have so far
        return true;
      if (*p == '/' || *p == NUL)
        break;          // end of rule, it's too short
      if (*p == '[') {
        bool match = false;

        // compare against all the flags in []
        ++p;
        while (*p != ']' && *p != NUL)
          if (*p++ == c)
            match = true;
        if (!match)
          break;            // none matches
      } else if (*p != c)
        break;          // flag of word doesn't match flag in pattern
      ++p;
    }

    // Skip to the next "/", where the next pattern starts.
    p = vim_strchr(p, '/');
    if (p == NULL)
      break;
  }

  // Checked all the rules and none of them match the flags, so there
  // can't possibly be a compound starting with these flags.
  return false;
}

// Return non-zero if the prefix indicated by "arridx" matches with the prefix
// ID in "flags" for the word "word".
// The WF_RAREPFX flag is included in the return value for a rare prefix.
static int
valid_word_prefix (
    int totprefcnt,                 // nr of prefix IDs
    int arridx,                     // idx in sl_pidxs[]
    int flags,
    char_u *word,
    slang_T *slang,
    bool cond_req                   // only use prefixes with a condition
)
{
  int prefcnt;
  int pidx;
  regprog_T   *rp;
  regmatch_T regmatch;
  int prefid;

  prefid = (unsigned)flags >> 24;
  for (prefcnt = totprefcnt - 1; prefcnt >= 0; --prefcnt) {
    pidx = slang->sl_pidxs[arridx + prefcnt];

    // Check the prefix ID.
    if (prefid != (pidx & 0xff))
      continue;

    // Check if the prefix doesn't combine and the word already has a
    // suffix.
    if ((flags & WF_HAS_AFF) && (pidx & WF_PFX_NC))
      continue;

    // Check the condition, if there is one.  The condition index is
    // stored in the two bytes above the prefix ID byte.
    rp = slang->sl_prefprog[((unsigned)pidx >> 8) & 0xffff];
    if (rp != NULL) {
      regmatch.regprog = rp;
      regmatch.rm_ic = FALSE;
      if (!vim_regexec(&regmatch, word, 0))
        continue;
    } else if (cond_req)
      continue;

    // It's a match!  Return the WF_ flags.
    return pidx;
  }
  return 0;
}

// Check if the word at "mip->mi_word" has a matching prefix.
// If it does, then check the following word.
//
// If "mode" is "FIND_COMPOUND" then do the same after another word, find a
// prefix in a compound word.
//
// For a match mip->mi_result is updated.
static void find_prefix(matchinf_T *mip, int mode)
{
  idx_T arridx = 0;
  int len;
  int wlen = 0;
  int flen;
  int c;
  char_u      *ptr;
  idx_T lo, hi, m;
  slang_T     *slang = mip->mi_lp->lp_slang;
  char_u      *byts;
  idx_T       *idxs;

  byts = slang->sl_pbyts;
  if (byts == NULL)
    return;                     // array is empty

  // We use the case-folded word here, since prefixes are always
  // case-folded.
  ptr = mip->mi_fword;
  flen = mip->mi_fwordlen;      // available case-folded bytes
  if (mode == FIND_COMPOUND) {
    // Skip over the previously found word(s).
    ptr += mip->mi_compoff;
    flen -= mip->mi_compoff;
  }
  idxs = slang->sl_pidxs;

  // Repeat advancing in the tree until:
  // - there is a byte that doesn't match,
  // - we reach the end of the tree,
  // - or we reach the end of the line.
  for (;; ) {
    if (flen == 0 && *mip->mi_fend != NUL)
      flen = fold_more(mip);

    len = byts[arridx++];

    // If the first possible byte is a zero the prefix could end here.
    // Check if the following word matches and supports the prefix.
    if (byts[arridx] == 0) {
      // There can be several prefixes with different conditions.  We
      // try them all, since we don't know which one will give the
      // longest match.  The word is the same each time, pass the list
      // of possible prefixes to find_word().
      mip->mi_prefarridx = arridx;
      mip->mi_prefcnt = len;
      while (len > 0 && byts[arridx] == 0) {
        ++arridx;
        --len;
      }
      mip->mi_prefcnt -= len;

      // Find the word that comes after the prefix.
      mip->mi_prefixlen = wlen;
      if (mode == FIND_COMPOUND)
        // Skip over the previously found word(s).
        mip->mi_prefixlen += mip->mi_compoff;

      if (has_mbyte) {
        // Case-folded length may differ from original length.
        mip->mi_cprefixlen = nofold_len(mip->mi_fword,
            mip->mi_prefixlen, mip->mi_word);
      } else
        mip->mi_cprefixlen = mip->mi_prefixlen;
      find_word(mip, FIND_PREFIX);


      if (len == 0)
        break;              // no children, word must end here
    }

    // Stop looking at end of the line.
    if (ptr[wlen] == NUL)
      break;

    // Perform a binary search in the list of accepted bytes.
    c = ptr[wlen];
    lo = arridx;
    hi = arridx + len - 1;
    while (lo < hi) {
      m = (lo + hi) / 2;
      if (byts[m] > c)
        hi = m - 1;
      else if (byts[m] < c)
        lo = m + 1;
      else {
        lo = hi = m;
        break;
      }
    }

    // Stop if there is no matching byte.
    if (hi < lo || byts[lo] != c)
      break;

    // Continue at the child (if there is one).
    arridx = idxs[lo];
    ++wlen;
    --flen;
  }
}

// Need to fold at least one more character.  Do until next non-word character
// for efficiency.  Include the non-word character too.
// Return the length of the folded chars in bytes.
static int fold_more(matchinf_T *mip)
{
  int flen;
  char_u      *p;

  p = mip->mi_fend;
  do {
    mb_ptr_adv(mip->mi_fend);
  } while (*mip->mi_fend != NUL && spell_iswordp(mip->mi_fend, mip->mi_win));

  // Include the non-word character so that we can check for the word end.
  if (*mip->mi_fend != NUL)
    mb_ptr_adv(mip->mi_fend);

  (void)spell_casefold(p, (int)(mip->mi_fend - p),
      mip->mi_fword + mip->mi_fwordlen,
      MAXWLEN - mip->mi_fwordlen);
  flen = (int)STRLEN(mip->mi_fword + mip->mi_fwordlen);
  mip->mi_fwordlen += flen;
  return flen;
}

/// Checks case flags for a word. Returns true, if the word has the requested
/// case.
///
/// @param wordflags Flags for the checked word.
/// @param treeflags Flags for the word in the spell tree.
static bool spell_valid_case(int wordflags, int treeflags)
{
  return (wordflags == WF_ALLCAP && (treeflags & WF_FIXCAP) == 0)
         || ((treeflags & (WF_ALLCAP | WF_KEEPCAP)) == 0
             && ((treeflags & WF_ONECAP) == 0
                 || (wordflags & WF_ONECAP) != 0));
}

// Returns true if spell checking is not enabled.
static bool no_spell_checking(win_T *wp)
{
  if (!wp->w_p_spell || *wp->w_s->b_p_spl == NUL
      || GA_EMPTY(&wp->w_s->b_langp)) {
    EMSG(_("E756: Spell checking is not enabled"));
    return true;
  }
  return false;
}

// Moves to the next spell error.
// "curline" is false for "[s", "]s", "[S" and "]S".
// "curline" is true to find word under/after cursor in the same line.
// For Insert mode completion "dir" is BACKWARD and "curline" is true: move
// to after badly spelled word before the cursor.
// Return 0 if not found, length of the badly spelled word otherwise.
int
spell_move_to (
    win_T *wp,
    int dir,                  // FORWARD or BACKWARD
    bool allwords,            // true for "[s"/"]s", false for "[S"/"]S"
    bool curline,
    hlf_T *attrp              // return: attributes of bad word or NULL
                              // (only when "dir" is FORWARD)
)
{
  linenr_T lnum;
  pos_T found_pos;
  int found_len = 0;
  char_u      *line;
  char_u      *p;
  char_u      *endp;
  hlf_T attr = HLF_COUNT;
  int len;
  int has_syntax = syntax_present(wp);
  int col;
  bool can_spell;
  char_u      *buf = NULL;
  int buflen = 0;
  int skip = 0;
  int capcol = -1;
  bool found_one = false;
  bool wrapped = false;

  if (no_spell_checking(wp))
    return 0;

  // Start looking for bad word at the start of the line, because we can't
  // start halfway a word, we don't know where it starts or ends.
  //
  // When searching backwards, we continue in the line to find the last
  // bad word (in the cursor line: before the cursor).
  //
  // We concatenate the start of the next line, so that wrapped words work
  // (e.g. "et<line-break>cetera").  Doesn't work when searching backwards
  // though...
  lnum = wp->w_cursor.lnum;
  clearpos(&found_pos);

  while (!got_int) {
    line = ml_get_buf(wp->w_buffer, lnum, FALSE);

    len = (int)STRLEN(line);
    if (buflen < len + MAXWLEN + 2) {
      free(buf);
      buflen = len + MAXWLEN + 2;
      buf = xmalloc(buflen);
    }
    assert(buf && buflen >= len + MAXWLEN + 2);

    // In first line check first word for Capital.
    if (lnum == 1)
      capcol = 0;

    // For checking first word with a capital skip white space.
    if (capcol == 0)
      capcol = (int)(skipwhite(line) - line);
    else if (curline && wp == curwin) {
      // For spellbadword(): check if first word needs a capital.
      col = (int)(skipwhite(line) - line);
      if (check_need_cap(lnum, col))
        capcol = col;

      // Need to get the line again, may have looked at the previous
      // one.
      line = ml_get_buf(wp->w_buffer, lnum, FALSE);
    }

    // Copy the line into "buf" and append the start of the next line if
    // possible.
    STRCPY(buf, line);
    if (lnum < wp->w_buffer->b_ml.ml_line_count)
      spell_cat_line(buf + STRLEN(buf),
          ml_get_buf(wp->w_buffer, lnum + 1, FALSE), MAXWLEN);

    p = buf + skip;
    endp = buf + len;
    while (p < endp) {
      // When searching backward don't search after the cursor.  Unless
      // we wrapped around the end of the buffer.
      if (dir == BACKWARD
          && lnum == wp->w_cursor.lnum
          && !wrapped
          && (colnr_T)(p - buf) >= wp->w_cursor.col)
        break;

      // start of word
      attr = HLF_COUNT;
      len = spell_check(wp, p, &attr, &capcol, false);

      if (attr != HLF_COUNT) {
        // We found a bad word.  Check the attribute.
        if (allwords || attr == HLF_SPB) {
          // When searching forward only accept a bad word after
          // the cursor.
          if (dir == BACKWARD
              || lnum != wp->w_cursor.lnum
              || (lnum == wp->w_cursor.lnum
                  && (wrapped
                      || (colnr_T)(curline ? p - buf + len
                                   : p - buf)
                      > wp->w_cursor.col))) {
            if (has_syntax) {
              col = (int)(p - buf);
              (void)syn_get_id(wp, lnum, (colnr_T)col,
                  FALSE, &can_spell, FALSE);
              if (!can_spell)
                attr = HLF_COUNT;
            } else
              can_spell = true;

            if (can_spell) {
              found_one = true;
              found_pos.lnum = lnum;
              found_pos.col = (int)(p - buf);
              found_pos.coladd = 0;
              if (dir == FORWARD) {
                // No need to search further.
                wp->w_cursor = found_pos;
                free(buf);
                if (attrp != NULL)
                  *attrp = attr;
                return len;
              } else if (curline)
                // Insert mode completion: put cursor after
                // the bad word.
                found_pos.col += len;
              found_len = len;
            }
          } else
            found_one = true;
        }
      }

      // advance to character after the word
      p += len;
      capcol -= len;
    }

    if (dir == BACKWARD && found_pos.lnum != 0) {
      // Use the last match in the line (before the cursor).
      wp->w_cursor = found_pos;
      free(buf);
      return found_len;
    }

    if (curline)
      break;            // only check cursor line

    // Advance to next line.
    if (dir == BACKWARD) {
      // If we are back at the starting line and searched it again there
      // is no match, give up.
      if (lnum == wp->w_cursor.lnum && wrapped)
        break;

      if (lnum > 1)
        --lnum;
      else if (!p_ws)
        break;              // at first line and 'nowrapscan'
      else {
        // Wrap around to the end of the buffer.  May search the
        // starting line again and accept the last match.
        lnum = wp->w_buffer->b_ml.ml_line_count;
        wrapped = true;
        if (!shortmess(SHM_SEARCH))
          give_warning((char_u *)_(top_bot_msg), true);
      }
      capcol = -1;
    } else {
      if (lnum < wp->w_buffer->b_ml.ml_line_count)
        ++lnum;
      else if (!p_ws)
        break;              // at first line and 'nowrapscan'
      else {
        // Wrap around to the start of the buffer.  May search the
        // starting line again and accept the first match.
        lnum = 1;
        wrapped = true;
        if (!shortmess(SHM_SEARCH))
          give_warning((char_u *)_(bot_top_msg), true);
      }

      // If we are back at the starting line and there is no match then
      // give up.
      if (lnum == wp->w_cursor.lnum && (!found_one || wrapped))
        break;

      // Skip the characters at the start of the next line that were
      // included in a match crossing line boundaries.
      if (attr == HLF_COUNT)
        skip = (int)(p - endp);
      else
        skip = 0;

      // Capcol skips over the inserted space.
      --capcol;

      // But after empty line check first word in next line
      if (*skipwhite(line) == NUL)
        capcol = 0;
    }

    line_breakcheck();
  }

  free(buf);
  return 0;
}

// For spell checking: concatenate the start of the following line "line" into
// "buf", blanking-out special characters.  Copy less then "maxlen" bytes.
// Keep the blanks at the start of the next line, this is used in win_line()
// to skip those bytes if the word was OK.
void spell_cat_line(char_u *buf, char_u *line, int maxlen)
{
  char_u      *p;
  int n;

  p = skipwhite(line);
  while (vim_strchr((char_u *)"*#/\"\t", *p) != NULL)
    p = skipwhite(p + 1);

  if (*p != NUL) {
    // Only worth concatenating if there is something else than spaces to
    // concatenate.
    n = (int)(p - line) + 1;
    if (n < maxlen - 1) {
      memset(buf, ' ', n);
      STRLCPY(buf +  n, p, maxlen - n);
    }
  }
}

// Load word list(s) for "lang" from Vim spell file(s).
// "lang" must be the language without the region: e.g., "en".
static void spell_load_lang(char_u *lang)
{
  char_u fname_enc[85];
  int r;
  spelload_T sl;
  int round;

  // Copy the language name to pass it to spell_load_cb() as a cookie.
  // It's truncated when an error is detected.
  STRCPY(sl.sl_lang, lang);
  sl.sl_slang = NULL;
  sl.sl_nobreak = false;

  // We may retry when no spell file is found for the language, an
  // autocommand may load it then.
  for (round = 1; round <= 2; ++round) {
    // Find the first spell file for "lang" in 'runtimepath' and load it.
    vim_snprintf((char *)fname_enc, sizeof(fname_enc) - 5,
        "spell/%s.%s.spl",
        lang, spell_enc());
    r = do_in_runtimepath(fname_enc, FALSE, spell_load_cb, &sl);

    if (r == FAIL && *sl.sl_lang != NUL) {
      // Try loading the ASCII version.
      vim_snprintf((char *)fname_enc, sizeof(fname_enc) - 5,
          "spell/%s.ascii.spl",
          lang);
      r = do_in_runtimepath(fname_enc, FALSE, spell_load_cb, &sl);

      if (r == FAIL && *sl.sl_lang != NUL && round == 1
          && apply_autocmds(EVENT_SPELLFILEMISSING, lang,
              curbuf->b_fname, FALSE, curbuf))
        continue;
      break;
    }
    break;
  }

  if (r == FAIL) {
    smsg((char_u *)
        _("Warning: Cannot find word list \"%s.%s.spl\" or \"%s.ascii.spl\""),
        lang, spell_enc(), lang);
  } else if (sl.sl_slang != NULL) {
    // At least one file was loaded, now load ALL the additions.
    STRCPY(fname_enc + STRLEN(fname_enc) - 3, "add.spl");
    do_in_runtimepath(fname_enc, TRUE, spell_load_cb, &sl);
  }
}

// Return the encoding used for spell checking: Use 'encoding', except that we
// use "latin1" for "latin9".  And limit to 60 characters (just in case).
static char_u *spell_enc(void)
{

  if (STRLEN(p_enc) < 60 && STRCMP(p_enc, "iso-8859-15") != 0)
    return p_enc;
  return (char_u *)"latin1";
}

// Get the name of the .spl file for the internal wordlist into
// "fname[MAXPATHL]".
static void int_wordlist_spl(char_u *fname)
{
  vim_snprintf((char *)fname, MAXPATHL, SPL_FNAME_TMPL,
      int_wordlist, spell_enc());
}

// Allocate a new slang_T for language "lang".  "lang" can be NULL.
// Caller must fill "sl_next".
static slang_T *slang_alloc(char_u *lang)
{
  slang_T *lp = xcalloc(1, sizeof(slang_T));

  if (lang != NULL)
    lp->sl_name = vim_strsave(lang);
  ga_init(&lp->sl_rep, sizeof(fromto_T), 10);
  ga_init(&lp->sl_repsal, sizeof(fromto_T), 10);
  lp->sl_compmax = MAXWLEN;
  lp->sl_compsylmax = MAXWLEN;
  hash_init(&lp->sl_wordcount);

  return lp;
}

// Free the contents of an slang_T and the structure itself.
static void slang_free(slang_T *lp)
{
  free(lp->sl_name);
  free(lp->sl_fname);
  slang_clear(lp);
  free(lp);
}

// Clear an slang_T so that the file can be reloaded.
static void slang_clear(slang_T *lp)
{
  garray_T    *gap;
  fromto_T    *ftp;
  salitem_T   *smp;
  int round;

  free(lp->sl_fbyts);
  lp->sl_fbyts = NULL;
  free(lp->sl_kbyts);
  lp->sl_kbyts = NULL;
  free(lp->sl_pbyts);
  lp->sl_pbyts = NULL;

  free(lp->sl_fidxs);
  lp->sl_fidxs = NULL;
  free(lp->sl_kidxs);
  lp->sl_kidxs = NULL;
  free(lp->sl_pidxs);
  lp->sl_pidxs = NULL;

  for (round = 1; round <= 2; ++round) {
    gap = round == 1 ? &lp->sl_rep : &lp->sl_repsal;
    while (!GA_EMPTY(gap)) {
      ftp = &((fromto_T *)gap->ga_data)[--gap->ga_len];
      free(ftp->ft_from);
      free(ftp->ft_to);
    }
    ga_clear(gap);
  }

  gap = &lp->sl_sal;
  if (lp->sl_sofo) {
    // "ga_len" is set to 1 without adding an item for latin1
    if (gap->ga_data != NULL)
      // SOFOFROM and SOFOTO items: free lists of wide characters.
      for (int i = 0; i < gap->ga_len; ++i) {
        free(((int **)gap->ga_data)[i]);
      }
  } else
    // SAL items: free salitem_T items
    while (!GA_EMPTY(gap)) {
      smp = &((salitem_T *)gap->ga_data)[--gap->ga_len];
      free(smp->sm_lead);
      // Don't free sm_oneof and sm_rules, they point into sm_lead.
      free(smp->sm_to);
      free(smp->sm_lead_w);
      free(smp->sm_oneof_w);
      free(smp->sm_to_w);
    }
  ga_clear(gap);

  for (int i = 0; i < lp->sl_prefixcnt; ++i) {
    vim_regfree(lp->sl_prefprog[i]);
  }
  lp->sl_prefixcnt = 0;
  free(lp->sl_prefprog);
  lp->sl_prefprog = NULL;

  free(lp->sl_info);
  lp->sl_info = NULL;

  free(lp->sl_midword);
  lp->sl_midword = NULL;

  vim_regfree(lp->sl_compprog);
  free(lp->sl_comprules);
  free(lp->sl_compstartflags);
  free(lp->sl_compallflags);
  lp->sl_compprog = NULL;
  lp->sl_comprules = NULL;
  lp->sl_compstartflags = NULL;
  lp->sl_compallflags = NULL;

  free(lp->sl_syllable);
  lp->sl_syllable = NULL;
  ga_clear(&lp->sl_syl_items);

  ga_clear_strings(&lp->sl_comppat);

  hash_clear_all(&lp->sl_wordcount, WC_KEY_OFF);
  hash_init(&lp->sl_wordcount);

  hash_clear_all(&lp->sl_map_hash, 0);

  // Clear info from .sug file.
  slang_clear_sug(lp);

  lp->sl_compmax = MAXWLEN;
  lp->sl_compminlen = 0;
  lp->sl_compsylmax = MAXWLEN;
  lp->sl_regions[0] = NUL;
}

// Clear the info from the .sug file in "lp".
static void slang_clear_sug(slang_T *lp)
{
  free(lp->sl_sbyts);
  lp->sl_sbyts = NULL;
  free(lp->sl_sidxs);
  lp->sl_sidxs = NULL;
  close_spellbuf(lp->sl_sugbuf);
  lp->sl_sugbuf = NULL;
  lp->sl_sugloaded = false;
  lp->sl_sugtime = 0;
}

// Load one spell file and store the info into a slang_T.
// Invoked through do_in_runtimepath().
static void spell_load_cb(char_u *fname, void *cookie)
{
  spelload_T  *slp = (spelload_T *)cookie;
  slang_T     *slang;

  slang = spell_load_file(fname, slp->sl_lang, NULL, false);
  if (slang != NULL) {
    // When a previously loaded file has NOBREAK also use it for the
    // ".add" files.
    if (slp->sl_nobreak && slang->sl_add)
      slang->sl_nobreak = true;
    else if (slang->sl_nobreak)
      slp->sl_nobreak = true;

    slp->sl_slang = slang;
  }
}

// Load one spell file and store the info into a slang_T.
//
// This is invoked in three ways:
// - From spell_load_cb() to load a spell file for the first time.  "lang" is
//   the language name, "old_lp" is NULL.  Will allocate an slang_T.
// - To reload a spell file that was changed.  "lang" is NULL and "old_lp"
//   points to the existing slang_T.
// - Just after writing a .spl file; it's read back to produce the .sug file.
//   "old_lp" is NULL and "lang" is NULL.  Will allocate an slang_T.
//
// Returns the slang_T the spell file was loaded into.  NULL for error.
static slang_T *
spell_load_file (
    char_u *fname,
    char_u *lang,
    slang_T *old_lp,
    bool silent                     // no error if file doesn't exist
)
{
  FILE        *fd;
  char_u buf[VIMSPELLMAGICL];
  char_u      *p;
  int i;
  int n;
  int len;
  char_u      *save_sourcing_name = sourcing_name;
  linenr_T save_sourcing_lnum = sourcing_lnum;
  slang_T     *lp = NULL;
  int c = 0;
  int res;

  fd = mch_fopen((char *)fname, "r");
  if (fd == NULL) {
    if (!silent)
      EMSG2(_(e_notopen), fname);
    else if (p_verbose > 2) {
      verbose_enter();
      smsg((char_u *)e_notopen, fname);
      verbose_leave();
    }
    goto endFAIL;
  }
  if (p_verbose > 2) {
    verbose_enter();
    smsg((char_u *)_("Reading spell file \"%s\""), fname);
    verbose_leave();
  }

  if (old_lp == NULL) {
    lp = slang_alloc(lang);

    // Remember the file name, used to reload the file when it's updated.
    lp->sl_fname = vim_strsave(fname);

    // Check for .add.spl.
    lp->sl_add = strstr((char *)path_tail(fname), SPL_FNAME_ADD) != NULL;
  } else
    lp = old_lp;

  // Set sourcing_name, so that error messages mention the file name.
  sourcing_name = fname;
  sourcing_lnum = 0;

  // <HEADER>: <fileID>
  for (i = 0; i < VIMSPELLMAGICL; ++i)
    buf[i] = getc(fd);                                  // <fileID>
  if (STRNCMP(buf, VIMSPELLMAGIC, VIMSPELLMAGICL) != 0) {
    EMSG(_("E757: This does not look like a spell file"));
    goto endFAIL;
  }
  c = getc(fd);                                         // <versionnr>
  if (c < VIMSPELLVERSION) {
    EMSG(_("E771: Old spell file, needs to be updated"));
    goto endFAIL;
  } else if (c > VIMSPELLVERSION) {
    EMSG(_("E772: Spell file is for newer version of Vim"));
    goto endFAIL;
  }


  // <SECTIONS>: <section> ... <sectionend>
  // <section>: <sectionID> <sectionflags> <sectionlen> (section contents)
  for (;; ) {
    n = getc(fd);                           // <sectionID> or <sectionend>
    if (n == SN_END)
      break;
    c = getc(fd);                                       // <sectionflags>
    len = get4c(fd);                                    // <sectionlen>
    if (len < 0)
      goto truncerr;

    res = 0;
    switch (n) {
    case SN_INFO:
      lp->sl_info = READ_STRING(fd, len);               // <infotext>
      if (lp->sl_info == NULL)
        goto endFAIL;
      break;

    case SN_REGION:
      res = read_region_section(fd, lp, len);
      break;

    case SN_CHARFLAGS:
      res = read_charflags_section(fd);
      break;

    case SN_MIDWORD:
      lp->sl_midword = READ_STRING(fd, len);            // <midword>
      if (lp->sl_midword == NULL)
        goto endFAIL;
      break;

    case SN_PREFCOND:
      res = read_prefcond_section(fd, lp);
      break;

    case SN_REP:
      res = read_rep_section(fd, &lp->sl_rep, lp->sl_rep_first);
      break;

    case SN_REPSAL:
      res = read_rep_section(fd, &lp->sl_repsal, lp->sl_repsal_first);
      break;

    case SN_SAL:
      res = read_sal_section(fd, lp);
      break;

    case SN_SOFO:
      res = read_sofo_section(fd, lp);
      break;

    case SN_MAP:
      p = READ_STRING(fd, len);                         // <mapstr>
      if (p == NULL)
        goto endFAIL;
      set_map_str(lp, p);
      free(p);
      break;

    case SN_WORDS:
      res = read_words_section(fd, lp, len);
      break;

    case SN_SUGFILE:
      lp->sl_sugtime = get8ctime(fd);                   // <timestamp>
      break;

    case SN_NOSPLITSUGS:
      lp->sl_nosplitsugs = true;                        // <timestamp>
      break;

    case SN_COMPOUND:
      res = read_compound(fd, lp, len);
      break;

    case SN_NOBREAK:
      lp->sl_nobreak = true;
      break;

    case SN_SYLLABLE:
      lp->sl_syllable = READ_STRING(fd, len);           // <syllable>
      if (lp->sl_syllable == NULL)
        goto endFAIL;
      if (init_syl_tab(lp) == FAIL)
        goto endFAIL;
      break;

    default:
      // Unsupported section.  When it's required give an error
      // message.  When it's not required skip the contents.
      if (c & SNF_REQUIRED) {
        EMSG(_("E770: Unsupported section in spell file"));
        goto endFAIL;
      }
      while (--len >= 0)
        if (getc(fd) < 0)
          goto truncerr;
      break;
    }
someerror:
    if (res == SP_FORMERROR) {
      EMSG(_(e_format));
      goto endFAIL;
    }
    if (res == SP_TRUNCERROR) {
truncerr:
      EMSG(_(e_spell_trunc));
      goto endFAIL;
    }
    if (res == SP_OTHERERROR)
      goto endFAIL;
  }

  // <LWORDTREE>
  res = spell_read_tree(fd, &lp->sl_fbyts, &lp->sl_fidxs, false, 0);
  if (res != 0)
    goto someerror;

  // <KWORDTREE>
  res = spell_read_tree(fd, &lp->sl_kbyts, &lp->sl_kidxs, false, 0);
  if (res != 0)
    goto someerror;

  // <PREFIXTREE>
  res = spell_read_tree(fd, &lp->sl_pbyts, &lp->sl_pidxs, true,
      lp->sl_prefixcnt);
  if (res != 0)
    goto someerror;

  // For a new file link it in the list of spell files.
  if (old_lp == NULL && lang != NULL) {
    lp->sl_next = first_lang;
    first_lang = lp;
  }

  goto endOK;

endFAIL:
  if (lang != NULL)
    // truncating the name signals the error to spell_load_lang()
    *lang = NUL;
  if (lp != NULL && old_lp == NULL)
    slang_free(lp);
  lp = NULL;

endOK:
  if (fd != NULL)
    fclose(fd);
  sourcing_name = save_sourcing_name;
  sourcing_lnum = save_sourcing_lnum;

  return lp;
}

// Read a length field from "fd" in "cnt_bytes" bytes.
// Allocate memory, read the string into it and add a NUL at the end.
// Returns NULL when the count is zero.
// Sets "*cntp" to SP_*ERROR when there is an error, length of the result
// otherwise.
static char_u *read_cnt_string(FILE *fd, int cnt_bytes, int *cntp)
{
  int cnt = 0;
  int i;
  char_u      *str;

  // read the length bytes, MSB first
  for (i = 0; i < cnt_bytes; ++i)
    cnt = (cnt << 8) + getc(fd);
  if (cnt < 0) {
    *cntp = SP_TRUNCERROR;
    return NULL;
  }
  *cntp = cnt;
  if (cnt == 0)
    return NULL;            // nothing to read, return NULL

  str = READ_STRING(fd, cnt);
  if (str == NULL)
    *cntp = SP_OTHERERROR;
  return str;
}

// Read SN_REGION: <regionname> ...
// Return SP_*ERROR flags.
static int read_region_section(FILE *fd, slang_T *lp, int len)
{
  int i;

  if (len > 16)
    return SP_FORMERROR;
  for (i = 0; i < len; ++i)
    lp->sl_regions[i] = getc(fd);                       // <regionname>
  lp->sl_regions[len] = NUL;
  return 0;
}

// Read SN_CHARFLAGS section: <charflagslen> <charflags>
//                              <folcharslen> <folchars>
// Return SP_*ERROR flags.
static int read_charflags_section(FILE *fd)
{
  char_u      *flags;
  char_u      *fol;
  int flagslen, follen;

  // <charflagslen> <charflags>
  flags = read_cnt_string(fd, 1, &flagslen);
  if (flagslen < 0)
    return flagslen;

  // <folcharslen> <folchars>
  fol = read_cnt_string(fd, 2, &follen);
  if (follen < 0) {
    free(flags);
    return follen;
  }

  // Set the word-char flags and fill SPELL_ISUPPER() table.
  if (flags != NULL && fol != NULL)
    set_spell_charflags(flags, flagslen, fol);

  free(flags);
  free(fol);

  // When <charflagslen> is zero then <fcharlen> must also be zero.
  if ((flags == NULL) != (fol == NULL))
    return SP_FORMERROR;
  return 0;
}

// Read SN_PREFCOND section.
// Return SP_*ERROR flags.
static int read_prefcond_section(FILE *fd, slang_T *lp)
{
  int cnt;
  int i;
  int n;
  char_u      *p;
  char_u buf[MAXWLEN + 1];

  // <prefcondcnt> <prefcond> ...
  cnt = get2c(fd);                                      // <prefcondcnt>
  if (cnt <= 0)
    return SP_FORMERROR;

  lp->sl_prefprog = xcalloc(cnt, sizeof(regprog_T *));
  lp->sl_prefixcnt = cnt;

  for (i = 0; i < cnt; ++i) {
    // <prefcond> : <condlen> <condstr>
    n = getc(fd);                                       // <condlen>
    if (n < 0 || n >= MAXWLEN)
      return SP_FORMERROR;

    // When <condlen> is zero we have an empty condition.  Otherwise
    // compile the regexp program used to check for the condition.
    if (n > 0) {
      buf[0] = '^';                 // always match at one position only
      p = buf + 1;
      while (n-- > 0)
        *p++ = getc(fd);                                // <condstr>
      *p = NUL;
      lp->sl_prefprog[i] = vim_regcomp(buf, RE_MAGIC + RE_STRING);
    }
  }
  return 0;
}

// Read REP or REPSAL items section from "fd": <repcount> <rep> ...
// Return SP_*ERROR flags.
static int read_rep_section(FILE *fd, garray_T *gap, short *first)
{
  int cnt;
  fromto_T    *ftp;

  cnt = get2c(fd);                                      // <repcount>
  if (cnt < 0)
    return SP_TRUNCERROR;

  ga_grow(gap, cnt);

  // <rep> : <repfromlen> <repfrom> <reptolen> <repto>
  for (; gap->ga_len < cnt; ++gap->ga_len) {
    int c;
    ftp = &((fromto_T *)gap->ga_data)[gap->ga_len];
    ftp->ft_from = read_cnt_string(fd, 1, &c);
    if (c < 0)
      return c;
    if (c == 0)
      return SP_FORMERROR;
    ftp->ft_to = read_cnt_string(fd, 1, &c);
    if (c <= 0) {
      free(ftp->ft_from);
      if (c < 0)
        return c;
      return SP_FORMERROR;
    }
  }

  // Fill the first-index table.
  for (int i = 0; i < 256; ++i) {
    first[i] = -1;
  }
  for (int i = 0; i < gap->ga_len; ++i) {
    ftp = &((fromto_T *)gap->ga_data)[i];
    if (first[*ftp->ft_from] == -1)
      first[*ftp->ft_from] = i;
  }
  return 0;
}

// Read SN_SAL section: <salflags> <salcount> <sal> ...
// Return SP_*ERROR flags.
static int read_sal_section(FILE *fd, slang_T *slang)
{
  int i;
  int cnt;
  garray_T    *gap;
  salitem_T   *smp;
  int ccnt;
  char_u      *p;
  int c = NUL;

  slang->sl_sofo = false;

  i = getc(fd);                                 // <salflags>
  if (i & SAL_F0LLOWUP)
    slang->sl_followup = true;
  if (i & SAL_COLLAPSE)
    slang->sl_collapse = true;
  if (i & SAL_REM_ACCENTS)
    slang->sl_rem_accents = true;

  cnt = get2c(fd);                              // <salcount>
  if (cnt < 0)
    return SP_TRUNCERROR;

  gap = &slang->sl_sal;
  ga_init(gap, sizeof(salitem_T), 10);
  ga_grow(gap, cnt + 1);

  // <sal> : <salfromlen> <salfrom> <saltolen> <salto>
  for (; gap->ga_len < cnt; ++gap->ga_len) {
    smp = &((salitem_T *)gap->ga_data)[gap->ga_len];
    ccnt = getc(fd);                            // <salfromlen>
    if (ccnt < 0)
      return SP_TRUNCERROR;
    p = xmalloc(ccnt + 2);
    smp->sm_lead = p;

    // Read up to the first special char into sm_lead.
    for (i = 0; i < ccnt; ++i) {
      c = getc(fd);                             // <salfrom>
      if (vim_strchr((char_u *)"0123456789(-<^$", c) != NULL)
        break;
      *p++ = c;
    }
    smp->sm_leadlen = (int)(p - smp->sm_lead);
    *p++ = NUL;

    // Put (abc) chars in sm_oneof, if any.
    if (c == '(') {
      smp->sm_oneof = p;
      for (++i; i < ccnt; ++i) {
        c = getc(fd);                           // <salfrom>
        if (c == ')')
          break;
        *p++ = c;
      }
      *p++ = NUL;
      if (++i < ccnt)
        c = getc(fd);
    } else
      smp->sm_oneof = NULL;

    // Any following chars go in sm_rules.
    smp->sm_rules = p;
    if (i < ccnt)
      // store the char we got while checking for end of sm_lead
      *p++ = c;
    for (++i; i < ccnt; ++i)
      *p++ = getc(fd);                          // <salfrom>
    *p++ = NUL;

    // <saltolen> <salto>
    smp->sm_to = read_cnt_string(fd, 1, &ccnt);
    if (ccnt < 0) {
      free(smp->sm_lead);
      return ccnt;
    }

    if (has_mbyte) {
      // convert the multi-byte strings to wide char strings
      smp->sm_lead_w = mb_str2wide(smp->sm_lead);
      smp->sm_leadlen = mb_charlen(smp->sm_lead);
      if (smp->sm_oneof == NULL)
        smp->sm_oneof_w = NULL;
      else
        smp->sm_oneof_w = mb_str2wide(smp->sm_oneof);
      if (smp->sm_to == NULL)
        smp->sm_to_w = NULL;
      else
        smp->sm_to_w = mb_str2wide(smp->sm_to);
    }
  }

  if (!GA_EMPTY(gap)) {
    // Add one extra entry to mark the end with an empty sm_lead.  Avoids
    // that we need to check the index every time.
    smp = &((salitem_T *)gap->ga_data)[gap->ga_len];
    p = xmalloc(1);
    p[0] = NUL;
    smp->sm_lead = p;
    smp->sm_leadlen = 0;
    smp->sm_oneof = NULL;
    smp->sm_rules = p;
    smp->sm_to = NULL;
    if (has_mbyte) {
      smp->sm_lead_w = mb_str2wide(smp->sm_lead);
      smp->sm_leadlen = 0;
      smp->sm_oneof_w = NULL;
      smp->sm_to_w = NULL;
    }
    ++gap->ga_len;
  }

  // Fill the first-index table.
  set_sal_first(slang);

  return 0;
}

// Read SN_WORDS: <word> ...
// Return SP_*ERROR flags.
static int read_words_section(FILE *fd, slang_T *lp, int len)
{
  int done = 0;
  int i;
  int c;
  char_u word[MAXWLEN];

  while (done < len) {
    // Read one word at a time.
    for (i = 0;; ++i) {
      c = getc(fd);
      if (c == EOF)
        return SP_TRUNCERROR;
      word[i] = c;
      if (word[i] == NUL)
        break;
      if (i == MAXWLEN - 1)
        return SP_FORMERROR;
    }

    // Init the count to 10.
    count_common_word(lp, word, -1, 10);
    done += i + 1;
  }
  return 0;
}

// Add a word to the hashtable of common words.
// If it's already there then the counter is increased.
static void
count_common_word (
    slang_T *lp,
    char_u *word,
    int len,                    // word length, -1 for upto NUL
    int count                  // 1 to count once, 10 to init
)
{
  hash_T hash;
  hashitem_T  *hi;
  wordcount_T *wc;
  char_u buf[MAXWLEN];
  char_u      *p;

  if (len == -1)
    p = word;
  else {
    STRLCPY(buf, word, len + 1);
    p = buf;
  }

  hash = hash_hash(p);
  hi = hash_lookup(&lp->sl_wordcount, p, hash);
  if (HASHITEM_EMPTY(hi)) {
    wc = xmalloc(sizeof(wordcount_T) + STRLEN(p));
    STRCPY(wc->wc_word, p);
    wc->wc_count = count;
    hash_add_item(&lp->sl_wordcount, hi, wc->wc_word, hash);
  } else {
    wc = HI2WC(hi);
    if ((wc->wc_count += count) < (unsigned)count)      // check for overflow
      wc->wc_count = MAXWORDCOUNT;
  }
}

// Adjust the score of common words.
static int
score_wordcount_adj (
    slang_T *slang,
    int score,
    char_u *word,
    bool split                  // word was split, less bonus
)
{
  hashitem_T  *hi;
  wordcount_T *wc;
  int bonus;
  int newscore;

  hi = hash_find(&slang->sl_wordcount, word);
  if (!HASHITEM_EMPTY(hi)) {
    wc = HI2WC(hi);
    if (wc->wc_count < SCORE_THRES2)
      bonus = SCORE_COMMON1;
    else if (wc->wc_count < SCORE_THRES3)
      bonus = SCORE_COMMON2;
    else
      bonus = SCORE_COMMON3;
    if (split)
      newscore = score - bonus / 2;
    else
      newscore = score - bonus;
    if (newscore < 0)
      return 0;
    return newscore;
  }
  return score;
}

// SN_SOFO: <sofofromlen> <sofofrom> <sofotolen> <sofoto>
// Return SP_*ERROR flags.
static int read_sofo_section(FILE *fd, slang_T *slang)
{
  int cnt;
  char_u      *from, *to;
  int res;

  slang->sl_sofo = true;

  // <sofofromlen> <sofofrom>
  from = read_cnt_string(fd, 2, &cnt);
  if (cnt < 0)
    return cnt;

  // <sofotolen> <sofoto>
  to = read_cnt_string(fd, 2, &cnt);
  if (cnt < 0) {
    free(from);
    return cnt;
  }

  // Store the info in slang->sl_sal and/or slang->sl_sal_first.
  if (from != NULL && to != NULL)
    res = set_sofo(slang, from, to);
  else if (from != NULL || to != NULL)
    res = SP_FORMERROR;        // only one of two strings is an error
  else
    res = 0;

  free(from);
  free(to);
  return res;
}

// Read the compound section from the .spl file:
//      <compmax> <compminlen> <compsylmax> <compoptions> <compflags>
// Returns SP_*ERROR flags.
static int read_compound(FILE *fd, slang_T *slang, int len)
{
  int todo = len;
  int c;
  int atstart;
  char_u      *pat;
  char_u      *pp;
  char_u      *cp;
  char_u      *ap;
  char_u      *crp;
  int cnt;
  garray_T    *gap;

  if (todo < 2)
    return SP_FORMERROR;        // need at least two bytes

  --todo;
  c = getc(fd);                                         // <compmax>
  if (c < 2)
    c = MAXWLEN;
  slang->sl_compmax = c;

  --todo;
  c = getc(fd);                                         // <compminlen>
  if (c < 1)
    c = 0;
  slang->sl_compminlen = c;

  --todo;
  c = getc(fd);                                         // <compsylmax>
  if (c < 1)
    c = MAXWLEN;
  slang->sl_compsylmax = c;

  c = getc(fd);                                         // <compoptions>
  if (c != 0)
    ungetc(c, fd);          // be backwards compatible with Vim 7.0b
  else {
    --todo;
    c = getc(fd);           // only use the lower byte for now
    --todo;
    slang->sl_compoptions = c;

    gap = &slang->sl_comppat;
    c = get2c(fd);                                      // <comppatcount>
    todo -= 2;
    ga_init(gap, sizeof(char_u *), c);
    ga_grow(gap, c);
    while (--c >= 0) {
      ((char_u **)(gap->ga_data))[gap->ga_len++] =
        read_cnt_string(fd, 1, &cnt);
      // <comppatlen> <comppattext>
      if (cnt < 0)
        return cnt;
      todo -= cnt + 1;
    }
  }
  if (todo < 0)
    return SP_FORMERROR;

  // Turn the COMPOUNDRULE items into a regexp pattern:
  // "a[bc]/a*b+" -> "^\(a[bc]\|a*b\+\)$".
  // Inserting backslashes may double the length, "^\(\)$<Nul>" is 7 bytes.
  // Conversion to utf-8 may double the size.
  c = todo * 2 + 7;
  if (enc_utf8)
    c += todo * 2;
  pat = xmalloc(c);

  // We also need a list of all flags that can appear at the start and one
  // for all flags.
  cp = xmalloc(todo + 1);
  slang->sl_compstartflags = cp;
  *cp = NUL;

  ap = xmalloc(todo + 1);
  slang->sl_compallflags = ap;
  *ap = NUL;

  // And a list of all patterns in their original form, for checking whether
  // compounding may work in match_compoundrule().  This is freed when we
  // encounter a wildcard, the check doesn't work then.
  crp = xmalloc(todo + 1);
  slang->sl_comprules = crp;

  pp = pat;
  *pp++ = '^';
  *pp++ = '\\';
  *pp++ = '(';

  atstart = 1;
  while (todo-- > 0) {
    c = getc(fd);                                       // <compflags>
    if (c == EOF) {
      free(pat);
      return SP_TRUNCERROR;
    }

    // Add all flags to "sl_compallflags".
    if (vim_strchr((char_u *)"?*+[]/", c) == NULL
        && !byte_in_str(slang->sl_compallflags, c)) {
      *ap++ = c;
      *ap = NUL;
    }

    if (atstart != 0) {
      // At start of item: copy flags to "sl_compstartflags".  For a
      // [abc] item set "atstart" to 2 and copy up to the ']'.
      if (c == '[')
        atstart = 2;
      else if (c == ']')
        atstart = 0;
      else {
        if (!byte_in_str(slang->sl_compstartflags, c)) {
          *cp++ = c;
          *cp = NUL;
        }
        if (atstart == 1)
          atstart = 0;
      }
    }

    // Copy flag to "sl_comprules", unless we run into a wildcard.
    if (crp != NULL) {
      if (c == '?' || c == '+' || c == '*') {
        free(slang->sl_comprules);
        slang->sl_comprules = NULL;
        crp = NULL;
      } else
        *crp++ = c;
    }

    if (c == '/') {         // slash separates two items
      *pp++ = '\\';
      *pp++ = '|';
      atstart = 1;
    } else {              // normal char, "[abc]" and '*' are copied as-is
      if (c == '?' || c == '+' || c == '~')
        *pp++ = '\\';               // "a?" becomes "a\?", "a+" becomes "a\+"
      if (enc_utf8)
        pp += mb_char2bytes(c, pp);
      else
        *pp++ = c;
    }
  }

  *pp++ = '\\';
  *pp++ = ')';
  *pp++ = '$';
  *pp = NUL;

  if (crp != NULL)
    *crp = NUL;

  slang->sl_compprog = vim_regcomp(pat, RE_MAGIC + RE_STRING + RE_STRICT);
  free(pat);
  if (slang->sl_compprog == NULL)
    return SP_FORMERROR;

  return 0;
}

// Returns true if byte "n" appears in "str".
// Like strchr() but independent of locale.
static bool byte_in_str(char_u *str, int n)
{
  char_u      *p;

  for (p = str; *p != NUL; ++p)
    if (*p == n)
      return true;
  return false;
}

// Truncate "slang->sl_syllable" at the first slash and put the following items
// in "slang->sl_syl_items".
static int init_syl_tab(slang_T *slang)
{
  char_u      *p;
  char_u      *s;
  int l;

  ga_init(&slang->sl_syl_items, sizeof(syl_item_T), 4);
  p = vim_strchr(slang->sl_syllable, '/');
  while (p != NULL) {
    *p++ = NUL;
    if (*p == NUL)          // trailing slash
      break;
    s = p;
    p = vim_strchr(p, '/');
    if (p == NULL)
      l = (int)STRLEN(s);
    else
      l = (int)(p - s);
    if (l >= SY_MAXLEN)
      return SP_FORMERROR;

    syl_item_T *syl = GA_APPEND_VIA_PTR(syl_item_T, &slang->sl_syl_items);
    STRLCPY(syl->sy_chars, s, l + 1);
    syl->sy_len = l;
  }
  return OK;
}

// Count the number of syllables in "word".
// When "word" contains spaces the syllables after the last space are counted.
// Returns zero if syllables are not defines.
static int count_syllables(slang_T *slang, char_u *word)
{
  int cnt = 0;
  bool skip = false;
  char_u      *p;
  int len;
  syl_item_T  *syl;
  int c;

  if (slang->sl_syllable == NULL)
    return 0;

  for (p = word; *p != NUL; p += len) {
    // When running into a space reset counter.
    if (*p == ' ') {
      len = 1;
      cnt = 0;
      continue;
    }

    // Find longest match of syllable items.
    len = 0;
    for (int i = 0; i < slang->sl_syl_items.ga_len; ++i) {
      syl = ((syl_item_T *)slang->sl_syl_items.ga_data) + i;
      if (syl->sy_len > len
          && STRNCMP(p, syl->sy_chars, syl->sy_len) == 0)
        len = syl->sy_len;
    }
    if (len != 0) {     // found a match, count syllable
      ++cnt;
      skip = false;
    } else {
      // No recognized syllable item, at least a syllable char then?
      c = mb_ptr2char(p);
      len = (*mb_ptr2len)(p);
      if (vim_strchr(slang->sl_syllable, c) == NULL)
        skip = false;               // No, search for next syllable
      else if (!skip) {
        ++cnt;                      // Yes, count it
        skip = true;                // don't count following syllable chars
      }
    }
  }
  return cnt;
}

// Set the SOFOFROM and SOFOTO items in language "lp".
// Returns SP_*ERROR flags when there is something wrong.
static int set_sofo(slang_T *lp, char_u *from, char_u *to)
{
  int i;

  garray_T    *gap;
  char_u      *s;
  char_u      *p;
  int c;
  int         *inp;

  if (has_mbyte) {
    // Use "sl_sal" as an array with 256 pointers to a list of wide
    // characters.  The index is the low byte of the character.
    // The list contains from-to pairs with a terminating NUL.
    // sl_sal_first[] is used for latin1 "from" characters.
    gap = &lp->sl_sal;
    ga_init(gap, sizeof(int *), 1);
    ga_grow(gap, 256);
    memset(gap->ga_data, 0, sizeof(int *) * 256);
    gap->ga_len = 256;

    // First count the number of items for each list.  Temporarily use
    // sl_sal_first[] for this.
    for (p = from, s = to; *p != NUL && *s != NUL; ) {
      c = mb_cptr2char_adv(&p);
      mb_cptr_adv(s);
      if (c >= 256)
        ++lp->sl_sal_first[c & 0xff];
    }
    if (*p != NUL || *s != NUL)             // lengths differ
      return SP_FORMERROR;

    // Allocate the lists.
    for (i = 0; i < 256; ++i)
      if (lp->sl_sal_first[i] > 0) {
        p = xmalloc(sizeof(int) * (lp->sl_sal_first[i] * 2 + 1));
        ((int **)gap->ga_data)[i] = (int *)p;
        *(int *)p = 0;
      }

    // Put the characters up to 255 in sl_sal_first[] the rest in a sl_sal
    // list.
    memset(lp->sl_sal_first, 0, sizeof(salfirst_T) * 256);
    for (p = from, s = to; *p != NUL && *s != NUL; ) {
      c = mb_cptr2char_adv(&p);
      i = mb_cptr2char_adv(&s);
      if (c >= 256) {
        // Append the from-to chars at the end of the list with
        // the low byte.
        inp = ((int **)gap->ga_data)[c & 0xff];
        while (*inp != 0)
          ++inp;
        *inp++ = c;                     // from char
        *inp++ = i;                     // to char
        *inp++ = NUL;                   // NUL at the end
      } else
        // mapping byte to char is done in sl_sal_first[]
        lp->sl_sal_first[c] = i;
    }
  } else {
    // mapping bytes to bytes is done in sl_sal_first[]
    if (STRLEN(from) != STRLEN(to))
      return SP_FORMERROR;

    for (i = 0; to[i] != NUL; ++i)
      lp->sl_sal_first[from[i]] = to[i];
    lp->sl_sal.ga_len = 1;              // indicates we have soundfolding
  }

  return 0;
}

// Fill the first-index table for "lp".
static void set_sal_first(slang_T *lp)
{
  salfirst_T  *sfirst;
  salitem_T   *smp;
  int c;
  garray_T    *gap = &lp->sl_sal;

  sfirst = lp->sl_sal_first;
  for (int i = 0; i < 256; ++i) {
    sfirst[i] = -1;
  }
  smp = (salitem_T *)gap->ga_data;
  for (int i = 0; i < gap->ga_len; ++i) {
    if (has_mbyte)
      // Use the lowest byte of the first character.  For latin1 it's
      // the character, for other encodings it should differ for most
      // characters.
      c = *smp[i].sm_lead_w & 0xff;
    else
      c = *smp[i].sm_lead;
    if (sfirst[c] == -1) {
      sfirst[c] = i;
      if (has_mbyte) {
        int n;

        // Make sure all entries with this byte are following each
        // other.  Move the ones that are in the wrong position.  Do
        // keep the same ordering!
        while (i + 1 < gap->ga_len
               && (*smp[i + 1].sm_lead_w & 0xff) == c)
          // Skip over entry with same index byte.
          ++i;

        for (n = 1; i + n < gap->ga_len; ++n)
          if ((*smp[i + n].sm_lead_w & 0xff) == c) {
            salitem_T tsal;

            // Move entry with same index byte after the entries
            // we already found.
            ++i;
            --n;
            tsal = smp[i + n];
            memmove(smp + i + 1, smp + i,
                sizeof(salitem_T) * n);
            smp[i] = tsal;
          }
      }
    }
  }
}

// Turn a multi-byte string into a wide character string.
// Return it in allocated memory.
static int *mb_str2wide(char_u *s)
{
  int i = 0;

  int *res = xmalloc((mb_charlen(s) + 1) * sizeof(int));
  for (char_u *p = s; *p != NUL; )
    res[i++] = mb_ptr2char_adv(&p);
  res[i] = NUL;

  return res;
}

// Reads a tree from the .spl or .sug file.
// Allocates the memory and stores pointers in "bytsp" and "idxsp".
// This is skipped when the tree has zero length.
// Returns zero when OK, SP_ value for an error.
static int
spell_read_tree (
    FILE *fd,
    char_u **bytsp,
    idx_T **idxsp,
    bool prefixtree,               // true for the prefix tree
    int prefixcnt                  // when "prefixtree" is true: prefix count
)
{
  int idx;
  char_u      *bp;
  idx_T       *ip;

  // The tree size was computed when writing the file, so that we can
  // allocate it as one long block. <nodecount>
  int len = get4c(fd);
  if (len < 0)
    return SP_TRUNCERROR;
  if (len > 0) {
    // Allocate the byte array.
    bp = xmalloc(len);
    *bytsp = bp;

    // Allocate the index array.
    ip = xcalloc(len, sizeof(*ip));
    *idxsp = ip;

    // Recursively read the tree and store it in the array.
    idx = read_tree_node(fd, bp, ip, len, 0, prefixtree, prefixcnt);
    if (idx < 0)
      return idx;
  }
  return 0;
}

// Read one row of siblings from the spell file and store it in the byte array
// "byts" and index array "idxs".  Recursively read the children.
//
// NOTE: The code here must match put_node()!
//
// Returns the index (>= 0) following the siblings.
// Returns SP_TRUNCERROR if the file is shorter than expected.
// Returns SP_FORMERROR if there is a format error.
static idx_T
read_tree_node (
    FILE *fd,
    char_u *byts,
    idx_T *idxs,
    int maxidx,                         // size of arrays
    idx_T startidx,                     // current index in "byts" and "idxs"
    bool prefixtree,                    // true for reading PREFIXTREE
    int maxprefcondnr                   // maximum for <prefcondnr>
)
{
  int len;
  int i;
  int n;
  idx_T idx = startidx;
  int c;
  int c2;
#define SHARED_MASK     0x8000000

  len = getc(fd);                                       // <siblingcount>
  if (len <= 0)
    return SP_TRUNCERROR;

  if (startidx + len >= maxidx)
    return SP_FORMERROR;
  byts[idx++] = len;

  // Read the byte values, flag/region bytes and shared indexes.
  for (i = 1; i <= len; ++i) {
    c = getc(fd);                                       // <byte>
    if (c < 0)
      return SP_TRUNCERROR;
    if (c <= BY_SPECIAL) {
      if (c == BY_NOFLAGS && !prefixtree) {
        // No flags, all regions.
        idxs[idx] = 0;
        c = 0;
      } else if (c != BY_INDEX) {
        if (prefixtree) {
          // Read the optional pflags byte, the prefix ID and the
          // condition nr.  In idxs[] store the prefix ID in the low
          // byte, the condition index shifted up 8 bits, the flags
          // shifted up 24 bits.
          if (c == BY_FLAGS)
            c = getc(fd) << 24;                         // <pflags>
          else
            c = 0;

          c |= getc(fd);                                // <affixID>

          n = get2c(fd);                                // <prefcondnr>
          if (n >= maxprefcondnr)
            return SP_FORMERROR;
          c |= (n << 8);
        } else {    // c must be BY_FLAGS or BY_FLAGS2
                    // Read flags and optional region and prefix ID.  In
                    // idxs[] the flags go in the low two bytes, region above
                    // that and prefix ID above the region.
          c2 = c;
          c = getc(fd);                                 // <flags>
          if (c2 == BY_FLAGS2)
            c = (getc(fd) << 8) + c;                    // <flags2>
          if (c & WF_REGION)
            c = (getc(fd) << 16) + c;                   // <region>
          if (c & WF_AFX)
            c = (getc(fd) << 24) + c;                   // <affixID>
        }

        idxs[idx] = c;
        c = 0;
      } else { // c == BY_INDEX
        // <nodeidx>
        n = get3c(fd);
        if (n < 0 || n >= maxidx)
          return SP_FORMERROR;
        idxs[idx] = n + SHARED_MASK;
        c = getc(fd);                                   // <xbyte>
      }
    }
    byts[idx++] = c;
  }

  // Recursively read the children for non-shared siblings.
  // Skip the end-of-word ones (zero byte value) and the shared ones (and
  // remove SHARED_MASK)
  for (i = 1; i <= len; ++i)
    if (byts[startidx + i] != 0) {
      if (idxs[startidx + i] & SHARED_MASK)
        idxs[startidx + i] &= ~SHARED_MASK;
      else {
        idxs[startidx + i] = idx;
        idx = read_tree_node(fd, byts, idxs, maxidx, idx,
            prefixtree, maxprefcondnr);
        if (idx < 0)
          break;
      }
    }

  return idx;
}

// Parse 'spelllang' and set w_s->b_langp accordingly.
// Returns NULL if it's OK, an error message otherwise.
char_u *did_set_spelllang(win_T *wp)
{
  garray_T ga;
  char_u      *splp;
  char_u      *region;
  char_u region_cp[3];
  bool filename;
  int region_mask;
  slang_T     *slang;
  int c;
  char_u lang[MAXWLEN + 1];
  char_u spf_name[MAXPATHL];
  int len;
  char_u      *p;
  int round;
  char_u      *spf;
  char_u      *use_region = NULL;
  bool dont_use_region = false;
  bool nobreak = false;
  langp_T     *lp, *lp2;
  static bool recursive = false;
  char_u      *ret_msg = NULL;
  char_u      *spl_copy;

  // We don't want to do this recursively.  May happen when a language is
  // not available and the SpellFileMissing autocommand opens a new buffer
  // in which 'spell' is set.
  if (recursive)
    return NULL;
  recursive = true;

  ga_init(&ga, sizeof(langp_T), 2);
  clear_midword(wp);

  // Make a copy of 'spelllang', the SpellFileMissing autocommands may change
  // it under our fingers.
  spl_copy = vim_strsave(wp->w_s->b_p_spl);

  wp->w_s->b_cjk = 0;

  // Loop over comma separated language names.
  for (splp = spl_copy; *splp != NUL; ) {
    // Get one language name.
    copy_option_part(&splp, lang, MAXWLEN, ",");
    region = NULL;
    len = (int)STRLEN(lang);

    if (STRCMP(lang, "cjk") == 0) {
      wp->w_s->b_cjk = 1;
      continue;
    }

    // If the name ends in ".spl" use it as the name of the spell file.
    // If there is a region name let "region" point to it and remove it
    // from the name.
    if (len > 4 && fnamecmp(lang + len - 4, ".spl") == 0) {
      filename = true;

      // Locate a region and remove it from the file name.
      p = vim_strchr(path_tail(lang), '_');
      if (p != NULL && ASCII_ISALPHA(p[1]) && ASCII_ISALPHA(p[2])
          && !ASCII_ISALPHA(p[3])) {
        STRLCPY(region_cp, p + 1, 3);
        memmove(p, p + 3, len - (p - lang) - 2);
        region = region_cp;
      } else
        dont_use_region = true;

      // Check if we loaded this language before.
      for (slang = first_lang; slang != NULL; slang = slang->sl_next)
        if (path_full_compare(lang, slang->sl_fname, FALSE) == kEqualFiles)
          break;
    } else {
      filename = false;
      if (len > 3 && lang[len - 3] == '_') {
        region = lang + len - 2;
        lang[len - 3] = NUL;
      } else
        dont_use_region = true;

      // Check if we loaded this language before.
      for (slang = first_lang; slang != NULL; slang = slang->sl_next)
        if (STRICMP(lang, slang->sl_name) == 0)
          break;
    }

    if (region != NULL) {
      // If the region differs from what was used before then don't
      // use it for 'spellfile'.
      if (use_region != NULL && STRCMP(region, use_region) != 0)
        dont_use_region = true;
      use_region = region;
    }

    // If not found try loading the language now.
    if (slang == NULL) {
      if (filename)
        (void)spell_load_file(lang, lang, NULL, false);
      else {
        spell_load_lang(lang);
        // SpellFileMissing autocommands may do anything, including
        // destroying the buffer we are using...
        if (!buf_valid(wp->w_buffer)) {
          ret_msg =
            (char_u *)"E797: SpellFileMissing autocommand deleted buffer";
          goto theend;
        }
      }
    }

    // Loop over the languages, there can be several files for "lang".
    for (slang = first_lang; slang != NULL; slang = slang->sl_next)
      if (filename ? path_full_compare(lang, slang->sl_fname, FALSE) == kEqualFiles
          : STRICMP(lang, slang->sl_name) == 0) {
        region_mask = REGION_ALL;
        if (!filename && region != NULL) {
          // find region in sl_regions
          c = find_region(slang->sl_regions, region);
          if (c == REGION_ALL) {
            if (slang->sl_add) {
              if (*slang->sl_regions != NUL)
                // This addition file is for other regions.
                region_mask = 0;
            } else
              // This is probably an error.  Give a warning and
              // accept the words anyway.
              smsg((char_u *)
                  _("Warning: region %s not supported"),
                  region);
          } else
            region_mask = 1 << c;
        }

        if (region_mask != 0) {
          langp_T *p = GA_APPEND_VIA_PTR(langp_T, &ga);
          p->lp_slang = slang;
          p->lp_region = region_mask;

          use_midword(slang, wp);
          if (slang->sl_nobreak)
            nobreak = true;
        }
      }
  }

  // round 0: load int_wordlist, if possible.
  // round 1: load first name in 'spellfile'.
  // round 2: load second name in 'spellfile.
  // etc.
  spf = curwin->w_s->b_p_spf;
  for (round = 0; round == 0 || *spf != NUL; ++round) {
    if (round == 0) {
      // Internal wordlist, if there is one.
      if (int_wordlist == NULL)
        continue;
      int_wordlist_spl(spf_name);
    } else {
      // One entry in 'spellfile'.
      copy_option_part(&spf, spf_name, MAXPATHL - 5, ",");
      STRCAT(spf_name, ".spl");

      // If it was already found above then skip it.
      for (c = 0; c < ga.ga_len; ++c) {
        p = LANGP_ENTRY(ga, c)->lp_slang->sl_fname;
        if (p != NULL && path_full_compare(spf_name, p, FALSE) == kEqualFiles)
          break;
      }
      if (c < ga.ga_len)
        continue;
    }

    // Check if it was loaded already.
    for (slang = first_lang; slang != NULL; slang = slang->sl_next)
      if (path_full_compare(spf_name, slang->sl_fname, FALSE) == kEqualFiles)
        break;
    if (slang == NULL) {
      // Not loaded, try loading it now.  The language name includes the
      // region name, the region is ignored otherwise.  for int_wordlist
      // use an arbitrary name.
      if (round == 0)
        STRCPY(lang, "internal wordlist");
      else {
        STRLCPY(lang, path_tail(spf_name), MAXWLEN + 1);
        p = vim_strchr(lang, '.');
        if (p != NULL)
          *p = NUL;             // truncate at ".encoding.add"
      }
      slang = spell_load_file(spf_name, lang, NULL, true);

      // If one of the languages has NOBREAK we assume the addition
      // files also have this.
      if (slang != NULL && nobreak)
        slang->sl_nobreak = true;
    }
    if (slang != NULL) {
      region_mask = REGION_ALL;
      if (use_region != NULL && !dont_use_region) {
        // find region in sl_regions
        c = find_region(slang->sl_regions, use_region);
        if (c != REGION_ALL)
          region_mask = 1 << c;
        else if (*slang->sl_regions != NUL)
          // This spell file is for other regions.
          region_mask = 0;
      }

      if (region_mask != 0) {
        langp_T *p = GA_APPEND_VIA_PTR(langp_T, &ga);
        p->lp_slang = slang;
        p->lp_sallang = NULL;
        p->lp_replang = NULL;
        p->lp_region = region_mask;

        use_midword(slang, wp);
      }
    }
  }

  // Everything is fine, store the new b_langp value.
  ga_clear(&wp->w_s->b_langp);
  wp->w_s->b_langp = ga;

  // For each language figure out what language to use for sound folding and
  // REP items.  If the language doesn't support it itself use another one
  // with the same name.  E.g. for "en-math" use "en".
  for (int i = 0; i < ga.ga_len; ++i) {
    lp = LANGP_ENTRY(ga, i);

    // sound folding
    if (!GA_EMPTY(&lp->lp_slang->sl_sal))
      // language does sound folding itself
      lp->lp_sallang = lp->lp_slang;
    else
      // find first similar language that does sound folding
      for (int j = 0; j < ga.ga_len; ++j) {
        lp2 = LANGP_ENTRY(ga, j);
        if (!GA_EMPTY(&lp2->lp_slang->sl_sal)
            && STRNCMP(lp->lp_slang->sl_name,
                lp2->lp_slang->sl_name, 2) == 0) {
          lp->lp_sallang = lp2->lp_slang;
          break;
        }
      }

    // REP items
    if (!GA_EMPTY(&lp->lp_slang->sl_rep))
      // language has REP items itself
      lp->lp_replang = lp->lp_slang;
    else
      // find first similar language that has REP items
      for (int j = 0; j < ga.ga_len; ++j) {
        lp2 = LANGP_ENTRY(ga, j);
        if (!GA_EMPTY(&lp2->lp_slang->sl_rep)
            && STRNCMP(lp->lp_slang->sl_name,
                lp2->lp_slang->sl_name, 2) == 0) {
          lp->lp_replang = lp2->lp_slang;
          break;
        }
      }
  }

theend:
  free(spl_copy);
  recursive = false;
  redraw_win_later(wp, NOT_VALID);
  return ret_msg;
}

// Clear the midword characters for buffer "buf".
static void clear_midword(win_T *wp)
{
  memset(wp->w_s->b_spell_ismw, 0, 256);
  free(wp->w_s->b_spell_ismw_mb);
  wp->w_s->b_spell_ismw_mb = NULL;
}

// Use the "sl_midword" field of language "lp" for buffer "buf".
// They add up to any currently used midword characters.
static void use_midword(slang_T *lp, win_T *wp)
{
  char_u      *p;

  if (lp->sl_midword == NULL)       // there aren't any
    return;

  for (p = lp->sl_midword; *p != NUL; )
    if (has_mbyte) {
      int c, l, n;
      char_u  *bp;

      c = mb_ptr2char(p);
      l = (*mb_ptr2len)(p);
      if (c < 256 && l <= 2)
        wp->w_s->b_spell_ismw[c] = true;
      else if (wp->w_s->b_spell_ismw_mb == NULL)
        // First multi-byte char in "b_spell_ismw_mb".
        wp->w_s->b_spell_ismw_mb = vim_strnsave(p, l);
      else {
        // Append multi-byte chars to "b_spell_ismw_mb".
        n = (int)STRLEN(wp->w_s->b_spell_ismw_mb);
        bp = vim_strnsave(wp->w_s->b_spell_ismw_mb, n + l);
        free(wp->w_s->b_spell_ismw_mb);
        wp->w_s->b_spell_ismw_mb = bp;
        STRLCPY(bp + n, p, l + 1);
      }
      p += l;
    } else
      wp->w_s->b_spell_ismw[*p++] = true;
}

// Find the region "region[2]" in "rp" (points to "sl_regions").
// Each region is simply stored as the two characters of it's name.
// Returns the index if found (first is 0), REGION_ALL if not found.
static int find_region(char_u *rp, char_u *region)
{
  int i;

  for (i = 0;; i += 2) {
    if (rp[i] == NUL)
      return REGION_ALL;
    if (rp[i] == region[0] && rp[i + 1] == region[1])
      break;
  }
  return i / 2;
}

// Return case type of word:
// w word       0
// Word         WF_ONECAP
// W WORD       WF_ALLCAP
// WoRd wOrd    WF_KEEPCAP
static int
captype (
    char_u *word,
    char_u *end           // When NULL use up to NUL byte.
)
{
  char_u      *p;
  int c;
  int firstcap;
  bool allcap;
  bool past_second = false;              // past second word char

  // find first letter
  for (p = word; !spell_iswordp_nmw(p, curwin); mb_ptr_adv(p))
    if (end == NULL ? *p == NUL : p >= end)
      return 0;             // only non-word characters, illegal word
  if (has_mbyte)
    c = mb_ptr2char_adv(&p);
  else
    c = *p++;
  firstcap = allcap = SPELL_ISUPPER(c);

  // Need to check all letters to find a word with mixed upper/lower.
  // But a word with an upper char only at start is a ONECAP.
  for (; end == NULL ? *p != NUL : p < end; mb_ptr_adv(p))
    if (spell_iswordp_nmw(p, curwin)) {
      c = PTR2CHAR(p);
      if (!SPELL_ISUPPER(c)) {
        // UUl -> KEEPCAP
        if (past_second && allcap)
          return WF_KEEPCAP;
        allcap = false;
      } else if (!allcap)
        // UlU -> KEEPCAP
        return WF_KEEPCAP;
      past_second = true;
    }

  if (allcap)
    return WF_ALLCAP;
  if (firstcap)
    return WF_ONECAP;
  return 0;
}

// Like captype() but for a KEEPCAP word add ONECAP if the word starts with a
// capital.  So that make_case_word() can turn WOrd into Word.
// Add ALLCAP for "WOrD".
static int badword_captype(char_u *word, char_u *end)
{
  int flags = captype(word, end);
  int c;
  int l, u;
  bool first;
  char_u      *p;

  if (flags & WF_KEEPCAP) {
    // Count the number of UPPER and lower case letters.
    l = u = 0;
    first = false;
    for (p = word; p < end; mb_ptr_adv(p)) {
      c = PTR2CHAR(p);
      if (SPELL_ISUPPER(c)) {
        ++u;
        if (p == word)
          first = true;
      } else
        ++l;
    }

    // If there are more UPPER than lower case letters suggest an
    // ALLCAP word.  Otherwise, if the first letter is UPPER then
    // suggest ONECAP.  Exception: "ALl" most likely should be "All",
    // require three upper case letters.
    if (u > l && u > 2)
      flags |= WF_ALLCAP;
    else if (first)
      flags |= WF_ONECAP;

    if (u >= 2 && l >= 2)       // maCARONI maCAroni
      flags |= WF_MIXCAP;
  }
  return flags;
}

// Delete the internal wordlist and its .spl file.
void spell_delete_wordlist(void)
{
  char_u fname[MAXPATHL];

  if (int_wordlist != NULL) {
    os_remove((char *)int_wordlist);
    int_wordlist_spl(fname);
    os_remove((char *)fname);
    free(int_wordlist);
    int_wordlist = NULL;
  }
}

// Free all languages.
void spell_free_all(void)
{
  slang_T     *slang;

  // Go through all buffers and handle 'spelllang'. <VN>
  FOR_ALL_BUFFERS(buf) {
    ga_clear(&buf->b_s.b_langp);
  }

  while (first_lang != NULL) {
    slang = first_lang;
    first_lang = slang->sl_next;
    slang_free(slang);
  }

  spell_delete_wordlist();

  free(repl_to);
  repl_to = NULL;
  free(repl_from);
  repl_from = NULL;
}

// Clear all spelling tables and reload them.
// Used after 'encoding' is set and when ":mkspell" was used.
void spell_reload(void)
{
  // Initialize the table for spell_iswordp().
  init_spell_chartab();

  // Unload all allocated memory.
  spell_free_all();

  // Go through all buffers and handle 'spelllang'.
  FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
    // Only load the wordlists when 'spelllang' is set and there is a
    // window for this buffer in which 'spell' is set.
    if (*wp->w_s->b_p_spl != NUL) {
      if (wp->w_p_spell) {
        (void)did_set_spelllang(wp);
        break;
      }
    }
  }
}

// Reload the spell file "fname" if it's loaded.
static void
spell_reload_one (
    char_u *fname,
    bool added_word                // invoked through "zg"
)
{
  slang_T     *slang;
  bool didit = false;

  for (slang = first_lang; slang != NULL; slang = slang->sl_next) {
    if (path_full_compare(fname, slang->sl_fname, FALSE) == kEqualFiles) {
      slang_clear(slang);
      if (spell_load_file(fname, NULL, slang, false) == NULL)
        // reloading failed, clear the language
        slang_clear(slang);
      redraw_all_later(SOME_VALID);
      didit = true;
    }
  }

  // When "zg" was used and the file wasn't loaded yet, should redo
  // 'spelllang' to load it now.
  if (added_word && !didit)
    did_set_spelllang(curwin);
}


// Functions for ":mkspell".


// In the postponed prefixes tree wn_flags is used to store the WFP_ flags,
// but it must be negative to indicate the prefix tree to tree_add_word().
// Use a negative number with the lower 8 bits zero.
#define PFX_FLAGS       -256

// flags for "condit" argument of store_aff_word()
#define CONDIT_COMB     1       // affix must combine
#define CONDIT_CFIX     2       // affix must have CIRCUMFIX flag
#define CONDIT_SUF      4       // add a suffix for matching flags
#define CONDIT_AFF      8       // word already has an affix

// Tunable parameters for when the tree is compressed.  See 'mkspellmem'.
static long compress_start = 30000;     // memory / SBLOCKSIZE
static long compress_inc = 100;         // memory / SBLOCKSIZE
static long compress_added = 500000;    // word count

#ifdef SPELL_PRINTTREE
// For debugging the tree code: print the current tree in a (more or less)
// readable format, so that we can see what happens when adding a word and/or
// compressing the tree.
// Based on code from Olaf Seibert.
#define PRINTLINESIZE   1000
#define PRINTWIDTH      6

#define PRINTSOME(l, depth, fmt, a1, a2) vim_snprintf(l + depth * PRINTWIDTH, \
    PRINTLINESIZE - PRINTWIDTH * depth, fmt, a1, a2)

static char line1[PRINTLINESIZE];
static char line2[PRINTLINESIZE];
static char line3[PRINTLINESIZE];

static void spell_clear_flags(wordnode_T *node)
{
  wordnode_T  *np;

  for (np = node; np != NULL; np = np->wn_sibling) {
    np->wn_u1.index = FALSE;
    spell_clear_flags(np->wn_child);
  }
}

static void spell_print_node(wordnode_T *node, int depth)
{
  if (node->wn_u1.index) {
    // Done this node before, print the reference.
    PRINTSOME(line1, depth, "(%d)", node->wn_nr, 0);
    PRINTSOME(line2, depth, "    ", 0, 0);
    PRINTSOME(line3, depth, "    ", 0, 0);
    msg(line1);
    msg(line2);
    msg(line3);
  } else {
    node->wn_u1.index = TRUE;

    if (node->wn_byte != NUL) {
      if (node->wn_child != NULL)
        PRINTSOME(line1, depth, " %c -> ", node->wn_byte, 0);
      else
        // Cannot happen?
        PRINTSOME(line1, depth, " %c ???", node->wn_byte, 0);
    } else
      PRINTSOME(line1, depth, " $    ", 0, 0);

    PRINTSOME(line2, depth, "%d/%d    ", node->wn_nr, node->wn_refs);

    if (node->wn_sibling != NULL)
      PRINTSOME(line3, depth, " |    ", 0, 0);
    else
      PRINTSOME(line3, depth, "      ", 0, 0);

    if (node->wn_byte == NUL) {
      msg(line1);
      msg(line2);
      msg(line3);
    }

    // do the children
    if (node->wn_byte != NUL && node->wn_child != NULL)
      spell_print_node(node->wn_child, depth + 1);

    // do the siblings
    if (node->wn_sibling != NULL) {
      // get rid of all parent details except |
      STRCPY(line1, line3);
      STRCPY(line2, line3);
      spell_print_node(node->wn_sibling, depth);
    }
  }
}

static void spell_print_tree(wordnode_T *root)
{
  if (root != NULL) {
    // Clear the "wn_u1.index" fields, used to remember what has been
    // done.
    spell_clear_flags(root);

    // Recursively print the tree.
    spell_print_node(root, 0);
  }
}

#endif // SPELL_PRINTTREE

// Reads the affix file "fname".
// Returns an afffile_T, NULL for complete failure.
static afffile_T *spell_read_aff(spellinfo_T *spin, char_u *fname)
{
  FILE        *fd;
  afffile_T   *aff;
  char_u rline[MAXLINELEN];
  char_u      *line;
  char_u      *pc = NULL;
#define MAXITEMCNT  30
  char_u      *(items[MAXITEMCNT]);
  int itemcnt;
  char_u      *p;
  int lnum = 0;
  affheader_T *cur_aff = NULL;
  bool did_postpone_prefix = false;
  int aff_todo = 0;
  hashtab_T   *tp;
  char_u      *low = NULL;
  char_u      *fol = NULL;
  char_u      *upp = NULL;
  int do_rep;
  int do_repsal;
  int do_sal;
  int do_mapline;
  bool found_map = false;
  hashitem_T  *hi;
  int l;
  int compminlen = 0;                   // COMPOUNDMIN value
  int compsylmax = 0;                   // COMPOUNDSYLMAX value
  int compoptions = 0;                  // COMP_ flags
  int compmax = 0;                      // COMPOUNDWORDMAX value
  char_u      *compflags = NULL;        // COMPOUNDFLAG and COMPOUNDRULE
                                        // concatenated
  char_u      *midword = NULL;          // MIDWORD value
  char_u      *syllable = NULL;         // SYLLABLE value
  char_u      *sofofrom = NULL;         // SOFOFROM value
  char_u      *sofoto = NULL;           // SOFOTO value

  // Open the file.
  fd = mch_fopen((char *)fname, "r");
  if (fd == NULL) {
    EMSG2(_(e_notopen), fname);
    return NULL;
  }

  vim_snprintf((char *)IObuff, IOSIZE, _("Reading affix file %s ..."), fname);
  spell_message(spin, IObuff);

  // Only do REP lines when not done in another .aff file already.
  do_rep = GA_EMPTY(&spin->si_rep);

  // Only do REPSAL lines when not done in another .aff file already.
  do_repsal = GA_EMPTY(&spin->si_repsal);

  // Only do SAL lines when not done in another .aff file already.
  do_sal = GA_EMPTY(&spin->si_sal);

  // Only do MAP lines when not done in another .aff file already.
  do_mapline = GA_EMPTY(&spin->si_map);

  // Allocate and init the afffile_T structure.
  aff = (afffile_T *)getroom(spin, sizeof(afffile_T), true);
  if (aff == NULL) {
    fclose(fd);
    return NULL;
  }
  hash_init(&aff->af_pref);
  hash_init(&aff->af_suff);
  hash_init(&aff->af_comp);

  // Read all the lines in the file one by one.
  while (!vim_fgets(rline, MAXLINELEN, fd) && !got_int) {
    line_breakcheck();
    ++lnum;

    // Skip comment lines.
    if (*rline == '#')
      continue;

    // Convert from "SET" to 'encoding' when needed.
    free(pc);
    if (spin->si_conv.vc_type != CONV_NONE) {
      pc = string_convert(&spin->si_conv, rline, NULL);
      if (pc == NULL) {
        smsg((char_u *)_("Conversion failure for word in %s line %d: %s"),
            fname, lnum, rline);
        continue;
      }
      line = pc;
    } else {
      pc = NULL;
      line = rline;
    }

    // Split the line up in white separated items.  Put a NUL after each
    // item.
    itemcnt = 0;
    for (p = line;; ) {
      while (*p != NUL && *p <= ' ')        // skip white space and CR/NL
        ++p;
      if (*p == NUL)
        break;
      if (itemcnt == MAXITEMCNT)            // too many items
        break;
      items[itemcnt++] = p;
      // A few items have arbitrary text argument, don't split them.
      if (itemcnt == 2 && spell_info_item(items[0]))
        while (*p >= ' ' || *p == TAB)            // skip until CR/NL
          ++p;
      else
        while (*p > ' ')            // skip until white space or CR/NL
          ++p;
      if (*p == NUL)
        break;
      *p++ = NUL;
    }

    // Handle non-empty lines.
    if (itemcnt > 0) {
      if (is_aff_rule(items, itemcnt, "SET", 2) && aff->af_enc == NULL) {
        // Setup for conversion from "ENC" to 'encoding'.
        aff->af_enc = enc_canonize(items[1]);
        if (!spin->si_ascii
            && convert_setup(&spin->si_conv, aff->af_enc,
                p_enc) == FAIL)
          smsg((char_u *)_("Conversion in %s not supported: from %s to %s"),
              fname, aff->af_enc, p_enc);
        spin->si_conv.vc_fail = true;
      } else if (is_aff_rule(items, itemcnt, "FLAG", 2)
                 && aff->af_flagtype == AFT_CHAR) {
        if (STRCMP(items[1], "long") == 0)
          aff->af_flagtype = AFT_LONG;
        else if (STRCMP(items[1], "num") == 0)
          aff->af_flagtype = AFT_NUM;
        else if (STRCMP(items[1], "caplong") == 0)
          aff->af_flagtype = AFT_CAPLONG;
        else
          smsg((char_u *)_("Invalid value for FLAG in %s line %d: %s"),
              fname, lnum, items[1]);
        if (aff->af_rare != 0
            || aff->af_keepcase != 0
            || aff->af_bad != 0
            || aff->af_needaffix != 0
            || aff->af_circumfix != 0
            || aff->af_needcomp != 0
            || aff->af_comproot != 0
            || aff->af_nosuggest != 0
            || compflags != NULL
            || aff->af_suff.ht_used > 0
            || aff->af_pref.ht_used > 0)
          smsg((char_u *)_("FLAG after using flags in %s line %d: %s"),
              fname, lnum, items[1]);
      } else if (spell_info_item(items[0]) && itemcnt > 1)   {
        p = (char_u *)getroom(spin,
            (spin->si_info == NULL ? 0 : STRLEN(spin->si_info))
            + STRLEN(items[0])
            + STRLEN(items[1]) + 3, false);
        if (p != NULL) {
          if (spin->si_info != NULL) {
            STRCPY(p, spin->si_info);
            STRCAT(p, "\n");
          }
          STRCAT(p, items[0]);
          STRCAT(p, " ");
          STRCAT(p, items[1]);
          spin->si_info = p;
        }
      } else if (is_aff_rule(items, itemcnt, "MIDWORD", 2)
                 && midword == NULL) {
        midword = getroom_save(spin, items[1]);
      } else if (is_aff_rule(items, itemcnt, "TRY", 2))   {
        // ignored, we look in the tree for what chars may appear
      }
      // TODO: remove "RAR" later
      else if ((is_aff_rule(items, itemcnt, "RAR", 2)
                || is_aff_rule(items, itemcnt, "RARE", 2))
               && aff->af_rare == 0) {
        aff->af_rare = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
      }
      // TODO: remove "KEP" later
      else if ((is_aff_rule(items, itemcnt, "KEP", 2)
                || is_aff_rule(items, itemcnt, "KEEPCASE", 2))
               && aff->af_keepcase == 0) {
        aff->af_keepcase = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
      } else if ((is_aff_rule(items, itemcnt, "BAD", 2)
                  || is_aff_rule(items, itemcnt, "FORBIDDENWORD", 2))
                 && aff->af_bad == 0) {
        aff->af_bad = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
      } else if (is_aff_rule(items, itemcnt, "NEEDAFFIX", 2)
                 && aff->af_needaffix == 0) {
        aff->af_needaffix = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
      } else if (is_aff_rule(items, itemcnt, "CIRCUMFIX", 2)
                 && aff->af_circumfix == 0) {
        aff->af_circumfix = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
      } else if (is_aff_rule(items, itemcnt, "NOSUGGEST", 2)
                 && aff->af_nosuggest == 0) {
        aff->af_nosuggest = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
      } else if ((is_aff_rule(items, itemcnt, "NEEDCOMPOUND", 2)
                  || is_aff_rule(items, itemcnt, "ONLYINCOMPOUND", 2))
                 && aff->af_needcomp == 0) {
        aff->af_needcomp = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDROOT", 2)
                 && aff->af_comproot == 0) {
        aff->af_comproot = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDFORBIDFLAG", 2)
                 && aff->af_compforbid == 0) {
        aff->af_compforbid = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
        if (aff->af_pref.ht_used > 0)
          smsg((char_u *)_(
                  "Defining COMPOUNDFORBIDFLAG after PFX item may give wrong results in %s line %d"),
              fname, lnum);
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDPERMITFLAG", 2)
                 && aff->af_comppermit == 0) {
        aff->af_comppermit = affitem2flag(aff->af_flagtype, items[1],
            fname, lnum);
        if (aff->af_pref.ht_used > 0)
          smsg((char_u *)_(
                  "Defining COMPOUNDPERMITFLAG after PFX item may give wrong results in %s line %d"),
              fname, lnum);
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDFLAG", 2)
                 && compflags == NULL) {
        // Turn flag "c" into COMPOUNDRULE compatible string "c+",
        // "Na" into "Na+", "1234" into "1234+".
        p = getroom(spin, STRLEN(items[1]) + 2, false);
        if (p != NULL) {
          STRCPY(p, items[1]);
          STRCAT(p, "+");
          compflags = p;
        }
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDRULES", 2))   {
        // We don't use the count, but do check that it's a number and
        // not COMPOUNDRULE mistyped.
        if (atoi((char *)items[1]) == 0)
          smsg((char_u *)_("Wrong COMPOUNDRULES value in %s line %d: %s"),
              fname, lnum, items[1]);
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDRULE", 2))   {
        // Don't use the first rule if it is a number.
        if (compflags != NULL || *skipdigits(items[1]) != NUL) {
          // Concatenate this string to previously defined ones,
          // using a slash to separate them.
          l = (int)STRLEN(items[1]) + 1;
          if (compflags != NULL)
            l += (int)STRLEN(compflags) + 1;
          p = getroom(spin, l, false);
          if (p != NULL) {
            if (compflags != NULL) {
              STRCPY(p, compflags);
              STRCAT(p, "/");
            }
            STRCAT(p, items[1]);
            compflags = p;
          }
        }
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDWORDMAX", 2)
                 && compmax == 0) {
        compmax = atoi((char *)items[1]);
        if (compmax == 0)
          smsg((char_u *)_("Wrong COMPOUNDWORDMAX value in %s line %d: %s"),
              fname, lnum, items[1]);
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDMIN", 2)
                 && compminlen == 0) {
        compminlen = atoi((char *)items[1]);
        if (compminlen == 0)
          smsg((char_u *)_("Wrong COMPOUNDMIN value in %s line %d: %s"),
              fname, lnum, items[1]);
      } else if (is_aff_rule(items, itemcnt, "COMPOUNDSYLMAX", 2)
                 && compsylmax == 0) {
        compsylmax = atoi((char *)items[1]);
        if (compsylmax == 0)
          smsg((char_u *)_("Wrong COMPOUNDSYLMAX value in %s line %d: %s"),
              fname, lnum, items[1]);
      } else if (is_aff_rule(items, itemcnt, "CHECKCOMPOUNDDUP", 1))   {
        compoptions |= COMP_CHECKDUP;
      } else if (is_aff_rule(items, itemcnt, "CHECKCOMPOUNDREP", 1))   {
        compoptions |= COMP_CHECKREP;
      } else if (is_aff_rule(items, itemcnt, "CHECKCOMPOUNDCASE", 1))   {
        compoptions |= COMP_CHECKCASE;
      } else if (is_aff_rule(items, itemcnt, "CHECKCOMPOUNDTRIPLE", 1))   {
        compoptions |= COMP_CHECKTRIPLE;
      } else if (is_aff_rule(items, itemcnt, "CHECKCOMPOUNDPATTERN", 2))   {
        if (atoi((char *)items[1]) == 0)
          smsg((char_u *)_("Wrong CHECKCOMPOUNDPATTERN value in %s line %d: %s"),
              fname, lnum, items[1]);
      } else if (is_aff_rule(items, itemcnt, "CHECKCOMPOUNDPATTERN", 3))   {
        garray_T    *gap = &spin->si_comppat;
        int i;

        // Only add the couple if it isn't already there.
        for (i = 0; i < gap->ga_len - 1; i += 2)
          if (STRCMP(((char_u **)(gap->ga_data))[i], items[1]) == 0
              && STRCMP(((char_u **)(gap->ga_data))[i + 1],
                  items[2]) == 0)
            break;
        if (i >= gap->ga_len) {
          ga_grow(gap, 2);
          ((char_u **)(gap->ga_data))[gap->ga_len++]
            = getroom_save(spin, items[1]);
          ((char_u **)(gap->ga_data))[gap->ga_len++]
            = getroom_save(spin, items[2]);
        }
      } else if (is_aff_rule(items, itemcnt, "SYLLABLE", 2)
                 && syllable == NULL) {
        syllable = getroom_save(spin, items[1]);
      } else if (is_aff_rule(items, itemcnt, "NOBREAK", 1))   {
        spin->si_nobreak = true;
      } else if (is_aff_rule(items, itemcnt, "NOSPLITSUGS", 1))   {
        spin->si_nosplitsugs = true;
      } else if (is_aff_rule(items, itemcnt, "NOSUGFILE", 1))   {
        spin->si_nosugfile = true;
      } else if (is_aff_rule(items, itemcnt, "PFXPOSTPONE", 1))   {
        aff->af_pfxpostpone = true;
      } else if ((STRCMP(items[0], "PFX") == 0
                  || STRCMP(items[0], "SFX") == 0)
                 && aff_todo == 0
                 && itemcnt >= 4) {
        int lasti = 4;
        char_u key[AH_KEY_LEN];

        if (*items[0] == 'P')
          tp = &aff->af_pref;
        else
          tp = &aff->af_suff;

        // Myspell allows the same affix name to be used multiple
        // times.  The affix files that do this have an undocumented
        // "S" flag on all but the last block, thus we check for that
        // and store it in ah_follows.
        STRLCPY(key, items[1], AH_KEY_LEN);
        hi = hash_find(tp, key);
        if (!HASHITEM_EMPTY(hi)) {
          cur_aff = HI2AH(hi);
          if (cur_aff->ah_combine != (*items[2] == 'Y'))
            smsg((char_u *)_(
                    "Different combining flag in continued affix block in %s line %d: %s"),
                fname, lnum, items[1]);
          if (!cur_aff->ah_follows)
            smsg((char_u *)_("Duplicate affix in %s line %d: %s"),
                fname, lnum, items[1]);
        } else {
          // New affix letter.
          cur_aff = (affheader_T *)getroom(spin,
              sizeof(affheader_T), true);
          if (cur_aff == NULL)
            break;
          cur_aff->ah_flag = affitem2flag(aff->af_flagtype, items[1],
              fname, lnum);
          if (cur_aff->ah_flag == 0 || STRLEN(items[1]) >= AH_KEY_LEN)
            break;
          if (cur_aff->ah_flag == aff->af_bad
              || cur_aff->ah_flag == aff->af_rare
              || cur_aff->ah_flag == aff->af_keepcase
              || cur_aff->ah_flag == aff->af_needaffix
              || cur_aff->ah_flag == aff->af_circumfix
              || cur_aff->ah_flag == aff->af_nosuggest
              || cur_aff->ah_flag == aff->af_needcomp
              || cur_aff->ah_flag == aff->af_comproot)
            smsg((char_u *)_(
                    "Affix also used for BAD/RARE/KEEPCASE/NEEDAFFIX/NEEDCOMPOUND/NOSUGGEST in %s line %d: %s"),
                fname, lnum, items[1]);
          STRCPY(cur_aff->ah_key, items[1]);
          hash_add(tp, cur_aff->ah_key);

          cur_aff->ah_combine = (*items[2] == 'Y');
        }

        // Check for the "S" flag, which apparently means that another
        // block with the same affix name is following.
        if (itemcnt > lasti && STRCMP(items[lasti], "S") == 0) {
          ++lasti;
          cur_aff->ah_follows = true;
        } else
          cur_aff->ah_follows = false;

        // Myspell allows extra text after the item, but that might
        // mean mistakes go unnoticed.  Require a comment-starter.
        if (itemcnt > lasti && *items[lasti] != '#')
          smsg((char_u *)_(e_afftrailing), fname, lnum, items[lasti]);

        if (STRCMP(items[2], "Y") != 0 && STRCMP(items[2], "N") != 0)
          smsg((char_u *)_("Expected Y or N in %s line %d: %s"),
              fname, lnum, items[2]);

        if (*items[0] == 'P' && aff->af_pfxpostpone) {
          if (cur_aff->ah_newID == 0) {
            // Use a new number in the .spl file later, to be able
            // to handle multiple .aff files.
            check_renumber(spin);
            cur_aff->ah_newID = ++spin->si_newprefID;

            // We only really use ah_newID if the prefix is
            // postponed.  We know that only after handling all
            // the items.
            did_postpone_prefix = false;
          } else
            // Did use the ID in a previous block.
            did_postpone_prefix = true;
        }

        aff_todo = atoi((char *)items[3]);
      } else if ((STRCMP(items[0], "PFX") == 0
                  || STRCMP(items[0], "SFX") == 0)
                 && aff_todo > 0
                 && STRCMP(cur_aff->ah_key, items[1]) == 0
                 && itemcnt >= 5) {
        affentry_T      *aff_entry;
        bool upper = false;
        int lasti = 5;

        // Myspell allows extra text after the item, but that might
        // mean mistakes go unnoticed.  Require a comment-starter.
        // Hunspell uses a "-" item.
        if (itemcnt > lasti && *items[lasti] != '#'
            && (STRCMP(items[lasti], "-") != 0
                || itemcnt != lasti + 1))
          smsg((char_u *)_(e_afftrailing), fname, lnum, items[lasti]);

        // New item for an affix letter.
        --aff_todo;
        aff_entry = (affentry_T *)getroom(spin,
            sizeof(affentry_T), true);
        if (aff_entry == NULL)
          break;

        if (STRCMP(items[2], "0") != 0)
          aff_entry->ae_chop = getroom_save(spin, items[2]);
        if (STRCMP(items[3], "0") != 0) {
          aff_entry->ae_add = getroom_save(spin, items[3]);

          // Recognize flags on the affix: abcd/XYZ
          aff_entry->ae_flags = vim_strchr(aff_entry->ae_add, '/');
          if (aff_entry->ae_flags != NULL) {
            *aff_entry->ae_flags++ = NUL;
            aff_process_flags(aff, aff_entry);
          }
        }

        // Don't use an affix entry with non-ASCII characters when
        // "spin->si_ascii" is true.
        if (!spin->si_ascii || !(has_non_ascii(aff_entry->ae_chop)
                                 || has_non_ascii(aff_entry->ae_add))) {
          aff_entry->ae_next = cur_aff->ah_first;
          cur_aff->ah_first = aff_entry;

          if (STRCMP(items[4], ".") != 0) {
            char_u buf[MAXLINELEN];

            aff_entry->ae_cond = getroom_save(spin, items[4]);
            if (*items[0] == 'P')
              sprintf((char *)buf, "^%s", items[4]);
            else
              sprintf((char *)buf, "%s$", items[4]);
            aff_entry->ae_prog = vim_regcomp(buf,
                RE_MAGIC + RE_STRING + RE_STRICT);
            if (aff_entry->ae_prog == NULL)
              smsg((char_u *)_("Broken condition in %s line %d: %s"),
                  fname, lnum, items[4]);
          }

          // For postponed prefixes we need an entry in si_prefcond
          // for the condition.  Use an existing one if possible.
          // Can't be done for an affix with flags, ignoring
          // COMPOUNDFORBIDFLAG and COMPOUNDPERMITFLAG.
          if (*items[0] == 'P' && aff->af_pfxpostpone
              && aff_entry->ae_flags == NULL) {
            // When the chop string is one lower-case letter and
            // the add string ends in the upper-case letter we set
            // the "upper" flag, clear "ae_chop" and remove the
            // letters from "ae_add".  The condition must either
            // be empty or start with the same letter.
            if (aff_entry->ae_chop != NULL
                && aff_entry->ae_add != NULL
                && aff_entry->ae_chop[(*mb_ptr2len)(
                                        aff_entry->ae_chop)] == NUL
                ) {
              int c, c_up;

              c = PTR2CHAR(aff_entry->ae_chop);
              c_up = SPELL_TOUPPER(c);
              if (c_up != c
                  && (aff_entry->ae_cond == NULL
                      || PTR2CHAR(aff_entry->ae_cond) == c)) {
                p = aff_entry->ae_add
                    + STRLEN(aff_entry->ae_add);
                mb_ptr_back(aff_entry->ae_add, p);
                if (PTR2CHAR(p) == c_up) {
                  upper = true;
                  aff_entry->ae_chop = NULL;
                  *p = NUL;

                  // The condition is matched with the
                  // actual word, thus must check for the
                  // upper-case letter.
                  if (aff_entry->ae_cond != NULL) {
                    char_u buf[MAXLINELEN];
                    if (has_mbyte) {
                      onecap_copy(items[4], buf, true);
                      aff_entry->ae_cond = getroom_save(
                          spin, buf);
                    } else
                      *aff_entry->ae_cond = c_up;
                    if (aff_entry->ae_cond != NULL) {
                      sprintf((char *)buf, "^%s",
                          aff_entry->ae_cond);
                      vim_regfree(aff_entry->ae_prog);
                      aff_entry->ae_prog = vim_regcomp(
                          buf, RE_MAGIC + RE_STRING);
                    }
                  }
                }
              }
            }

            if (aff_entry->ae_chop == NULL
                && aff_entry->ae_flags == NULL) {
              int idx;
              char_u      **pp;
              int n;

              // Find a previously used condition.
              for (idx = spin->si_prefcond.ga_len - 1; idx >= 0;
                   --idx) {
                p = ((char_u **)spin->si_prefcond.ga_data)[idx];
                if (str_equal(p, aff_entry->ae_cond))
                  break;
              }
              if (idx < 0) {
                // Not found, add a new condition.
                idx = spin->si_prefcond.ga_len;
                pp = GA_APPEND_VIA_PTR(char_u *, &spin->si_prefcond);
                *pp = (aff_entry->ae_cond == NULL) ?
                  NULL : getroom_save(spin, aff_entry->ae_cond);
              }

              // Add the prefix to the prefix tree.
              if (aff_entry->ae_add == NULL)
                p = (char_u *)"";
              else
                p = aff_entry->ae_add;

              // PFX_FLAGS is a negative number, so that
              // tree_add_word() knows this is the prefix tree.
              n = PFX_FLAGS;
              if (!cur_aff->ah_combine)
                n |= WFP_NC;
              if (upper)
                n |= WFP_UP;
              if (aff_entry->ae_comppermit)
                n |= WFP_COMPPERMIT;
              if (aff_entry->ae_compforbid)
                n |= WFP_COMPFORBID;
              tree_add_word(spin, p, spin->si_prefroot, n,
                  idx, cur_aff->ah_newID);
              did_postpone_prefix = true;
            }

            // Didn't actually use ah_newID, backup si_newprefID.
            if (aff_todo == 0 && !did_postpone_prefix) {
              --spin->si_newprefID;
              cur_aff->ah_newID = 0;
            }
          }
        }
      } else if (is_aff_rule(items, itemcnt, "FOL", 2) && fol == NULL)   {
        fol = vim_strsave(items[1]);
      } else if (is_aff_rule(items, itemcnt, "LOW", 2) && low == NULL)   {
        low = vim_strsave(items[1]);
      } else if (is_aff_rule(items, itemcnt, "UPP", 2) && upp == NULL)   {
        upp = vim_strsave(items[1]);
      } else if (is_aff_rule(items, itemcnt, "REP", 2)
                 || is_aff_rule(items, itemcnt, "REPSAL", 2)) {
        /* Ignore REP/REPSAL count */;
        if (!isdigit(*items[1]))
          smsg((char_u *)_("Expected REP(SAL) count in %s line %d"),
              fname, lnum);
      } else if ((STRCMP(items[0], "REP") == 0
                  || STRCMP(items[0], "REPSAL") == 0)
                 && itemcnt >= 3) {
        // REP/REPSAL item
        // Myspell ignores extra arguments, we require it starts with
        // # to detect mistakes.
        if (itemcnt > 3 && items[3][0] != '#')
          smsg((char_u *)_(e_afftrailing), fname, lnum, items[3]);
        if (items[0][3] == 'S' ? do_repsal : do_rep) {
          // Replace underscore with space (can't include a space
          // directly).
          for (p = items[1]; *p != NUL; mb_ptr_adv(p))
            if (*p == '_')
              *p = ' ';
          for (p = items[2]; *p != NUL; mb_ptr_adv(p))
            if (*p == '_')
              *p = ' ';
          add_fromto(spin, items[0][3] == 'S'
              ? &spin->si_repsal
              : &spin->si_rep, items[1], items[2]);
        }
      } else if (is_aff_rule(items, itemcnt, "MAP", 2))   {
        // MAP item or count
        if (!found_map) {
          // First line contains the count.
          found_map = true;
          if (!isdigit(*items[1]))
            smsg((char_u *)_("Expected MAP count in %s line %d"),
                fname, lnum);
        } else if (do_mapline)   {
          int c;

          // Check that every character appears only once.
          for (p = items[1]; *p != NUL; ) {
            c = mb_ptr2char_adv(&p);
            if ((!GA_EMPTY(&spin->si_map)
                 && vim_strchr(spin->si_map.ga_data, c)
                 != NULL)
                || vim_strchr(p, c) != NULL)
              smsg((char_u *)_("Duplicate character in MAP in %s line %d"),
                  fname, lnum);
          }

          // We simply concatenate all the MAP strings, separated by
          // slashes.
          ga_concat(&spin->si_map, items[1]);
          ga_append(&spin->si_map, '/');
        }
      }
      // Accept "SAL from to" and "SAL from to  #comment".
      else if (is_aff_rule(items, itemcnt, "SAL", 3)) {
        if (do_sal) {
          // SAL item (sounds-a-like)
          // Either one of the known keys or a from-to pair.
          if (STRCMP(items[1], "followup") == 0)
            spin->si_followup = sal_to_bool(items[2]);
          else if (STRCMP(items[1], "collapse_result") == 0)
            spin->si_collapse = sal_to_bool(items[2]);
          else if (STRCMP(items[1], "remove_accents") == 0)
            spin->si_rem_accents = sal_to_bool(items[2]);
          else
            // when "to" is "_" it means empty
            add_fromto(spin, &spin->si_sal, items[1],
                STRCMP(items[2], "_") == 0 ? (char_u *)""
                : items[2]);
        }
      } else if (is_aff_rule(items, itemcnt, "SOFOFROM", 2)
                 && sofofrom == NULL) {
        sofofrom = getroom_save(spin, items[1]);
      } else if (is_aff_rule(items, itemcnt, "SOFOTO", 2)
                 && sofoto == NULL) {
        sofoto = getroom_save(spin, items[1]);
      } else if (STRCMP(items[0], "COMMON") == 0)   {
        int i;

        for (i = 1; i < itemcnt; ++i) {
          if (HASHITEM_EMPTY(hash_find(&spin->si_commonwords,
                      items[i]))) {
            p = vim_strsave(items[i]);
            hash_add(&spin->si_commonwords, p);
          }
        }
      } else
        smsg((char_u *)_("Unrecognized or duplicate item in %s line %d: %s"),
            fname, lnum, items[0]);
    }
  }

  if (fol != NULL || low != NULL || upp != NULL) {
    if (spin->si_clear_chartab) {
      // Clear the char type tables, don't want to use any of the
      // currently used spell properties.
      init_spell_chartab();
      spin->si_clear_chartab = false;
    }

    // Don't write a word table for an ASCII file, so that we don't check
    // for conflicts with a word table that matches 'encoding'.
    // Don't write one for utf-8 either, we use utf_*() and
    // mb_get_class(), the list of chars in the file will be incomplete.
    if (!spin->si_ascii
        && !enc_utf8
        ) {
      if (fol == NULL || low == NULL || upp == NULL)
        smsg((char_u *)_("Missing FOL/LOW/UPP line in %s"), fname);
      else
        (void)set_spell_chartab(fol, low, upp);
    }

    free(fol);
    free(low);
    free(upp);
  }

  // Use compound specifications of the .aff file for the spell info.
  if (compmax != 0) {
    aff_check_number(spin->si_compmax, compmax, "COMPOUNDWORDMAX");
    spin->si_compmax = compmax;
  }

  if (compminlen != 0) {
    aff_check_number(spin->si_compminlen, compminlen, "COMPOUNDMIN");
    spin->si_compminlen = compminlen;
  }

  if (compsylmax != 0) {
    if (syllable == NULL)
      smsg((char_u *)_("COMPOUNDSYLMAX used without SYLLABLE"));
    aff_check_number(spin->si_compsylmax, compsylmax, "COMPOUNDSYLMAX");
    spin->si_compsylmax = compsylmax;
  }

  if (compoptions != 0) {
    aff_check_number(spin->si_compoptions, compoptions, "COMPOUND options");
    spin->si_compoptions |= compoptions;
  }

  if (compflags != NULL)
    process_compflags(spin, aff, compflags);

  // Check that we didn't use too many renumbered flags.
  if (spin->si_newcompID < spin->si_newprefID) {
    if (spin->si_newcompID == 127 || spin->si_newcompID == 255)
      MSG(_("Too many postponed prefixes"));
    else if (spin->si_newprefID == 0 || spin->si_newprefID == 127)
      MSG(_("Too many compound flags"));
    else
      MSG(_("Too many postponed prefixes and/or compound flags"));
  }

  if (syllable != NULL) {
    aff_check_string(spin->si_syllable, syllable, "SYLLABLE");
    spin->si_syllable = syllable;
  }

  if (sofofrom != NULL || sofoto != NULL) {
    if (sofofrom == NULL || sofoto == NULL)
      smsg((char_u *)_("Missing SOFO%s line in %s"),
          sofofrom == NULL ? "FROM" : "TO", fname);
    else if (!GA_EMPTY(&spin->si_sal))
      smsg((char_u *)_("Both SAL and SOFO lines in %s"), fname);
    else {
      aff_check_string(spin->si_sofofr, sofofrom, "SOFOFROM");
      aff_check_string(spin->si_sofoto, sofoto, "SOFOTO");
      spin->si_sofofr = sofofrom;
      spin->si_sofoto = sofoto;
    }
  }

  if (midword != NULL) {
    aff_check_string(spin->si_midword, midword, "MIDWORD");
    spin->si_midword = midword;
  }

  free(pc);
  fclose(fd);
  return aff;
}

// Returns true when items[0] equals "rulename", there are "mincount" items or
// a comment is following after item "mincount".
static bool is_aff_rule(char_u **items, int itemcnt, char *rulename, int mincount)
{
  return STRCMP(items[0], rulename) == 0
         && (itemcnt == mincount
             || (itemcnt > mincount && items[mincount][0] == '#'));
}

// For affix "entry" move COMPOUNDFORBIDFLAG and COMPOUNDPERMITFLAG from
// ae_flags to ae_comppermit and ae_compforbid.
static void aff_process_flags(afffile_T *affile, affentry_T *entry)
{
  char_u      *p;
  char_u      *prevp;
  unsigned flag;

  if (entry->ae_flags != NULL
      && (affile->af_compforbid != 0 || affile->af_comppermit != 0)) {
    for (p = entry->ae_flags; *p != NUL; ) {
      prevp = p;
      flag = get_affitem(affile->af_flagtype, &p);
      if (flag == affile->af_comppermit || flag == affile->af_compforbid) {
        STRMOVE(prevp, p);
        p = prevp;
        if (flag == affile->af_comppermit)
          entry->ae_comppermit = true;
        else
          entry->ae_compforbid = true;
      }
      if (affile->af_flagtype == AFT_NUM && *p == ',')
        ++p;
    }
    if (*entry->ae_flags == NUL)
      entry->ae_flags = NULL;           // nothing left
  }
}

// Returns true if "s" is the name of an info item in the affix file.
static bool spell_info_item(char_u *s)
{
  return STRCMP(s, "NAME") == 0
         || STRCMP(s, "HOME") == 0
         || STRCMP(s, "VERSION") == 0
         || STRCMP(s, "AUTHOR") == 0
         || STRCMP(s, "EMAIL") == 0
         || STRCMP(s, "COPYRIGHT") == 0;
}

// Turn an affix flag name into a number, according to the FLAG type.
// returns zero for failure.
static unsigned affitem2flag(int flagtype, char_u *item, char_u *fname, int lnum)
{
  unsigned res;
  char_u      *p = item;

  res = get_affitem(flagtype, &p);
  if (res == 0) {
    if (flagtype == AFT_NUM)
      smsg((char_u *)_("Flag is not a number in %s line %d: %s"),
          fname, lnum, item);
    else
      smsg((char_u *)_("Illegal flag in %s line %d: %s"),
          fname, lnum, item);
  }
  if (*p != NUL) {
    smsg((char_u *)_(e_affname), fname, lnum, item);
    return 0;
  }

  return res;
}

// Get one affix name from "*pp" and advance the pointer.
// Returns zero for an error, still advances the pointer then.
static unsigned get_affitem(int flagtype, char_u **pp)
{
  int res;

  if (flagtype == AFT_NUM) {
    if (!VIM_ISDIGIT(**pp)) {
      ++*pp;            // always advance, avoid getting stuck
      return 0;
    }
    res = getdigits(pp);
  } else {
    res = mb_ptr2char_adv(pp);
    if (flagtype == AFT_LONG || (flagtype == AFT_CAPLONG
                                 && res >= 'A' && res <= 'Z')) {
      if (**pp == NUL)
        return 0;
      res = mb_ptr2char_adv(pp) + (res << 16);
    }
  }
  return res;
}

// Process the "compflags" string used in an affix file and append it to
// spin->si_compflags.
// The processing involves changing the affix names to ID numbers, so that
// they fit in one byte.
static void process_compflags(spellinfo_T *spin, afffile_T *aff, char_u *compflags)
{
  char_u      *p;
  char_u      *prevp;
  unsigned flag;
  compitem_T  *ci;
  int id;
  int len;
  char_u      *tp;
  char_u key[AH_KEY_LEN];
  hashitem_T  *hi;

  // Make room for the old and the new compflags, concatenated with a / in
  // between.  Processing it makes it shorter, but we don't know by how
  // much, thus allocate the maximum.
  len = (int)STRLEN(compflags) + 1;
  if (spin->si_compflags != NULL)
    len += (int)STRLEN(spin->si_compflags) + 1;
  p = getroom(spin, len, false);
  if (p == NULL)
    return;
  if (spin->si_compflags != NULL) {
    STRCPY(p, spin->si_compflags);
    STRCAT(p, "/");
  }
  spin->si_compflags = p;
  tp = p + STRLEN(p);

  for (p = compflags; *p != NUL; ) {
    if (vim_strchr((char_u *)"/?*+[]", *p) != NULL)
      // Copy non-flag characters directly.
      *tp++ = *p++;
    else {
      // First get the flag number, also checks validity.
      prevp = p;
      flag = get_affitem(aff->af_flagtype, &p);
      if (flag != 0) {
        // Find the flag in the hashtable.  If it was used before, use
        // the existing ID.  Otherwise add a new entry.
        STRLCPY(key, prevp, p - prevp + 1);
        hi = hash_find(&aff->af_comp, key);
        if (!HASHITEM_EMPTY(hi))
          id = HI2CI(hi)->ci_newID;
        else {
          ci = (compitem_T *)getroom(spin, sizeof(compitem_T), true);
          if (ci == NULL)
            break;
          STRCPY(ci->ci_key, key);
          ci->ci_flag = flag;
          // Avoid using a flag ID that has a special meaning in a
          // regexp (also inside []).
          do {
            check_renumber(spin);
            id = spin->si_newcompID--;
          } while (vim_strchr((char_u *)"/?*+[]\\-^", id) != NULL);
          ci->ci_newID = id;
          hash_add(&aff->af_comp, ci->ci_key);
        }
        *tp++ = id;
      }
      if (aff->af_flagtype == AFT_NUM && *p == ',')
        ++p;
    }
  }

  *tp = NUL;
}

// Check that the new IDs for postponed affixes and compounding don't overrun
// each other.  We have almost 255 available, but start at 0-127 to avoid
// using two bytes for utf-8.  When the 0-127 range is used up go to 128-255.
// When that is used up an error message is given.
static void check_renumber(spellinfo_T *spin)
{
  if (spin->si_newprefID == spin->si_newcompID && spin->si_newcompID < 128) {
    spin->si_newprefID = 127;
    spin->si_newcompID = 255;
  }
}

// Returns true if flag "flag" appears in affix list "afflist".
static bool flag_in_afflist(int flagtype, char_u *afflist, unsigned flag)
{
  char_u      *p;
  unsigned n;

  switch (flagtype) {
  case AFT_CHAR:
    return vim_strchr(afflist, flag) != NULL;

  case AFT_CAPLONG:
  case AFT_LONG:
    for (p = afflist; *p != NUL; ) {
      n = mb_ptr2char_adv(&p);
      if ((flagtype == AFT_LONG || (n >= 'A' && n <= 'Z'))
          && *p != NUL)
        n = mb_ptr2char_adv(&p) + (n << 16);
      if (n == flag)
        return true;
    }
    break;

  case AFT_NUM:
    for (p = afflist; *p != NUL; ) {
      n = getdigits(&p);
      if (n == flag)
        return true;
      if (*p != NUL)            // skip over comma
        ++p;
    }
    break;
  }
  return false;
}

// Give a warning when "spinval" and "affval" numbers are set and not the same.
static void aff_check_number(int spinval, int affval, char *name)
{
  if (spinval != 0 && spinval != affval)
    smsg((char_u *)_(
            "%s value differs from what is used in another .aff file"), name);
}

// Give a warning when "spinval" and "affval" strings are set and not the same.
static void aff_check_string(char_u *spinval, char_u *affval, char *name)
{
  if (spinval != NULL && STRCMP(spinval, affval) != 0)
    smsg((char_u *)_(
            "%s value differs from what is used in another .aff file"), name);
}

// Returns true if strings "s1" and "s2" are equal.  Also consider both being
// NULL as equal.
static bool str_equal(char_u *s1, char_u *s2)
{
  if (s1 == NULL || s2 == NULL)
    return s1 == s2;
  return STRCMP(s1, s2) == 0;
}

// Add a from-to item to "gap".  Used for REP and SAL items.
// They are stored case-folded.
static void add_fromto(spellinfo_T *spin, garray_T *gap, char_u *from, char_u *to)
{
  char_u word[MAXWLEN];

  fromto_T *ftp = GA_APPEND_VIA_PTR(fromto_T, gap);
  (void)spell_casefold(from, (int)STRLEN(from), word, MAXWLEN);
  ftp->ft_from = getroom_save(spin, word);
  (void)spell_casefold(to, (int)STRLEN(to), word, MAXWLEN);
  ftp->ft_to = getroom_save(spin, word);
}

// Converts a boolean argument in a SAL line to true or false;
static bool sal_to_bool(char_u *s)
{
  return STRCMP(s, "1") == 0 || STRCMP(s, "true") == 0;
}

// Free the structure filled by spell_read_aff().
static void spell_free_aff(afffile_T *aff)
{
  hashtab_T   *ht;
  hashitem_T  *hi;
  int todo;
  affheader_T *ah;
  affentry_T  *ae;

  free(aff->af_enc);

  // All this trouble to free the "ae_prog" items...
  for (ht = &aff->af_pref;; ht = &aff->af_suff) {
    todo = (int)ht->ht_used;
    for (hi = ht->ht_array; todo > 0; ++hi) {
      if (!HASHITEM_EMPTY(hi)) {
        --todo;
        ah = HI2AH(hi);
        for (ae = ah->ah_first; ae != NULL; ae = ae->ae_next)
          vim_regfree(ae->ae_prog);
      }
    }
    if (ht == &aff->af_suff)
      break;
  }

  hash_clear(&aff->af_pref);
  hash_clear(&aff->af_suff);
  hash_clear(&aff->af_comp);
}

// Read dictionary file "fname".
// Returns OK or FAIL;
static int spell_read_dic(spellinfo_T *spin, char_u *fname, afffile_T *affile)
{
  hashtab_T ht;
  char_u line[MAXLINELEN];
  char_u      *p;
  char_u      *afflist;
  char_u store_afflist[MAXWLEN];
  int pfxlen;
  bool need_affix;
  char_u      *dw;
  char_u      *pc;
  char_u      *w;
  int l;
  hash_T hash;
  hashitem_T  *hi;
  FILE        *fd;
  int lnum = 1;
  int non_ascii = 0;
  int retval = OK;
  char_u message[MAXLINELEN + MAXWLEN];
  int flags;
  int duplicate = 0;

  // Open the file.
  fd = mch_fopen((char *)fname, "r");
  if (fd == NULL) {
    EMSG2(_(e_notopen), fname);
    return FAIL;
  }

  // The hashtable is only used to detect duplicated words.
  hash_init(&ht);

  vim_snprintf((char *)IObuff, IOSIZE,
      _("Reading dictionary file %s ..."), fname);
  spell_message(spin, IObuff);

  // start with a message for the first line
  spin->si_msg_count = 999999;

  // Read and ignore the first line: word count.
  (void)vim_fgets(line, MAXLINELEN, fd);
  if (!vim_isdigit(*skipwhite(line)))
    EMSG2(_("E760: No word count in %s"), fname);

  // Read all the lines in the file one by one.
  // The words are converted to 'encoding' here, before being added to
  // the hashtable.
  while (!vim_fgets(line, MAXLINELEN, fd) && !got_int) {
    line_breakcheck();
    ++lnum;
    if (line[0] == '#' || line[0] == '/')
      continue;         // comment line

    // Remove CR, LF and white space from the end.  White space halfway
    // the word is kept to allow e.g., "et al.".
    l = (int)STRLEN(line);
    while (l > 0 && line[l - 1] <= ' ')
      --l;
    if (l == 0)
      continue;         // empty line
    line[l] = NUL;

    // Convert from "SET" to 'encoding' when needed.
    if (spin->si_conv.vc_type != CONV_NONE) {
      pc = string_convert(&spin->si_conv, line, NULL);
      if (pc == NULL) {
        smsg((char_u *)_("Conversion failure for word in %s line %d: %s"),
            fname, lnum, line);
        continue;
      }
      w = pc;
    } else {
      pc = NULL;
      w = line;
    }

    // Truncate the word at the "/", set "afflist" to what follows.
    // Replace "\/" by "/" and "\\" by "\".
    afflist = NULL;
    for (p = w; *p != NUL; mb_ptr_adv(p)) {
      if (*p == '\\' && (p[1] == '\\' || p[1] == '/'))
        STRMOVE(p, p + 1);
      else if (*p == '/') {
        *p = NUL;
        afflist = p + 1;
        break;
      }
    }

    // Skip non-ASCII words when "spin->si_ascii" is true.
    if (spin->si_ascii && has_non_ascii(w)) {
      ++non_ascii;
      free(pc);
      continue;
    }

    // This takes time, print a message every 10000 words.
    if (spin->si_verbose && spin->si_msg_count > 10000) {
      spin->si_msg_count = 0;
      vim_snprintf((char *)message, sizeof(message),
          _("line %6d, word %6d - %s"),
          lnum, spin->si_foldwcount + spin->si_keepwcount, w);
      msg_start();
      msg_puts_long_attr(message, 0);
      msg_clr_eos();
      msg_didout = FALSE;
      msg_col = 0;
      out_flush();
    }

    // Store the word in the hashtable to be able to find duplicates.
    dw = (char_u *)getroom_save(spin, w);
    if (dw == NULL) {
      retval = FAIL;
      free(pc);
      break;
    }

    hash = hash_hash(dw);
    hi = hash_lookup(&ht, dw, hash);
    if (!HASHITEM_EMPTY(hi)) {
      if (p_verbose > 0)
        smsg((char_u *)_("Duplicate word in %s line %d: %s"),
            fname, lnum, dw);
      else if (duplicate == 0)
        smsg((char_u *)_("First duplicate word in %s line %d: %s"),
            fname, lnum, dw);
      ++duplicate;
    } else
      hash_add_item(&ht, hi, dw, hash);

    flags = 0;
    store_afflist[0] = NUL;
    pfxlen = 0;
    need_affix = false;
    if (afflist != NULL) {
      // Extract flags from the affix list.
      flags |= get_affix_flags(affile, afflist);

      if (affile->af_needaffix != 0 && flag_in_afflist(
              affile->af_flagtype, afflist, affile->af_needaffix))
        need_affix = true;

      if (affile->af_pfxpostpone)
        // Need to store the list of prefix IDs with the word.
        pfxlen = get_pfxlist(affile, afflist, store_afflist);

      if (spin->si_compflags != NULL)
        // Need to store the list of compound flags with the word.
        // Concatenate them to the list of prefix IDs.
        get_compflags(affile, afflist, store_afflist + pfxlen);
    }

    // Add the word to the word tree(s).
    if (store_word(spin, dw, flags, spin->si_region,
            store_afflist, need_affix) == FAIL)
      retval = FAIL;

    if (afflist != NULL) {
      // Find all matching suffixes and add the resulting words.
      // Additionally do matching prefixes that combine.
      if (store_aff_word(spin, dw, afflist, affile,
              &affile->af_suff, &affile->af_pref,
              CONDIT_SUF, flags, store_afflist, pfxlen) == FAIL)
        retval = FAIL;

      // Find all matching prefixes and add the resulting words.
      if (store_aff_word(spin, dw, afflist, affile,
              &affile->af_pref, NULL,
              CONDIT_SUF, flags, store_afflist, pfxlen) == FAIL)
        retval = FAIL;
    }

    free(pc);
  }

  if (duplicate > 0)
    smsg((char_u *)_("%d duplicate word(s) in %s"), duplicate, fname);
  if (spin->si_ascii && non_ascii > 0)
    smsg((char_u *)_("Ignored %d word(s) with non-ASCII characters in %s"),
        non_ascii, fname);
  hash_clear(&ht);

  fclose(fd);
  return retval;
}

// Check for affix flags in "afflist" that are turned into word flags.
// Return WF_ flags.
static int get_affix_flags(afffile_T *affile, char_u *afflist)
{
  int flags = 0;

  if (affile->af_keepcase != 0 && flag_in_afflist(
          affile->af_flagtype, afflist, affile->af_keepcase))
    flags |= WF_KEEPCAP | WF_FIXCAP;
  if (affile->af_rare != 0 && flag_in_afflist(
          affile->af_flagtype, afflist, affile->af_rare))
    flags |= WF_RARE;
  if (affile->af_bad != 0 && flag_in_afflist(
          affile->af_flagtype, afflist, affile->af_bad))
    flags |= WF_BANNED;
  if (affile->af_needcomp != 0 && flag_in_afflist(
          affile->af_flagtype, afflist, affile->af_needcomp))
    flags |= WF_NEEDCOMP;
  if (affile->af_comproot != 0 && flag_in_afflist(
          affile->af_flagtype, afflist, affile->af_comproot))
    flags |= WF_COMPROOT;
  if (affile->af_nosuggest != 0 && flag_in_afflist(
          affile->af_flagtype, afflist, affile->af_nosuggest))
    flags |= WF_NOSUGGEST;
  return flags;
}

// Get the list of prefix IDs from the affix list "afflist".
// Used for PFXPOSTPONE.
// Put the resulting flags in "store_afflist[MAXWLEN]" with a terminating NUL
// and return the number of affixes.
static int get_pfxlist(afffile_T *affile, char_u *afflist, char_u *store_afflist)
{
  char_u      *p;
  char_u      *prevp;
  int cnt = 0;
  int id;
  char_u key[AH_KEY_LEN];
  hashitem_T  *hi;

  for (p = afflist; *p != NUL; ) {
    prevp = p;
    if (get_affitem(affile->af_flagtype, &p) != 0) {
      // A flag is a postponed prefix flag if it appears in "af_pref"
      // and it's ID is not zero.
      STRLCPY(key, prevp, p - prevp + 1);
      hi = hash_find(&affile->af_pref, key);
      if (!HASHITEM_EMPTY(hi)) {
        id = HI2AH(hi)->ah_newID;
        if (id != 0)
          store_afflist[cnt++] = id;
      }
    }
    if (affile->af_flagtype == AFT_NUM && *p == ',')
      ++p;
  }

  store_afflist[cnt] = NUL;
  return cnt;
}

// Get the list of compound IDs from the affix list "afflist" that are used
// for compound words.
// Puts the flags in "store_afflist[]".
static void get_compflags(afffile_T *affile, char_u *afflist, char_u *store_afflist)
{
  char_u      *p;
  char_u      *prevp;
  int cnt = 0;
  char_u key[AH_KEY_LEN];
  hashitem_T  *hi;

  for (p = afflist; *p != NUL; ) {
    prevp = p;
    if (get_affitem(affile->af_flagtype, &p) != 0) {
      // A flag is a compound flag if it appears in "af_comp".
      STRLCPY(key, prevp, p - prevp + 1);
      hi = hash_find(&affile->af_comp, key);
      if (!HASHITEM_EMPTY(hi))
        store_afflist[cnt++] = HI2CI(hi)->ci_newID;
    }
    if (affile->af_flagtype == AFT_NUM && *p == ',')
      ++p;
  }

  store_afflist[cnt] = NUL;
}

// Apply affixes to a word and store the resulting words.
// "ht" is the hashtable with affentry_T that need to be applied, either
// prefixes or suffixes.
// "xht", when not NULL, is the prefix hashtable, to be used additionally on
// the resulting words for combining affixes.
//
// Returns FAIL when out of memory.
static int
store_aff_word (
    spellinfo_T *spin,         // spell info
    char_u *word,              // basic word start
    char_u *afflist,           // list of names of supported affixes
    afffile_T *affile,
    hashtab_T *ht,
    hashtab_T *xht,
    int condit,                // CONDIT_SUF et al.
    int flags,                 // flags for the word
    char_u *pfxlist,           // list of prefix IDs
    int pfxlen                 // nr of flags in "pfxlist" for prefixes, rest
                               // is compound flags
)
{
  int todo;
  hashitem_T  *hi;
  affheader_T *ah;
  affentry_T  *ae;
  regmatch_T regmatch;
  char_u newword[MAXWLEN];
  int retval = OK;
  int i, j;
  char_u      *p;
  int use_flags;
  char_u      *use_pfxlist;
  int use_pfxlen;
  bool need_affix;
  char_u store_afflist[MAXWLEN];
  char_u pfx_pfxlist[MAXWLEN];
  size_t wordlen = STRLEN(word);
  int use_condit;

  todo = (int)ht->ht_used;
  for (hi = ht->ht_array; todo > 0 && retval == OK; ++hi) {
    if (!HASHITEM_EMPTY(hi)) {
      --todo;
      ah = HI2AH(hi);

      // Check that the affix combines, if required, and that the word
      // supports this affix.
      if (((condit & CONDIT_COMB) == 0 || ah->ah_combine)
          && flag_in_afflist(affile->af_flagtype, afflist,
              ah->ah_flag)) {
        // Loop over all affix entries with this name.
        for (ae = ah->ah_first; ae != NULL; ae = ae->ae_next) {
          // Check the condition.  It's not logical to match case
          // here, but it is required for compatibility with
          // Myspell.
          // Another requirement from Myspell is that the chop
          // string is shorter than the word itself.
          // For prefixes, when "PFXPOSTPONE" was used, only do
          // prefixes with a chop string and/or flags.
          // When a previously added affix had CIRCUMFIX this one
          // must have it too, if it had not then this one must not
          // have one either.
          regmatch.regprog = ae->ae_prog;
          regmatch.rm_ic = FALSE;
          if ((xht != NULL || !affile->af_pfxpostpone
               || ae->ae_chop != NULL
               || ae->ae_flags != NULL)
              && (ae->ae_chop == NULL
                  || STRLEN(ae->ae_chop) < wordlen)
              && (ae->ae_prog == NULL
                  || vim_regexec(&regmatch, word, (colnr_T)0))
              && (((condit & CONDIT_CFIX) == 0)
                  == ((condit & CONDIT_AFF) == 0
                      || ae->ae_flags == NULL
                      || !flag_in_afflist(affile->af_flagtype,
                          ae->ae_flags, affile->af_circumfix)))) {
            // Match.  Remove the chop and add the affix.
            if (xht == NULL) {
              // prefix: chop/add at the start of the word
              if (ae->ae_add == NULL)
                *newword = NUL;
              else
                STRLCPY(newword, ae->ae_add, MAXWLEN);
              p = word;
              if (ae->ae_chop != NULL) {
                // Skip chop string.
                if (has_mbyte) {
                  i = mb_charlen(ae->ae_chop);
                  for (; i > 0; --i)
                    mb_ptr_adv(p);
                } else
                  p += STRLEN(ae->ae_chop);
              }
              STRCAT(newword, p);
            } else {
              // suffix: chop/add at the end of the word
              STRLCPY(newword, word, MAXWLEN);
              if (ae->ae_chop != NULL) {
                // Remove chop string.
                p = newword + STRLEN(newword);
                i = (int)MB_CHARLEN(ae->ae_chop);
                for (; i > 0; --i)
                  mb_ptr_back(newword, p);
                *p = NUL;
              }
              if (ae->ae_add != NULL)
                STRCAT(newword, ae->ae_add);
            }

            use_flags = flags;
            use_pfxlist = pfxlist;
            use_pfxlen = pfxlen;
            need_affix = false;
            use_condit = condit | CONDIT_COMB | CONDIT_AFF;
            if (ae->ae_flags != NULL) {
              // Extract flags from the affix list.
              use_flags |= get_affix_flags(affile, ae->ae_flags);

              if (affile->af_needaffix != 0 && flag_in_afflist(
                      affile->af_flagtype, ae->ae_flags,
                      affile->af_needaffix))
                need_affix = true;

              // When there is a CIRCUMFIX flag the other affix
              // must also have it and we don't add the word
              // with one affix.
              if (affile->af_circumfix != 0 && flag_in_afflist(
                      affile->af_flagtype, ae->ae_flags,
                      affile->af_circumfix)) {
                use_condit |= CONDIT_CFIX;
                if ((condit & CONDIT_CFIX) == 0)
                  need_affix = true;
              }

              if (affile->af_pfxpostpone
                  || spin->si_compflags != NULL) {
                if (affile->af_pfxpostpone)
                  // Get prefix IDS from the affix list.
                  use_pfxlen = get_pfxlist(affile,
                      ae->ae_flags, store_afflist);
                else
                  use_pfxlen = 0;
                use_pfxlist = store_afflist;

                // Combine the prefix IDs. Avoid adding the
                // same ID twice.
                for (i = 0; i < pfxlen; ++i) {
                  for (j = 0; j < use_pfxlen; ++j)
                    if (pfxlist[i] == use_pfxlist[j])
                      break;
                  if (j == use_pfxlen)
                    use_pfxlist[use_pfxlen++] = pfxlist[i];
                }

                if (spin->si_compflags != NULL)
                  // Get compound IDS from the affix list.
                  get_compflags(affile, ae->ae_flags,
                      use_pfxlist + use_pfxlen);
                else
                  use_pfxlist[use_pfxlen] = NUL;

                // Combine the list of compound flags.
                // Concatenate them to the prefix IDs list.
                // Avoid adding the same ID twice.
                for (i = pfxlen; pfxlist[i] != NUL; ++i) {
                  for (j = use_pfxlen;
                       use_pfxlist[j] != NUL; ++j)
                    if (pfxlist[i] == use_pfxlist[j])
                      break;
                  if (use_pfxlist[j] == NUL) {
                    use_pfxlist[j++] = pfxlist[i];
                    use_pfxlist[j] = NUL;
                  }
                }
              }
            }

            // Obey a "COMPOUNDFORBIDFLAG" of the affix: don't
            // use the compound flags.
            if (use_pfxlist != NULL && ae->ae_compforbid) {
              STRLCPY(pfx_pfxlist, use_pfxlist, use_pfxlen + 1);
              use_pfxlist = pfx_pfxlist;
            }

            // When there are postponed prefixes...
            if (spin->si_prefroot != NULL
                && spin->si_prefroot->wn_sibling != NULL) {
              // ... add a flag to indicate an affix was used.
              use_flags |= WF_HAS_AFF;

              // ... don't use a prefix list if combining
              // affixes is not allowed.  But do use the
              // compound flags after them.
              if (!ah->ah_combine && use_pfxlist != NULL)
                use_pfxlist += use_pfxlen;
            }

            // When compounding is supported and there is no
            // "COMPOUNDPERMITFLAG" then forbid compounding on the
            // side where the affix is applied.
            if (spin->si_compflags != NULL && !ae->ae_comppermit) {
              if (xht != NULL)
                use_flags |= WF_NOCOMPAFT;
              else
                use_flags |= WF_NOCOMPBEF;
            }

            // Store the modified word.
            if (store_word(spin, newword, use_flags,
                    spin->si_region, use_pfxlist,
                    need_affix) == FAIL)
              retval = FAIL;

            // When added a prefix or a first suffix and the affix
            // has flags may add a(nother) suffix.  RECURSIVE!
            if ((condit & CONDIT_SUF) && ae->ae_flags != NULL)
              if (store_aff_word(spin, newword, ae->ae_flags,
                      affile, &affile->af_suff, xht,
                      use_condit & (xht == NULL
                                    ? ~0 :  ~CONDIT_SUF),
                      use_flags, use_pfxlist, pfxlen) == FAIL)
                retval = FAIL;

            // When added a suffix and combining is allowed also
            // try adding a prefix additionally.  Both for the
            // word flags and for the affix flags.  RECURSIVE!
            if (xht != NULL && ah->ah_combine) {
              if (store_aff_word(spin, newword,
                      afflist, affile,
                      xht, NULL, use_condit,
                      use_flags, use_pfxlist,
                      pfxlen) == FAIL
                  || (ae->ae_flags != NULL
                      && store_aff_word(spin, newword,
                          ae->ae_flags, affile,
                          xht, NULL, use_condit,
                          use_flags, use_pfxlist,
                          pfxlen) == FAIL))
                retval = FAIL;
            }
          }
        }
      }
    }
  }

  return retval;
}

// Read a file with a list of words.
static int spell_read_wordfile(spellinfo_T *spin, char_u *fname)
{
  FILE        *fd;
  long lnum = 0;
  char_u rline[MAXLINELEN];
  char_u      *line;
  char_u      *pc = NULL;
  char_u      *p;
  int l;
  int retval = OK;
  bool did_word = false;
  int non_ascii = 0;
  int flags;
  int regionmask;

  // Open the file.
  fd = mch_fopen((char *)fname, "r");
  if (fd == NULL) {
    EMSG2(_(e_notopen), fname);
    return FAIL;
  }

  vim_snprintf((char *)IObuff, IOSIZE, _("Reading word file %s ..."), fname);
  spell_message(spin, IObuff);

  // Read all the lines in the file one by one.
  while (!vim_fgets(rline, MAXLINELEN, fd) && !got_int) {
    line_breakcheck();
    ++lnum;

    // Skip comment lines.
    if (*rline == '#')
      continue;

    // Remove CR, LF and white space from the end.
    l = (int)STRLEN(rline);
    while (l > 0 && rline[l - 1] <= ' ')
      --l;
    if (l == 0)
      continue;         // empty or blank line
    rline[l] = NUL;

    // Convert from "/encoding={encoding}" to 'encoding' when needed.
    free(pc);
    if (spin->si_conv.vc_type != CONV_NONE) {
      pc = string_convert(&spin->si_conv, rline, NULL);
      if (pc == NULL) {
        smsg((char_u *)_("Conversion failure for word in %s line %d: %s"),
            fname, lnum, rline);
        continue;
      }
      line = pc;
    } else {
      pc = NULL;
      line = rline;
    }

    if (*line == '/') {
      ++line;
      if (STRNCMP(line, "encoding=", 9) == 0) {
        if (spin->si_conv.vc_type != CONV_NONE)
          smsg((char_u *)_(
                  "Duplicate /encoding= line ignored in %s line %d: %s"),
              fname, lnum, line - 1);
        else if (did_word)
          smsg((char_u *)_(
                  "/encoding= line after word ignored in %s line %d: %s"),
              fname, lnum, line - 1);
        else {
          char_u      *enc;

          // Setup for conversion to 'encoding'.
          line += 9;
          enc = enc_canonize(line);
          if (!spin->si_ascii
              && convert_setup(&spin->si_conv, enc,
                  p_enc) == FAIL)
            smsg((char_u *)_("Conversion in %s not supported: from %s to %s"),
                fname, line, p_enc);
          free(enc);
          spin->si_conv.vc_fail = true;
        }
        continue;
      }

      if (STRNCMP(line, "regions=", 8) == 0) {
        if (spin->si_region_count > 1)
          smsg((char_u *)_("Duplicate /regions= line ignored in %s line %d: %s"),
              fname, lnum, line);
        else {
          line += 8;
          if (STRLEN(line) > 16)
            smsg((char_u *)_("Too many regions in %s line %d: %s"),
                fname, lnum, line);
          else {
            spin->si_region_count = (int)STRLEN(line) / 2;
            STRCPY(spin->si_region_name, line);

            // Adjust the mask for a word valid in all regions.
            spin->si_region = (1 << spin->si_region_count) - 1;
          }
        }
        continue;
      }

      smsg((char_u *)_("/ line ignored in %s line %d: %s"),
          fname, lnum, line - 1);
      continue;
    }

    flags = 0;
    regionmask = spin->si_region;

    // Check for flags and region after a slash.
    p = vim_strchr(line, '/');
    if (p != NULL) {
      *p++ = NUL;
      while (*p != NUL) {
        if (*p == '=')                  // keep-case word
          flags |= WF_KEEPCAP | WF_FIXCAP;
        else if (*p == '!')             // Bad, bad, wicked word.
          flags |= WF_BANNED;
        else if (*p == '?')             // Rare word.
          flags |= WF_RARE;
        else if (VIM_ISDIGIT(*p)) {       // region number(s)
          if ((flags & WF_REGION) == 0)             // first one
            regionmask = 0;
          flags |= WF_REGION;

          l = *p - '0';
          if (l > spin->si_region_count) {
            smsg((char_u *)_("Invalid region nr in %s line %d: %s"),
                fname, lnum, p);
            break;
          }
          regionmask |= 1 << (l - 1);
        } else {
          smsg((char_u *)_("Unrecognized flags in %s line %d: %s"),
              fname, lnum, p);
          break;
        }
        ++p;
      }
    }

    // Skip non-ASCII words when "spin->si_ascii" is true.
    if (spin->si_ascii && has_non_ascii(line)) {
      ++non_ascii;
      continue;
    }

    // Normal word: store it.
    if (store_word(spin, line, flags, regionmask, NULL, false) == FAIL) {
      retval = FAIL;
      break;
    }
    did_word = true;
  }

  free(pc);
  fclose(fd);

  if (spin->si_ascii && non_ascii > 0) {
    vim_snprintf((char *)IObuff, IOSIZE,
        _("Ignored %d words with non-ASCII characters"), non_ascii);
    spell_message(spin, IObuff);
  }

  return retval;
}

/// Get part of an sblock_T, "len" bytes long.
/// This avoids calling free() for every little struct we use (and keeping
/// track of them).
/// The memory is cleared to all zeros.
///
/// @param len Length needed (<= SBLOCKSIZE).
/// @param align Align for pointer.
/// @return Pointer into block data.
static void *getroom(spellinfo_T *spin, size_t len, bool align)
  FUNC_ATTR_NONNULL_RET
{
  char_u      *p;
  sblock_T    *bl = spin->si_blocks;

  assert(len <= SBLOCKSIZE);
  
  if (align && bl != NULL)
    // Round size up for alignment.  On some systems structures need to be
    // aligned to the size of a pointer (e.g., SPARC).
    bl->sb_used = (bl->sb_used + sizeof(char *) - 1)
                  & ~(sizeof(char *) - 1);

  if (bl == NULL || bl->sb_used + len > SBLOCKSIZE) {
    // Allocate a block of memory. It is not freed until much later.
    bl = xcalloc(1, (sizeof(sblock_T) + SBLOCKSIZE));
    bl->sb_next = spin->si_blocks;
    spin->si_blocks = bl;
    bl->sb_used = 0;
    ++spin->si_blocks_cnt;
  }

  p = bl->sb_data + bl->sb_used;
  bl->sb_used += (int)len;

  return p;
}

// Make a copy of a string into memory allocated with getroom().
// Returns NULL when out of memory.
static char_u *getroom_save(spellinfo_T *spin, char_u *s)
{
  char_u      *sc;

  sc = (char_u *)getroom(spin, STRLEN(s) + 1, false);
  if (sc != NULL)
    STRCPY(sc, s);
  return sc;
}


// Free the list of allocated sblock_T.
static void free_blocks(sblock_T *bl)
{
  sblock_T    *next;

  while (bl != NULL) {
    next = bl->sb_next;
    free(bl);
    bl = next;
  }
}

// Allocate the root of a word tree.
// Returns NULL when out of memory.
static wordnode_T *wordtree_alloc(spellinfo_T *spin)
{
  return (wordnode_T *)getroom(spin, sizeof(wordnode_T), true);
}

// Store a word in the tree(s).
// Always store it in the case-folded tree.  For a keep-case word this is
// useful when the word can also be used with all caps (no WF_FIXCAP flag) and
// used to find suggestions.
// For a keep-case word also store it in the keep-case tree.
// When "pfxlist" is not NULL store the word for each postponed prefix ID and
// compound flag.
static int
store_word (
    spellinfo_T *spin,
    char_u *word,
    int flags,                      // extra flags, WF_BANNED
    int region,                     // supported region(s)
    char_u *pfxlist,                // list of prefix IDs or NULL
    bool need_affix                 // only store word with affix ID
)
{
  int len = (int)STRLEN(word);
  int ct = captype(word, word + len);
  char_u foldword[MAXWLEN];
  int res = OK;
  char_u      *p;

  (void)spell_casefold(word, len, foldword, MAXWLEN);
  for (p = pfxlist; res == OK; ++p) {
    if (!need_affix || (p != NULL && *p != NUL))
      res = tree_add_word(spin, foldword, spin->si_foldroot, ct | flags,
          region, p == NULL ? 0 : *p);
    if (p == NULL || *p == NUL)
      break;
  }
  ++spin->si_foldwcount;

  if (res == OK && (ct == WF_KEEPCAP || (flags & WF_KEEPCAP))) {
    for (p = pfxlist; res == OK; ++p) {
      if (!need_affix || (p != NULL && *p != NUL))
        res = tree_add_word(spin, word, spin->si_keeproot, flags,
            region, p == NULL ? 0 : *p);
      if (p == NULL || *p == NUL)
        break;
    }
    ++spin->si_keepwcount;
  }
  return res;
}

// Add word "word" to a word tree at "root".
// When "flags" < 0 we are adding to the prefix tree where "flags" is used for
// "rare" and "region" is the condition nr.
// Returns FAIL when out of memory.
static int tree_add_word(spellinfo_T *spin, char_u *word, wordnode_T *root, int flags, int region, int affixID)
{
  wordnode_T  *node = root;
  wordnode_T  *np;
  wordnode_T  *copyp, **copyprev;
  wordnode_T  **prev = NULL;
  int i;

  // Add each byte of the word to the tree, including the NUL at the end.
  for (i = 0;; ++i) {
    // When there is more than one reference to this node we need to make
    // a copy, so that we can modify it.  Copy the whole list of siblings
    // (we don't optimize for a partly shared list of siblings).
    if (node != NULL && node->wn_refs > 1) {
      --node->wn_refs;
      copyprev = prev;
      for (copyp = node; copyp != NULL; copyp = copyp->wn_sibling) {
        // Allocate a new node and copy the info.
        np = get_wordnode(spin);
        if (np == NULL)
          return FAIL;
        np->wn_child = copyp->wn_child;
        if (np->wn_child != NULL)
          ++np->wn_child->wn_refs;              // child gets extra ref
        np->wn_byte = copyp->wn_byte;
        if (np->wn_byte == NUL) {
          np->wn_flags = copyp->wn_flags;
          np->wn_region = copyp->wn_region;
          np->wn_affixID = copyp->wn_affixID;
        }

        // Link the new node in the list, there will be one ref.
        np->wn_refs = 1;
        if (copyprev != NULL)
          *copyprev = np;
        copyprev = &np->wn_sibling;

        // Let "node" point to the head of the copied list.
        if (copyp == node)
          node = np;
      }
    }

    // Look for the sibling that has the same character.  They are sorted
    // on byte value, thus stop searching when a sibling is found with a
    // higher byte value.  For zero bytes (end of word) the sorting is
    // done on flags and then on affixID.
    while (node != NULL
           && (node->wn_byte < word[i]
               || (node->wn_byte == NUL
                   && (flags < 0
                       ? node->wn_affixID < (unsigned)affixID
                       : (node->wn_flags < (unsigned)(flags & WN_MASK)
                          || (node->wn_flags == (flags & WN_MASK)
                              && (spin->si_sugtree
                                  ? (node->wn_region & 0xffff) < region
                                  : node->wn_affixID
                                  < (unsigned)affixID))))))) {
      prev = &node->wn_sibling;
      node = *prev;
    }
    if (node == NULL
        || node->wn_byte != word[i]
        || (word[i] == NUL
            && (flags < 0
                || spin->si_sugtree
                || node->wn_flags != (flags & WN_MASK)
                || node->wn_affixID != affixID))) {
      // Allocate a new node.
      np = get_wordnode(spin);
      if (np == NULL)
        return FAIL;
      np->wn_byte = word[i];

      // If "node" is NULL this is a new child or the end of the sibling
      // list: ref count is one.  Otherwise use ref count of sibling and
      // make ref count of sibling one (matters when inserting in front
      // of the list of siblings).
      if (node == NULL)
        np->wn_refs = 1;
      else {
        np->wn_refs = node->wn_refs;
        node->wn_refs = 1;
      }
      if (prev != NULL)
        *prev = np;
      np->wn_sibling = node;
      node = np;
    }

    if (word[i] == NUL) {
      node->wn_flags = flags;
      node->wn_region |= region;
      node->wn_affixID = affixID;
      break;
    }
    prev = &node->wn_child;
    node = *prev;
  }
#ifdef SPELL_PRINTTREE
  smsg("Added \"%s\"", word);
  spell_print_tree(root->wn_sibling);
#endif

  // count nr of words added since last message
  ++spin->si_msg_count;

  if (spin->si_compress_cnt > 1) {
    if (--spin->si_compress_cnt == 1)
      // Did enough words to lower the block count limit.
      spin->si_blocks_cnt += compress_inc;
  }

  // When we have allocated lots of memory we need to compress the word tree
  // to free up some room.  But compression is slow, and we might actually
  // need that room, thus only compress in the following situations:
  // 1. When not compressed before (si_compress_cnt == 0): when using
  //    "compress_start" blocks.
  // 2. When compressed before and used "compress_inc" blocks before
  //    adding "compress_added" words (si_compress_cnt > 1).
  // 3. When compressed before, added "compress_added" words
  //    (si_compress_cnt == 1) and the number of free nodes drops below the
  //    maximum word length.
#ifndef SPELL_PRINTTREE
  if (spin->si_compress_cnt == 1
      ? spin->si_free_count < MAXWLEN
                              : spin->si_blocks_cnt >= compress_start)
#endif
  {
    // Decrement the block counter.  The effect is that we compress again
    // when the freed up room has been used and another "compress_inc"
    // blocks have been allocated.  Unless "compress_added" words have
    // been added, then the limit is put back again.
    spin->si_blocks_cnt -= compress_inc;
    spin->si_compress_cnt = compress_added;

    if (spin->si_verbose) {
      msg_start();
      msg_puts((char_u *)_(msg_compressing));
      msg_clr_eos();
      msg_didout = FALSE;
      msg_col = 0;
      out_flush();
    }

    // Compress both trees.  Either they both have many nodes, which makes
    // compression useful, or one of them is small, which means
    // compression goes fast.  But when filling the soundfold word tree
    // there is no keep-case tree.
    wordtree_compress(spin, spin->si_foldroot);
    if (affixID >= 0)
      wordtree_compress(spin, spin->si_keeproot);
  }

  return OK;
}

// Check the 'mkspellmem' option.  Return FAIL if it's wrong.
// Sets "sps_flags".
int spell_check_msm(void)
{
  char_u      *p = p_msm;
  long start = 0;
  long incr = 0;
  long added = 0;

  if (!VIM_ISDIGIT(*p))
    return FAIL;
  // block count = (value * 1024) / SBLOCKSIZE (but avoid overflow)
  start = (getdigits(&p) * 10) / (SBLOCKSIZE / 102);
  if (*p != ',')
    return FAIL;
  ++p;
  if (!VIM_ISDIGIT(*p))
    return FAIL;
  incr = (getdigits(&p) * 102) / (SBLOCKSIZE / 10);
  if (*p != ',')
    return FAIL;
  ++p;
  if (!VIM_ISDIGIT(*p))
    return FAIL;
  added = getdigits(&p) * 1024;
  if (*p != NUL)
    return FAIL;

  if (start == 0 || incr == 0 || added == 0 || incr > start)
    return FAIL;

  compress_start = start;
  compress_inc = incr;
  compress_added = added;
  return OK;
}

// Get a wordnode_T, either from the list of previously freed nodes or
// allocate a new one.
// Returns NULL when out of memory.
static wordnode_T *get_wordnode(spellinfo_T *spin)
{
  wordnode_T *n;

  if (spin->si_first_free == NULL)
    n = (wordnode_T *)getroom(spin, sizeof(wordnode_T), true);
  else {
    n = spin->si_first_free;
    spin->si_first_free = n->wn_child;
    memset(n, 0, sizeof(wordnode_T));
    --spin->si_free_count;
  }
#ifdef SPELL_PRINTTREE
  if (n != NULL)
    n->wn_nr = ++spin->si_wordnode_nr;
#endif
  return n;
}

// Decrement the reference count on a node (which is the head of a list of
// siblings).  If the reference count becomes zero free the node and its
// siblings.
// Returns the number of nodes actually freed.
static int deref_wordnode(spellinfo_T *spin, wordnode_T *node)
{
  wordnode_T  *np;
  int cnt = 0;

  if (--node->wn_refs == 0) {
    for (np = node; np != NULL; np = np->wn_sibling) {
      if (np->wn_child != NULL)
        cnt += deref_wordnode(spin, np->wn_child);
      free_wordnode(spin, np);
      ++cnt;
    }
    ++cnt;          // length field
  }
  return cnt;
}

// Free a wordnode_T for re-use later.
// Only the "wn_child" field becomes invalid.
static void free_wordnode(spellinfo_T *spin, wordnode_T *n)
{
  n->wn_child = spin->si_first_free;
  spin->si_first_free = n;
  ++spin->si_free_count;
}

// Compress a tree: find tails that are identical and can be shared.
static void wordtree_compress(spellinfo_T *spin, wordnode_T *root)
{
  hashtab_T ht;
  int n;
  int tot = 0;
  int perc;

  // Skip the root itself, it's not actually used.  The first sibling is the
  // start of the tree.
  if (root->wn_sibling != NULL) {
    hash_init(&ht);
    n = node_compress(spin, root->wn_sibling, &ht, &tot);

#ifndef SPELL_PRINTTREE
    if (spin->si_verbose || p_verbose > 2)
#endif
    {
      if (tot > 1000000)
        perc = (tot - n) / (tot / 100);
      else if (tot == 0)
        perc = 0;
      else
        perc = (tot - n) * 100 / tot;
      vim_snprintf((char *)IObuff, IOSIZE,
          _("Compressed %d of %d nodes; %d (%d%%) remaining"),
          n, tot, tot - n, perc);
      spell_message(spin, IObuff);
    }
#ifdef SPELL_PRINTTREE
    spell_print_tree(root->wn_sibling);
#endif
    hash_clear(&ht);
  }
}

// Compress a node, its siblings and its children, depth first.
// Returns the number of compressed nodes.
static int
node_compress (
    spellinfo_T *spin,
    wordnode_T *node,
    hashtab_T *ht,
    int *tot            // total count of nodes before compressing,
                        // incremented while going through the tree
)
{
  wordnode_T  *np;
  wordnode_T  *tp;
  wordnode_T  *child;
  hash_T hash;
  hashitem_T  *hi;
  int len = 0;
  unsigned nr, n;
  int compressed = 0;

  // Go through the list of siblings.  Compress each child and then try
  // finding an identical child to replace it.
  // Note that with "child" we mean not just the node that is pointed to,
  // but the whole list of siblings of which the child node is the first.
  for (np = node; np != NULL && !got_int; np = np->wn_sibling) {
    ++len;
    if ((child = np->wn_child) != NULL) {
      // Compress the child first.  This fills hashkey.
      compressed += node_compress(spin, child, ht, tot);

      // Try to find an identical child.
      hash = hash_hash(child->wn_u1.hashkey);
      hi = hash_lookup(ht, child->wn_u1.hashkey, hash);
      if (!HASHITEM_EMPTY(hi)) {
        // There are children we encountered before with a hash value
        // identical to the current child.  Now check if there is one
        // that is really identical.
        for (tp = HI2WN(hi); tp != NULL; tp = tp->wn_u2.next)
          if (node_equal(child, tp)) {
            // Found one!  Now use that child in place of the
            // current one.  This means the current child and all
            // its siblings is unlinked from the tree.
            ++tp->wn_refs;
            compressed += deref_wordnode(spin, child);
            np->wn_child = tp;
            break;
          }
        if (tp == NULL) {
          // No other child with this hash value equals the child of
          // the node, add it to the linked list after the first
          // item.
          tp = HI2WN(hi);
          child->wn_u2.next = tp->wn_u2.next;
          tp->wn_u2.next = child;
        }
      } else
        // No other child has this hash value, add it to the
        // hashtable.
        hash_add_item(ht, hi, child->wn_u1.hashkey, hash);
    }
  }
  *tot += len + 1;      // add one for the node that stores the length

  // Make a hash key for the node and its siblings, so that we can quickly
  // find a lookalike node.  This must be done after compressing the sibling
  // list, otherwise the hash key would become invalid by the compression.
  node->wn_u1.hashkey[0] = len;
  nr = 0;
  for (np = node; np != NULL; np = np->wn_sibling) {
    if (np->wn_byte == NUL)
      // end node: use wn_flags, wn_region and wn_affixID
      n = np->wn_flags + (np->wn_region << 8) + (np->wn_affixID << 16);
    else
      // byte node: use the byte value and the child pointer
      n = (unsigned)(np->wn_byte + ((long_u)np->wn_child << 8));
    nr = nr * 101 + n;
  }

  // Avoid NUL bytes, it terminates the hash key.
  n = nr & 0xff;
  node->wn_u1.hashkey[1] = n == 0 ? 1 : n;
  n = (nr >> 8) & 0xff;
  node->wn_u1.hashkey[2] = n == 0 ? 1 : n;
  n = (nr >> 16) & 0xff;
  node->wn_u1.hashkey[3] = n == 0 ? 1 : n;
  n = (nr >> 24) & 0xff;
  node->wn_u1.hashkey[4] = n == 0 ? 1 : n;
  node->wn_u1.hashkey[5] = NUL;

  // Check for CTRL-C pressed now and then.
  fast_breakcheck();

  return compressed;
}

// Returns true when two nodes have identical siblings and children.
static bool node_equal(wordnode_T *n1, wordnode_T *n2)
{
  wordnode_T  *p1;
  wordnode_T  *p2;

  for (p1 = n1, p2 = n2; p1 != NULL && p2 != NULL;
       p1 = p1->wn_sibling, p2 = p2->wn_sibling)
    if (p1->wn_byte != p2->wn_byte
        || (p1->wn_byte == NUL
            ? (p1->wn_flags != p2->wn_flags
               || p1->wn_region != p2->wn_region
               || p1->wn_affixID != p2->wn_affixID)
            : (p1->wn_child != p2->wn_child)))
      break;

  return p1 == NULL && p2 == NULL;
}


// Function given to qsort() to sort the REP items on "from" string.
static int rep_compare(const void *s1, const void *s2)
{
  fromto_T    *p1 = (fromto_T *)s1;
  fromto_T    *p2 = (fromto_T *)s2;

  return STRCMP(p1->ft_from, p2->ft_from);
}

// Write the Vim .spl file "fname".
// Return FAIL or OK;
static int write_vim_spell(spellinfo_T *spin, char_u *fname)
{
  FILE        *fd;
  int regionmask;
  int round;
  wordnode_T  *tree;
  int nodecount;
  int i;
  int l;
  garray_T    *gap;
  fromto_T    *ftp;
  char_u      *p;
  int rr;
  int retval = OK;
  size_t fwv = 1;         // collect return value of fwrite() to avoid
                          // warnings from picky compiler

  fd = mch_fopen((char *)fname, "w");
  if (fd == NULL) {
    EMSG2(_(e_notopen), fname);
    return FAIL;
  }

  // <HEADER>: <fileID> <versionnr>
  // <fileID>
  fwv &= fwrite(VIMSPELLMAGIC, VIMSPELLMAGICL, (size_t)1, fd);
  if (fwv != (size_t)1)
    // Catch first write error, don't try writing more.
    goto theend;

  putc(VIMSPELLVERSION, fd);                                // <versionnr>

  // <SECTIONS>: <section> ... <sectionend>

  // SN_INFO: <infotext>
  if (spin->si_info != NULL) {
    putc(SN_INFO, fd);                                  // <sectionID>
    putc(0, fd);                                        // <sectionflags>

    i = (int)STRLEN(spin->si_info);
    put_bytes(fd, (long_u)i, 4);                        // <sectionlen>
    fwv &= fwrite(spin->si_info, (size_t)i, (size_t)1, fd);     // <infotext>
  }

  // SN_REGION: <regionname> ...
  // Write the region names only if there is more than one.
  if (spin->si_region_count > 1) {
    putc(SN_REGION, fd);                                // <sectionID>
    putc(SNF_REQUIRED, fd);                             // <sectionflags>
    l = spin->si_region_count * 2;
    put_bytes(fd, (long_u)l, 4);                        // <sectionlen>
    fwv &= fwrite(spin->si_region_name, (size_t)l, (size_t)1, fd);
    // <regionname> ...
    regionmask = (1 << spin->si_region_count) - 1;
  } else
    regionmask = 0;

  // SN_CHARFLAGS: <charflagslen> <charflags> <folcharslen> <folchars>
  //
  // The table with character flags and the table for case folding.
  // This makes sure the same characters are recognized as word characters
  // when generating an when using a spell file.
  // Skip this for ASCII, the table may conflict with the one used for
  // 'encoding'.
  // Also skip this for an .add.spl file, the main spell file must contain
  // the table (avoids that it conflicts).  File is shorter too.
  if (!spin->si_ascii && !spin->si_add) {
    char_u folchars[128 * 8];
    int flags;

    putc(SN_CHARFLAGS, fd);                             // <sectionID>
    putc(SNF_REQUIRED, fd);                             // <sectionflags>

    // Form the <folchars> string first, we need to know its length.
    l = 0;
    for (i = 128; i < 256; ++i) {
      if (has_mbyte)
        l += mb_char2bytes(spelltab.st_fold[i], folchars + l);
      else
        folchars[l++] = spelltab.st_fold[i];
    }
    put_bytes(fd, (long_u)(1 + 128 + 2 + l), 4);        // <sectionlen>

    fputc(128, fd);                                     // <charflagslen>
    for (i = 128; i < 256; ++i) {
      flags = 0;
      if (spelltab.st_isw[i])
        flags |= CF_WORD;
      if (spelltab.st_isu[i])
        flags |= CF_UPPER;
      fputc(flags, fd);                                 // <charflags>
    }

    put_bytes(fd, (long_u)l, 2);                        // <folcharslen>
    fwv &= fwrite(folchars, (size_t)l, (size_t)1, fd);     // <folchars>
  }

  // SN_MIDWORD: <midword>
  if (spin->si_midword != NULL) {
    putc(SN_MIDWORD, fd);                               // <sectionID>
    putc(SNF_REQUIRED, fd);                             // <sectionflags>

    i = (int)STRLEN(spin->si_midword);
    put_bytes(fd, (long_u)i, 4);                        // <sectionlen>
    fwv &= fwrite(spin->si_midword, (size_t)i, (size_t)1, fd);
    // <midword>
  }

  // SN_PREFCOND: <prefcondcnt> <prefcond> ...
  if (!GA_EMPTY(&spin->si_prefcond)) {
    putc(SN_PREFCOND, fd);                              // <sectionID>
    putc(SNF_REQUIRED, fd);                             // <sectionflags>

    l = write_spell_prefcond(NULL, &spin->si_prefcond);
    put_bytes(fd, (long_u)l, 4);                        // <sectionlen>

    write_spell_prefcond(fd, &spin->si_prefcond);
  }

  // SN_REP: <repcount> <rep> ...
  // SN_SAL: <salflags> <salcount> <sal> ...
  // SN_REPSAL: <repcount> <rep> ...

  // round 1: SN_REP section
  // round 2: SN_SAL section (unless SN_SOFO is used)
  // round 3: SN_REPSAL section
  for (round = 1; round <= 3; ++round) {
    if (round == 1)
      gap = &spin->si_rep;
    else if (round == 2) {
      // Don't write SN_SAL when using a SN_SOFO section
      if (spin->si_sofofr != NULL && spin->si_sofoto != NULL)
        continue;
      gap = &spin->si_sal;
    } else
      gap = &spin->si_repsal;

    // Don't write the section if there are no items.
    if (GA_EMPTY(gap))
      continue;

    // Sort the REP/REPSAL items.
    if (round != 2)
      qsort(gap->ga_data, (size_t)gap->ga_len,
          sizeof(fromto_T), rep_compare);

    i = round == 1 ? SN_REP : (round == 2 ? SN_SAL : SN_REPSAL);
    putc(i, fd);                                        // <sectionID>

    // This is for making suggestions, section is not required.
    putc(0, fd);                                        // <sectionflags>

    // Compute the length of what follows.
    l = 2;          // count <repcount> or <salcount>
    for (int i = 0; i < gap->ga_len; ++i) {
      ftp = &((fromto_T *)gap->ga_data)[i];
      l += 1 + (int)STRLEN(ftp->ft_from);        // count <*fromlen> and <*from>
      l += 1 + (int)STRLEN(ftp->ft_to);          // count <*tolen> and <*to>
    }
    if (round == 2)
      ++l;              // count <salflags>
    put_bytes(fd, (long_u)l, 4);                        // <sectionlen>

    if (round == 2) {
      i = 0;
      if (spin->si_followup)
        i |= SAL_F0LLOWUP;
      if (spin->si_collapse)
        i |= SAL_COLLAPSE;
      if (spin->si_rem_accents)
        i |= SAL_REM_ACCENTS;
      putc(i, fd);                              // <salflags>
    }

    put_bytes(fd, (long_u)gap->ga_len, 2);      // <repcount> or <salcount>
    for (int i = 0; i < gap->ga_len; ++i) {
      // <rep> : <repfromlen> <repfrom> <reptolen> <repto>
      // <sal> : <salfromlen> <salfrom> <saltolen> <salto>
      ftp = &((fromto_T *)gap->ga_data)[i];
      for (rr = 1; rr <= 2; ++rr) {
        p = rr == 1 ? ftp->ft_from : ftp->ft_to;
        l = (int)STRLEN(p);
        putc(l, fd);
        if (l > 0)
          fwv &= fwrite(p, l, (size_t)1, fd);
      }
    }

  }

  // SN_SOFO: <sofofromlen> <sofofrom> <sofotolen> <sofoto>
  // This is for making suggestions, section is not required.
  if (spin->si_sofofr != NULL && spin->si_sofoto != NULL) {
    putc(SN_SOFO, fd);                                  // <sectionID>
    putc(0, fd);                                        // <sectionflags>

    l = (int)STRLEN(spin->si_sofofr);
    put_bytes(fd, (long_u)(l + STRLEN(spin->si_sofoto) + 4), 4);
    // <sectionlen>

    put_bytes(fd, (long_u)l, 2);                        // <sofofromlen>
    fwv &= fwrite(spin->si_sofofr, l, (size_t)1, fd);     // <sofofrom>

    l = (int)STRLEN(spin->si_sofoto);
    put_bytes(fd, (long_u)l, 2);                        // <sofotolen>
    fwv &= fwrite(spin->si_sofoto, l, (size_t)1, fd);     // <sofoto>
  }

  // SN_WORDS: <word> ...
  // This is for making suggestions, section is not required.
  if (spin->si_commonwords.ht_used > 0) {
    putc(SN_WORDS, fd);                                 // <sectionID>
    putc(0, fd);                                        // <sectionflags>

    // round 1: count the bytes
    // round 2: write the bytes
    for (round = 1; round <= 2; ++round) {
      int todo;
      int len = 0;
      hashitem_T  *hi;

      todo = (int)spin->si_commonwords.ht_used;
      for (hi = spin->si_commonwords.ht_array; todo > 0; ++hi)
        if (!HASHITEM_EMPTY(hi)) {
          l = (int)STRLEN(hi->hi_key) + 1;
          len += l;
          if (round == 2)                               // <word>
            fwv &= fwrite(hi->hi_key, (size_t)l, (size_t)1, fd);
          --todo;
        }
      if (round == 1)
        put_bytes(fd, (long_u)len, 4);                  // <sectionlen>
    }
  }

  // SN_MAP: <mapstr>
  // This is for making suggestions, section is not required.
  if (!GA_EMPTY(&spin->si_map)) {
    putc(SN_MAP, fd);                                   // <sectionID>
    putc(0, fd);                                        // <sectionflags>
    l = spin->si_map.ga_len;
    put_bytes(fd, (long_u)l, 4);                        // <sectionlen>
    fwv &= fwrite(spin->si_map.ga_data, (size_t)l, (size_t)1, fd);
    // <mapstr>
  }

  // SN_SUGFILE: <timestamp>
  // This is used to notify that a .sug file may be available and at the
  // same time allows for checking that a .sug file that is found matches
  // with this .spl file.  That's because the word numbers must be exactly
  // right.
  if (!spin->si_nosugfile
      && (!GA_EMPTY(&spin->si_sal)
          || (spin->si_sofofr != NULL && spin->si_sofoto != NULL))) {
    putc(SN_SUGFILE, fd);                               // <sectionID>
    putc(0, fd);                                        // <sectionflags>
    put_bytes(fd, (long_u)8, 4);                        // <sectionlen>

    // Set si_sugtime and write it to the file.
    spin->si_sugtime = time(NULL);
    put_time(fd, spin->si_sugtime);                     // <timestamp>
  }

  // SN_NOSPLITSUGS: nothing
  // This is used to notify that no suggestions with word splits are to be
  // made.
  if (spin->si_nosplitsugs) {
    putc(SN_NOSPLITSUGS, fd);                           // <sectionID>
    putc(0, fd);                                        // <sectionflags>
    put_bytes(fd, (long_u)0, 4);                        // <sectionlen>
  }

  // SN_COMPOUND: compound info.
  // We don't mark it required, when not supported all compound words will
  // be bad words.
  if (spin->si_compflags != NULL) {
    putc(SN_COMPOUND, fd);                              // <sectionID>
    putc(0, fd);                                        // <sectionflags>

    l = (int)STRLEN(spin->si_compflags);
    for (int i = 0; i < spin->si_comppat.ga_len; ++i) {
      l += (int)STRLEN(((char_u **)(spin->si_comppat.ga_data))[i]) + 1;
    }
    put_bytes(fd, (long_u)(l + 7), 4);                  // <sectionlen>

    putc(spin->si_compmax, fd);                         // <compmax>
    putc(spin->si_compminlen, fd);                      // <compminlen>
    putc(spin->si_compsylmax, fd);                      // <compsylmax>
    putc(0, fd);                // for Vim 7.0b compatibility
    putc(spin->si_compoptions, fd);                     // <compoptions>
    put_bytes(fd, (long_u)spin->si_comppat.ga_len, 2);
    // <comppatcount>
    for (int i = 0; i < spin->si_comppat.ga_len; ++i) {
      p = ((char_u **)(spin->si_comppat.ga_data))[i];
      putc((int)STRLEN(p), fd);                         // <comppatlen>
      fwv &= fwrite(p, (size_t)STRLEN(p), (size_t)1, fd);
      // <comppattext>
    }
    // <compflags>
    fwv &= fwrite(spin->si_compflags, (size_t)STRLEN(spin->si_compflags),
        (size_t)1, fd);
  }

  // SN_NOBREAK: NOBREAK flag
  if (spin->si_nobreak) {
    putc(SN_NOBREAK, fd);                               // <sectionID>
    putc(0, fd);                                        // <sectionflags>

    // It's empty, the presence of the section flags the feature.
    put_bytes(fd, (long_u)0, 4);                        // <sectionlen>
  }

  // SN_SYLLABLE: syllable info.
  // We don't mark it required, when not supported syllables will not be
  // counted.
  if (spin->si_syllable != NULL) {
    putc(SN_SYLLABLE, fd);                              // <sectionID>
    putc(0, fd);                                        // <sectionflags>

    l = (int)STRLEN(spin->si_syllable);
    put_bytes(fd, (long_u)l, 4);                        // <sectionlen>
    fwv &= fwrite(spin->si_syllable, (size_t)l, (size_t)1, fd);
    // <syllable>
  }

  // end of <SECTIONS>
  putc(SN_END, fd);                                     // <sectionend>


  // <LWORDTREE>  <KWORDTREE>  <PREFIXTREE>
  spin->si_memtot = 0;
  for (round = 1; round <= 3; ++round) {
    if (round == 1)
      tree = spin->si_foldroot->wn_sibling;
    else if (round == 2)
      tree = spin->si_keeproot->wn_sibling;
    else
      tree = spin->si_prefroot->wn_sibling;

    // Clear the index and wnode fields in the tree.
    clear_node(tree);

    // Count the number of nodes.  Needed to be able to allocate the
    // memory when reading the nodes.  Also fills in index for shared
    // nodes.
    nodecount = put_node(NULL, tree, 0, regionmask, round == 3);

    // number of nodes in 4 bytes
    put_bytes(fd, (long_u)nodecount, 4);        // <nodecount>
    spin->si_memtot += nodecount + nodecount * sizeof(int);

    // Write the nodes.
    (void)put_node(fd, tree, 0, regionmask, round == 3);
  }

  // Write another byte to check for errors (file system full).
  if (putc(0, fd) == EOF)
    retval = FAIL;
theend:
  if (fclose(fd) == EOF)
    retval = FAIL;

  if (fwv != (size_t)1)
    retval = FAIL;
  if (retval == FAIL)
    EMSG(_(e_write));

  return retval;
}

// Clear the index and wnode fields of "node", it siblings and its
// children.  This is needed because they are a union with other items to save
// space.
static void clear_node(wordnode_T *node)
{
  wordnode_T  *np;

  if (node != NULL)
    for (np = node; np != NULL; np = np->wn_sibling) {
      np->wn_u1.index = 0;
      np->wn_u2.wnode = NULL;

      if (np->wn_byte != NUL)
        clear_node(np->wn_child);
    }
}


// Dump a word tree at node "node".
//
// This first writes the list of possible bytes (siblings).  Then for each
// byte recursively write the children.
//
// NOTE: The code here must match the code in read_tree_node(), since
// assumptions are made about the indexes (so that we don't have to write them
// in the file).
//
// Returns the number of nodes used.
static int
put_node (
    FILE *fd,                // NULL when only counting
    wordnode_T *node,
    int idx,
    int regionmask,
    bool prefixtree                 // true for PREFIXTREE
)
{
  int newindex = idx;
  int siblingcount = 0;
  wordnode_T  *np;
  int flags;

  // If "node" is zero the tree is empty.
  if (node == NULL)
    return 0;

  // Store the index where this node is written.
  node->wn_u1.index = idx;

  // Count the number of siblings.
  for (np = node; np != NULL; np = np->wn_sibling)
    ++siblingcount;

  // Write the sibling count.
  if (fd != NULL)
    putc(siblingcount, fd);                             // <siblingcount>

  // Write each sibling byte and optionally extra info.
  for (np = node; np != NULL; np = np->wn_sibling) {
    if (np->wn_byte == 0) {
      if (fd != NULL) {
        // For a NUL byte (end of word) write the flags etc.
        if (prefixtree) {
          // In PREFIXTREE write the required affixID and the
          // associated condition nr (stored in wn_region).  The
          // byte value is misused to store the "rare" and "not
          // combining" flags
          if (np->wn_flags == (uint16_t)PFX_FLAGS)
            putc(BY_NOFLAGS, fd);                       // <byte>
          else {
            putc(BY_FLAGS, fd);                         // <byte>
            putc(np->wn_flags, fd);                     // <pflags>
          }
          putc(np->wn_affixID, fd);                     // <affixID>
          put_bytes(fd, (long_u)np->wn_region, 2);           // <prefcondnr>
        } else {
          // For word trees we write the flag/region items.
          flags = np->wn_flags;
          if (regionmask != 0 && np->wn_region != regionmask)
            flags |= WF_REGION;
          if (np->wn_affixID != 0)
            flags |= WF_AFX;
          if (flags == 0) {
            // word without flags or region
            putc(BY_NOFLAGS, fd);                               // <byte>
          } else {
            if (np->wn_flags >= 0x100) {
              putc(BY_FLAGS2, fd);                              // <byte>
              putc(flags, fd);                                  // <flags>
              putc((unsigned)flags >> 8, fd);                   // <flags2>
            } else {
              putc(BY_FLAGS, fd);                               // <byte>
              putc(flags, fd);                                  // <flags>
            }
            if (flags & WF_REGION)
              putc(np->wn_region, fd);                          // <region>
            if (flags & WF_AFX)
              putc(np->wn_affixID, fd);                         // <affixID>
          }
        }
      }
    } else {
      if (np->wn_child->wn_u1.index != 0
          && np->wn_child->wn_u2.wnode != node) {
        // The child is written elsewhere, write the reference.
        if (fd != NULL) {
          putc(BY_INDEX, fd);                           // <byte>
                                                        // <nodeidx>
          put_bytes(fd, (long_u)np->wn_child->wn_u1.index, 3);
        }
      } else if (np->wn_child->wn_u2.wnode == NULL)
        // We will write the child below and give it an index.
        np->wn_child->wn_u2.wnode = node;

      if (fd != NULL)
        if (putc(np->wn_byte, fd) == EOF) {       // <byte> or <xbyte>
          EMSG(_(e_write));
          return 0;
        }
    }
  }

  // Space used in the array when reading: one for each sibling and one for
  // the count.
  newindex += siblingcount + 1;

  // Recursively dump the children of each sibling.
  for (np = node; np != NULL; np = np->wn_sibling)
    if (np->wn_byte != 0 && np->wn_child->wn_u2.wnode == node)
      newindex = put_node(fd, np->wn_child, newindex, regionmask,
          prefixtree);

  return newindex;
}


// ":mkspell [-ascii] outfile  infile ..."
// ":mkspell [-ascii] addfile"
void ex_mkspell(exarg_T *eap)
{
  int fcount;
  char_u      **fnames;
  char_u      *arg = eap->arg;
  bool ascii = false;

  if (STRNCMP(arg, "-ascii", 6) == 0) {
    ascii = true;
    arg = skipwhite(arg + 6);
  }

  // Expand all the remaining arguments (e.g., $VIMRUNTIME).
  if (get_arglist_exp(arg, &fcount, &fnames, false) == OK) {
    mkspell(fcount, fnames, ascii, eap->forceit, false);
    FreeWild(fcount, fnames);
  }
}

// Create the .sug file.
// Uses the soundfold info in "spin".
// Writes the file with the name "wfname", with ".spl" changed to ".sug".
static void spell_make_sugfile(spellinfo_T *spin, char_u *wfname)
{
  char_u      *fname = NULL;
  int len;
  slang_T     *slang;
  bool free_slang = false;

  // Read back the .spl file that was written.  This fills the required
  // info for soundfolding.  This also uses less memory than the
  // pointer-linked version of the trie.  And it avoids having two versions
  // of the code for the soundfolding stuff.
  // It might have been done already by spell_reload_one().
  for (slang = first_lang; slang != NULL; slang = slang->sl_next)
    if (path_full_compare(wfname, slang->sl_fname, FALSE) == kEqualFiles)
      break;
  if (slang == NULL) {
    spell_message(spin, (char_u *)_("Reading back spell file..."));
    slang = spell_load_file(wfname, NULL, NULL, false);
    if (slang == NULL)
      return;
    free_slang = true;
  }

  // Clear the info in "spin" that is used.
  spin->si_blocks = NULL;
  spin->si_blocks_cnt = 0;
  spin->si_compress_cnt = 0;        // will stay at 0 all the time
  spin->si_free_count = 0;
  spin->si_first_free = NULL;
  spin->si_foldwcount = 0;

  // Go through the trie of good words, soundfold each word and add it to
  // the soundfold trie.
  spell_message(spin, (char_u *)_("Performing soundfolding..."));
  if (sug_filltree(spin, slang) == FAIL)
    goto theend;

  // Create the table which links each soundfold word with a list of the
  // good words it may come from.  Creates buffer "spin->si_spellbuf".
  // This also removes the wordnr from the NUL byte entries to make
  // compression possible.
  if (sug_maketable(spin) == FAIL)
    goto theend;

  smsg((char_u *)_("Number of words after soundfolding: %" PRId64),
      (int64_t)spin->si_spellbuf->b_ml.ml_line_count);

  // Compress the soundfold trie.
  spell_message(spin, (char_u *)_(msg_compressing));
  wordtree_compress(spin, spin->si_foldroot);

  // Write the .sug file.
  // Make the file name by changing ".spl" to ".sug".
  fname = xmalloc(MAXPATHL);
  STRLCPY(fname, wfname, MAXPATHL);
  len = (int)STRLEN(fname);
  fname[len - 2] = 'u';
  fname[len - 1] = 'g';
  sug_write(spin, fname);

theend:
  free(fname);
  if (free_slang)
    slang_free(slang);
  free_blocks(spin->si_blocks);
  close_spellbuf(spin->si_spellbuf);
}

// Build the soundfold trie for language "slang".
static int sug_filltree(spellinfo_T *spin, slang_T *slang)
{
  char_u      *byts;
  idx_T       *idxs;
  int depth;
  idx_T arridx[MAXWLEN];
  int curi[MAXWLEN];
  char_u tword[MAXWLEN];
  char_u tsalword[MAXWLEN];
  int c;
  idx_T n;
  unsigned words_done = 0;
  int wordcount[MAXWLEN];

  // We use si_foldroot for the soundfolded trie.
  spin->si_foldroot = wordtree_alloc(spin);
  if (spin->si_foldroot == NULL)
    return FAIL;

  // Let tree_add_word() know we're adding to the soundfolded tree
  spin->si_sugtree = true;

  // Go through the whole case-folded tree, soundfold each word and put it
  // in the trie.
  byts = slang->sl_fbyts;
  idxs = slang->sl_fidxs;

  arridx[0] = 0;
  curi[0] = 1;
  wordcount[0] = 0;

  depth = 0;
  while (depth >= 0 && !got_int) {
    if (curi[depth] > byts[arridx[depth]]) {
      // Done all bytes at this node, go up one level.
      idxs[arridx[depth]] = wordcount[depth];
      if (depth > 0)
        wordcount[depth - 1] += wordcount[depth];

      --depth;
      line_breakcheck();
    } else {

      // Do one more byte at this node.
      n = arridx[depth] + curi[depth];
      ++curi[depth];

      c = byts[n];
      if (c == 0) {
        // Sound-fold the word.
        tword[depth] = NUL;
        spell_soundfold(slang, tword, true, tsalword);

        // We use the "flags" field for the MSB of the wordnr,
        // "region" for the LSB of the wordnr.
        if (tree_add_word(spin, tsalword, spin->si_foldroot,
                words_done >> 16, words_done & 0xffff,
                0) == FAIL)
          return FAIL;

        ++words_done;
        ++wordcount[depth];

        // Reset the block count each time to avoid compression
        // kicking in.
        spin->si_blocks_cnt = 0;

        // Skip over any other NUL bytes (same word with different
        // flags).
        while (byts[n + 1] == 0) {
          ++n;
          ++curi[depth];
        }
      } else {
        // Normal char, go one level deeper.
        tword[depth++] = c;
        arridx[depth] = idxs[n];
        curi[depth] = 1;
        wordcount[depth] = 0;
      }
    }
  }

  smsg((char_u *)_("Total number of words: %d"), words_done);

  return OK;
}

// Make the table that links each word in the soundfold trie to the words it
// can be produced from.
// This is not unlike lines in a file, thus use a memfile to be able to access
// the table efficiently.
// Returns FAIL when out of memory.
static int sug_maketable(spellinfo_T *spin)
{
  garray_T ga;
  int res = OK;

  // Allocate a buffer, open a memline for it and create the swap file
  // (uses a temp file, not a .swp file).
  spin->si_spellbuf = open_spellbuf();

  // Use a buffer to store the line info, avoids allocating many small
  // pieces of memory.
  ga_init(&ga, 1, 100);

  // recursively go through the tree
  if (sug_filltable(spin, spin->si_foldroot->wn_sibling, 0, &ga) == -1)
    res = FAIL;

  ga_clear(&ga);
  return res;
}

// Fill the table for one node and its children.
// Returns the wordnr at the start of the node.
// Returns -1 when out of memory.
static int
sug_filltable (
    spellinfo_T *spin,
    wordnode_T *node,
    int startwordnr,
    garray_T *gap           // place to store line of numbers
)
{
  wordnode_T  *p, *np;
  int wordnr = startwordnr;
  int nr;
  int prev_nr;

  for (p = node; p != NULL; p = p->wn_sibling) {
    if (p->wn_byte == NUL) {
      gap->ga_len = 0;
      prev_nr = 0;
      for (np = p; np != NULL && np->wn_byte == NUL; np = np->wn_sibling) {
        ga_grow(gap, 10);

        nr = (np->wn_flags << 16) + (np->wn_region & 0xffff);
        // Compute the offset from the previous nr and store the
        // offset in a way that it takes a minimum number of bytes.
        // It's a bit like utf-8, but without the need to mark
        // following bytes.
        nr -= prev_nr;
        prev_nr += nr;
        gap->ga_len += offset2bytes(nr,
            (char_u *)gap->ga_data + gap->ga_len);
      }

      // add the NUL byte
      ((char_u *)gap->ga_data)[gap->ga_len++] = NUL;

      if (ml_append_buf(spin->si_spellbuf, (linenr_T)wordnr,
              gap->ga_data, gap->ga_len, TRUE) == FAIL)
        return -1;
      ++wordnr;

      // Remove extra NUL entries, we no longer need them. We don't
      // bother freeing the nodes, the won't be reused anyway.
      while (p->wn_sibling != NULL && p->wn_sibling->wn_byte == NUL)
        p->wn_sibling = p->wn_sibling->wn_sibling;

      // Clear the flags on the remaining NUL node, so that compression
      // works a lot better.
      p->wn_flags = 0;
      p->wn_region = 0;
    } else {
      wordnr = sug_filltable(spin, p->wn_child, wordnr, gap);
      if (wordnr == -1)
        return -1;
    }
  }
  return wordnr;
}

// Convert an offset into a minimal number of bytes.
// Similar to utf_char2byters, but use 8 bits in followup bytes and avoid NUL
// bytes.
static int offset2bytes(int nr, char_u *buf)
{
  int rem;
  int b1, b2, b3, b4;

  // Split the number in parts of base 255.  We need to avoid NUL bytes.
  b1 = nr % 255 + 1;
  rem = nr / 255;
  b2 = rem % 255 + 1;
  rem = rem / 255;
  b3 = rem % 255 + 1;
  b4 = rem / 255 + 1;

  if (b4 > 1 || b3 > 0x1f) {    // 4 bytes
    buf[0] = 0xe0 + b4;
    buf[1] = b3;
    buf[2] = b2;
    buf[3] = b1;
    return 4;
  }
  if (b3 > 1 || b2 > 0x3f ) {   // 3 bytes
    buf[0] = 0xc0 + b3;
    buf[1] = b2;
    buf[2] = b1;
    return 3;
  }
  if (b2 > 1 || b1 > 0x7f ) {   // 2 bytes
    buf[0] = 0x80 + b2;
    buf[1] = b1;
    return 2;
  }
  // 1 byte
  buf[0] = b1;
  return 1;
}

// Opposite of offset2bytes().
// "pp" points to the bytes and is advanced over it.
// Returns the offset.
static int bytes2offset(char_u **pp)
{
  char_u *p = *pp;
  int nr;
  int c;

  c = *p++;
  if ((c & 0x80) == 0x00) {             // 1 byte
    nr = c - 1;
  } else if ((c & 0xc0) == 0x80)   {    // 2 bytes
    nr = (c & 0x3f) - 1;
    nr = nr * 255 + (*p++ - 1);
  } else if ((c & 0xe0) == 0xc0)   {    // 3 bytes
    nr = (c & 0x1f) - 1;
    nr = nr * 255 + (*p++ - 1);
    nr = nr * 255 + (*p++ - 1);
  } else {                              // 4 bytes
    nr = (c & 0x0f) - 1;
    nr = nr * 255 + (*p++ - 1);
    nr = nr * 255 + (*p++ - 1);
    nr = nr * 255 + (*p++ - 1);
  }

  *pp = p;
  return nr;
}

// Write the .sug file in "fname".
static void sug_write(spellinfo_T *spin, char_u *fname)
{
  FILE        *fd;
  wordnode_T  *tree;
  int nodecount;
  int wcount;
  char_u      *line;
  linenr_T lnum;
  int len;

  // Create the file.  Note that an existing file is silently overwritten!
  fd = mch_fopen((char *)fname, "w");
  if (fd == NULL) {
    EMSG2(_(e_notopen), fname);
    return;
  }

  vim_snprintf((char *)IObuff, IOSIZE,
      _("Writing suggestion file %s ..."), fname);
  spell_message(spin, IObuff);

  // <SUGHEADER>: <fileID> <versionnr> <timestamp>
  if (fwrite(VIMSUGMAGIC, VIMSUGMAGICL, (size_t)1, fd) != 1) { // <fileID>
    EMSG(_(e_write));
    goto theend;
  }
  putc(VIMSUGVERSION, fd);                              // <versionnr>

  // Write si_sugtime to the file.
  put_time(fd, spin->si_sugtime);                       // <timestamp>

  // <SUGWORDTREE>
  spin->si_memtot = 0;
  tree = spin->si_foldroot->wn_sibling;

  // Clear the index and wnode fields in the tree.
  clear_node(tree);

  // Count the number of nodes.  Needed to be able to allocate the
  // memory when reading the nodes.  Also fills in index for shared
  // nodes.
  nodecount = put_node(NULL, tree, 0, 0, false);

  // number of nodes in 4 bytes
  put_bytes(fd, (long_u)nodecount, 4);          // <nodecount>
  spin->si_memtot += nodecount + nodecount * sizeof(int);

  // Write the nodes.
  (void)put_node(fd, tree, 0, 0, false);

  // <SUGTABLE>: <sugwcount> <sugline> ...
  wcount = spin->si_spellbuf->b_ml.ml_line_count;
  put_bytes(fd, (long_u)wcount, 4);     // <sugwcount>

  for (lnum = 1; lnum <= (linenr_T)wcount; ++lnum) {
    // <sugline>: <sugnr> ... NUL
    line = ml_get_buf(spin->si_spellbuf, lnum, FALSE);
    len = (int)STRLEN(line) + 1;
    if (fwrite(line, (size_t)len, (size_t)1, fd) == 0) {
      EMSG(_(e_write));
      goto theend;
    }
    spin->si_memtot += len;
  }

  // Write another byte to check for errors.
  if (putc(0, fd) == EOF)
    EMSG(_(e_write));

  vim_snprintf((char *)IObuff, IOSIZE,
      _("Estimated runtime memory use: %d bytes"), spin->si_memtot);
  spell_message(spin, IObuff);

theend:
  // close the file
  fclose(fd);
}

// Open a spell buffer.  This is a nameless buffer that is not in the buffer
// list and only contains text lines.  Can use a swapfile to reduce memory
// use.
// Most other fields are invalid!  Esp. watch out for string options being
// NULL and there is no undo info.
static buf_T *open_spellbuf(void)
{
  buf_T *buf = xcalloc(1, sizeof(buf_T));

  buf->b_spell = true;
  buf->b_p_swf = true;        // may create a swap file
  ml_open(buf);
  ml_open_file(buf);          // create swap file now

  return buf;
}

// Close the buffer used for spell info.
static void close_spellbuf(buf_T *buf)
{
  if (buf != NULL) {
    ml_close(buf, TRUE);
    free(buf);
  }
}


// Create a Vim spell file from one or more word lists.
// "fnames[0]" is the output file name.
// "fnames[fcount - 1]" is the last input file name.
// Exception: when "fnames[0]" ends in ".add" it's used as the input file name
// and ".spl" is appended to make the output file name.
static void
mkspell (
    int fcount,
    char_u **fnames,
    bool ascii,                         // -ascii argument given
    bool over_write,                    // overwrite existing output file
    bool added_word                     // invoked through "zg"
)
{
  char_u      *fname = NULL;
  char_u      *wfname;
  char_u      **innames;
  int incount;
  afffile_T   *(afile[8]);
  int i;
  int len;
  bool error = false;
  spellinfo_T spin;

  memset(&spin, 0, sizeof(spin));
  spin.si_verbose = !added_word;
  spin.si_ascii = ascii;
  spin.si_followup = true;
  spin.si_rem_accents = true;
  ga_init(&spin.si_rep, (int)sizeof(fromto_T), 20);
  ga_init(&spin.si_repsal, (int)sizeof(fromto_T), 20);
  ga_init(&spin.si_sal, (int)sizeof(fromto_T), 20);
  ga_init(&spin.si_map, (int)sizeof(char_u), 100);
  ga_init(&spin.si_comppat, (int)sizeof(char_u *), 20);
  ga_init(&spin.si_prefcond, (int)sizeof(char_u *), 50);
  hash_init(&spin.si_commonwords);
  spin.si_newcompID = 127;      // start compound ID at first maximum

  // default: fnames[0] is output file, following are input files
  innames = &fnames[1];
  incount = fcount - 1;

  wfname = xmalloc(MAXPATHL);

  if (fcount >= 1) {
    len = (int)STRLEN(fnames[0]);
    if (fcount == 1 && len > 4 && STRCMP(fnames[0] + len - 4, ".add") == 0) {
      // For ":mkspell path/en.latin1.add" output file is
      // "path/en.latin1.add.spl".
      innames = &fnames[0];
      incount = 1;
      vim_snprintf((char *)wfname, MAXPATHL, "%s.spl", fnames[0]);
    } else if (fcount == 1)   {
      // For ":mkspell path/vim" output file is "path/vim.latin1.spl".
      innames = &fnames[0];
      incount = 1;
      vim_snprintf((char *)wfname, MAXPATHL, SPL_FNAME_TMPL,
          fnames[0], spin.si_ascii ? (char_u *)"ascii" : spell_enc());
    } else if (len > 4 && STRCMP(fnames[0] + len - 4, ".spl") == 0)   {
      // Name ends in ".spl", use as the file name.
      STRLCPY(wfname, fnames[0], MAXPATHL);
    } else
      // Name should be language, make the file name from it.
      vim_snprintf((char *)wfname, MAXPATHL, SPL_FNAME_TMPL,
          fnames[0], spin.si_ascii ? (char_u *)"ascii" : spell_enc());

    // Check for .ascii.spl.
    if (strstr((char *)path_tail(wfname), SPL_FNAME_ASCII) != NULL)
      spin.si_ascii = true;

    // Check for .add.spl.
    if (strstr((char *)path_tail(wfname), SPL_FNAME_ADD) != NULL)
      spin.si_add = true;
  }

  if (incount <= 0)
    EMSG(_(e_invarg));          // need at least output and input names
  else if (vim_strchr(path_tail(wfname), '_') != NULL)
    EMSG(_("E751: Output file name must not have region name"));
  else if (incount > 8)
    EMSG(_("E754: Only up to 8 regions supported"));
  else {
    // Check for overwriting before doing things that may take a lot of
    // time.
    if (!over_write && os_file_exists(wfname)) {
      EMSG(_(e_exists));
      goto theend;
    }
    if (os_isdir(wfname)) {
      EMSG2(_(e_isadir2), wfname);
      goto theend;
    }

    fname = xmalloc(MAXPATHL);

    // Init the aff and dic pointers.
    // Get the region names if there are more than 2 arguments.
    for (i = 0; i < incount; ++i) {
      afile[i] = NULL;

      if (incount > 1) {
        len = (int)STRLEN(innames[i]);
        if (STRLEN(path_tail(innames[i])) < 5
            || innames[i][len - 3] != '_') {
          EMSG2(_("E755: Invalid region in %s"), innames[i]);
          goto theend;
        }
        spin.si_region_name[i * 2] = TOLOWER_ASC(innames[i][len - 2]);
        spin.si_region_name[i * 2 + 1] =
          TOLOWER_ASC(innames[i][len - 1]);
      }
    }
    spin.si_region_count = incount;

    spin.si_foldroot = wordtree_alloc(&spin);
    spin.si_keeproot = wordtree_alloc(&spin);
    spin.si_prefroot = wordtree_alloc(&spin);
    if (spin.si_foldroot == NULL
        || spin.si_keeproot == NULL
        || spin.si_prefroot == NULL) {
      free_blocks(spin.si_blocks);
      goto theend;
    }

    // When not producing a .add.spl file clear the character table when
    // we encounter one in the .aff file.  This means we dump the current
    // one in the .spl file if the .aff file doesn't define one.  That's
    // better than guessing the contents, the table will match a
    // previously loaded spell file.
    if (!spin.si_add)
      spin.si_clear_chartab = true;

    // Read all the .aff and .dic files.
    // Text is converted to 'encoding'.
    // Words are stored in the case-folded and keep-case trees.
    for (i = 0; i < incount && !error; ++i) {
      spin.si_conv.vc_type = CONV_NONE;
      spin.si_region = 1 << i;

      vim_snprintf((char *)fname, MAXPATHL, "%s.aff", innames[i]);
      if (os_file_exists(fname)) {
        // Read the .aff file.  Will init "spin->si_conv" based on the
        // "SET" line.
        afile[i] = spell_read_aff(&spin, fname);
        if (afile[i] == NULL)
          error = true;
        else {
          // Read the .dic file and store the words in the trees.
          vim_snprintf((char *)fname, MAXPATHL, "%s.dic",
              innames[i]);
          if (spell_read_dic(&spin, fname, afile[i]) == FAIL)
            error = true;
        }
      } else {
        // No .aff file, try reading the file as a word list.  Store
        // the words in the trees.
        if (spell_read_wordfile(&spin, innames[i]) == FAIL)
          error = true;
      }

      // Free any conversion stuff.
      convert_setup(&spin.si_conv, NULL, NULL);
    }

    if (spin.si_compflags != NULL && spin.si_nobreak)
      MSG(_("Warning: both compounding and NOBREAK specified"));

    if (!error && !got_int) {
      // Combine tails in the tree.
      spell_message(&spin, (char_u *)_(msg_compressing));
      wordtree_compress(&spin, spin.si_foldroot);
      wordtree_compress(&spin, spin.si_keeproot);
      wordtree_compress(&spin, spin.si_prefroot);
    }

    if (!error && !got_int) {
      // Write the info in the spell file.
      vim_snprintf((char *)IObuff, IOSIZE,
          _("Writing spell file %s ..."), wfname);
      spell_message(&spin, IObuff);

      error = write_vim_spell(&spin, wfname) == FAIL;

      spell_message(&spin, (char_u *)_("Done!"));
      vim_snprintf((char *)IObuff, IOSIZE,
          _("Estimated runtime memory use: %d bytes"), spin.si_memtot);
      spell_message(&spin, IObuff);

      // If the file is loaded need to reload it.
      if (!error)
        spell_reload_one(wfname, added_word);
    }

    // Free the allocated memory.
    ga_clear(&spin.si_rep);
    ga_clear(&spin.si_repsal);
    ga_clear(&spin.si_sal);
    ga_clear(&spin.si_map);
    ga_clear(&spin.si_comppat);
    ga_clear(&spin.si_prefcond);
    hash_clear_all(&spin.si_commonwords, 0);

    // Free the .aff file structures.
    for (i = 0; i < incount; ++i)
      if (afile[i] != NULL)
        spell_free_aff(afile[i]);

    // Free all the bits and pieces at once.
    free_blocks(spin.si_blocks);

    // If there is soundfolding info and no NOSUGFILE item create the
    // .sug file with the soundfolded word trie.
    if (spin.si_sugtime != 0 && !error && !got_int)
      spell_make_sugfile(&spin, wfname);

  }

theend:
  free(fname);
  free(wfname);
}

// Display a message for spell file processing when 'verbose' is set or using
// ":mkspell".  "str" can be IObuff.
static void spell_message(spellinfo_T *spin, char_u *str)
{
  if (spin->si_verbose || p_verbose > 2) {
    if (!spin->si_verbose)
      verbose_enter();
    MSG(str);
    out_flush();
    if (!spin->si_verbose)
      verbose_leave();
  }
}

// ":[count]spellgood  {word}"
// ":[count]spellwrong  {word}"
// ":[count]spellundo  {word}"
void ex_spell(exarg_T *eap)
{
  spell_add_word(eap->arg, (int)STRLEN(eap->arg), eap->cmdidx == CMD_spellwrong,
      eap->forceit ? 0 : (int)eap->line2,
      eap->cmdidx == CMD_spellundo);
}

// Add "word[len]" to 'spellfile' as a good or bad word.
void
spell_add_word (
    char_u *word,
    int len,
    int bad,
    int idx,                   // "zG" and "zW": zero, otherwise index in
                               // 'spellfile'
    bool undo                   // true for "zug", "zuG", "zuw" and "zuW"
)
{
  FILE        *fd = NULL;
  buf_T       *buf = NULL;
  bool new_spf = false;
  char_u      *fname;
  char_u      *fnamebuf = NULL;
  char_u line[MAXWLEN * 2];
  long fpos, fpos_next = 0;
  int i;
  char_u      *spf;

  if (idx == 0) {           // use internal wordlist
    if (int_wordlist == NULL) {
      int_wordlist = vim_tempname();
      if (int_wordlist == NULL)
        return;
    }
    fname = int_wordlist;
  } else {
    // If 'spellfile' isn't set figure out a good default value.
    if (*curwin->w_s->b_p_spf == NUL) {
      init_spellfile();
      new_spf = true;
    }

    if (*curwin->w_s->b_p_spf == NUL) {
      EMSG2(_(e_notset), "spellfile");
      return;
    }
    fnamebuf = xmalloc(MAXPATHL);

    for (spf = curwin->w_s->b_p_spf, i = 1; *spf != NUL; ++i) {
      copy_option_part(&spf, fnamebuf, MAXPATHL, ",");
      if (i == idx)
        break;
      if (*spf == NUL) {
        EMSGN(_("E765: 'spellfile' does not have %" PRId64 " entries"), idx);
        free(fnamebuf);
        return;
      }
    }

    // Check that the user isn't editing the .add file somewhere.
    buf = buflist_findname_exp(fnamebuf);
    if (buf != NULL && buf->b_ml.ml_mfp == NULL)
      buf = NULL;
    if (buf != NULL && bufIsChanged(buf)) {
      EMSG(_(e_bufloaded));
      free(fnamebuf);
      return;
    }

    fname = fnamebuf;
  }

  if (bad || undo) {
    // When the word appears as good word we need to remove that one,
    // since its flags sort before the one with WF_BANNED.
    fd = mch_fopen((char *)fname, "r");
    if (fd != NULL) {
      while (!vim_fgets(line, MAXWLEN * 2, fd)) {
        fpos = fpos_next;
        fpos_next = ftell(fd);
        if (STRNCMP(word, line, len) == 0
            && (line[len] == '/' || line[len] < ' ')) {
          // Found duplicate word.  Remove it by writing a '#' at
          // the start of the line.  Mixing reading and writing
          // doesn't work for all systems, close the file first.
          fclose(fd);
          fd = mch_fopen((char *)fname, "r+");
          if (fd == NULL)
            break;
          if (fseek(fd, fpos, SEEK_SET) == 0) {
            fputc('#', fd);
            if (undo) {
              home_replace(NULL, fname, NameBuff, MAXPATHL, TRUE);
              smsg((char_u *)_("Word '%.*s' removed from %s"),
                  len, word, NameBuff);
            }
          }
          fseek(fd, fpos_next, SEEK_SET);
        }
      }
      if (fd != NULL)
        fclose(fd);
    }
  }

  if (!undo) {
    fd = mch_fopen((char *)fname, "a");
    if (fd == NULL && new_spf) {
      char_u *p;

      // We just initialized the 'spellfile' option and can't open the
      // file.  We may need to create the "spell" directory first.  We
      // already checked the runtime directory is writable in
      // init_spellfile().
      if (!dir_of_file_exists(fname) && (p = path_tail_with_sep(fname)) != fname) {
        int c = *p;

        // The directory doesn't exist.  Try creating it and opening
        // the file again.
        *p = NUL;
        os_mkdir((char *)fname, 0755);
        *p = c;
        fd = mch_fopen((char *)fname, "a");
      }
    }

    if (fd == NULL)
      EMSG2(_(e_notopen), fname);
    else {
      if (bad)
        fprintf(fd, "%.*s/!\n", len, word);
      else
        fprintf(fd, "%.*s\n", len, word);
      fclose(fd);

      home_replace(NULL, fname, NameBuff, MAXPATHL, TRUE);
      smsg((char_u *)_("Word '%.*s' added to %s"), len, word, NameBuff);
    }
  }

  if (fd != NULL) {
    // Update the .add.spl file.
    mkspell(1, &fname, false, true, true);

    // If the .add file is edited somewhere, reload it.
    if (buf != NULL)
      buf_reload(buf, buf->b_orig_mode);

    redraw_all_later(SOME_VALID);
  }
  free(fnamebuf);
}

// Initialize 'spellfile' for the current buffer.
static void init_spellfile(void)
{
  char_u      *buf;
  int l;
  char_u      *fname;
  char_u      *rtp;
  char_u      *lend;
  bool aspath = false;
  char_u      *lstart = curbuf->b_s.b_p_spl;

  if (*curwin->w_s->b_p_spl != NUL && !GA_EMPTY(&curwin->w_s->b_langp)) {
    buf = xmalloc(MAXPATHL);

    // Find the end of the language name.  Exclude the region.  If there
    // is a path separator remember the start of the tail.
    for (lend = curwin->w_s->b_p_spl; *lend != NUL
         && vim_strchr((char_u *)",._", *lend) == NULL; ++lend)
      if (vim_ispathsep(*lend)) {
        aspath = true;
        lstart = lend + 1;
      }

    // Loop over all entries in 'runtimepath'.  Use the first one where we
    // are allowed to write.
    rtp = p_rtp;
    while (*rtp != NUL) {
      if (aspath)
        // Use directory of an entry with path, e.g., for
        // "/dir/lg.utf-8.spl" use "/dir".
        STRLCPY(buf, curbuf->b_s.b_p_spl,
            lstart - curbuf->b_s.b_p_spl);
      else
        // Copy the path from 'runtimepath' to buf[].
        copy_option_part(&rtp, buf, MAXPATHL, ",");
      if (os_file_is_writable((char *)buf) == 2) {
        // Use the first language name from 'spelllang' and the
        // encoding used in the first loaded .spl file.
        if (aspath)
          STRLCPY(buf, curbuf->b_s.b_p_spl,
              lend - curbuf->b_s.b_p_spl + 1);
        else {
          // Create the "spell" directory if it doesn't exist yet.
          l = (int)STRLEN(buf);
          vim_snprintf((char *)buf + l, MAXPATHL - l, "/spell");
          if (os_file_is_writable((char *)buf) != 2) {
            os_mkdir((char *)buf, 0755);
          }

          l = (int)STRLEN(buf);
          vim_snprintf((char *)buf + l, MAXPATHL - l,
              "/%.*s", (int)(lend - lstart), lstart);
        }
        l = (int)STRLEN(buf);
        fname = LANGP_ENTRY(curwin->w_s->b_langp, 0)
                ->lp_slang->sl_fname;
        vim_snprintf((char *)buf + l, MAXPATHL - l, ".%s.add",
            fname != NULL
            && strstr((char *)path_tail(fname), ".ascii.") != NULL
            ? (char_u *)"ascii" : spell_enc());
        set_option_value((char_u *)"spellfile", 0L, buf, OPT_LOCAL);
        break;
      }
      aspath = false;
    }

    free(buf);
  }
}

// Init the chartab used for spelling for ASCII.
static void clear_spell_chartab(spelltab_T *sp)
{
  int i;

  // Init everything to false.
  memset(sp->st_isw, false, sizeof(sp->st_isw));
  memset(sp->st_isu, false, sizeof(sp->st_isu));

  for (i = 0; i < 256; ++i) {
    sp->st_fold[i] = i;
    sp->st_upper[i] = i;
  }

  // We include digits. A word shouldn't start with a digit, but handling
  // that is done separately.
  for (i = '0'; i <= '9'; ++i)
    sp->st_isw[i] = true;
  for (i = 'A'; i <= 'Z'; ++i) {
    sp->st_isw[i] = true;
    sp->st_isu[i] = true;
    sp->st_fold[i] = i + 0x20;
  }
  for (i = 'a'; i <= 'z'; ++i) {
    sp->st_isw[i] = true;
    sp->st_upper[i] = i - 0x20;
  }
}

// Init the chartab used for spelling.  Only depends on 'encoding'.
// Called once while starting up and when 'encoding' changes.
// The default is to use isalpha(), but the spell file should define the word
// characters to make it possible that 'encoding' differs from the current
// locale.  For utf-8 we don't use isalpha() but our own functions.
void init_spell_chartab(void)
{
  int i;

  did_set_spelltab = false;
  clear_spell_chartab(&spelltab);
  if (enc_dbcs) {
    // DBCS: assume double-wide characters are word characters.
    for (i = 128; i <= 255; ++i)
      if (MB_BYTE2LEN(i) == 2)
        spelltab.st_isw[i] = true;
  } else if (enc_utf8)   {
    for (i = 128; i < 256; ++i) {
      int f = utf_fold(i);
      int u = utf_toupper(i);

      spelltab.st_isu[i] = utf_isupper(i);
      spelltab.st_isw[i] = spelltab.st_isu[i] || utf_islower(i);
      // The folded/upper-cased value is different between latin1 and
      // utf8 for 0xb5, causing E763 for no good reason.  Use the latin1
      // value for utf-8 to avoid this.
      spelltab.st_fold[i] = (f < 256) ? f : i;
      spelltab.st_upper[i] = (u < 256) ? u : i;
    }
  } else {
    // Rough guess: use locale-dependent library functions.
    for (i = 128; i < 256; ++i) {
      if (vim_isupper(i)) {
        spelltab.st_isw[i] = true;
        spelltab.st_isu[i] = true;
        spelltab.st_fold[i] = vim_tolower(i);
      } else if (vim_islower(i))   {
        spelltab.st_isw[i] = true;
        spelltab.st_upper[i] = vim_toupper(i);
      }
    }
  }
}

// Set the spell character tables from strings in the affix file.
static int set_spell_chartab(char_u *fol, char_u *low, char_u *upp)
{
  // We build the new tables here first, so that we can compare with the
  // previous one.
  spelltab_T new_st;
  char_u      *pf = fol, *pl = low, *pu = upp;
  int f, l, u;

  clear_spell_chartab(&new_st);

  while (*pf != NUL) {
    if (*pl == NUL || *pu == NUL) {
      EMSG(_(e_affform));
      return FAIL;
    }
    f = mb_ptr2char_adv(&pf);
    l = mb_ptr2char_adv(&pl);
    u = mb_ptr2char_adv(&pu);
    // Every character that appears is a word character.
    if (f < 256)
      new_st.st_isw[f] = true;
    if (l < 256)
      new_st.st_isw[l] = true;
    if (u < 256)
      new_st.st_isw[u] = true;

    // if "LOW" and "FOL" are not the same the "LOW" char needs
    // case-folding
    if (l < 256 && l != f) {
      if (f >= 256) {
        EMSG(_(e_affrange));
        return FAIL;
      }
      new_st.st_fold[l] = f;
    }

    // if "UPP" and "FOL" are not the same the "UPP" char needs
    // case-folding, it's upper case and the "UPP" is the upper case of
    // "FOL" .
    if (u < 256 && u != f) {
      if (f >= 256) {
        EMSG(_(e_affrange));
        return FAIL;
      }
      new_st.st_fold[u] = f;
      new_st.st_isu[u] = true;
      new_st.st_upper[f] = u;
    }
  }

  if (*pl != NUL || *pu != NUL) {
    EMSG(_(e_affform));
    return FAIL;
  }

  return set_spell_finish(&new_st);
}

// Set the spell character tables from strings in the .spl file.
static void
set_spell_charflags (
    char_u *flags,
    int cnt,                    // length of "flags"
    char_u *fol
)
{
  // We build the new tables here first, so that we can compare with the
  // previous one.
  spelltab_T new_st;
  int i;
  char_u      *p = fol;
  int c;

  clear_spell_chartab(&new_st);

  for (i = 0; i < 128; ++i) {
    if (i < cnt) {
      new_st.st_isw[i + 128] = (flags[i] & CF_WORD) != 0;
      new_st.st_isu[i + 128] = (flags[i] & CF_UPPER) != 0;
    }

    if (*p != NUL) {
      c = mb_ptr2char_adv(&p);
      new_st.st_fold[i + 128] = c;
      if (i + 128 != c && new_st.st_isu[i + 128] && c < 256)
        new_st.st_upper[c] = i + 128;
    }
  }

  (void)set_spell_finish(&new_st);
}

static int set_spell_finish(spelltab_T *new_st)
{
  int i;

  if (did_set_spelltab) {
    // check that it's the same table
    for (i = 0; i < 256; ++i) {
      if (spelltab.st_isw[i] != new_st->st_isw[i]
          || spelltab.st_isu[i] != new_st->st_isu[i]
          || spelltab.st_fold[i] != new_st->st_fold[i]
          || spelltab.st_upper[i] != new_st->st_upper[i]) {
        EMSG(_("E763: Word characters differ between spell files"));
        return FAIL;
      }
    }
  } else {
    // copy the new spelltab into the one being used
    spelltab = *new_st;
    did_set_spelltab = true;
  }

  return OK;
}

/// Returns true if "p" points to a word character.
/// As a special case we see "midword" characters as word character when it is
/// followed by a word character.  This finds they'there but not 'they there'.
/// Thus this only works properly when past the first character of the word.
///
/// @param wp Buffer used.
static bool spell_iswordp(char_u *p, win_T *wp)
{
  char_u *s;
  int l;
  int c;

  if (has_mbyte) {
    l = MB_BYTE2LEN(*p);
    s = p;
    if (l == 1) {
      // be quick for ASCII
      if (wp->w_s->b_spell_ismw[*p])
        s = p + 1;                      // skip a mid-word character
    } else {
      c = mb_ptr2char(p);
      if (c < 256 ? wp->w_s->b_spell_ismw[c]
          : (wp->w_s->b_spell_ismw_mb != NULL
             && vim_strchr(wp->w_s->b_spell_ismw_mb, c) != NULL))
        s = p + l;
    }

    c = mb_ptr2char(s);
    if (c > 255)
      return spell_mb_isword_class(mb_get_class(s), wp);
    return spelltab.st_isw[c];
  }

  return spelltab.st_isw[wp->w_s->b_spell_ismw[*p] ? p[1] : p[0]];
}

// Returns true if "p" points to a word character.
// Unlike spell_iswordp() this doesn't check for "midword" characters.
static bool spell_iswordp_nmw(char_u *p, win_T *wp)
{
  int c;

  if (has_mbyte) {
    c = mb_ptr2char(p);
    if (c > 255)
      return spell_mb_isword_class(mb_get_class(p), wp);
    return spelltab.st_isw[c];
  }
  return spelltab.st_isw[*p];
}

// Returns true if word class indicates a word character.
// Only for characters above 255.
// Unicode subscript and superscript are not considered word characters.
// See also dbcs_class() and utf_class() in mbyte.c.
static bool spell_mb_isword_class(int cl, win_T *wp)
{
  if (wp->w_s->b_cjk)
    // East Asian characters are not considered word characters.
    return cl == 2 || cl == 0x2800;
  return cl >= 2 && cl != 0x2070 && cl != 0x2080;
}

// Returns true if "p" points to a word character.
// Wide version of spell_iswordp().
static bool spell_iswordp_w(int *p, win_T *wp)
{
  int *s;

  if (*p < 256 ? wp->w_s->b_spell_ismw[*p]
      : (wp->w_s->b_spell_ismw_mb != NULL
         && vim_strchr(wp->w_s->b_spell_ismw_mb, *p) != NULL))
    s = p + 1;
  else
    s = p;

  if (*s > 255) {
    if (enc_utf8)
      return spell_mb_isword_class(utf_class(*s), wp);
    if (enc_dbcs)
      return spell_mb_isword_class(
          dbcs_class((unsigned)*s >> 8, *s & 0xff), wp);
    return false;
  }
  return spelltab.st_isw[*s];
}

// Write the table with prefix conditions to the .spl file.
// When "fd" is NULL only count the length of what is written.
static int write_spell_prefcond(FILE *fd, garray_T *gap)
{
  char_u      *p;
  int len;
  int totlen;
  size_t x = 1;         // collect return value of fwrite()

  if (fd != NULL)
    put_bytes(fd, (long_u)gap->ga_len, 2);          // <prefcondcnt>

  totlen = 2 + gap->ga_len;   // length of <prefcondcnt> and <condlen> bytes

  for (int i = 0; i < gap->ga_len; ++i) {
    // <prefcond> : <condlen> <condstr>
    p = ((char_u **)gap->ga_data)[i];
    if (p != NULL) {
      len = (int)STRLEN(p);
      if (fd != NULL) {
        fputc(len, fd);
        x &= fwrite(p, (size_t)len, (size_t)1, fd);
      }
      totlen += len;
    } else if (fd != NULL)
      fputc(0, fd);
  }

  return totlen;
}

// Case-fold "str[len]" into "buf[buflen]".  The result is NUL terminated.
// Uses the character definitions from the .spl file.
// When using a multi-byte 'encoding' the length may change!
// Returns FAIL when something wrong.
static int spell_casefold(char_u *str, int len, char_u *buf, int buflen)
{
  int i;

  if (len >= buflen) {
    buf[0] = NUL;
    return FAIL;                // result will not fit
  }

  if (has_mbyte) {
    int outi = 0;
    char_u  *p;
    int c;

    // Fold one character at a time.
    for (p = str; p < str + len; ) {
      if (outi + MB_MAXBYTES > buflen) {
        buf[outi] = NUL;
        return FAIL;
      }
      c = mb_cptr2char_adv(&p);
      outi += mb_char2bytes(SPELL_TOFOLD(c), buf + outi);
    }
    buf[outi] = NUL;
  } else {
    // Be quick for non-multibyte encodings.
    for (i = 0; i < len; ++i)
      buf[i] = spelltab.st_fold[str[i]];
    buf[i] = NUL;
  }

  return OK;
}

// values for sps_flags
#define SPS_BEST    1
#define SPS_FAST    2
#define SPS_DOUBLE  4

static int sps_flags = SPS_BEST;        // flags from 'spellsuggest'
static int sps_limit = 9999;            // max nr of suggestions given

// Check the 'spellsuggest' option.  Return FAIL if it's wrong.
// Sets "sps_flags" and "sps_limit".
int spell_check_sps(void)
{
  char_u      *p;
  char_u      *s;
  char_u buf[MAXPATHL];
  int f;

  sps_flags = 0;
  sps_limit = 9999;

  for (p = p_sps; *p != NUL; ) {
    copy_option_part(&p, buf, MAXPATHL, ",");

    f = 0;
    if (VIM_ISDIGIT(*buf)) {
      s = buf;
      sps_limit = getdigits(&s);
      if (*s != NUL && !VIM_ISDIGIT(*s))
        f = -1;
    } else if (STRCMP(buf, "best") == 0)
      f = SPS_BEST;
    else if (STRCMP(buf, "fast") == 0)
      f = SPS_FAST;
    else if (STRCMP(buf, "double") == 0)
      f = SPS_DOUBLE;
    else if (STRNCMP(buf, "expr:", 5) != 0
             && STRNCMP(buf, "file:", 5) != 0)
      f = -1;

    if (f == -1 || (sps_flags != 0 && f != 0)) {
      sps_flags = SPS_BEST;
      sps_limit = 9999;
      return FAIL;
    }
    if (f != 0)
      sps_flags = f;
  }

  if (sps_flags == 0)
    sps_flags = SPS_BEST;

  return OK;
}

// "z=": Find badly spelled word under or after the cursor.
// Give suggestions for the properly spelled word.
// In Visual mode use the highlighted word as the bad word.
// When "count" is non-zero use that suggestion.
void spell_suggest(int count)
{
  char_u      *line;
  pos_T prev_cursor = curwin->w_cursor;
  char_u wcopy[MAXWLEN + 2];
  char_u      *p;
  int c;
  suginfo_T sug;
  suggest_T   *stp;
  int mouse_used;
  int need_cap;
  int limit;
  int selected = count;
  int badlen = 0;
  int msg_scroll_save = msg_scroll;

  if (no_spell_checking(curwin))
    return;

  if (VIsual_active) {
    // Use the Visually selected text as the bad word.  But reject
    // a multi-line selection.
    if (curwin->w_cursor.lnum != VIsual.lnum) {
      vim_beep();
      return;
    }
    badlen = (int)curwin->w_cursor.col - (int)VIsual.col;
    if (badlen < 0)
      badlen = -badlen;
    else
      curwin->w_cursor.col = VIsual.col;
    ++badlen;
    end_visual_mode();
  } else
  // Find the start of the badly spelled word.
  if (spell_move_to(curwin, FORWARD, true, true, NULL) == 0
      || curwin->w_cursor.col > prev_cursor.col) {
    // No bad word or it starts after the cursor: use the word under the
    // cursor.
    curwin->w_cursor = prev_cursor;
    line = get_cursor_line_ptr();
    p = line + curwin->w_cursor.col;
    // Backup to before start of word.
    while (p > line && spell_iswordp_nmw(p, curwin))
      mb_ptr_back(line, p);
    // Forward to start of word.
    while (*p != NUL && !spell_iswordp_nmw(p, curwin))
      mb_ptr_adv(p);

    if (!spell_iswordp_nmw(p, curwin)) {                // No word found.
      beep_flush();
      return;
    }
    curwin->w_cursor.col = (colnr_T)(p - line);
  }

  // Get the word and its length.

  // Figure out if the word should be capitalised.
  need_cap = check_need_cap(curwin->w_cursor.lnum, curwin->w_cursor.col);

  // Make a copy of current line since autocommands may free the line.
  line = vim_strsave(get_cursor_line_ptr());

  // Get the list of suggestions.  Limit to 'lines' - 2 or the number in
  // 'spellsuggest', whatever is smaller.
  if (sps_limit > (int)Rows - 2)
    limit = (int)Rows - 2;
  else
    limit = sps_limit;
  spell_find_suggest(line + curwin->w_cursor.col, badlen, &sug, limit,
      true, need_cap, true);

  if (GA_EMPTY(&sug.su_ga))
    MSG(_("Sorry, no suggestions"));
  else if (count > 0) {
    if (count > sug.su_ga.ga_len)
      smsg((char_u *)_("Sorry, only %" PRId64 " suggestions"),
          (int64_t)sug.su_ga.ga_len);
  } else {
    free(repl_from);
    repl_from = NULL;
    free(repl_to);
    repl_to = NULL;

    // When 'rightleft' is set the list is drawn right-left.
    cmdmsg_rl = curwin->w_p_rl;
    if (cmdmsg_rl)
      msg_col = Columns - 1;

    // List the suggestions.
    msg_start();
    msg_row = Rows - 1;         // for when 'cmdheight' > 1
    lines_left = Rows;          // avoid more prompt
    vim_snprintf((char *)IObuff, IOSIZE, _("Change \"%.*s\" to:"),
        sug.su_badlen, sug.su_badptr);
    if (cmdmsg_rl && STRNCMP(IObuff, "Change", 6) == 0) {
      // And now the rabbit from the high hat: Avoid showing the
      // untranslated message rightleft.
      vim_snprintf((char *)IObuff, IOSIZE, ":ot \"%.*s\" egnahC",
          sug.su_badlen, sug.su_badptr);
    }
    msg_puts(IObuff);
    msg_clr_eos();
    msg_putchar('\n');

    msg_scroll = TRUE;
    for (int i = 0; i < sug.su_ga.ga_len; ++i) {
      stp = &SUG(sug.su_ga, i);

      // The suggested word may replace only part of the bad word, add
      // the not replaced part.
      STRLCPY(wcopy, stp->st_word, MAXWLEN + 1);
      if (sug.su_badlen > stp->st_orglen)
        STRLCPY(wcopy + stp->st_wordlen,
            sug.su_badptr + stp->st_orglen,
            sug.su_badlen - stp->st_orglen + 1);
      vim_snprintf((char *)IObuff, IOSIZE, "%2d", i + 1);
      if (cmdmsg_rl)
        rl_mirror(IObuff);
      msg_puts(IObuff);

      vim_snprintf((char *)IObuff, IOSIZE, " \"%s\"", wcopy);
      msg_puts(IObuff);

      // The word may replace more than "su_badlen".
      if (sug.su_badlen < stp->st_orglen) {
        vim_snprintf((char *)IObuff, IOSIZE, _(" < \"%.*s\""),
            stp->st_orglen, sug.su_badptr);
        msg_puts(IObuff);
      }

      if (p_verbose > 0) {
        // Add the score.
        if (sps_flags & (SPS_DOUBLE | SPS_BEST))
          vim_snprintf((char *)IObuff, IOSIZE, " (%s%d - %d)",
              stp->st_salscore ? "s " : "",
              stp->st_score, stp->st_altscore);
        else
          vim_snprintf((char *)IObuff, IOSIZE, " (%d)",
              stp->st_score);
        if (cmdmsg_rl)
          // Mirror the numbers, but keep the leading space.
          rl_mirror(IObuff + 1);
        msg_advance(30);
        msg_puts(IObuff);
      }
      msg_putchar('\n');
    }

    cmdmsg_rl = FALSE;
    msg_col = 0;
    // Ask for choice.
    selected = prompt_for_number(&mouse_used);
    if (mouse_used)
      selected -= lines_left;
    lines_left = Rows;                  // avoid more prompt
    // don't delay for 'smd' in normal_cmd()
    msg_scroll = msg_scroll_save;
  }

  if (selected > 0 && selected <= sug.su_ga.ga_len && u_save_cursor() == OK) {
    // Save the from and to text for :spellrepall.
    stp = &SUG(sug.su_ga, selected - 1);
    if (sug.su_badlen > stp->st_orglen) {
      // Replacing less than "su_badlen", append the remainder to
      // repl_to.
      repl_from = vim_strnsave(sug.su_badptr, sug.su_badlen);
      vim_snprintf((char *)IObuff, IOSIZE, "%s%.*s", stp->st_word,
          sug.su_badlen - stp->st_orglen,
          sug.su_badptr + stp->st_orglen);
      repl_to = vim_strsave(IObuff);
    } else {
      // Replacing su_badlen or more, use the whole word.
      repl_from = vim_strnsave(sug.su_badptr, stp->st_orglen);
      repl_to = vim_strsave(stp->st_word);
    }

    // Replace the word.
    p = xmalloc(STRLEN(line) - stp->st_orglen + stp->st_wordlen + 1);
    c = (int)(sug.su_badptr - line);
    memmove(p, line, c);
    STRCPY(p + c, stp->st_word);
    STRCAT(p, sug.su_badptr + stp->st_orglen);
    ml_replace(curwin->w_cursor.lnum, p, FALSE);
    curwin->w_cursor.col = c;

    // For redo we use a change-word command.
    ResetRedobuff();
    AppendToRedobuff((char_u *)"ciw");
    AppendToRedobuffLit(p + c,
        stp->st_wordlen + sug.su_badlen - stp->st_orglen);
    AppendCharToRedobuff(ESC);

    // After this "p" may be invalid.
    changed_bytes(curwin->w_cursor.lnum, c);
  } else
    curwin->w_cursor = prev_cursor;

  spell_find_cleanup(&sug);
}

// Check if the word at line "lnum" column "col" is required to start with a
// capital.  This uses 'spellcapcheck' of the current buffer.
static bool check_need_cap(linenr_T lnum, colnr_T col)
{
  bool need_cap = false;
  char_u      *line;
  char_u      *line_copy = NULL;
  char_u      *p;
  colnr_T endcol;
  regmatch_T regmatch;

  if (curwin->w_s->b_cap_prog == NULL)
    return false;

  line = get_cursor_line_ptr();
  endcol = 0;
  if ((int)(skipwhite(line) - line) >= (int)col) {
    // At start of line, check if previous line is empty or sentence
    // ends there.
    if (lnum == 1)
      need_cap = true;
    else {
      line = ml_get(lnum - 1);
      if (*skipwhite(line) == NUL)
        need_cap = true;
      else {
        // Append a space in place of the line break.
        line_copy = concat_str(line, (char_u *)" ");
        line = line_copy;
        endcol = (colnr_T)STRLEN(line);
      }
    }
  } else
    endcol = col;

  if (endcol > 0) {
    // Check if sentence ends before the bad word.
    regmatch.regprog = curwin->w_s->b_cap_prog;
    regmatch.rm_ic = FALSE;
    p = line + endcol;
    for (;; ) {
      mb_ptr_back(line, p);
      if (p == line || spell_iswordp_nmw(p, curwin))
        break;
      if (vim_regexec(&regmatch, p, 0)
          && regmatch.endp[0] == line + endcol) {
        need_cap = true;
        break;
      }
    }
  }

  free(line_copy);

  return need_cap;
}


// ":spellrepall"
void ex_spellrepall(exarg_T *eap)
{
  pos_T pos = curwin->w_cursor;
  char_u      *frompat;
  int addlen;
  char_u      *line;
  char_u      *p;
  bool save_ws = p_ws;
  linenr_T prev_lnum = 0;

  if (repl_from == NULL || repl_to == NULL) {
    EMSG(_("E752: No previous spell replacement"));
    return;
  }
  addlen = (int)(STRLEN(repl_to) - STRLEN(repl_from));

  frompat = xmalloc(STRLEN(repl_from) + 7);
  sprintf((char *)frompat, "\\V\\<%s\\>", repl_from);
  p_ws = false;

  sub_nsubs = 0;
  sub_nlines = 0;
  curwin->w_cursor.lnum = 0;
  while (!got_int) {
    if (do_search(NULL, '/', frompat, 1L, SEARCH_KEEP, NULL) == 0
        || u_save_cursor() == FAIL)
      break;

    // Only replace when the right word isn't there yet.  This happens
    // when changing "etc" to "etc.".
    line = get_cursor_line_ptr();
    if (addlen <= 0 || STRNCMP(line + curwin->w_cursor.col,
            repl_to, STRLEN(repl_to)) != 0) {
      p = xmalloc(STRLEN(line) + addlen + 1);
      memmove(p, line, curwin->w_cursor.col);
      STRCPY(p + curwin->w_cursor.col, repl_to);
      STRCAT(p, line + curwin->w_cursor.col + STRLEN(repl_from));
      ml_replace(curwin->w_cursor.lnum, p, FALSE);
      changed_bytes(curwin->w_cursor.lnum, curwin->w_cursor.col);

      if (curwin->w_cursor.lnum != prev_lnum) {
        ++sub_nlines;
        prev_lnum = curwin->w_cursor.lnum;
      }
      ++sub_nsubs;
    }
    curwin->w_cursor.col += (colnr_T)STRLEN(repl_to);
  }

  p_ws = save_ws;
  curwin->w_cursor = pos;
  free(frompat);

  if (sub_nsubs == 0)
    EMSG2(_("E753: Not found: %s"), repl_from);
  else
    do_sub_msg(false);
}

// Find spell suggestions for "word".  Return them in the growarray "*gap" as
// a list of allocated strings.
void
spell_suggest_list (
    garray_T *gap,
    char_u *word,
    int maxcount,                   // maximum nr of suggestions
    bool need_cap,                  // 'spellcapcheck' matched
    bool interactive
)
{
  suginfo_T sug;
  suggest_T   *stp;
  char_u      *wcopy;

  spell_find_suggest(word, 0, &sug, maxcount, false, need_cap, interactive);

  // Make room in "gap".
  ga_init(gap, sizeof(char_u *), sug.su_ga.ga_len + 1);
  ga_grow(gap, sug.su_ga.ga_len);
  for (int i = 0; i < sug.su_ga.ga_len; ++i) {
    stp = &SUG(sug.su_ga, i);

    // The suggested word may replace only part of "word", add the not
    // replaced part.
    wcopy = xmalloc(stp->st_wordlen
                    + STRLEN(sug.su_badptr + stp->st_orglen) + 1);
    STRCPY(wcopy, stp->st_word);
    STRCPY(wcopy + stp->st_wordlen, sug.su_badptr + stp->st_orglen);
    ((char_u **)gap->ga_data)[gap->ga_len++] = wcopy;
  }

  spell_find_cleanup(&sug);
}

// Find spell suggestions for the word at the start of "badptr".
// Return the suggestions in "su->su_ga".
// The maximum number of suggestions is "maxcount".
// Note: does use info for the current window.
// This is based on the mechanisms of Aspell, but completely reimplemented.
static void
spell_find_suggest (
    char_u *badptr,
    int badlen,                     // length of bad word or 0 if unknown
    suginfo_T *su,
    int maxcount,
    bool banbadword,                 // don't include badword in suggestions
    bool need_cap,                  // word should start with capital
    bool interactive
)
{
  hlf_T attr = HLF_COUNT;
  char_u buf[MAXPATHL];
  char_u      *p;
  bool do_combine = false;
  char_u      *sps_copy;
  static bool expr_busy = false;
  int c;
  langp_T     *lp;

  // Set the info in "*su".
  memset(su, 0, sizeof(suginfo_T));
  ga_init(&su->su_ga, (int)sizeof(suggest_T), 10);
  ga_init(&su->su_sga, (int)sizeof(suggest_T), 10);
  if (*badptr == NUL)
    return;
  hash_init(&su->su_banned);

  su->su_badptr = badptr;
  if (badlen != 0)
    su->su_badlen = badlen;
  else
    su->su_badlen = spell_check(curwin, su->su_badptr, &attr, NULL, false);
  su->su_maxcount = maxcount;
  su->su_maxscore = SCORE_MAXINIT;

  if (su->su_badlen >= MAXWLEN)
    su->su_badlen = MAXWLEN - 1;        // just in case
  STRLCPY(su->su_badword, su->su_badptr, su->su_badlen + 1);
  (void)spell_casefold(su->su_badptr, su->su_badlen,
      su->su_fbadword, MAXWLEN);
  // get caps flags for bad word
  su->su_badflags = badword_captype(su->su_badptr,
      su->su_badptr + su->su_badlen);
  if (need_cap)
    su->su_badflags |= WF_ONECAP;

  // Find the default language for sound folding.  We simply use the first
  // one in 'spelllang' that supports sound folding.  That's good for when
  // using multiple files for one language, it's not that bad when mixing
  // languages (e.g., "pl,en").
  for (int i = 0; i < curbuf->b_s.b_langp.ga_len; ++i) {
    lp = LANGP_ENTRY(curbuf->b_s.b_langp, i);
    if (lp->lp_sallang != NULL) {
      su->su_sallang = lp->lp_sallang;
      break;
    }
  }

  // Soundfold the bad word with the default sound folding, so that we don't
  // have to do this many times.
  if (su->su_sallang != NULL)
    spell_soundfold(su->su_sallang, su->su_fbadword, true,
        su->su_sal_badword);

  // If the word is not capitalised and spell_check() doesn't consider the
  // word to be bad then it might need to be capitalised.  Add a suggestion
  // for that.
  c = PTR2CHAR(su->su_badptr);
  if (!SPELL_ISUPPER(c) && attr == HLF_COUNT) {
    make_case_word(su->su_badword, buf, WF_ONECAP);
    add_suggestion(su, &su->su_ga, buf, su->su_badlen, SCORE_ICASE,
        0, true, su->su_sallang, false);
  }

  // Ban the bad word itself.  It may appear in another region.
  if (banbadword)
    add_banned(su, su->su_badword);

  // Make a copy of 'spellsuggest', because the expression may change it.
  sps_copy = vim_strsave(p_sps);

  // Loop over the items in 'spellsuggest'.
  for (p = sps_copy; *p != NUL; ) {
    copy_option_part(&p, buf, MAXPATHL, ",");

    if (STRNCMP(buf, "expr:", 5) == 0) {
      // Evaluate an expression.  Skip this when called recursively,
      // when using spellsuggest() in the expression.
      if (!expr_busy) {
        expr_busy = true;
        spell_suggest_expr(su, buf + 5);
        expr_busy = false;
      }
    } else if (STRNCMP(buf, "file:", 5) == 0)
      // Use list of suggestions in a file.
      spell_suggest_file(su, buf + 5);
    else {
      // Use internal method.
      spell_suggest_intern(su, interactive);
      if (sps_flags & SPS_DOUBLE)
        do_combine = true;
    }
  }

  free(sps_copy);

  if (do_combine)
    // Combine the two list of suggestions.  This must be done last,
    // because sorting changes the order again.
    score_combine(su);
}

// Find suggestions by evaluating expression "expr".
static void spell_suggest_expr(suginfo_T *su, char_u *expr)
{
  list_T      *list;
  listitem_T  *li;
  int score;
  char_u      *p;

  // The work is split up in a few parts to avoid having to export
  // suginfo_T.
  // First evaluate the expression and get the resulting list.
  list = eval_spell_expr(su->su_badword, expr);
  if (list != NULL) {
    // Loop over the items in the list.
    for (li = list->lv_first; li != NULL; li = li->li_next)
      if (li->li_tv.v_type == VAR_LIST) {
        // Get the word and the score from the items.
        score = get_spellword(li->li_tv.vval.v_list, &p);
        if (score >= 0 && score <= su->su_maxscore)
          add_suggestion(su, &su->su_ga, p, su->su_badlen,
              score, 0, true, su->su_sallang, false);
      }
    list_unref(list);
  }

  // Remove bogus suggestions, sort and truncate at "maxcount".
  check_suggestions(su, &su->su_ga);
  (void)cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
}

// Find suggestions in file "fname".  Used for "file:" in 'spellsuggest'.
static void spell_suggest_file(suginfo_T *su, char_u *fname)
{
  FILE        *fd;
  char_u line[MAXWLEN * 2];
  char_u      *p;
  int len;
  char_u cword[MAXWLEN];

  // Open the file.
  fd = mch_fopen((char *)fname, "r");
  if (fd == NULL) {
    EMSG2(_(e_notopen), fname);
    return;
  }

  // Read it line by line.
  while (!vim_fgets(line, MAXWLEN * 2, fd) && !got_int) {
    line_breakcheck();

    p = vim_strchr(line, '/');
    if (p == NULL)
      continue;             // No Tab found, just skip the line.
    *p++ = NUL;
    if (STRICMP(su->su_badword, line) == 0) {
      // Match!  Isolate the good word, until CR or NL.
      for (len = 0; p[len] >= ' '; ++len)
        ;
      p[len] = NUL;

      // If the suggestion doesn't have specific case duplicate the case
      // of the bad word.
      if (captype(p, NULL) == 0) {
        make_case_word(p, cword, su->su_badflags);
        p = cword;
      }

      add_suggestion(su, &su->su_ga, p, su->su_badlen,
          SCORE_FILE, 0, true, su->su_sallang, false);
    }
  }

  fclose(fd);

  // Remove bogus suggestions, sort and truncate at "maxcount".
  check_suggestions(su, &su->su_ga);
  (void)cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
}

// Find suggestions for the internal method indicated by "sps_flags".
static void spell_suggest_intern(suginfo_T *su, bool interactive)
{
  // Load the .sug file(s) that are available and not done yet.
  suggest_load_files();

  // 1. Try special cases, such as repeating a word: "the the" -> "the".
  //
  // Set a maximum score to limit the combination of operations that is
  // tried.
  suggest_try_special(su);

  // 2. Try inserting/deleting/swapping/changing a letter, use REP entries
  //    from the .aff file and inserting a space (split the word).
  suggest_try_change(su);

  // For the resulting top-scorers compute the sound-a-like score.
  if (sps_flags & SPS_DOUBLE)
    score_comp_sal(su);

  // 3. Try finding sound-a-like words.
  if ((sps_flags & SPS_FAST) == 0) {
    if (sps_flags & SPS_BEST)
      // Adjust the word score for the suggestions found so far for how
      // they sounds like.
      rescore_suggestions(su);

    // While going through the soundfold tree "su_maxscore" is the score
    // for the soundfold word, limits the changes that are being tried,
    // and "su_sfmaxscore" the rescored score, which is set by
    // cleanup_suggestions().
    // First find words with a small edit distance, because this is much
    // faster and often already finds the top-N suggestions.  If we didn't
    // find many suggestions try again with a higher edit distance.
    // "sl_sounddone" is used to avoid doing the same word twice.
    suggest_try_soundalike_prep();
    su->su_maxscore = SCORE_SFMAX1;
    su->su_sfmaxscore = SCORE_MAXINIT * 3;
    suggest_try_soundalike(su);
    if (su->su_ga.ga_len < SUG_CLEAN_COUNT(su)) {
      // We didn't find enough matches, try again, allowing more
      // changes to the soundfold word.
      su->su_maxscore = SCORE_SFMAX2;
      suggest_try_soundalike(su);
      if (su->su_ga.ga_len < SUG_CLEAN_COUNT(su)) {
        // Still didn't find enough matches, try again, allowing even
        // more changes to the soundfold word.
        su->su_maxscore = SCORE_SFMAX3;
        suggest_try_soundalike(su);
      }
    }
    su->su_maxscore = su->su_sfmaxscore;
    suggest_try_soundalike_finish();
  }

  // When CTRL-C was hit while searching do show the results.  Only clear
  // got_int when using a command, not for spellsuggest().
  os_breakcheck();
  if (interactive && got_int) {
    (void)vgetc();
    got_int = FALSE;
  }

  if ((sps_flags & SPS_DOUBLE) == 0 && su->su_ga.ga_len != 0) {
    if (sps_flags & SPS_BEST)
      // Adjust the word score for how it sounds like.
      rescore_suggestions(su);

    // Remove bogus suggestions, sort and truncate at "maxcount".
    check_suggestions(su, &su->su_ga);
    (void)cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
  }
}

// Load the .sug files for languages that have one and weren't loaded yet.
static void suggest_load_files(void)
{
  langp_T     *lp;
  slang_T     *slang;
  char_u      *dotp;
  FILE        *fd;
  char_u buf[MAXWLEN];
  int i;
  time_t timestamp;
  int wcount;
  int wordnr;
  garray_T ga;
  int c;

  // Do this for all languages that support sound folding.
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    slang = lp->lp_slang;
    if (slang->sl_sugtime != 0 && !slang->sl_sugloaded) {
      // Change ".spl" to ".sug" and open the file.  When the file isn't
      // found silently skip it.  Do set "sl_sugloaded" so that we
      // don't try again and again.
      slang->sl_sugloaded = true;

      dotp = vim_strrchr(slang->sl_fname, '.');
      if (dotp == NULL || fnamecmp(dotp, ".spl") != 0)
        continue;
      STRCPY(dotp, ".sug");
      fd = mch_fopen((char *)slang->sl_fname, "r");
      if (fd == NULL)
        goto nextone;

      // <SUGHEADER>: <fileID> <versionnr> <timestamp>
      for (i = 0; i < VIMSUGMAGICL; ++i)
        buf[i] = getc(fd);                              // <fileID>
      if (STRNCMP(buf, VIMSUGMAGIC, VIMSUGMAGICL) != 0) {
        EMSG2(_("E778: This does not look like a .sug file: %s"),
            slang->sl_fname);
        goto nextone;
      }
      c = getc(fd);                                     // <versionnr>
      if (c < VIMSUGVERSION) {
        EMSG2(_("E779: Old .sug file, needs to be updated: %s"),
            slang->sl_fname);
        goto nextone;
      } else if (c > VIMSUGVERSION)   {
        EMSG2(_("E780: .sug file is for newer version of Vim: %s"),
            slang->sl_fname);
        goto nextone;
      }

      // Check the timestamp, it must be exactly the same as the one in
      // the .spl file.  Otherwise the word numbers won't match.
      timestamp = get8ctime(fd);                        // <timestamp>
      if (timestamp != slang->sl_sugtime) {
        EMSG2(_("E781: .sug file doesn't match .spl file: %s"),
            slang->sl_fname);
        goto nextone;
      }

      // <SUGWORDTREE>: <wordtree>
      // Read the trie with the soundfolded words.
      if (spell_read_tree(fd, &slang->sl_sbyts, &slang->sl_sidxs,
              false, 0) != 0) {
someerror:
        EMSG2(_("E782: error while reading .sug file: %s"),
            slang->sl_fname);
        slang_clear_sug(slang);
        goto nextone;
      }

      // <SUGTABLE>: <sugwcount> <sugline> ...
      //
      // Read the table with word numbers.  We use a file buffer for
      // this, because it's so much like a file with lines.  Makes it
      // possible to swap the info and save on memory use.
      slang->sl_sugbuf = open_spellbuf();

      // <sugwcount>
      wcount = get4c(fd);
      if (wcount < 0)
        goto someerror;

      // Read all the wordnr lists into the buffer, one NUL terminated
      // list per line.
      ga_init(&ga, 1, 100);
      for (wordnr = 0; wordnr < wcount; ++wordnr) {
        ga.ga_len = 0;
        for (;; ) {
          c = getc(fd);                                     // <sugline>
          if (c < 0) {
            goto someerror;
          }
          GA_APPEND(char_u, &ga, c);
          if (c == NUL)
            break;
        }
        if (ml_append_buf(slang->sl_sugbuf, (linenr_T)wordnr,
                ga.ga_data, ga.ga_len, TRUE) == FAIL)
          goto someerror;
      }
      ga_clear(&ga);

      // Need to put word counts in the word tries, so that we can find
      // a word by its number.
      tree_count_words(slang->sl_fbyts, slang->sl_fidxs);
      tree_count_words(slang->sl_sbyts, slang->sl_sidxs);

nextone:
      if (fd != NULL)
        fclose(fd);
      STRCPY(dotp, ".spl");
    }
  }
}

// Fill in the wordcount fields for a trie.
// Returns the total number of words.
static void tree_count_words(char_u *byts, idx_T *idxs)
{
  int depth;
  idx_T arridx[MAXWLEN];
  int curi[MAXWLEN];
  int c;
  idx_T n;
  int wordcount[MAXWLEN];

  arridx[0] = 0;
  curi[0] = 1;
  wordcount[0] = 0;
  depth = 0;
  while (depth >= 0 && !got_int) {
    if (curi[depth] > byts[arridx[depth]]) {
      // Done all bytes at this node, go up one level.
      idxs[arridx[depth]] = wordcount[depth];
      if (depth > 0)
        wordcount[depth - 1] += wordcount[depth];

      --depth;
      fast_breakcheck();
    } else {
      // Do one more byte at this node.
      n = arridx[depth] + curi[depth];
      ++curi[depth];

      c = byts[n];
      if (c == 0) {
        // End of word, count it.
        ++wordcount[depth];

        // Skip over any other NUL bytes (same word with different
        // flags).
        while (byts[n + 1] == 0) {
          ++n;
          ++curi[depth];
        }
      } else {
        // Normal char, go one level deeper to count the words.
        ++depth;
        arridx[depth] = idxs[n];
        curi[depth] = 1;
        wordcount[depth] = 0;
      }
    }
  }
}

// Free the info put in "*su" by spell_find_suggest().
static void spell_find_cleanup(suginfo_T *su)
{
  // Free the suggestions.
  for (int i = 0; i < su->su_ga.ga_len; ++i) {
    free(SUG(su->su_ga, i).st_word);
  }
  ga_clear(&su->su_ga);
  for (int i = 0; i < su->su_sga.ga_len; ++i) {
    free(SUG(su->su_sga, i).st_word);
  }
  ga_clear(&su->su_sga);

  // Free the banned words.
  hash_clear_all(&su->su_banned, 0);
}

// Make a copy of "word", with the first letter upper or lower cased, to
// "wcopy[MAXWLEN]".  "word" must not be empty.
// The result is NUL terminated.
static void
onecap_copy (
    char_u *word,
    char_u *wcopy,
    bool upper                  // true: first letter made upper case
)
{
  char_u      *p;
  int c;
  int l;

  p = word;
  if (has_mbyte)
    c = mb_cptr2char_adv(&p);
  else
    c = *p++;
  if (upper)
    c = SPELL_TOUPPER(c);
  else
    c = SPELL_TOFOLD(c);
  if (has_mbyte)
    l = mb_char2bytes(c, wcopy);
  else {
    l = 1;
    wcopy[0] = c;
  }
  STRLCPY(wcopy + l, p, MAXWLEN - l);
}

// Make a copy of "word" with all the letters upper cased into
// "wcopy[MAXWLEN]".  The result is NUL terminated.
static void allcap_copy(char_u *word, char_u *wcopy)
{
  char_u      *s;
  char_u      *d;
  int c;

  d = wcopy;
  for (s = word; *s != NUL; ) {
    if (has_mbyte)
      c = mb_cptr2char_adv(&s);
    else
      c = *s++;

    // We only change 0xdf to SS when we are certain latin1 is used.  It
    // would cause weird errors in other 8-bit encodings.
    if (enc_latin1like && c == 0xdf) {
      c = 'S';
      if (d - wcopy >= MAXWLEN - 1)
        break;
      *d++ = c;
    } else
      c = SPELL_TOUPPER(c);

    if (has_mbyte) {
      if (d - wcopy >= MAXWLEN - MB_MAXBYTES)
        break;
      d += mb_char2bytes(c, d);
    } else {
      if (d - wcopy >= MAXWLEN - 1)
        break;
      *d++ = c;
    }
  }
  *d = NUL;
}

// Try finding suggestions by recognizing specific situations.
static void suggest_try_special(suginfo_T *su)
{
  char_u      *p;
  size_t len;
  int c;
  char_u word[MAXWLEN];

  // Recognize a word that is repeated: "the the".
  p = skiptowhite(su->su_fbadword);
  len = p - su->su_fbadword;
  p = skipwhite(p);
  if (STRLEN(p) == len && STRNCMP(su->su_fbadword, p, len) == 0) {
    // Include badflags: if the badword is onecap or allcap
    // use that for the goodword too: "The the" -> "The".
    c = su->su_fbadword[len];
    su->su_fbadword[len] = NUL;
    make_case_word(su->su_fbadword, word, su->su_badflags);
    su->su_fbadword[len] = c;

    // Give a soundalike score of 0, compute the score as if deleting one
    // character.
    add_suggestion(su, &su->su_ga, word, su->su_badlen,
        RESCORE(SCORE_REP, 0), 0, true, su->su_sallang, false);
  }
}

// Try finding suggestions by adding/removing/swapping letters.
static void suggest_try_change(suginfo_T *su)
{
  char_u fword[MAXWLEN];            // copy of the bad word, case-folded
  int n;
  char_u      *p;
  langp_T     *lp;

  // We make a copy of the case-folded bad word, so that we can modify it
  // to find matches (esp. REP items).  Append some more text, changing
  // chars after the bad word may help.
  STRCPY(fword, su->su_fbadword);
  n = (int)STRLEN(fword);
  p = su->su_badptr + su->su_badlen;
  (void)spell_casefold(p, (int)STRLEN(p), fword + n, MAXWLEN - n);

  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);

    // If reloading a spell file fails it's still in the list but
    // everything has been cleared.
    if (lp->lp_slang->sl_fbyts == NULL)
      continue;

    // Try it for this language.  Will add possible suggestions.
    suggest_trie_walk(su, lp, fword, false);
  }
}

// Check the maximum score, if we go over it we won't try this change.
#define TRY_DEEPER(su, stack, depth, add) \
  (stack[depth].ts_score + (add) < su->su_maxscore)

// Try finding suggestions by adding/removing/swapping letters.
//
// This uses a state machine.  At each node in the tree we try various
// operations.  When trying if an operation works "depth" is increased and the
// stack[] is used to store info.  This allows combinations, thus insert one
// character, replace one and delete another.  The number of changes is
// limited by su->su_maxscore.
//
// After implementing this I noticed an article by Kemal Oflazer that
// describes something similar: "Error-tolerant Finite State Recognition with
// Applications to Morphological Analysis and Spelling Correction" (1996).
// The implementation in the article is simplified and requires a stack of
// unknown depth.  The implementation here only needs a stack depth equal to
// the length of the word.
//
// This is also used for the sound-folded word, "soundfold" is true then.
// The mechanism is the same, but we find a match with a sound-folded word
// that comes from one or more original words.  Each of these words may be
// added, this is done by add_sound_suggest().
// Don't use:
//      the prefix tree or the keep-case tree
//      "su->su_badlen"
//      anything to do with upper and lower case
//      anything to do with word or non-word characters ("spell_iswordp()")
//      banned words
//      word flags (rare, region, compounding)
//      word splitting for now
//      "similar_chars()"
//      use "slang->sl_repsal" instead of "lp->lp_replang->sl_rep"
static void suggest_trie_walk(suginfo_T *su, langp_T *lp, char_u *fword, bool soundfold)
{
  char_u tword[MAXWLEN];            // good word collected so far
  trystate_T stack[MAXWLEN];
  char_u preword[MAXWLEN * 3];      // word found with proper case;
                                    // concatenation of prefix compound
                                    // words and split word.  NUL terminated
                                    // when going deeper but not when coming
                                    // back.
  char_u compflags[MAXWLEN];        // compound flags, one for each word
  trystate_T  *sp;
  int newscore;
  int score;
  char_u      *byts, *fbyts, *pbyts;
  idx_T       *idxs, *fidxs, *pidxs;
  int depth;
  int c, c2, c3;
  int n = 0;
  int flags;
  garray_T    *gap;
  idx_T arridx;
  int len;
  char_u      *p;
  fromto_T    *ftp;
  int fl = 0, tl;
  int repextra = 0;                 // extra bytes in fword[] from REP item
  slang_T     *slang = lp->lp_slang;
  int fword_ends;
  bool goodword_ends;
#ifdef DEBUG_TRIEWALK
  // Stores the name of the change made at each level.
  char_u changename[MAXWLEN][80];
#endif
  int breakcheckcount = 1000;
  bool compound_ok;

  // Go through the whole case-fold tree, try changes at each node.
  // "tword[]" contains the word collected from nodes in the tree.
  // "fword[]" the word we are trying to match with (initially the bad
  // word).
  depth = 0;
  sp = &stack[0];
  memset(sp, 0, sizeof(trystate_T));
  sp->ts_curi = 1;

  if (soundfold) {
    // Going through the soundfold tree.
    byts = fbyts = slang->sl_sbyts;
    idxs = fidxs = slang->sl_sidxs;
    pbyts = NULL;
    pidxs = NULL;
    sp->ts_prefixdepth = PFD_NOPREFIX;
    sp->ts_state = STATE_START;
  } else {
    // When there are postponed prefixes we need to use these first.  At
    // the end of the prefix we continue in the case-fold tree.
    fbyts = slang->sl_fbyts;
    fidxs = slang->sl_fidxs;
    pbyts = slang->sl_pbyts;
    pidxs = slang->sl_pidxs;
    if (pbyts != NULL) {
      byts = pbyts;
      idxs = pidxs;
      sp->ts_prefixdepth = PFD_PREFIXTREE;
      sp->ts_state = STATE_NOPREFIX;            // try without prefix first
    } else {
      byts = fbyts;
      idxs = fidxs;
      sp->ts_prefixdepth = PFD_NOPREFIX;
      sp->ts_state = STATE_START;
    }
  }

  // Loop to find all suggestions.  At each round we either:
  // - For the current state try one operation, advance "ts_curi",
  //   increase "depth".
  // - When a state is done go to the next, set "ts_state".
  // - When all states are tried decrease "depth".
  while (depth >= 0 && !got_int) {
    sp = &stack[depth];
    switch (sp->ts_state) {
    case STATE_START:
    case STATE_NOPREFIX:
      // Start of node: Deal with NUL bytes, which means
      // tword[] may end here.
      arridx = sp->ts_arridx;               // current node in the tree
      len = byts[arridx];                   // bytes in this node
      arridx += sp->ts_curi;                // index of current byte

      if (sp->ts_prefixdepth == PFD_PREFIXTREE) {
        // Skip over the NUL bytes, we use them later.
        for (n = 0; n < len && byts[arridx + n] == 0; ++n)
          ;
        sp->ts_curi += n;

        // Always past NUL bytes now.
        n = (int)sp->ts_state;
        sp->ts_state = STATE_ENDNUL;
        sp->ts_save_badflags = su->su_badflags;

        // At end of a prefix or at start of prefixtree: check for
        // following word.
        if (byts[arridx] == 0 || n == (int)STATE_NOPREFIX) {
          // Set su->su_badflags to the caps type at this position.
          // Use the caps type until here for the prefix itself.
          if (has_mbyte)
            n = nofold_len(fword, sp->ts_fidx, su->su_badptr);
          else
            n = sp->ts_fidx;
          flags = badword_captype(su->su_badptr, su->su_badptr + n);
          su->su_badflags = badword_captype(su->su_badptr + n,
              su->su_badptr + su->su_badlen);
#ifdef DEBUG_TRIEWALK
          sprintf(changename[depth], "prefix");
#endif
          go_deeper(stack, depth, 0);
          ++depth;
          sp = &stack[depth];
          sp->ts_prefixdepth = depth - 1;
          byts = fbyts;
          idxs = fidxs;
          sp->ts_arridx = 0;

          // Move the prefix to preword[] with the right case
          // and make find_keepcap_word() works.
          tword[sp->ts_twordlen] = NUL;
          make_case_word(tword + sp->ts_splitoff,
              preword + sp->ts_prewordlen, flags);
          sp->ts_prewordlen = (char_u)STRLEN(preword);
          sp->ts_splitoff = sp->ts_twordlen;
        }
        break;
      }

      if (sp->ts_curi > len || byts[arridx] != 0) {
        // Past bytes in node and/or past NUL bytes.
        sp->ts_state = STATE_ENDNUL;
        sp->ts_save_badflags = su->su_badflags;
        break;
      }

      // End of word in tree.
      ++sp->ts_curi;                    // eat one NUL byte

      flags = (int)idxs[arridx];

      // Skip words with the NOSUGGEST flag.
      if (flags & WF_NOSUGGEST)
        break;

      fword_ends = (fword[sp->ts_fidx] == NUL
                    || (soundfold
                        ? vim_iswhite(fword[sp->ts_fidx])
                        : !spell_iswordp(fword + sp->ts_fidx, curwin)));
      tword[sp->ts_twordlen] = NUL;

      if (sp->ts_prefixdepth <= PFD_NOTSPECIAL
          && (sp->ts_flags & TSF_PREFIXOK) == 0) {
        // There was a prefix before the word.  Check that the prefix
        // can be used with this word.
        // Count the length of the NULs in the prefix.  If there are
        // none this must be the first try without a prefix.
        n = stack[sp->ts_prefixdepth].ts_arridx;
        len = pbyts[n++];
        for (c = 0; c < len && pbyts[n + c] == 0; ++c)
          ;
        if (c > 0) {
          c = valid_word_prefix(c, n, flags,
              tword + sp->ts_splitoff, slang, false);
          if (c == 0)
            break;

          // Use the WF_RARE flag for a rare prefix.
          if (c & WF_RAREPFX)
            flags |= WF_RARE;

          // Tricky: when checking for both prefix and compounding
          // we run into the prefix flag first.
          // Remember that it's OK, so that we accept the prefix
          // when arriving at a compound flag.
          sp->ts_flags |= TSF_PREFIXOK;
        }
      }

      // Check NEEDCOMPOUND: can't use word without compounding.  Do try
      // appending another compound word below.
      if (sp->ts_complen == sp->ts_compsplit && fword_ends
          && (flags & WF_NEEDCOMP))
        goodword_ends = false;
      else
        goodword_ends = true;

      p = NULL;
      compound_ok = true;
      if (sp->ts_complen > sp->ts_compsplit) {
        if (slang->sl_nobreak) {
          // There was a word before this word.  When there was no
          // change in this word (it was correct) add the first word
          // as a suggestion.  If this word was corrected too, we
          // need to check if a correct word follows.
          if (sp->ts_fidx - sp->ts_splitfidx
              == sp->ts_twordlen - sp->ts_splitoff
              && STRNCMP(fword + sp->ts_splitfidx,
                  tword + sp->ts_splitoff,
                  sp->ts_fidx - sp->ts_splitfidx) == 0) {
            preword[sp->ts_prewordlen] = NUL;
            newscore = score_wordcount_adj(slang, sp->ts_score,
                preword + sp->ts_prewordlen,
                sp->ts_prewordlen > 0);
            // Add the suggestion if the score isn't too bad.
            if (newscore <= su->su_maxscore)
              add_suggestion(su, &su->su_ga, preword,
                  sp->ts_splitfidx - repextra,
                  newscore, 0, false,
                  lp->lp_sallang, false);
            break;
          }
        } else {
          // There was a compound word before this word.  If this
          // word does not support compounding then give up
          // (splitting is tried for the word without compound
          // flag).
          if (((unsigned)flags >> 24) == 0
              || sp->ts_twordlen - sp->ts_splitoff
              < slang->sl_compminlen)
            break;
          // For multi-byte chars check character length against
          // COMPOUNDMIN.
          if (has_mbyte
              && slang->sl_compminlen > 0
              && mb_charlen(tword + sp->ts_splitoff)
              < slang->sl_compminlen)
            break;

          compflags[sp->ts_complen] = ((unsigned)flags >> 24);
          compflags[sp->ts_complen + 1] = NUL;
          STRLCPY(preword + sp->ts_prewordlen,
              tword + sp->ts_splitoff,
              sp->ts_twordlen - sp->ts_splitoff + 1);

          // Verify CHECKCOMPOUNDPATTERN  rules.
          if (match_checkcompoundpattern(preword,  sp->ts_prewordlen,
                  &slang->sl_comppat))
            compound_ok = false;

          if (compound_ok) {
            p = preword;
            while (*skiptowhite(p) != NUL)
              p = skipwhite(skiptowhite(p));
            if (fword_ends && !can_compound(slang, p,
                    compflags + sp->ts_compsplit))
              // Compound is not allowed.  But it may still be
              // possible if we add another (short) word.
              compound_ok = false;
          }

          // Get pointer to last char of previous word.
          p = preword + sp->ts_prewordlen;
          mb_ptr_back(preword, p);
        }
      }

      // Form the word with proper case in preword.
      // If there is a word from a previous split, append.
      // For the soundfold tree don't change the case, simply append.
      if (soundfold)
        STRCPY(preword + sp->ts_prewordlen, tword + sp->ts_splitoff);
      else if (flags & WF_KEEPCAP)
        // Must find the word in the keep-case tree.
        find_keepcap_word(slang, tword + sp->ts_splitoff,
            preword + sp->ts_prewordlen);
      else {
        // Include badflags: If the badword is onecap or allcap
        // use that for the goodword too.  But if the badword is
        // allcap and it's only one char long use onecap.
        c = su->su_badflags;
        if ((c & WF_ALLCAP)
            && su->su_badlen == (*mb_ptr2len)(su->su_badptr)
            )
          c = WF_ONECAP;
        c |= flags;

        // When appending a compound word after a word character don't
        // use Onecap.
        if (p != NULL && spell_iswordp_nmw(p, curwin))
          c &= ~WF_ONECAP;
        make_case_word(tword + sp->ts_splitoff,
            preword + sp->ts_prewordlen, c);
      }

      if (!soundfold) {
        // Don't use a banned word.  It may appear again as a good
        // word, thus remember it.
        if (flags & WF_BANNED) {
          add_banned(su, preword + sp->ts_prewordlen);
          break;
        }
        if ((sp->ts_complen == sp->ts_compsplit
             && WAS_BANNED(su, preword + sp->ts_prewordlen))
            || WAS_BANNED(su, preword)) {
          if (slang->sl_compprog == NULL)
            break;
          // the word so far was banned but we may try compounding
          goodword_ends = false;
        }
      }

      newscore = 0;
      if (!soundfold) {         // soundfold words don't have flags
        if ((flags & WF_REGION)
            && (((unsigned)flags >> 16) & lp->lp_region) == 0)
          newscore += SCORE_REGION;
        if (flags & WF_RARE)
          newscore += SCORE_RARE;

        if (!spell_valid_case(su->su_badflags,
                captype(preword + sp->ts_prewordlen, NULL)))
          newscore += SCORE_ICASE;
      }

      // TODO: how about splitting in the soundfold tree?
      if (fword_ends
          && goodword_ends
          && sp->ts_fidx >= sp->ts_fidxtry
          && compound_ok) {
        // The badword also ends: add suggestions.
#ifdef DEBUG_TRIEWALK
        if (soundfold && STRCMP(preword, "smwrd") == 0) {
          int j;

          // print the stack of changes that brought us here
          smsg("------ %s -------", fword);
          for (j = 0; j < depth; ++j)
            smsg("%s", changename[j]);
        }
#endif
        if (soundfold) {
          // For soundfolded words we need to find the original
          // words, the edit distance and then add them.
          add_sound_suggest(su, preword, sp->ts_score, lp);
        } else if (sp->ts_fidx > 0)   {
          // Give a penalty when changing non-word char to word
          // char, e.g., "thes," -> "these".
          p = fword + sp->ts_fidx;
          mb_ptr_back(fword, p);
          if (!spell_iswordp(p, curwin)) {
            p = preword + STRLEN(preword);
            mb_ptr_back(preword, p);
            if (spell_iswordp(p, curwin))
              newscore += SCORE_NONWORD;
          }

          // Give a bonus to words seen before.
          score = score_wordcount_adj(slang,
              sp->ts_score + newscore,
              preword + sp->ts_prewordlen,
              sp->ts_prewordlen > 0);

          // Add the suggestion if the score isn't too bad.
          if (score <= su->su_maxscore) {
            add_suggestion(su, &su->su_ga, preword,
                sp->ts_fidx - repextra,
                score, 0, false, lp->lp_sallang, false);

            if (su->su_badflags & WF_MIXCAP) {
              // We really don't know if the word should be
              // upper or lower case, add both.
              c = captype(preword, NULL);
              if (c == 0 || c == WF_ALLCAP) {
                make_case_word(tword + sp->ts_splitoff,
                    preword + sp->ts_prewordlen,
                    c == 0 ? WF_ALLCAP : 0);

                add_suggestion(su, &su->su_ga, preword,
                    sp->ts_fidx - repextra,
                    score + SCORE_ICASE, 0, false,
                    lp->lp_sallang, false);
              }
            }
          }
        }
      }

      // Try word split and/or compounding.
      if ((sp->ts_fidx >= sp->ts_fidxtry || fword_ends)
          // Don't split halfway a character.
          && (!has_mbyte || sp->ts_tcharlen == 0)
          ) {
        bool try_compound;
        int try_split;

        // If past the end of the bad word don't try a split.
        // Otherwise try changing the next word.  E.g., find
        // suggestions for "the the" where the second "the" is
        // different.  It's done like a split.
        // TODO: word split for soundfold words
        try_split = (sp->ts_fidx - repextra < su->su_badlen)
                    && !soundfold;

        // Get here in several situations:
        // 1. The word in the tree ends:
        //    If the word allows compounding try that.  Otherwise try
        //    a split by inserting a space.  For both check that a
        //    valid words starts at fword[sp->ts_fidx].
        //    For NOBREAK do like compounding to be able to check if
        //    the next word is valid.
        // 2. The badword does end, but it was due to a change (e.g.,
        //    a swap).  No need to split, but do check that the
        //    following word is valid.
        // 3. The badword and the word in the tree end.  It may still
        //    be possible to compound another (short) word.
        try_compound = false;
        if (!soundfold
            && slang->sl_compprog != NULL
            && ((unsigned)flags >> 24) != 0
            && sp->ts_twordlen - sp->ts_splitoff
            >= slang->sl_compminlen
            && (!has_mbyte
                || slang->sl_compminlen == 0
                || mb_charlen(tword + sp->ts_splitoff)
                >= slang->sl_compminlen)
            && (slang->sl_compsylmax < MAXWLEN
                || sp->ts_complen + 1 - sp->ts_compsplit
                < slang->sl_compmax)
            && (can_be_compound(sp, slang,
                    compflags, ((unsigned)flags >> 24)))) {
          try_compound = true;
          compflags[sp->ts_complen] = ((unsigned)flags >> 24);
          compflags[sp->ts_complen + 1] = NUL;
        }

        // For NOBREAK we never try splitting, it won't make any word
        // valid.
        if (slang->sl_nobreak)
          try_compound = true;

        // If we could add a compound word, and it's also possible to
        // split at this point, do the split first and set
        // TSF_DIDSPLIT to avoid doing it again.
        else if (!fword_ends
                 && try_compound
                 && (sp->ts_flags & TSF_DIDSPLIT) == 0) {
          try_compound = false;
          sp->ts_flags |= TSF_DIDSPLIT;
          --sp->ts_curi;                    // do the same NUL again
          compflags[sp->ts_complen] = NUL;
        } else
          sp->ts_flags &= ~TSF_DIDSPLIT;

        if (try_split || try_compound) {
          if (!try_compound && (!fword_ends || !goodword_ends)) {
            // If we're going to split need to check that the
            // words so far are valid for compounding.  If there
            // is only one word it must not have the NEEDCOMPOUND
            // flag.
            if (sp->ts_complen == sp->ts_compsplit
                && (flags & WF_NEEDCOMP))
              break;
            p = preword;
            while (*skiptowhite(p) != NUL)
              p = skipwhite(skiptowhite(p));
            if (sp->ts_complen > sp->ts_compsplit
                && !can_compound(slang, p,
                    compflags + sp->ts_compsplit))
              break;

            if (slang->sl_nosplitsugs)
              newscore += SCORE_SPLIT_NO;
            else
              newscore += SCORE_SPLIT;

            // Give a bonus to words seen before.
            newscore = score_wordcount_adj(slang, newscore,
                preword + sp->ts_prewordlen, true);
          }

          if (TRY_DEEPER(su, stack, depth, newscore)) {
            go_deeper(stack, depth, newscore);
#ifdef DEBUG_TRIEWALK
            if (!try_compound && !fword_ends)
              sprintf(changename[depth], "%.*s-%s: split",
                  sp->ts_twordlen, tword, fword + sp->ts_fidx);
            else
              sprintf(changename[depth], "%.*s-%s: compound",
                  sp->ts_twordlen, tword, fword + sp->ts_fidx);
#endif
            // Save things to be restored at STATE_SPLITUNDO.
            sp->ts_save_badflags = su->su_badflags;
            sp->ts_state = STATE_SPLITUNDO;

            ++depth;
            sp = &stack[depth];

            // Append a space to preword when splitting.
            if (!try_compound && !fword_ends)
              STRCAT(preword, " ");
            sp->ts_prewordlen = (char_u)STRLEN(preword);
            sp->ts_splitoff = sp->ts_twordlen;
            sp->ts_splitfidx = sp->ts_fidx;

            // If the badword has a non-word character at this
            // position skip it.  That means replacing the
            // non-word character with a space.  Always skip a
            // character when the word ends.  But only when the
            // good word can end.
            if (((!try_compound && !spell_iswordp_nmw(fword
                      + sp->ts_fidx,
                      curwin))
                 || fword_ends)
                && fword[sp->ts_fidx] != NUL
                && goodword_ends) {
              int l;

              if (has_mbyte)
                l = MB_BYTE2LEN(fword[sp->ts_fidx]);
              else
                l = 1;
              if (fword_ends) {
                // Copy the skipped character to preword.
                memmove(preword + sp->ts_prewordlen,
                    fword + sp->ts_fidx, l);
                sp->ts_prewordlen += l;
                preword[sp->ts_prewordlen] = NUL;
              } else
                sp->ts_score -= SCORE_SPLIT - SCORE_SUBST;
              sp->ts_fidx += l;
            }

            // When compounding include compound flag in
            // compflags[] (already set above).  When splitting we
            // may start compounding over again.
            if (try_compound)
              ++sp->ts_complen;
            else
              sp->ts_compsplit = sp->ts_complen;
            sp->ts_prefixdepth = PFD_NOPREFIX;

            // set su->su_badflags to the caps type at this
            // position
            if (has_mbyte)
              n = nofold_len(fword, sp->ts_fidx, su->su_badptr);
            else
              n = sp->ts_fidx;
            su->su_badflags = badword_captype(su->su_badptr + n,
                su->su_badptr + su->su_badlen);

            // Restart at top of the tree.
            sp->ts_arridx = 0;

            // If there are postponed prefixes, try these too.
            if (pbyts != NULL) {
              byts = pbyts;
              idxs = pidxs;
              sp->ts_prefixdepth = PFD_PREFIXTREE;
              sp->ts_state = STATE_NOPREFIX;
            }
          }
        }
      }
      break;

    case STATE_SPLITUNDO:
      // Undo the changes done for word split or compound word.
      su->su_badflags = sp->ts_save_badflags;

      // Continue looking for NUL bytes.
      sp->ts_state = STATE_START;

      // In case we went into the prefix tree.
      byts = fbyts;
      idxs = fidxs;
      break;

    case STATE_ENDNUL:
      // Past the NUL bytes in the node.
      su->su_badflags = sp->ts_save_badflags;
      if (fword[sp->ts_fidx] == NUL
          && sp->ts_tcharlen == 0
          ) {
        // The badword ends, can't use STATE_PLAIN.
        sp->ts_state = STATE_DEL;
        break;
      }
      sp->ts_state = STATE_PLAIN;
    // FALLTHROUGH

    case STATE_PLAIN:
      // Go over all possible bytes at this node, add each to tword[]
      // and use child node.  "ts_curi" is the index.
      arridx = sp->ts_arridx;
      if (sp->ts_curi > byts[arridx]) {
        // Done all bytes at this node, do next state.  When still at
        // already changed bytes skip the other tricks.
        if (sp->ts_fidx >= sp->ts_fidxtry)
          sp->ts_state = STATE_DEL;
        else
          sp->ts_state = STATE_FINAL;
      } else {
        arridx += sp->ts_curi++;
        c = byts[arridx];

        // Normal byte, go one level deeper.  If it's not equal to the
        // byte in the bad word adjust the score.  But don't even try
        // when the byte was already changed.  And don't try when we
        // just deleted this byte, accepting it is always cheaper than
        // delete + substitute.
        if (c == fword[sp->ts_fidx]
            || (sp->ts_tcharlen > 0 && sp->ts_isdiff != DIFF_NONE)
            )
          newscore = 0;
        else
          newscore = SCORE_SUBST;
        if ((newscore == 0
             || (sp->ts_fidx >= sp->ts_fidxtry
                 && ((sp->ts_flags & TSF_DIDDEL) == 0
                     || c != fword[sp->ts_delidx])))
            && TRY_DEEPER(su, stack, depth, newscore)) {
          go_deeper(stack, depth, newscore);
#ifdef DEBUG_TRIEWALK
          if (newscore > 0)
            sprintf(changename[depth], "%.*s-%s: subst %c to %c",
                sp->ts_twordlen, tword, fword + sp->ts_fidx,
                fword[sp->ts_fidx], c);
          else
            sprintf(changename[depth], "%.*s-%s: accept %c",
                sp->ts_twordlen, tword, fword + sp->ts_fidx,
                fword[sp->ts_fidx]);
#endif
          ++depth;
          sp = &stack[depth];
          ++sp->ts_fidx;
          tword[sp->ts_twordlen++] = c;
          sp->ts_arridx = idxs[arridx];
          if (newscore == SCORE_SUBST)
            sp->ts_isdiff = DIFF_YES;
          if (has_mbyte) {
            // Multi-byte characters are a bit complicated to
            // handle: They differ when any of the bytes differ
            // and then their length may also differ.
            if (sp->ts_tcharlen == 0) {
              // First byte.
              sp->ts_tcharidx = 0;
              sp->ts_tcharlen = MB_BYTE2LEN(c);
              sp->ts_fcharstart = sp->ts_fidx - 1;
              sp->ts_isdiff = (newscore != 0)
                              ? DIFF_YES : DIFF_NONE;
            } else if (sp->ts_isdiff == DIFF_INSERT)
              // When inserting trail bytes don't advance in the
              // bad word.
              --sp->ts_fidx;
            if (++sp->ts_tcharidx == sp->ts_tcharlen) {
              // Last byte of character.
              if (sp->ts_isdiff == DIFF_YES) {
                // Correct ts_fidx for the byte length of the
                // character (we didn't check that before).
                sp->ts_fidx = sp->ts_fcharstart
                              + MB_BYTE2LEN(
                    fword[sp->ts_fcharstart]);

                // For changing a composing character adjust
                // the score from SCORE_SUBST to
                // SCORE_SUBCOMP.
                if (enc_utf8
                    && utf_iscomposing(
                        mb_ptr2char(tword
                            + sp->ts_twordlen
                            - sp->ts_tcharlen))
                    && utf_iscomposing(
                        mb_ptr2char(fword
                            + sp->ts_fcharstart)))
                  sp->ts_score -=
                    SCORE_SUBST - SCORE_SUBCOMP;

                // For a similar character adjust score from
                // SCORE_SUBST to SCORE_SIMILAR.
                else if (!soundfold
                         && slang->sl_has_map
                         && similar_chars(slang,
                             mb_ptr2char(tword
                                 + sp->ts_twordlen
                                 - sp->ts_tcharlen),
                             mb_ptr2char(fword
                                 + sp->ts_fcharstart)))
                  sp->ts_score -=
                    SCORE_SUBST - SCORE_SIMILAR;
              } else if (sp->ts_isdiff == DIFF_INSERT
                         && sp->ts_twordlen > sp->ts_tcharlen) {
                p = tword + sp->ts_twordlen - sp->ts_tcharlen;
                c = mb_ptr2char(p);
                if (enc_utf8 && utf_iscomposing(c)) {
                  // Inserting a composing char doesn't
                  // count that much.
                  sp->ts_score -= SCORE_INS - SCORE_INSCOMP;
                } else {
                  // If the previous character was the same,
                  // thus doubling a character, give a bonus
                  // to the score.  Also for the soundfold
                  // tree (might seem illogical but does
                  // give better scores).
                  mb_ptr_back(tword, p);
                  if (c == mb_ptr2char(p))
                    sp->ts_score -= SCORE_INS
                                    - SCORE_INSDUP;
                }
              }

              // Starting a new char, reset the length.
              sp->ts_tcharlen = 0;
            }
          } else {
            // If we found a similar char adjust the score.
            // We do this after calling go_deeper() because
            // it's slow.
            if (newscore != 0
                && !soundfold
                && slang->sl_has_map
                && similar_chars(slang,
                    c, fword[sp->ts_fidx - 1]))
              sp->ts_score -= SCORE_SUBST - SCORE_SIMILAR;
          }
        }
      }
      break;

    case STATE_DEL:
      // When past the first byte of a multi-byte char don't try
      // delete/insert/swap a character.
      if (has_mbyte && sp->ts_tcharlen > 0) {
        sp->ts_state = STATE_FINAL;
        break;
      }
      // Try skipping one character in the bad word (delete it).
      sp->ts_state = STATE_INS_PREP;
      sp->ts_curi = 1;
      if (soundfold && sp->ts_fidx == 0 && fword[sp->ts_fidx] == '*')
        // Deleting a vowel at the start of a word counts less, see
        // soundalike_score().
        newscore = 2 * SCORE_DEL / 3;
      else
        newscore = SCORE_DEL;
      if (fword[sp->ts_fidx] != NUL
          && TRY_DEEPER(su, stack, depth, newscore)) {
        go_deeper(stack, depth, newscore);
#ifdef DEBUG_TRIEWALK
        sprintf(changename[depth], "%.*s-%s: delete %c",
            sp->ts_twordlen, tword, fword + sp->ts_fidx,
            fword[sp->ts_fidx]);
#endif
        ++depth;

        // Remember what character we deleted, so that we can avoid
        // inserting it again.
        stack[depth].ts_flags |= TSF_DIDDEL;
        stack[depth].ts_delidx = sp->ts_fidx;

        // Advance over the character in fword[].  Give a bonus to the
        // score if the same character is following "nn" -> "n".  It's
        // a bit illogical for soundfold tree but it does give better
        // results.
        if (has_mbyte) {
          c = mb_ptr2char(fword + sp->ts_fidx);
          stack[depth].ts_fidx += MB_BYTE2LEN(fword[sp->ts_fidx]);
          if (enc_utf8 && utf_iscomposing(c))
            stack[depth].ts_score -= SCORE_DEL - SCORE_DELCOMP;
          else if (c == mb_ptr2char(fword + stack[depth].ts_fidx))
            stack[depth].ts_score -= SCORE_DEL - SCORE_DELDUP;
        } else {
          ++stack[depth].ts_fidx;
          if (fword[sp->ts_fidx] == fword[sp->ts_fidx + 1])
            stack[depth].ts_score -= SCORE_DEL - SCORE_DELDUP;
        }
        break;
      }
    // FALLTHROUGH

    case STATE_INS_PREP:
      if (sp->ts_flags & TSF_DIDDEL) {
        // If we just deleted a byte then inserting won't make sense,
        // a substitute is always cheaper.
        sp->ts_state = STATE_SWAP;
        break;
      }

      // skip over NUL bytes
      n = sp->ts_arridx;
      for (;; ) {
        if (sp->ts_curi > byts[n]) {
          // Only NUL bytes at this node, go to next state.
          sp->ts_state = STATE_SWAP;
          break;
        }
        if (byts[n + sp->ts_curi] != NUL) {
          // Found a byte to insert.
          sp->ts_state = STATE_INS;
          break;
        }
        ++sp->ts_curi;
      }
      break;

    // FALLTHROUGH

    case STATE_INS:
      // Insert one byte.  Repeat this for each possible byte at this
      // node.
      n = sp->ts_arridx;
      if (sp->ts_curi > byts[n]) {
        // Done all bytes at this node, go to next state.
        sp->ts_state = STATE_SWAP;
        break;
      }

      // Do one more byte at this node, but:
      // - Skip NUL bytes.
      // - Skip the byte if it's equal to the byte in the word,
      //   accepting that byte is always better.
      n += sp->ts_curi++;
      c = byts[n];
      if (soundfold && sp->ts_twordlen == 0 && c == '*')
        // Inserting a vowel at the start of a word counts less,
        // see soundalike_score().
        newscore = 2 * SCORE_INS / 3;
      else
        newscore = SCORE_INS;
      if (c != fword[sp->ts_fidx]
          && TRY_DEEPER(su, stack, depth, newscore)) {
        go_deeper(stack, depth, newscore);
#ifdef DEBUG_TRIEWALK
        sprintf(changename[depth], "%.*s-%s: insert %c",
            sp->ts_twordlen, tword, fword + sp->ts_fidx,
            c);
#endif
        ++depth;
        sp = &stack[depth];
        tword[sp->ts_twordlen++] = c;
        sp->ts_arridx = idxs[n];
        if (has_mbyte) {
          fl = MB_BYTE2LEN(c);
          if (fl > 1) {
            // There are following bytes for the same character.
            // We must find all bytes before trying
            // delete/insert/swap/etc.
            sp->ts_tcharlen = fl;
            sp->ts_tcharidx = 1;
            sp->ts_isdiff = DIFF_INSERT;
          }
        } else
          fl = 1;
        if (fl == 1) {
          // If the previous character was the same, thus doubling a
          // character, give a bonus to the score.  Also for
          // soundfold words (illogical but does give a better
          // score).
          if (sp->ts_twordlen >= 2
              && tword[sp->ts_twordlen - 2] == c)
            sp->ts_score -= SCORE_INS - SCORE_INSDUP;
        }
      }
      break;

    case STATE_SWAP:
      // Swap two bytes in the bad word: "12" -> "21".
      // We change "fword" here, it's changed back afterwards at
      // STATE_UNSWAP.
      p = fword + sp->ts_fidx;
      c = *p;
      if (c == NUL) {
        // End of word, can't swap or replace.
        sp->ts_state = STATE_FINAL;
        break;
      }

      // Don't swap if the first character is not a word character.
      // SWAP3 etc. also don't make sense then.
      if (!soundfold && !spell_iswordp(p, curwin)) {
        sp->ts_state = STATE_REP_INI;
        break;
      }

      if (has_mbyte) {
        n = mb_cptr2len(p);
        c = mb_ptr2char(p);
        if (p[n] == NUL)
          c2 = NUL;
        else if (!soundfold && !spell_iswordp(p + n, curwin))
          c2 = c;           // don't swap non-word char
        else
          c2 = mb_ptr2char(p + n);
      } else {
        if (p[1] == NUL)
          c2 = NUL;
        else if (!soundfold && !spell_iswordp(p + 1, curwin))
          c2 = c;           // don't swap non-word char
        else
          c2 = p[1];
      }

      // When the second character is NUL we can't swap.
      if (c2 == NUL) {
        sp->ts_state = STATE_REP_INI;
        break;
      }

      // When characters are identical, swap won't do anything.
      // Also get here if the second char is not a word character.
      if (c == c2) {
        sp->ts_state = STATE_SWAP3;
        break;
      }
      if (c2 != NUL && TRY_DEEPER(su, stack, depth, SCORE_SWAP)) {
        go_deeper(stack, depth, SCORE_SWAP);
#ifdef DEBUG_TRIEWALK
        sprintf(changename[depth], "%.*s-%s: swap %c and %c",
            sp->ts_twordlen, tword, fword + sp->ts_fidx,
            c, c2);
#endif
        sp->ts_state = STATE_UNSWAP;
        ++depth;
        if (has_mbyte) {
          fl = mb_char2len(c2);
          memmove(p, p + n, fl);
          mb_char2bytes(c, p + fl);
          stack[depth].ts_fidxtry = sp->ts_fidx + n + fl;
        } else {
          p[0] = c2;
          p[1] = c;
          stack[depth].ts_fidxtry = sp->ts_fidx + 2;
        }
      } else
        // If this swap doesn't work then SWAP3 won't either.
        sp->ts_state = STATE_REP_INI;
      break;

    case STATE_UNSWAP:
      // Undo the STATE_SWAP swap: "21" -> "12".
      p = fword + sp->ts_fidx;
      if (has_mbyte) {
        n = MB_BYTE2LEN(*p);
        c = mb_ptr2char(p + n);
        memmove(p + MB_BYTE2LEN(p[n]), p, n);
        mb_char2bytes(c, p);
      } else {
        c = *p;
        *p = p[1];
        p[1] = c;
      }
    // FALLTHROUGH

    case STATE_SWAP3:
      // Swap two bytes, skipping one: "123" -> "321".  We change
      // "fword" here, it's changed back afterwards at STATE_UNSWAP3.
      p = fword + sp->ts_fidx;
      if (has_mbyte) {
        n = mb_cptr2len(p);
        c = mb_ptr2char(p);
        fl = mb_cptr2len(p + n);
        c2 = mb_ptr2char(p + n);
        if (!soundfold && !spell_iswordp(p + n + fl, curwin))
          c3 = c;               // don't swap non-word char
        else
          c3 = mb_ptr2char(p + n + fl);
      } else {
        c = *p;
        c2 = p[1];
        if (!soundfold && !spell_iswordp(p + 2, curwin))
          c3 = c;               // don't swap non-word char
        else
          c3 = p[2];
      }

      // When characters are identical: "121" then SWAP3 result is
      // identical, ROT3L result is same as SWAP: "211", ROT3L result is
      // same as SWAP on next char: "112".  Thus skip all swapping.
      // Also skip when c3 is NUL.
      // Also get here when the third character is not a word character.
      // Second character may any char: "a.b" -> "b.a"
      if (c == c3 || c3 == NUL) {
        sp->ts_state = STATE_REP_INI;
        break;
      }
      if (TRY_DEEPER(su, stack, depth, SCORE_SWAP3)) {
        go_deeper(stack, depth, SCORE_SWAP3);
#ifdef DEBUG_TRIEWALK
        sprintf(changename[depth], "%.*s-%s: swap3 %c and %c",
            sp->ts_twordlen, tword, fword + sp->ts_fidx,
            c, c3);
#endif
        sp->ts_state = STATE_UNSWAP3;
        ++depth;
        if (has_mbyte) {
          tl = mb_char2len(c3);
          memmove(p, p + n + fl, tl);
          mb_char2bytes(c2, p + tl);
          mb_char2bytes(c, p + fl + tl);
          stack[depth].ts_fidxtry = sp->ts_fidx + n + fl + tl;
        } else {
          p[0] = p[2];
          p[2] = c;
          stack[depth].ts_fidxtry = sp->ts_fidx + 3;
        }
      } else
        sp->ts_state = STATE_REP_INI;
      break;

    case STATE_UNSWAP3:
      // Undo STATE_SWAP3: "321" -> "123"
      p = fword + sp->ts_fidx;
      if (has_mbyte) {
        n = MB_BYTE2LEN(*p);
        c2 = mb_ptr2char(p + n);
        fl = MB_BYTE2LEN(p[n]);
        c = mb_ptr2char(p + n + fl);
        tl = MB_BYTE2LEN(p[n + fl]);
        memmove(p + fl + tl, p, n);
        mb_char2bytes(c, p);
        mb_char2bytes(c2, p + tl);
        p = p + tl;
      } else {
        c = *p;
        *p = p[2];
        p[2] = c;
        ++p;
      }

      if (!soundfold && !spell_iswordp(p, curwin)) {
        // Middle char is not a word char, skip the rotate.  First and
        // third char were already checked at swap and swap3.
        sp->ts_state = STATE_REP_INI;
        break;
      }

      // Rotate three characters left: "123" -> "231".  We change
      // "fword" here, it's changed back afterwards at STATE_UNROT3L.
      if (TRY_DEEPER(su, stack, depth, SCORE_SWAP3)) {
        go_deeper(stack, depth, SCORE_SWAP3);
#ifdef DEBUG_TRIEWALK
        p = fword + sp->ts_fidx;
        sprintf(changename[depth], "%.*s-%s: rotate left %c%c%c",
            sp->ts_twordlen, tword, fword + sp->ts_fidx,
            p[0], p[1], p[2]);
#endif
        sp->ts_state = STATE_UNROT3L;
        ++depth;
        p = fword + sp->ts_fidx;
        if (has_mbyte) {
          n = mb_cptr2len(p);
          c = mb_ptr2char(p);
          fl = mb_cptr2len(p + n);
          fl += mb_cptr2len(p + n + fl);
          memmove(p, p + n, fl);
          mb_char2bytes(c, p + fl);
          stack[depth].ts_fidxtry = sp->ts_fidx + n + fl;
        } else {
          c = *p;
          *p = p[1];
          p[1] = p[2];
          p[2] = c;
          stack[depth].ts_fidxtry = sp->ts_fidx + 3;
        }
      } else
        sp->ts_state = STATE_REP_INI;
      break;

    case STATE_UNROT3L:
      // Undo ROT3L: "231" -> "123"
      p = fword + sp->ts_fidx;
      if (has_mbyte) {
        n = MB_BYTE2LEN(*p);
        n += MB_BYTE2LEN(p[n]);
        c = mb_ptr2char(p + n);
        tl = MB_BYTE2LEN(p[n]);
        memmove(p + tl, p, n);
        mb_char2bytes(c, p);
      } else {
        c = p[2];
        p[2] = p[1];
        p[1] = *p;
        *p = c;
      }

      // Rotate three bytes right: "123" -> "312".  We change "fword"
      // here, it's changed back afterwards at STATE_UNROT3R.
      if (TRY_DEEPER(su, stack, depth, SCORE_SWAP3)) {
        go_deeper(stack, depth, SCORE_SWAP3);
#ifdef DEBUG_TRIEWALK
        p = fword + sp->ts_fidx;
        sprintf(changename[depth], "%.*s-%s: rotate right %c%c%c",
            sp->ts_twordlen, tword, fword + sp->ts_fidx,
            p[0], p[1], p[2]);
#endif
        sp->ts_state = STATE_UNROT3R;
        ++depth;
        p = fword + sp->ts_fidx;
        if (has_mbyte) {
          n = mb_cptr2len(p);
          n += mb_cptr2len(p + n);
          c = mb_ptr2char(p + n);
          tl = mb_cptr2len(p + n);
          memmove(p + tl, p, n);
          mb_char2bytes(c, p);
          stack[depth].ts_fidxtry = sp->ts_fidx + n + tl;
        } else {
          c = p[2];
          p[2] = p[1];
          p[1] = *p;
          *p = c;
          stack[depth].ts_fidxtry = sp->ts_fidx + 3;
        }
      } else
        sp->ts_state = STATE_REP_INI;
      break;

    case STATE_UNROT3R:
      // Undo ROT3R: "312" -> "123"
      p = fword + sp->ts_fidx;
      if (has_mbyte) {
        c = mb_ptr2char(p);
        tl = MB_BYTE2LEN(*p);
        n = MB_BYTE2LEN(p[tl]);
        n += MB_BYTE2LEN(p[tl + n]);
        memmove(p, p + tl, n);
        mb_char2bytes(c, p + n);
      } else {
        c = *p;
        *p = p[1];
        p[1] = p[2];
        p[2] = c;
      }
    // FALLTHROUGH

    case STATE_REP_INI:
      // Check if matching with REP items from the .aff file would work.
      // Quickly skip if:
      // - there are no REP items and we are not in the soundfold trie
      // - the score is going to be too high anyway
      // - already applied a REP item or swapped here
      if ((lp->lp_replang == NULL && !soundfold)
          || sp->ts_score + SCORE_REP >= su->su_maxscore
          || sp->ts_fidx < sp->ts_fidxtry) {
        sp->ts_state = STATE_FINAL;
        break;
      }

      // Use the first byte to quickly find the first entry that may
      // match.  If the index is -1 there is none.
      if (soundfold)
        sp->ts_curi = slang->sl_repsal_first[fword[sp->ts_fidx]];
      else
        sp->ts_curi = lp->lp_replang->sl_rep_first[fword[sp->ts_fidx]];

      if (sp->ts_curi < 0) {
        sp->ts_state = STATE_FINAL;
        break;
      }

      sp->ts_state = STATE_REP;
    // FALLTHROUGH

    case STATE_REP:
      // Try matching with REP items from the .aff file.  For each match
      // replace the characters and check if the resulting word is
      // valid.
      p = fword + sp->ts_fidx;

      if (soundfold)
        gap = &slang->sl_repsal;
      else
        gap = &lp->lp_replang->sl_rep;
      while (sp->ts_curi < gap->ga_len) {
        ftp = (fromto_T *)gap->ga_data + sp->ts_curi++;
        if (*ftp->ft_from != *p) {
          // past possible matching entries
          sp->ts_curi = gap->ga_len;
          break;
        }
        if (STRNCMP(ftp->ft_from, p, STRLEN(ftp->ft_from)) == 0
            && TRY_DEEPER(su, stack, depth, SCORE_REP)) {
          go_deeper(stack, depth, SCORE_REP);
#ifdef DEBUG_TRIEWALK
          sprintf(changename[depth], "%.*s-%s: replace %s with %s",
              sp->ts_twordlen, tword, fword + sp->ts_fidx,
              ftp->ft_from, ftp->ft_to);
#endif
          // Need to undo this afterwards.
          sp->ts_state = STATE_REP_UNDO;

          // Change the "from" to the "to" string.
          ++depth;
          fl = (int)STRLEN(ftp->ft_from);
          tl = (int)STRLEN(ftp->ft_to);
          if (fl != tl) {
            STRMOVE(p + tl, p + fl);
            repextra += tl - fl;
          }
          memmove(p, ftp->ft_to, tl);
          stack[depth].ts_fidxtry = sp->ts_fidx + tl;
          stack[depth].ts_tcharlen = 0;
          break;
        }
      }

      if (sp->ts_curi >= gap->ga_len && sp->ts_state == STATE_REP)
        // No (more) matches.
        sp->ts_state = STATE_FINAL;

      break;

    case STATE_REP_UNDO:
      // Undo a REP replacement and continue with the next one.
      if (soundfold)
        gap = &slang->sl_repsal;
      else
        gap = &lp->lp_replang->sl_rep;
      ftp = (fromto_T *)gap->ga_data + sp->ts_curi - 1;
      fl = (int)STRLEN(ftp->ft_from);
      tl = (int)STRLEN(ftp->ft_to);
      p = fword + sp->ts_fidx;
      if (fl != tl) {
        STRMOVE(p + fl, p + tl);
        repextra -= tl - fl;
      }
      memmove(p, ftp->ft_from, fl);
      sp->ts_state = STATE_REP;
      break;

    default:
      // Did all possible states at this level, go up one level.
      --depth;

      if (depth >= 0 && stack[depth].ts_prefixdepth == PFD_PREFIXTREE) {
        // Continue in or go back to the prefix tree.
        byts = pbyts;
        idxs = pidxs;
      }

      // Don't check for CTRL-C too often, it takes time.
      if (--breakcheckcount == 0) {
        os_breakcheck();
        breakcheckcount = 1000;
      }
    }
  }
}


// Go one level deeper in the tree.
static void go_deeper(trystate_T *stack, int depth, int score_add)
{
  stack[depth + 1] = stack[depth];
  stack[depth + 1].ts_state = STATE_START;
  stack[depth + 1].ts_score = stack[depth].ts_score + score_add;
  stack[depth + 1].ts_curi = 1;         // start just after length byte
  stack[depth + 1].ts_flags = 0;
}

// Case-folding may change the number of bytes: Count nr of chars in
// fword[flen] and return the byte length of that many chars in "word".
static int nofold_len(char_u *fword, int flen, char_u *word)
{
  char_u      *p;
  int i = 0;

  for (p = fword; p < fword + flen; mb_ptr_adv(p))
    ++i;
  for (p = word; i > 0; mb_ptr_adv(p))
    --i;
  return (int)(p - word);
}

// "fword" is a good word with case folded.  Find the matching keep-case
// words and put it in "kword".
// Theoretically there could be several keep-case words that result in the
// same case-folded word, but we only find one...
static void find_keepcap_word(slang_T *slang, char_u *fword, char_u *kword)
{
  char_u uword[MAXWLEN];                // "fword" in upper-case
  int depth;
  idx_T tryidx;

  // The following arrays are used at each depth in the tree.
  idx_T arridx[MAXWLEN];
  int round[MAXWLEN];
  int fwordidx[MAXWLEN];
  int uwordidx[MAXWLEN];
  int kwordlen[MAXWLEN];

  int flen, ulen;
  int l;
  int len;
  int c;
  idx_T lo, hi, m;
  char_u      *p;
  char_u      *byts = slang->sl_kbyts;      // array with bytes of the words
  idx_T       *idxs = slang->sl_kidxs;      // array with indexes

  if (byts == NULL) {
    // array is empty: "cannot happen"
    *kword = NUL;
    return;
  }

  // Make an all-cap version of "fword".
  allcap_copy(fword, uword);

  // Each character needs to be tried both case-folded and upper-case.
  // All this gets very complicated if we keep in mind that changing case
  // may change the byte length of a multi-byte character...
  depth = 0;
  arridx[0] = 0;
  round[0] = 0;
  fwordidx[0] = 0;
  uwordidx[0] = 0;
  kwordlen[0] = 0;
  while (depth >= 0) {
    if (fword[fwordidx[depth]] == NUL) {
      // We are at the end of "fword".  If the tree allows a word to end
      // here we have found a match.
      if (byts[arridx[depth] + 1] == 0) {
        kword[kwordlen[depth]] = NUL;
        return;
      }

      // kword is getting too long, continue one level up
      --depth;
    } else if (++round[depth] > 2)   {
      // tried both fold-case and upper-case character, continue one
      // level up
      --depth;
    } else {
      // round[depth] == 1: Try using the folded-case character.
      // round[depth] == 2: Try using the upper-case character.
      if (has_mbyte) {
        flen = mb_cptr2len(fword + fwordidx[depth]);
        ulen = mb_cptr2len(uword + uwordidx[depth]);
      } else
        ulen = flen = 1;
      if (round[depth] == 1) {
        p = fword + fwordidx[depth];
        l = flen;
      } else {
        p = uword + uwordidx[depth];
        l = ulen;
      }

      for (tryidx = arridx[depth]; l > 0; --l) {
        // Perform a binary search in the list of accepted bytes.
        len = byts[tryidx++];
        c = *p++;
        lo = tryidx;
        hi = tryidx + len - 1;
        while (lo < hi) {
          m = (lo + hi) / 2;
          if (byts[m] > c)
            hi = m - 1;
          else if (byts[m] < c)
            lo = m + 1;
          else {
            lo = hi = m;
            break;
          }
        }

        // Stop if there is no matching byte.
        if (hi < lo || byts[lo] != c)
          break;

        // Continue at the child (if there is one).
        tryidx = idxs[lo];
      }

      if (l == 0) {
        // Found the matching char.  Copy it to "kword" and go a
        // level deeper.
        if (round[depth] == 1) {
          STRNCPY(kword + kwordlen[depth], fword + fwordidx[depth],
              flen);
          kwordlen[depth + 1] = kwordlen[depth] + flen;
        } else {
          STRNCPY(kword + kwordlen[depth], uword + uwordidx[depth],
              ulen);
          kwordlen[depth + 1] = kwordlen[depth] + ulen;
        }
        fwordidx[depth + 1] = fwordidx[depth] + flen;
        uwordidx[depth + 1] = uwordidx[depth] + ulen;

        ++depth;
        arridx[depth] = tryidx;
        round[depth] = 0;
      }
    }
  }

  // Didn't find it: "cannot happen".
  *kword = NUL;
}

// Compute the sound-a-like score for suggestions in su->su_ga and add them to
// su->su_sga.
static void score_comp_sal(suginfo_T *su)
{
  langp_T     *lp;
  char_u badsound[MAXWLEN];
  int i;
  suggest_T   *stp;
  suggest_T   *sstp;
  int score;

  ga_grow(&su->su_sga, su->su_ga.ga_len);

  // Use the sound-folding of the first language that supports it.
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    if (!GA_EMPTY(&lp->lp_slang->sl_sal)) {
      // soundfold the bad word
      spell_soundfold(lp->lp_slang, su->su_fbadword, true, badsound);

      for (i = 0; i < su->su_ga.ga_len; ++i) {
        stp = &SUG(su->su_ga, i);

        // Case-fold the suggested word, sound-fold it and compute the
        // sound-a-like score.
        score = stp_sal_score(stp, su, lp->lp_slang, badsound);
        if (score < SCORE_MAXMAX) {
          // Add the suggestion.
          sstp = &SUG(su->su_sga, su->su_sga.ga_len);
          sstp->st_word = vim_strsave(stp->st_word);
          sstp->st_wordlen = stp->st_wordlen;
          sstp->st_score = score;
          sstp->st_altscore = 0;
          sstp->st_orglen = stp->st_orglen;
          ++su->su_sga.ga_len;
        }
      }
      break;
    }
  }
}

// Combine the list of suggestions in su->su_ga and su->su_sga.
// They are entwined.
static void score_combine(suginfo_T *su)
{
  garray_T ga;
  garray_T    *gap;
  langp_T     *lp;
  suggest_T   *stp;
  char_u      *p;
  char_u badsound[MAXWLEN];
  int round;
  slang_T     *slang = NULL;

  // Add the alternate score to su_ga.
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    if (!GA_EMPTY(&lp->lp_slang->sl_sal)) {
      // soundfold the bad word
      slang = lp->lp_slang;
      spell_soundfold(slang, su->su_fbadword, true, badsound);

      for (int i = 0; i < su->su_ga.ga_len; ++i) {
        stp = &SUG(su->su_ga, i);
        stp->st_altscore = stp_sal_score(stp, su, slang, badsound);
        if (stp->st_altscore == SCORE_MAXMAX)
          stp->st_score = (stp->st_score * 3 + SCORE_BIG) / 4;
        else
          stp->st_score = (stp->st_score * 3
                           + stp->st_altscore) / 4;
        stp->st_salscore = false;
      }
      break;
    }
  }

  if (slang == NULL) {  // Using "double" without sound folding.
    (void)cleanup_suggestions(&su->su_ga, su->su_maxscore,
        su->su_maxcount);
    return;
  }

  // Add the alternate score to su_sga.
  for (int i = 0; i < su->su_sga.ga_len; ++i) {
    stp = &SUG(su->su_sga, i);
    stp->st_altscore = spell_edit_score(slang,
        su->su_badword, stp->st_word);
    if (stp->st_score == SCORE_MAXMAX)
      stp->st_score = (SCORE_BIG * 7 + stp->st_altscore) / 8;
    else
      stp->st_score = (stp->st_score * 7 + stp->st_altscore) / 8;
    stp->st_salscore = true;
  }

  // Remove bad suggestions, sort the suggestions and truncate at "maxcount"
  // for both lists.
  check_suggestions(su, &su->su_ga);
  (void)cleanup_suggestions(&su->su_ga, su->su_maxscore, su->su_maxcount);
  check_suggestions(su, &su->su_sga);
  (void)cleanup_suggestions(&su->su_sga, su->su_maxscore, su->su_maxcount);

  ga_init(&ga, (int)sizeof(suginfo_T), 1);
  ga_grow(&ga, su->su_ga.ga_len + su->su_sga.ga_len);

  stp = &SUG(ga, 0);
  for (int i = 0; i < su->su_ga.ga_len || i < su->su_sga.ga_len; ++i) {
    // round 1: get a suggestion from su_ga
    // round 2: get a suggestion from su_sga
    for (round = 1; round <= 2; ++round) {
      gap = round == 1 ? &su->su_ga : &su->su_sga;
      if (i < gap->ga_len) {
        // Don't add a word if it's already there.
        p = SUG(*gap, i).st_word;
        int j;
        for (j = 0; j < ga.ga_len; ++j)
          if (STRCMP(stp[j].st_word, p) == 0)
            break;
        if (j == ga.ga_len)
          stp[ga.ga_len++] = SUG(*gap, i);
        else
          free(p);
      }
    }
  }

  ga_clear(&su->su_ga);
  ga_clear(&su->su_sga);

  // Truncate the list to the number of suggestions that will be displayed.
  if (ga.ga_len > su->su_maxcount) {
    for (int i = su->su_maxcount; i < ga.ga_len; ++i) {
      free(stp[i].st_word);
    }
    ga.ga_len = su->su_maxcount;
  }

  su->su_ga = ga;
}

// For the goodword in "stp" compute the soundalike score compared to the
// badword.
static int
stp_sal_score (
    suggest_T *stp,
    suginfo_T *su,
    slang_T *slang,
    char_u *badsound          // sound-folded badword
)
{
  char_u      *p;
  char_u      *pbad;
  char_u      *pgood;
  char_u badsound2[MAXWLEN];
  char_u fword[MAXWLEN];
  char_u goodsound[MAXWLEN];
  char_u goodword[MAXWLEN];
  int lendiff;

  lendiff = (int)(su->su_badlen - stp->st_orglen);
  if (lendiff >= 0)
    pbad = badsound;
  else {
    // soundfold the bad word with more characters following
    (void)spell_casefold(su->su_badptr, stp->st_orglen, fword, MAXWLEN);

    // When joining two words the sound often changes a lot.  E.g., "t he"
    // sounds like "t h" while "the" sounds like "@".  Avoid that by
    // removing the space.  Don't do it when the good word also contains a
    // space.
    if (vim_iswhite(su->su_badptr[su->su_badlen])
        && *skiptowhite(stp->st_word) == NUL)
      for (p = fword; *(p = skiptowhite(p)) != NUL; )
        STRMOVE(p, p + 1);

    spell_soundfold(slang, fword, true, badsound2);
    pbad = badsound2;
  }

  if (lendiff > 0 && stp->st_wordlen + lendiff < MAXWLEN) {
    // Add part of the bad word to the good word, so that we soundfold
    // what replaces the bad word.
    STRCPY(goodword, stp->st_word);
    STRLCPY(goodword + stp->st_wordlen,
        su->su_badptr + su->su_badlen - lendiff, lendiff + 1);
    pgood = goodword;
  } else
    pgood = stp->st_word;

  // Sound-fold the word and compute the score for the difference.
  spell_soundfold(slang, pgood, false, goodsound);

  return soundalike_score(goodsound, pbad);
}

static sftword_T dumsft;
#define HIKEY2SFT(p)  ((sftword_T *)(p - (dumsft.sft_word - (char_u *)&dumsft)))
#define HI2SFT(hi)     HIKEY2SFT((hi)->hi_key)

// Prepare for calling suggest_try_soundalike().
static void suggest_try_soundalike_prep(void)
{
  langp_T     *lp;
  slang_T     *slang;

  // Do this for all languages that support sound folding and for which a
  // .sug file has been loaded.
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    slang = lp->lp_slang;
    if (!GA_EMPTY(&slang->sl_sal) && slang->sl_sbyts != NULL)
      // prepare the hashtable used by add_sound_suggest()
      hash_init(&slang->sl_sounddone);
  }
}

// Find suggestions by comparing the word in a sound-a-like form.
// Note: This doesn't support postponed prefixes.
static void suggest_try_soundalike(suginfo_T *su)
{
  char_u salword[MAXWLEN];
  langp_T     *lp;
  slang_T     *slang;

  // Do this for all languages that support sound folding and for which a
  // .sug file has been loaded.
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    slang = lp->lp_slang;
    if (!GA_EMPTY(&slang->sl_sal) && slang->sl_sbyts != NULL) {
      // soundfold the bad word
      spell_soundfold(slang, su->su_fbadword, true, salword);

      // try all kinds of inserts/deletes/swaps/etc.
      // TODO: also soundfold the next words, so that we can try joining
      // and splitting
      suggest_trie_walk(su, lp, salword, true);
    }
  }
}

// Finish up after calling suggest_try_soundalike().
static void suggest_try_soundalike_finish(void)
{
  langp_T     *lp;
  slang_T     *slang;
  int todo;
  hashitem_T  *hi;

  // Do this for all languages that support sound folding and for which a
  // .sug file has been loaded.
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    slang = lp->lp_slang;
    if (!GA_EMPTY(&slang->sl_sal) && slang->sl_sbyts != NULL) {
      // Free the info about handled words.
      todo = (int)slang->sl_sounddone.ht_used;
      for (hi = slang->sl_sounddone.ht_array; todo > 0; ++hi)
        if (!HASHITEM_EMPTY(hi)) {
          free(HI2SFT(hi));
          --todo;
        }

      // Clear the hashtable, it may also be used by another region.
      hash_clear(&slang->sl_sounddone);
      hash_init(&slang->sl_sounddone);
    }
  }
}

// A match with a soundfolded word is found.  Add the good word(s) that
// produce this soundfolded word.
static void
add_sound_suggest (
    suginfo_T *su,
    char_u *goodword,
    int score,                      // soundfold score
    langp_T *lp
)
{
  slang_T     *slang = lp->lp_slang;    // language for sound folding
  int sfwordnr;
  char_u      *nrline;
  int orgnr;
  char_u theword[MAXWLEN];
  int i;
  int wlen;
  char_u      *byts;
  idx_T       *idxs;
  int n;
  int wordcount;
  int wc;
  int goodscore;
  hash_T hash;
  hashitem_T  *hi;
  sftword_T   *sft;
  int bc, gc;
  int limit;

  // It's very well possible that the same soundfold word is found several
  // times with different scores.  Since the following is quite slow only do
  // the words that have a better score than before.  Use a hashtable to
  // remember the words that have been done.
  hash = hash_hash(goodword);
  hi = hash_lookup(&slang->sl_sounddone, goodword, hash);
  if (HASHITEM_EMPTY(hi)) {
    sft = xmalloc(sizeof(sftword_T) + STRLEN(goodword));
    sft->sft_score = score;
    STRCPY(sft->sft_word, goodword);
    hash_add_item(&slang->sl_sounddone, hi, sft->sft_word, hash);
  } else {
    sft = HI2SFT(hi);
    if (score >= sft->sft_score)
      return;
    sft->sft_score = score;
  }

  // Find the word nr in the soundfold tree.
  sfwordnr = soundfold_find(slang, goodword);
  if (sfwordnr < 0) {
    EMSG2(_(e_intern2), "add_sound_suggest()");
    return;
  }

  // Go over the list of good words that produce this soundfold word
  nrline = ml_get_buf(slang->sl_sugbuf, (linenr_T)(sfwordnr + 1), FALSE);
  orgnr = 0;
  while (*nrline != NUL) {
    // The wordnr was stored in a minimal nr of bytes as an offset to the
    // previous wordnr.
    orgnr += bytes2offset(&nrline);

    byts = slang->sl_fbyts;
    idxs = slang->sl_fidxs;

    // Lookup the word "orgnr" one of the two tries.
    n = 0;
    wordcount = 0;
    for (wlen = 0; wlen < MAXWLEN - 3; ++wlen) {
      i = 1;
      if (wordcount == orgnr && byts[n + 1] == NUL)
        break;          // found end of word

      if (byts[n + 1] == NUL)
        ++wordcount;

      // skip over the NUL bytes
      for (; byts[n + i] == NUL; ++i)
        if (i > byts[n]) {              // safety check
          STRCPY(theword + wlen, "BAD");
          wlen += 3;
          goto badword;
        }

      // One of the siblings must have the word.
      for (; i < byts[n]; ++i) {
        wc = idxs[idxs[n + i]];         // nr of words under this byte
        if (wordcount + wc > orgnr)
          break;
        wordcount += wc;
      }

      theword[wlen] = byts[n + i];
      n = idxs[n + i];
    }
badword:
    theword[wlen] = NUL;

    // Go over the possible flags and regions.
    for (; i <= byts[n] && byts[n + i] == NUL; ++i) {
      char_u cword[MAXWLEN];
      char_u      *p;
      int flags = (int)idxs[n + i];

      // Skip words with the NOSUGGEST flag
      if (flags & WF_NOSUGGEST)
        continue;

      if (flags & WF_KEEPCAP) {
        // Must find the word in the keep-case tree.
        find_keepcap_word(slang, theword, cword);
        p = cword;
      } else {
        flags |= su->su_badflags;
        if ((flags & WF_CAPMASK) != 0) {
          // Need to fix case according to "flags".
          make_case_word(theword, cword, flags);
          p = cword;
        } else
          p = theword;
      }

      // Add the suggestion.
      if (sps_flags & SPS_DOUBLE) {
        // Add the suggestion if the score isn't too bad.
        if (score <= su->su_maxscore)
          add_suggestion(su, &su->su_sga, p, su->su_badlen,
              score, 0, false, slang, false);
      } else {
        // Add a penalty for words in another region.
        if ((flags & WF_REGION)
            && (((unsigned)flags >> 16) & lp->lp_region) == 0)
          goodscore = SCORE_REGION;
        else
          goodscore = 0;

        // Add a small penalty for changing the first letter from
        // lower to upper case.  Helps for "tath" -> "Kath", which is
        // less common than "tath" -> "path".  Don't do it when the
        // letter is the same, that has already been counted.
        gc = PTR2CHAR(p);
        if (SPELL_ISUPPER(gc)) {
          bc = PTR2CHAR(su->su_badword);
          if (!SPELL_ISUPPER(bc)
              && SPELL_TOFOLD(bc) != SPELL_TOFOLD(gc))
            goodscore += SCORE_ICASE / 2;
        }

        // Compute the score for the good word.  This only does letter
        // insert/delete/swap/replace.  REP items are not considered,
        // which may make the score a bit higher.
        // Use a limit for the score to make it work faster.  Use
        // MAXSCORE(), because RESCORE() will change the score.
        // If the limit is very high then the iterative method is
        // inefficient, using an array is quicker.
        limit = MAXSCORE(su->su_sfmaxscore - goodscore, score);
        if (limit > SCORE_LIMITMAX)
          goodscore += spell_edit_score(slang, su->su_badword, p);
        else
          goodscore += spell_edit_score_limit(slang, su->su_badword,
              p, limit);

        // When going over the limit don't bother to do the rest.
        if (goodscore < SCORE_MAXMAX) {
          // Give a bonus to words seen before.
          goodscore = score_wordcount_adj(slang, goodscore, p, false);

          // Add the suggestion if the score isn't too bad.
          goodscore = RESCORE(goodscore, score);
          if (goodscore <= su->su_sfmaxscore)
            add_suggestion(su, &su->su_ga, p, su->su_badlen,
                goodscore, score, true, slang, true);
        }
      }
    }
    // smsg("word %s (%d): %s (%d)", sftword, sftnr, theword, orgnr);
  }
}

// Find word "word" in fold-case tree for "slang" and return the word number.
static int soundfold_find(slang_T *slang, char_u *word)
{
  idx_T arridx = 0;
  int len;
  int wlen = 0;
  int c;
  char_u      *ptr = word;
  char_u      *byts;
  idx_T       *idxs;
  int wordnr = 0;

  byts = slang->sl_sbyts;
  idxs = slang->sl_sidxs;

  for (;; ) {
    // First byte is the number of possible bytes.
    len = byts[arridx++];

    // If the first possible byte is a zero the word could end here.
    // If the word ends we found the word.  If not skip the NUL bytes.
    c = ptr[wlen];
    if (byts[arridx] == NUL) {
      if (c == NUL)
        break;

      // Skip over the zeros, there can be several.
      while (len > 0 && byts[arridx] == NUL) {
        ++arridx;
        --len;
      }
      if (len == 0)
        return -1;            // no children, word should have ended here
      ++wordnr;
    }

    // If the word ends we didn't find it.
    if (c == NUL)
      return -1;

    // Perform a binary search in the list of accepted bytes.
    if (c == TAB)           // <Tab> is handled like <Space>
      c = ' ';
    while (byts[arridx] < c) {
      // The word count is in the first idxs[] entry of the child.
      wordnr += idxs[idxs[arridx]];
      ++arridx;
      if (--len == 0)           // end of the bytes, didn't find it
        return -1;
    }
    if (byts[arridx] != c)      // didn't find the byte
      return -1;

    // Continue at the child (if there is one).
    arridx = idxs[arridx];
    ++wlen;

    // One space in the good word may stand for several spaces in the
    // checked word.
    if (c == ' ')
      while (ptr[wlen] == ' ' || ptr[wlen] == TAB)
        ++wlen;
  }

  return wordnr;
}

// Copy "fword" to "cword", fixing case according to "flags".
static void make_case_word(char_u *fword, char_u *cword, int flags)
{
  if (flags & WF_ALLCAP)
    // Make it all upper-case
    allcap_copy(fword, cword);
  else if (flags & WF_ONECAP)
    // Make the first letter upper-case
    onecap_copy(fword, cword, true);
  else
    // Use goodword as-is.
    STRCPY(cword, fword);
}

// Use map string "map" for languages "lp".
static void set_map_str(slang_T *lp, char_u *map)
{
  char_u      *p;
  int headc = 0;
  int c;
  int i;

  if (*map == NUL) {
    lp->sl_has_map = false;
    return;
  }
  lp->sl_has_map = true;

  // Init the array and hash tables empty.
  for (i = 0; i < 256; ++i)
    lp->sl_map_array[i] = 0;
  hash_init(&lp->sl_map_hash);

  // The similar characters are stored separated with slashes:
  // "aaa/bbb/ccc/".  Fill sl_map_array[c] with the character before c and
  // before the same slash.  For characters above 255 sl_map_hash is used.
  for (p = map; *p != NUL; ) {
    c = mb_cptr2char_adv(&p);
    if (c == '/')
      headc = 0;
    else {
      if (headc == 0)
        headc = c;

      // Characters above 255 don't fit in sl_map_array[], put them in
      // the hash table.  Each entry is the char, a NUL the headchar and
      // a NUL.
      if (c >= 256) {
        int cl = mb_char2len(c);
        int headcl = mb_char2len(headc);
        char_u      *b;
        hash_T hash;
        hashitem_T  *hi;

        b = xmalloc(cl + headcl + 2);
        mb_char2bytes(c, b);
        b[cl] = NUL;
        mb_char2bytes(headc, b + cl + 1);
        b[cl + 1 + headcl] = NUL;
        hash = hash_hash(b);
        hi = hash_lookup(&lp->sl_map_hash, b, hash);
        if (HASHITEM_EMPTY(hi))
          hash_add_item(&lp->sl_map_hash, hi, b, hash);
        else {
          // This should have been checked when generating the .spl
          // file.
          EMSG(_("E783: duplicate char in MAP entry"));
          free(b);
        }
      } else
        lp->sl_map_array[c] = headc;
    }
  }
}

// Returns true if "c1" and "c2" are similar characters according to the MAP
// lines in the .aff file.
static bool similar_chars(slang_T *slang, int c1, int c2)
{
  int m1, m2;
  char_u buf[MB_MAXBYTES + 1];
  hashitem_T  *hi;

  if (c1 >= 256) {
    buf[mb_char2bytes(c1, buf)] = 0;
    hi = hash_find(&slang->sl_map_hash, buf);
    if (HASHITEM_EMPTY(hi))
      m1 = 0;
    else
      m1 = mb_ptr2char(hi->hi_key + STRLEN(hi->hi_key) + 1);
  } else
    m1 = slang->sl_map_array[c1];
  if (m1 == 0)
    return false;


  if (c2 >= 256) {
    buf[mb_char2bytes(c2, buf)] = 0;
    hi = hash_find(&slang->sl_map_hash, buf);
    if (HASHITEM_EMPTY(hi))
      m2 = 0;
    else
      m2 = mb_ptr2char(hi->hi_key + STRLEN(hi->hi_key) + 1);
  } else
    m2 = slang->sl_map_array[c2];

  return m1 == m2;
}

// Adds a suggestion to the list of suggestions.
// For a suggestion that is already in the list the lowest score is remembered.
static void
add_suggestion (
    suginfo_T *su,
    garray_T *gap,              // either su_ga or su_sga
    char_u *goodword,
    int badlenarg,              // len of bad word replaced with "goodword"
    int score,
    int altscore,
    bool had_bonus,             // value for st_had_bonus
    slang_T *slang,             // language for sound folding
    bool maxsf                  // su_maxscore applies to soundfold score,
                                // su_sfmaxscore to the total score.
)
{
  int goodlen;                  // len of goodword changed
  int badlen;                   // len of bad word changed
  suggest_T   *stp;
  suggest_T new_sug;
  int i;
  char_u      *pgood, *pbad;

  // Minimize "badlen" for consistency.  Avoids that changing "the the" to
  // "thee the" is added next to changing the first "the" the "thee".
  pgood = goodword + STRLEN(goodword);
  pbad = su->su_badptr + badlenarg;
  for (;; ) {
    goodlen = (int)(pgood - goodword);
    badlen = (int)(pbad - su->su_badptr);
    if (goodlen <= 0 || badlen <= 0)
      break;
    mb_ptr_back(goodword, pgood);
    mb_ptr_back(su->su_badptr, pbad);
    if (has_mbyte) {
      if (mb_ptr2char(pgood) != mb_ptr2char(pbad))
        break;
    } else if (*pgood != *pbad)
      break;
  }

  if (badlen == 0 && goodlen == 0)
    // goodword doesn't change anything; may happen for "the the" changing
    // the first "the" to itself.
    return;

  if (GA_EMPTY(gap))
    i = -1;
  else {
    // Check if the word is already there.  Also check the length that is
    // being replaced "thes," -> "these" is a different suggestion from
    // "thes" -> "these".
    stp = &SUG(*gap, 0);
    for (i = gap->ga_len; --i >= 0; ++stp) {
      if (stp->st_wordlen == goodlen
          && stp->st_orglen == badlen
          && STRNCMP(stp->st_word, goodword, goodlen) == 0) {
        // Found it.  Remember the word with the lowest score.
        if (stp->st_slang == NULL)
          stp->st_slang = slang;

        new_sug.st_score = score;
        new_sug.st_altscore = altscore;
        new_sug.st_had_bonus = had_bonus;

        if (stp->st_had_bonus != had_bonus) {
          // Only one of the two had the soundalike score computed.
          // Need to do that for the other one now, otherwise the
          // scores can't be compared.  This happens because
          // suggest_try_change() doesn't compute the soundalike
          // word to keep it fast, while some special methods set
          // the soundalike score to zero.
          if (had_bonus)
            rescore_one(su, stp);
          else {
            new_sug.st_word = stp->st_word;
            new_sug.st_wordlen = stp->st_wordlen;
            new_sug.st_slang = stp->st_slang;
            new_sug.st_orglen = badlen;
            rescore_one(su, &new_sug);
          }
        }

        if (stp->st_score > new_sug.st_score) {
          stp->st_score = new_sug.st_score;
          stp->st_altscore = new_sug.st_altscore;
          stp->st_had_bonus = new_sug.st_had_bonus;
        }
        break;
      }
    }
  }

  if (i < 0) {
    // Add a suggestion.
    stp = GA_APPEND_VIA_PTR(suggest_T, gap);
    stp->st_word = vim_strnsave(goodword, goodlen);
    stp->st_wordlen = goodlen;
    stp->st_score = score;
    stp->st_altscore = altscore;
    stp->st_had_bonus = had_bonus;
    stp->st_orglen = badlen;
    stp->st_slang = slang;

    // If we have too many suggestions now, sort the list and keep
    // the best suggestions.
    if (gap->ga_len > SUG_MAX_COUNT(su)) {
      if (maxsf)
        su->su_sfmaxscore = cleanup_suggestions(gap,
            su->su_sfmaxscore, SUG_CLEAN_COUNT(su));
      else
        su->su_maxscore = cleanup_suggestions(gap,
            su->su_maxscore, SUG_CLEAN_COUNT(su));
    }
  }
}

// Suggestions may in fact be flagged as errors.  Esp. for banned words and
// for split words, such as "the the".  Remove these from the list here.
static void
check_suggestions (
    suginfo_T *su,
    garray_T *gap                   // either su_ga or su_sga
)
{
  suggest_T   *stp;
  char_u longword[MAXWLEN + 1];
  int len;
  hlf_T attr;

  stp = &SUG(*gap, 0);
  for (int i = gap->ga_len - 1; i >= 0; --i) {
    // Need to append what follows to check for "the the".
    STRLCPY(longword, stp[i].st_word, MAXWLEN + 1);
    len = stp[i].st_wordlen;
    STRLCPY(longword + len, su->su_badptr + stp[i].st_orglen,
        MAXWLEN - len + 1);
    attr = HLF_COUNT;
    (void)spell_check(curwin, longword, &attr, NULL, false);
    if (attr != HLF_COUNT) {
      // Remove this entry.
      free(stp[i].st_word);
      --gap->ga_len;
      if (i < gap->ga_len)
        memmove(stp + i, stp + i + 1,
            sizeof(suggest_T) * (gap->ga_len - i));
    }
  }
}


// Add a word to be banned.
static void add_banned(suginfo_T *su, char_u *word)
{
  char_u      *s;
  hash_T hash;
  hashitem_T  *hi;

  hash = hash_hash(word);
  hi = hash_lookup(&su->su_banned, word, hash);
  if (HASHITEM_EMPTY(hi)) {
    s = vim_strsave(word);
    hash_add_item(&su->su_banned, hi, s, hash);
  }
}

// Recompute the score for all suggestions if sound-folding is possible.  This
// is slow, thus only done for the final results.
static void rescore_suggestions(suginfo_T *su)
{
  if (su->su_sallang != NULL) {
    for (int i = 0; i < su->su_ga.ga_len; ++i) {
      rescore_one(su, &SUG(su->su_ga, i));
    }
  }
}

// Recompute the score for one suggestion if sound-folding is possible.
static void rescore_one(suginfo_T *su, suggest_T *stp)
{
  slang_T     *slang = stp->st_slang;
  char_u sal_badword[MAXWLEN];
  char_u      *p;

  // Only rescore suggestions that have no sal score yet and do have a
  // language.
  if (slang != NULL && !GA_EMPTY(&slang->sl_sal) && !stp->st_had_bonus) {
    if (slang == su->su_sallang)
      p = su->su_sal_badword;
    else {
      spell_soundfold(slang, su->su_fbadword, true, sal_badword);
      p = sal_badword;
    }

    stp->st_altscore = stp_sal_score(stp, su, slang, p);
    if (stp->st_altscore == SCORE_MAXMAX)
      stp->st_altscore = SCORE_BIG;
    stp->st_score = RESCORE(stp->st_score, stp->st_altscore);
    stp->st_had_bonus = true;
  }
}


// Function given to qsort() to sort the suggestions on st_score.
// First on "st_score", then "st_altscore" then alphabetically.
static int sug_compare(const void *s1, const void *s2)
{
  suggest_T   *p1 = (suggest_T *)s1;
  suggest_T   *p2 = (suggest_T *)s2;
  int n = p1->st_score - p2->st_score;

  if (n == 0) {
    n = p1->st_altscore - p2->st_altscore;
    if (n == 0)
      n = STRICMP(p1->st_word, p2->st_word);
  }
  return n;
}

// Cleanup the suggestions:
// - Sort on score.
// - Remove words that won't be displayed.
// Returns the maximum score in the list or "maxscore" unmodified.
static int
cleanup_suggestions (
    garray_T *gap,
    int maxscore,
    int keep                       // nr of suggestions to keep
)
{
  suggest_T   *stp = &SUG(*gap, 0);

  // Sort the list.
  qsort(gap->ga_data, (size_t)gap->ga_len, sizeof(suggest_T), sug_compare);

  // Truncate the list to the number of suggestions that will be displayed.
  if (gap->ga_len > keep) {
    for (int i = keep; i < gap->ga_len; ++i) {
      free(stp[i].st_word);
    }
    gap->ga_len = keep;
    return stp[keep - 1].st_score;
  }
  return maxscore;
}

// Soundfold a string, for soundfold().
// Result is in allocated memory, NULL for an error.
char_u *eval_soundfold(char_u *word)
{
  langp_T     *lp;
  char_u sound[MAXWLEN];

  if (curwin->w_p_spell && *curwin->w_s->b_p_spl != NUL) {
    // Use the sound-folding of the first language that supports it.
    for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
      lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
      if (!GA_EMPTY(&lp->lp_slang->sl_sal)) {
        // soundfold the word
        spell_soundfold(lp->lp_slang, word, false, sound);
        return vim_strsave(sound);
      }
    }
  }

  // No language with sound folding, return word as-is.
  return vim_strsave(word);
}

// Turn "inword" into its sound-a-like equivalent in "res[MAXWLEN]".
//
// There are many ways to turn a word into a sound-a-like representation.  The
// oldest is Soundex (1918!).   A nice overview can be found in "Approximate
// swedish name matching - survey and test of different algorithms" by Klas
// Erikson.
//
// We support two methods:
// 1. SOFOFROM/SOFOTO do a simple character mapping.
// 2. SAL items define a more advanced sound-folding (and much slower).
static void
spell_soundfold (
    slang_T *slang,
    char_u *inword,
    bool folded,                 // "inword" is already case-folded
    char_u *res
)
{
  char_u fword[MAXWLEN];
  char_u      *word;

  if (slang->sl_sofo)
    // SOFOFROM and SOFOTO used
    spell_soundfold_sofo(slang, inword, res);
  else {
    // SAL items used.  Requires the word to be case-folded.
    if (folded)
      word = inword;
    else {
      (void)spell_casefold(inword, (int)STRLEN(inword), fword, MAXWLEN);
      word = fword;
    }

    if (has_mbyte)
      spell_soundfold_wsal(slang, word, res);
    else
      spell_soundfold_sal(slang, word, res);
  }
}

// Perform sound folding of "inword" into "res" according to SOFOFROM and
// SOFOTO lines.
static void spell_soundfold_sofo(slang_T *slang, char_u *inword, char_u *res)
{
  char_u      *s;
  int ri = 0;
  int c;

  if (has_mbyte) {
    int prevc = 0;
    int     *ip;

    // The sl_sal_first[] table contains the translation for chars up to
    // 255, sl_sal the rest.
    for (s = inword; *s != NUL; ) {
      c = mb_cptr2char_adv(&s);
      if (enc_utf8 ? utf_class(c) == 0 : vim_iswhite(c))
        c = ' ';
      else if (c < 256)
        c = slang->sl_sal_first[c];
      else {
        ip = ((int **)slang->sl_sal.ga_data)[c & 0xff];
        if (ip == NULL)                 // empty list, can't match
          c = NUL;
        else
          for (;; ) {                   // find "c" in the list
            if (*ip == 0) {             // not found
              c = NUL;
              break;
            }
            if (*ip == c) {             // match!
              c = ip[1];
              break;
            }
            ip += 2;
          }
      }

      if (c != NUL && c != prevc) {
        ri += mb_char2bytes(c, res + ri);
        if (ri + MB_MAXBYTES > MAXWLEN)
          break;
        prevc = c;
      }
    }
  } else {
    // The sl_sal_first[] table contains the translation.
    for (s = inword; (c = *s) != NUL; ++s) {
      if (vim_iswhite(c))
        c = ' ';
      else
        c = slang->sl_sal_first[c];
      if (c != NUL && (ri == 0 || res[ri - 1] != c))
        res[ri++] = c;
    }
  }

  res[ri] = NUL;
}

static void spell_soundfold_sal(slang_T *slang, char_u *inword, char_u *res)
{
  salitem_T   *smp;
  char_u word[MAXWLEN];
  char_u      *s = inword;
  char_u      *t;
  char_u      *pf;
  int i, j, z;
  int reslen;
  int n, k = 0;
  int z0;
  int k0;
  int n0;
  int c;
  int pri;
  int p0 = -333;
  int c0;

  // Remove accents, if wanted.  We actually remove all non-word characters.
  // But keep white space.  We need a copy, the word may be changed here.
  if (slang->sl_rem_accents) {
    t = word;
    while (*s != NUL) {
      if (vim_iswhite(*s)) {
        *t++ = ' ';
        s = skipwhite(s);
      } else {
        if (spell_iswordp_nmw(s, curwin))
          *t++ = *s;
        ++s;
      }
    }
    *t = NUL;
  } else
    STRLCPY(word, s, MAXWLEN);

  smp = (salitem_T *)slang->sl_sal.ga_data;

  // This comes from Aspell phonet.cpp.  Converted from C++ to C.
  // Changed to keep spaces.
  i = reslen = z = 0;
  while ((c = word[i]) != NUL) {
    // Start with the first rule that has the character in the word.
    n = slang->sl_sal_first[c];
    z0 = 0;

    if (n >= 0) {
      // check all rules for the same letter
      for (; (s = smp[n].sm_lead)[0] == c; ++n) {
        // Quickly skip entries that don't match the word.  Most
        // entries are less then three chars, optimize for that.
        k = smp[n].sm_leadlen;
        if (k > 1) {
          if (word[i + 1] != s[1])
            continue;
          if (k > 2) {
            for (j = 2; j < k; ++j)
              if (word[i + j] != s[j])
                break;
            if (j < k)
              continue;
          }
        }

        if ((pf = smp[n].sm_oneof) != NULL) {
          // Check for match with one of the chars in "sm_oneof".
          while (*pf != NUL && *pf != word[i + k])
            ++pf;
          if (*pf == NUL)
            continue;
          ++k;
        }
        s = smp[n].sm_rules;
        pri = 5;            // default priority

        p0 = *s;
        k0 = k;
        while (*s == '-' && k > 1) {
          k--;
          s++;
        }
        if (*s == '<')
          s++;
        if (VIM_ISDIGIT(*s)) {
          // determine priority
          pri = *s - '0';
          s++;
        }
        if (*s == '^' && *(s + 1) == '^')
          s++;

        if (*s == NUL
            || (*s == '^'
                && (i == 0 || !(word[i - 1] == ' '
                                || spell_iswordp(word + i - 1, curwin)))
                && (*(s + 1) != '$'
                    || (!spell_iswordp(word + i + k0, curwin))))
            || (*s == '$' && i > 0
                && spell_iswordp(word + i - 1, curwin)
                && (!spell_iswordp(word + i + k0, curwin)))) {
          // search for followup rules, if:
          // followup and k > 1  and  NO '-' in searchstring
          c0 = word[i + k - 1];
          n0 = slang->sl_sal_first[c0];

          if (slang->sl_followup && k > 1 && n0 >= 0
              && p0 != '-' && word[i + k] != NUL) {
            // test follow-up rule for "word[i + k]"
            for (; (s = smp[n0].sm_lead)[0] == c0; ++n0) {
              // Quickly skip entries that don't match the word.
              k0 = smp[n0].sm_leadlen;
              if (k0 > 1) {
                if (word[i + k] != s[1])
                  continue;
                if (k0 > 2) {
                  pf = word + i + k + 1;
                  for (j = 2; j < k0; ++j)
                    if (*pf++ != s[j])
                      break;
                  if (j < k0)
                    continue;
                }
              }
              k0 += k - 1;

              if ((pf = smp[n0].sm_oneof) != NULL) {
                // Check for match with one of the chars in
                // "sm_oneof".
                while (*pf != NUL && *pf != word[i + k0])
                  ++pf;
                if (*pf == NUL)
                  continue;
                ++k0;
              }

              p0 = 5;
              s = smp[n0].sm_rules;
              while (*s == '-') {
                // "k0" gets NOT reduced because
                // "if (k0 == k)"
                s++;
              }
              if (*s == '<')
                s++;
              if (VIM_ISDIGIT(*s)) {
                p0 = *s - '0';
                s++;
              }

              if (*s == NUL
                  // *s == '^' cuts
                  || (*s == '$'
                      && !spell_iswordp(word + i + k0,
                          curwin))) {
                if (k0 == k)
                  // this is just a piece of the string
                  continue;

                if (p0 < pri)
                  // priority too low
                  continue;
                // rule fits; stop search
                break;
              }
            }

            if (p0 >= pri && smp[n0].sm_lead[0] == c0)
              continue;
          }

          // replace string
          s = smp[n].sm_to;
          if (s == NULL)
            s = (char_u *)"";
          pf = smp[n].sm_rules;
          p0 = (vim_strchr(pf, '<') != NULL) ? 1 : 0;
          if (p0 == 1 && z == 0) {
            // rule with '<' is used
            if (reslen > 0 && *s != NUL && (res[reslen - 1] == c
                                            || res[reslen - 1] == *s))
              reslen--;
            z0 = 1;
            z = 1;
            k0 = 0;
            while (*s != NUL && word[i + k0] != NUL) {
              word[i + k0] = *s;
              k0++;
              s++;
            }
            if (k > k0)
              STRMOVE(word + i + k0, word + i + k);

            // new "actual letter"
            c = word[i];
          } else {
            // no '<' rule used
            i += k - 1;
            z = 0;
            while (*s != NUL && s[1] != NUL && reslen < MAXWLEN) {
              if (reslen == 0 || res[reslen - 1] != *s)
                res[reslen++] = *s;
              s++;
            }
            // new "actual letter"
            c = *s;
            if (strstr((char *)pf, "^^") != NULL) {
              if (c != NUL)
                res[reslen++] = c;
              STRMOVE(word, word + i + 1);
              i = 0;
              z0 = 1;
            }
          }
          break;
        }
      }
    } else if (vim_iswhite(c))   {
      c = ' ';
      k = 1;
    }

    if (z0 == 0) {
      if (k && !p0 && reslen < MAXWLEN && c != NUL
          && (!slang->sl_collapse || reslen == 0
              || res[reslen - 1] != c))
        // condense only double letters
        res[reslen++] = c;

      i++;
      z = 0;
      k = 0;
    }
  }

  res[reslen] = NUL;
}

// Turn "inword" into its sound-a-like equivalent in "res[MAXWLEN]".
// Multi-byte version of spell_soundfold().
static void spell_soundfold_wsal(slang_T *slang, char_u *inword, char_u *res)
{
  salitem_T   *smp = (salitem_T *)slang->sl_sal.ga_data;
  int word[MAXWLEN];
  int wres[MAXWLEN];
  int l;
  char_u      *s;
  int         *ws;
  char_u      *t;
  int         *pf;
  int i, j, z;
  int reslen;
  int n, k = 0;
  int z0;
  int k0;
  int n0;
  int c;
  int pri;
  int p0 = -333;
  int c0;
  bool did_white = false;
  int wordlen;


  // Convert the multi-byte string to a wide-character string.
  // Remove accents, if wanted.  We actually remove all non-word characters.
  // But keep white space.
  wordlen = 0;
  for (s = inword; *s != NUL; ) {
    t = s;
    c = mb_cptr2char_adv(&s);
    if (slang->sl_rem_accents) {
      if (enc_utf8 ? utf_class(c) == 0 : vim_iswhite(c)) {
        if (did_white)
          continue;
        c = ' ';
        did_white = true;
      } else {
        did_white = false;
        if (!spell_iswordp_nmw(t, curwin))
          continue;
      }
    }
    word[wordlen++] = c;
  }
  word[wordlen] = NUL;

  // This algorithm comes from Aspell phonet.cpp.
  // Converted from C++ to C.  Added support for multi-byte chars.
  // Changed to keep spaces.
  i = reslen = z = 0;
  while ((c = word[i]) != NUL) {
    // Start with the first rule that has the character in the word.
    n = slang->sl_sal_first[c & 0xff];
    z0 = 0;

    if (n >= 0) {
      // Check all rules for the same index byte.
      // If c is 0x300 need extra check for the end of the array, as
      // (c & 0xff) is NUL.
      for (; ((ws = smp[n].sm_lead_w)[0] & 0xff) == (c & 0xff)
           && ws[0] != NUL; ++n) {
        // Quickly skip entries that don't match the word.  Most
        // entries are less then three chars, optimize for that.
        if (c != ws[0])
          continue;
        k = smp[n].sm_leadlen;
        if (k > 1) {
          if (word[i + 1] != ws[1])
            continue;
          if (k > 2) {
            for (j = 2; j < k; ++j)
              if (word[i + j] != ws[j])
                break;
            if (j < k)
              continue;
          }
        }

        if ((pf = smp[n].sm_oneof_w) != NULL) {
          // Check for match with one of the chars in "sm_oneof".
          while (*pf != NUL && *pf != word[i + k])
            ++pf;
          if (*pf == NUL)
            continue;
          ++k;
        }
        s = smp[n].sm_rules;
        pri = 5;            // default priority

        p0 = *s;
        k0 = k;
        while (*s == '-' && k > 1) {
          k--;
          s++;
        }
        if (*s == '<')
          s++;
        if (VIM_ISDIGIT(*s)) {
          // determine priority
          pri = *s - '0';
          s++;
        }
        if (*s == '^' && *(s + 1) == '^')
          s++;

        if (*s == NUL
            || (*s == '^'
                && (i == 0 || !(word[i - 1] == ' '
                                || spell_iswordp_w(word + i - 1, curwin)))
                && (*(s + 1) != '$'
                    || (!spell_iswordp_w(word + i + k0, curwin))))
            || (*s == '$' && i > 0
                && spell_iswordp_w(word + i - 1, curwin)
                && (!spell_iswordp_w(word + i + k0, curwin)))) {
          // search for followup rules, if:
          // followup and k > 1  and  NO '-' in searchstring
          c0 = word[i + k - 1];
          n0 = slang->sl_sal_first[c0 & 0xff];

          if (slang->sl_followup && k > 1 && n0 >= 0
              && p0 != '-' && word[i + k] != NUL) {
            // Test follow-up rule for "word[i + k]"; loop over
            // all entries with the same index byte.
            for (; ((ws = smp[n0].sm_lead_w)[0] & 0xff)
                 == (c0 & 0xff); ++n0) {
              // Quickly skip entries that don't match the word.
              if (c0 != ws[0])
                continue;
              k0 = smp[n0].sm_leadlen;
              if (k0 > 1) {
                if (word[i + k] != ws[1])
                  continue;
                if (k0 > 2) {
                  pf = word + i + k + 1;
                  for (j = 2; j < k0; ++j)
                    if (*pf++ != ws[j])
                      break;
                  if (j < k0)
                    continue;
                }
              }
              k0 += k - 1;

              if ((pf = smp[n0].sm_oneof_w) != NULL) {
                // Check for match with one of the chars in
                // "sm_oneof".
                while (*pf != NUL && *pf != word[i + k0])
                  ++pf;
                if (*pf == NUL)
                  continue;
                ++k0;
              }

              p0 = 5;
              s = smp[n0].sm_rules;
              while (*s == '-') {
                // "k0" gets NOT reduced because
                // "if (k0 == k)"
                s++;
              }
              if (*s == '<')
                s++;
              if (VIM_ISDIGIT(*s)) {
                p0 = *s - '0';
                s++;
              }

              if (*s == NUL
                  // *s == '^' cuts
                  || (*s == '$'
                      && !spell_iswordp_w(word + i + k0,
                          curwin))) {
                if (k0 == k)
                  // this is just a piece of the string
                  continue;

                if (p0 < pri)
                  // priority too low
                  continue;
                // rule fits; stop search
                break;
              }
            }

            if (p0 >= pri && (smp[n0].sm_lead_w[0] & 0xff)
                == (c0 & 0xff))
              continue;
          }

          // replace string
          ws = smp[n].sm_to_w;
          s = smp[n].sm_rules;
          p0 = (vim_strchr(s, '<') != NULL) ? 1 : 0;
          if (p0 == 1 && z == 0) {
            // rule with '<' is used
            if (reslen > 0 && ws != NULL && *ws != NUL
                && (wres[reslen - 1] == c
                    || wres[reslen - 1] == *ws))
              reslen--;
            z0 = 1;
            z = 1;
            k0 = 0;
            if (ws != NULL)
              while (*ws != NUL && word[i + k0] != NUL) {
                word[i + k0] = *ws;
                k0++;
                ws++;
              }
            if (k > k0)
              memmove(word + i + k0, word + i + k,
                  sizeof(int) * (wordlen - (i + k) + 1));

            // new "actual letter"
            c = word[i];
          } else {
            // no '<' rule used
            i += k - 1;
            z = 0;
            if (ws != NULL)
              while (*ws != NUL && ws[1] != NUL
                     && reslen < MAXWLEN) {
                if (reslen == 0 || wres[reslen - 1] != *ws)
                  wres[reslen++] = *ws;
                ws++;
              }
            // new "actual letter"
            if (ws == NULL)
              c = NUL;
            else
              c = *ws;
            if (strstr((char *)s, "^^") != NULL) {
              if (c != NUL)
                wres[reslen++] = c;
              memmove(word, word + i + 1,
                  sizeof(int) * (wordlen - (i + 1) + 1));
              i = 0;
              z0 = 1;
            }
          }
          break;
        }
      }
    } else if (vim_iswhite(c))   {
      c = ' ';
      k = 1;
    }

    if (z0 == 0) {
      if (k && !p0 && reslen < MAXWLEN && c != NUL
          && (!slang->sl_collapse || reslen == 0
              || wres[reslen - 1] != c))
        // condense only double letters
        wres[reslen++] = c;

      i++;
      z = 0;
      k = 0;
    }
  }

  // Convert wide characters in "wres" to a multi-byte string in "res".
  l = 0;
  for (n = 0; n < reslen; ++n) {
    l += mb_char2bytes(wres[n], res + l);
    if (l + MB_MAXBYTES > MAXWLEN)
      break;
  }
  res[l] = NUL;
}

// Compute a score for two sound-a-like words.
// This permits up to two inserts/deletes/swaps/etc. to keep things fast.
// Instead of a generic loop we write out the code.  That keeps it fast by
// avoiding checks that will not be possible.
static int
soundalike_score (
    char_u *goodstart,         // sound-folded good word
    char_u *badstart          // sound-folded bad word
)
{
  char_u      *goodsound = goodstart;
  char_u      *badsound = badstart;
  int goodlen;
  int badlen;
  int n;
  char_u      *pl, *ps;
  char_u      *pl2, *ps2;
  int score = 0;

  // Adding/inserting "*" at the start (word starts with vowel) shouldn't be
  // counted so much, vowels halfway the word aren't counted at all.
  if ((*badsound == '*' || *goodsound == '*') && *badsound != *goodsound) {
    if ((badsound[0] == NUL && goodsound[1] == NUL)
        || (goodsound[0] == NUL && badsound[1] == NUL))
      // changing word with vowel to word without a sound
      return SCORE_DEL;
    if (badsound[0] == NUL || goodsound[0] == NUL)
      // more than two changes
      return SCORE_MAXMAX;

    if (badsound[1] == goodsound[1]
        || (badsound[1] != NUL
            && goodsound[1] != NUL
            && badsound[2] == goodsound[2])) {
      // handle like a substitute
    } else {
      score = 2 * SCORE_DEL / 3;
      if (*badsound == '*')
        ++badsound;
      else
        ++goodsound;
    }
  }

  goodlen = (int)STRLEN(goodsound);
  badlen = (int)STRLEN(badsound);

  // Return quickly if the lengths are too different to be fixed by two
  // changes.
  n = goodlen - badlen;
  if (n < -2 || n > 2)
    return SCORE_MAXMAX;

  if (n > 0) {
    pl = goodsound;         // goodsound is longest
    ps = badsound;
  } else {
    pl = badsound;          // badsound is longest
    ps = goodsound;
  }

  // Skip over the identical part.
  while (*pl == *ps && *pl != NUL) {
    ++pl;
    ++ps;
  }

  switch (n) {
  case -2:
  case 2:
    // Must delete two characters from "pl".
    ++pl;               // first delete
    while (*pl == *ps) {
      ++pl;
      ++ps;
    }
    // strings must be equal after second delete
    if (STRCMP(pl + 1, ps) == 0)
      return score + SCORE_DEL * 2;

    // Failed to compare.
    break;

  case -1:
  case 1:
    // Minimal one delete from "pl" required.

    // 1: delete
    pl2 = pl + 1;
    ps2 = ps;
    while (*pl2 == *ps2) {
      if (*pl2 == NUL)                  // reached the end
        return score + SCORE_DEL;
      ++pl2;
      ++ps2;
    }

    // 2: delete then swap, then rest must be equal
    if (pl2[0] == ps2[1] && pl2[1] == ps2[0]
        && STRCMP(pl2 + 2, ps2 + 2) == 0)
      return score + SCORE_DEL + SCORE_SWAP;

    // 3: delete then substitute, then the rest must be equal
    if (STRCMP(pl2 + 1, ps2 + 1) == 0)
      return score + SCORE_DEL + SCORE_SUBST;

    // 4: first swap then delete
    if (pl[0] == ps[1] && pl[1] == ps[0]) {
      pl2 = pl + 2;                 // swap, skip two chars
      ps2 = ps + 2;
      while (*pl2 == *ps2) {
        ++pl2;
        ++ps2;
      }
      // delete a char and then strings must be equal
      if (STRCMP(pl2 + 1, ps2) == 0)
        return score + SCORE_SWAP + SCORE_DEL;
    }

    // 5: first substitute then delete
    pl2 = pl + 1;                   // substitute, skip one char
    ps2 = ps + 1;
    while (*pl2 == *ps2) {
      ++pl2;
      ++ps2;
    }
    // delete a char and then strings must be equal
    if (STRCMP(pl2 + 1, ps2) == 0)
      return score + SCORE_SUBST + SCORE_DEL;

    // Failed to compare.
    break;

  case 0:
    // Lengths are equal, thus changes must result in same length: An
    // insert is only possible in combination with a delete.
    // 1: check if for identical strings
    if (*pl == NUL)
      return score;

    // 2: swap
    if (pl[0] == ps[1] && pl[1] == ps[0]) {
      pl2 = pl + 2;                 // swap, skip two chars
      ps2 = ps + 2;
      while (*pl2 == *ps2) {
        if (*pl2 == NUL)                // reached the end
          return score + SCORE_SWAP;
        ++pl2;
        ++ps2;
      }
      // 3: swap and swap again
      if (pl2[0] == ps2[1] && pl2[1] == ps2[0]
          && STRCMP(pl2 + 2, ps2 + 2) == 0)
        return score + SCORE_SWAP + SCORE_SWAP;

      // 4: swap and substitute
      if (STRCMP(pl2 + 1, ps2 + 1) == 0)
        return score + SCORE_SWAP + SCORE_SUBST;
    }

    // 5: substitute
    pl2 = pl + 1;
    ps2 = ps + 1;
    while (*pl2 == *ps2) {
      if (*pl2 == NUL)                  // reached the end
        return score + SCORE_SUBST;
      ++pl2;
      ++ps2;
    }

    // 6: substitute and swap
    if (pl2[0] == ps2[1] && pl2[1] == ps2[0]
        && STRCMP(pl2 + 2, ps2 + 2) == 0)
      return score + SCORE_SUBST + SCORE_SWAP;

    // 7: substitute and substitute
    if (STRCMP(pl2 + 1, ps2 + 1) == 0)
      return score + SCORE_SUBST + SCORE_SUBST;

    // 8: insert then delete
    pl2 = pl;
    ps2 = ps + 1;
    while (*pl2 == *ps2) {
      ++pl2;
      ++ps2;
    }
    if (STRCMP(pl2 + 1, ps2) == 0)
      return score + SCORE_INS + SCORE_DEL;

    // 9: delete then insert
    pl2 = pl + 1;
    ps2 = ps;
    while (*pl2 == *ps2) {
      ++pl2;
      ++ps2;
    }
    if (STRCMP(pl2, ps2 + 1) == 0)
      return score + SCORE_INS + SCORE_DEL;

    // Failed to compare.
    break;
  }

  return SCORE_MAXMAX;
}

// Compute the "edit distance" to turn "badword" into "goodword".  The less
// deletes/inserts/substitutes/swaps are required the lower the score.
//
// The algorithm is described by Du and Chang, 1992.
// The implementation of the algorithm comes from Aspell editdist.cpp,
// edit_distance().  It has been converted from C++ to C and modified to
// support multi-byte characters.
static int spell_edit_score(slang_T *slang, char_u *badword, char_u *goodword)
{
  int         *cnt;
  int badlen, goodlen;                  // lengths including NUL
  int j, i;
  int t;
  int bc, gc;
  int pbc, pgc;
  char_u      *p;
  int wbadword[MAXWLEN];
  int wgoodword[MAXWLEN];
  const int l_has_mbyte = has_mbyte;

  if (l_has_mbyte) {
    // Get the characters from the multi-byte strings and put them in an
    // int array for easy access.
    for (p = badword, badlen = 0; *p != NUL; )
      wbadword[badlen++] = mb_cptr2char_adv(&p);
    wbadword[badlen++] = 0;
    for (p = goodword, goodlen = 0; *p != NUL; )
      wgoodword[goodlen++] = mb_cptr2char_adv(&p);
    wgoodword[goodlen++] = 0;
  } else {
    badlen = (int)STRLEN(badword) + 1;
    goodlen = (int)STRLEN(goodword) + 1;
  }

  // We use "cnt" as an array: CNT(badword_idx, goodword_idx).
#define CNT(a, b)   cnt[(a) + (b) * (badlen + 1)]
  cnt = xmalloc(sizeof(int) * (badlen + 1) * (goodlen + 1));

  CNT(0, 0) = 0;
  for (j = 1; j <= goodlen; ++j)
    CNT(0, j) = CNT(0, j - 1) + SCORE_INS;

  for (i = 1; i <= badlen; ++i) {
    CNT(i, 0) = CNT(i - 1, 0) + SCORE_DEL;
    for (j = 1; j <= goodlen; ++j) {
      if (l_has_mbyte) {
        bc = wbadword[i - 1];
        gc = wgoodword[j - 1];
      } else {
        bc = badword[i - 1];
        gc = goodword[j - 1];
      }
      if (bc == gc)
        CNT(i, j) = CNT(i - 1, j - 1);
      else {
        // Use a better score when there is only a case difference.
        if (SPELL_TOFOLD(bc) == SPELL_TOFOLD(gc))
          CNT(i, j) = SCORE_ICASE + CNT(i - 1, j - 1);
        else {
          // For a similar character use SCORE_SIMILAR.
          if (slang != NULL
              && slang->sl_has_map
              && similar_chars(slang, gc, bc))
            CNT(i, j) = SCORE_SIMILAR + CNT(i - 1, j - 1);
          else
            CNT(i, j) = SCORE_SUBST + CNT(i - 1, j - 1);
        }

        if (i > 1 && j > 1) {
          if (l_has_mbyte) {
            pbc = wbadword[i - 2];
            pgc = wgoodword[j - 2];
          } else {
            pbc = badword[i - 2];
            pgc = goodword[j - 2];
          }
          if (bc == pgc && pbc == gc) {
            t = SCORE_SWAP + CNT(i - 2, j - 2);
            if (t < CNT(i, j))
              CNT(i, j) = t;
          }
        }
        t = SCORE_DEL + CNT(i - 1, j);
        if (t < CNT(i, j))
          CNT(i, j) = t;
        t = SCORE_INS + CNT(i, j - 1);
        if (t < CNT(i, j))
          CNT(i, j) = t;
      }
    }
  }

  i = CNT(badlen - 1, goodlen - 1);
  free(cnt);
  return i;
}

// Like spell_edit_score(), but with a limit on the score to make it faster.
// May return SCORE_MAXMAX when the score is higher than "limit".
//
// This uses a stack for the edits still to be tried.
// The idea comes from Aspell leditdist.cpp.  Rewritten in C and added support
// for multi-byte characters.
static int spell_edit_score_limit(slang_T *slang, char_u *badword, char_u *goodword, int limit)
{
  limitscore_T stack[10];               // allow for over 3 * 2 edits
  int stackidx;
  int bi, gi;
  int bi2, gi2;
  int bc, gc;
  int score;
  int score_off;
  int minscore;
  int round;

  // Multi-byte characters require a bit more work, use a different function
  // to avoid testing "has_mbyte" quite often.
  if (has_mbyte)
    return spell_edit_score_limit_w(slang, badword, goodword, limit);

  // The idea is to go from start to end over the words.  So long as
  // characters are equal just continue, this always gives the lowest score.
  // When there is a difference try several alternatives.  Each alternative
  // increases "score" for the edit distance.  Some of the alternatives are
  // pushed unto a stack and tried later, some are tried right away.  At the
  // end of the word the score for one alternative is known.  The lowest
  // possible score is stored in "minscore".
  stackidx = 0;
  bi = 0;
  gi = 0;
  score = 0;
  minscore = limit + 1;

  for (;; ) {
    // Skip over an equal part, score remains the same.
    for (;; ) {
      bc = badword[bi];
      gc = goodword[gi];
      if (bc != gc)             // stop at a char that's different
        break;
      if (bc == NUL) {          // both words end
        if (score < minscore)
          minscore = score;
        goto pop;               // do next alternative
      }
      ++bi;
      ++gi;
    }

    if (gc == NUL) {      // goodword ends, delete badword chars
      do {
        if ((score += SCORE_DEL) >= minscore)
          goto pop;                 // do next alternative
      } while (badword[++bi] != NUL);
      minscore = score;
    } else if (bc == NUL)   { // badword ends, insert badword chars
      do {
        if ((score += SCORE_INS) >= minscore)
          goto pop;                 // do next alternative
      } while (goodword[++gi] != NUL);
      minscore = score;
    } else {                  // both words continue
      // If not close to the limit, perform a change.  Only try changes
      // that may lead to a lower score than "minscore".
      // round 0: try deleting a char from badword
      // round 1: try inserting a char in badword
      for (round = 0; round <= 1; ++round) {
        score_off = score + (round == 0 ? SCORE_DEL : SCORE_INS);
        if (score_off < minscore) {
          if (score_off + SCORE_EDIT_MIN >= minscore) {
            // Near the limit, rest of the words must match.  We
            // can check that right now, no need to push an item
            // onto the stack.
            bi2 = bi + 1 - round;
            gi2 = gi + round;
            while (goodword[gi2] == badword[bi2]) {
              if (goodword[gi2] == NUL) {
                minscore = score_off;
                break;
              }
              ++bi2;
              ++gi2;
            }
          } else {
            // try deleting/inserting a character later
            stack[stackidx].badi = bi + 1 - round;
            stack[stackidx].goodi = gi + round;
            stack[stackidx].score = score_off;
            ++stackidx;
          }
        }
      }

      if (score + SCORE_SWAP < minscore) {
        // If swapping two characters makes a match then the
        // substitution is more expensive, thus there is no need to
        // try both.
        if (gc == badword[bi + 1] && bc == goodword[gi + 1]) {
          // Swap two characters, that is: skip them.
          gi += 2;
          bi += 2;
          score += SCORE_SWAP;
          continue;
        }
      }

      // Substitute one character for another which is the same
      // thing as deleting a character from both goodword and badword.
      // Use a better score when there is only a case difference.
      if (SPELL_TOFOLD(bc) == SPELL_TOFOLD(gc))
        score += SCORE_ICASE;
      else {
        // For a similar character use SCORE_SIMILAR.
        if (slang != NULL
            && slang->sl_has_map
            && similar_chars(slang, gc, bc))
          score += SCORE_SIMILAR;
        else
          score += SCORE_SUBST;
      }

      if (score < minscore) {
        // Do the substitution.
        ++gi;
        ++bi;
        continue;
      }
    }
pop:
    // Get here to try the next alternative, pop it from the stack.
    if (stackidx == 0)                  // stack is empty, finished
      break;

    // pop an item from the stack
    --stackidx;
    gi = stack[stackidx].goodi;
    bi = stack[stackidx].badi;
    score = stack[stackidx].score;
  }

  // When the score goes over "limit" it may actually be much higher.
  // Return a very large number to avoid going below the limit when giving a
  // bonus.
  if (minscore > limit)
    return SCORE_MAXMAX;
  return minscore;
}

// Multi-byte version of spell_edit_score_limit().
// Keep it in sync with the above!
static int spell_edit_score_limit_w(slang_T *slang, char_u *badword, char_u *goodword, int limit)
{
  limitscore_T stack[10];               // allow for over 3 * 2 edits
  int stackidx;
  int bi, gi;
  int bi2, gi2;
  int bc, gc;
  int score;
  int score_off;
  int minscore;
  int round;
  char_u          *p;
  int wbadword[MAXWLEN];
  int wgoodword[MAXWLEN];

  // Get the characters from the multi-byte strings and put them in an
  // int array for easy access.
  bi = 0;
  for (p = badword; *p != NUL; )
    wbadword[bi++] = mb_cptr2char_adv(&p);
  wbadword[bi++] = 0;
  gi = 0;
  for (p = goodword; *p != NUL; )
    wgoodword[gi++] = mb_cptr2char_adv(&p);
  wgoodword[gi++] = 0;

  // The idea is to go from start to end over the words.  So long as
  // characters are equal just continue, this always gives the lowest score.
  // When there is a difference try several alternatives.  Each alternative
  // increases "score" for the edit distance.  Some of the alternatives are
  // pushed unto a stack and tried later, some are tried right away.  At the
  // end of the word the score for one alternative is known.  The lowest
  // possible score is stored in "minscore".
  stackidx = 0;
  bi = 0;
  gi = 0;
  score = 0;
  minscore = limit + 1;

  for (;; ) {
    // Skip over an equal part, score remains the same.
    for (;; ) {
      bc = wbadword[bi];
      gc = wgoodword[gi];

      if (bc != gc)             // stop at a char that's different
        break;
      if (bc == NUL) {          // both words end
        if (score < minscore)
          minscore = score;
        goto pop;               // do next alternative
      }
      ++bi;
      ++gi;
    }

    if (gc == NUL) {      // goodword ends, delete badword chars
      do {
        if ((score += SCORE_DEL) >= minscore)
          goto pop;                 // do next alternative
      } while (wbadword[++bi] != NUL);
      minscore = score;
    } else if (bc == NUL)   { // badword ends, insert badword chars
      do {
        if ((score += SCORE_INS) >= minscore)
          goto pop;                 // do next alternative
      } while (wgoodword[++gi] != NUL);
      minscore = score;
    } else {                  // both words continue
      // If not close to the limit, perform a change.  Only try changes
      // that may lead to a lower score than "minscore".
      // round 0: try deleting a char from badword
      // round 1: try inserting a char in badword
      for (round = 0; round <= 1; ++round) {
        score_off = score + (round == 0 ? SCORE_DEL : SCORE_INS);
        if (score_off < minscore) {
          if (score_off + SCORE_EDIT_MIN >= minscore) {
            // Near the limit, rest of the words must match.  We
            // can check that right now, no need to push an item
            // onto the stack.
            bi2 = bi + 1 - round;
            gi2 = gi + round;
            while (wgoodword[gi2] == wbadword[bi2]) {
              if (wgoodword[gi2] == NUL) {
                minscore = score_off;
                break;
              }
              ++bi2;
              ++gi2;
            }
          } else {
            // try deleting a character from badword later
            stack[stackidx].badi = bi + 1 - round;
            stack[stackidx].goodi = gi + round;
            stack[stackidx].score = score_off;
            ++stackidx;
          }
        }
      }

      if (score + SCORE_SWAP < minscore) {
        // If swapping two characters makes a match then the
        // substitution is more expensive, thus there is no need to
        // try both.
        if (gc == wbadword[bi + 1] && bc == wgoodword[gi + 1]) {
          // Swap two characters, that is: skip them.
          gi += 2;
          bi += 2;
          score += SCORE_SWAP;
          continue;
        }
      }

      // Substitute one character for another which is the same
      // thing as deleting a character from both goodword and badword.
      // Use a better score when there is only a case difference.
      if (SPELL_TOFOLD(bc) == SPELL_TOFOLD(gc))
        score += SCORE_ICASE;
      else {
        // For a similar character use SCORE_SIMILAR.
        if (slang != NULL
            && slang->sl_has_map
            && similar_chars(slang, gc, bc))
          score += SCORE_SIMILAR;
        else
          score += SCORE_SUBST;
      }

      if (score < minscore) {
        // Do the substitution.
        ++gi;
        ++bi;
        continue;
      }
    }
pop:
    // Get here to try the next alternative, pop it from the stack.
    if (stackidx == 0)                  // stack is empty, finished
      break;

    // pop an item from the stack
    --stackidx;
    gi = stack[stackidx].goodi;
    bi = stack[stackidx].badi;
    score = stack[stackidx].score;
  }

  // When the score goes over "limit" it may actually be much higher.
  // Return a very large number to avoid going below the limit when giving a
  // bonus.
  if (minscore > limit)
    return SCORE_MAXMAX;
  return minscore;
}

// ":spellinfo"
void ex_spellinfo(exarg_T *eap)
{
  langp_T     *lp;
  char_u      *p;

  if (no_spell_checking(curwin))
    return;

  msg_start();
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len && !got_int; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    msg_puts((char_u *)"file: ");
    msg_puts(lp->lp_slang->sl_fname);
    msg_putchar('\n');
    p = lp->lp_slang->sl_info;
    if (p != NULL) {
      msg_puts(p);
      msg_putchar('\n');
    }
  }
  msg_end();
}

#define DUMPFLAG_KEEPCASE   1   // round 2: keep-case tree
#define DUMPFLAG_COUNT      2   // include word count
#define DUMPFLAG_ICASE      4   // ignore case when finding matches
#define DUMPFLAG_ONECAP     8   // pattern starts with capital
#define DUMPFLAG_ALLCAP     16  // pattern is all capitals

// ":spelldump"
void ex_spelldump(exarg_T *eap)
{
  char_u  *spl;
  long dummy;

  if (no_spell_checking(curwin))
    return;
  get_option_value((char_u*)"spl", &dummy, &spl, OPT_LOCAL);

  // Create a new empty buffer in a new window.
  do_cmdline_cmd((char_u *)"new");

  // enable spelling locally in the new window
  set_option_value((char_u*)"spell", TRUE, (char_u*)"", OPT_LOCAL);
  set_option_value((char_u*)"spl",  dummy,         spl, OPT_LOCAL);
  free(spl);

  if (!bufempty() || !buf_valid(curbuf))
    return;

  spell_dump_compl(NULL, 0, NULL, eap->forceit ? DUMPFLAG_COUNT : 0);

  // Delete the empty line that we started with.
  if (curbuf->b_ml.ml_line_count > 1)
    ml_delete(curbuf->b_ml.ml_line_count, FALSE);

  redraw_later(NOT_VALID);
}

// Go through all possible words and:
// 1. When "pat" is NULL: dump a list of all words in the current buffer.
//      "ic" and "dir" are not used.
// 2. When "pat" is not NULL: add matching words to insert mode completion.
void
spell_dump_compl (
    char_u *pat,           // leading part of the word
    int ic,                     // ignore case
    int *dir,           // direction for adding matches
    int dumpflags_arg              // DUMPFLAG_*
)
{
  langp_T     *lp;
  slang_T     *slang;
  idx_T arridx[MAXWLEN];
  int curi[MAXWLEN];
  char_u word[MAXWLEN];
  int c;
  char_u      *byts;
  idx_T       *idxs;
  linenr_T lnum = 0;
  int round;
  int depth;
  int n;
  int flags;
  char_u      *region_names = NULL;         // region names being used
  bool do_region = true;                    // dump region names and numbers
  char_u      *p;
  int dumpflags = dumpflags_arg;
  int patlen;

  // When ignoring case or when the pattern starts with capital pass this on
  // to dump_word().
  if (pat != NULL) {
    if (ic)
      dumpflags |= DUMPFLAG_ICASE;
    else {
      n = captype(pat, NULL);
      if (n == WF_ONECAP)
        dumpflags |= DUMPFLAG_ONECAP;
      else if (n == WF_ALLCAP
               && (int)STRLEN(pat) > mb_ptr2len(pat)
               )
        dumpflags |= DUMPFLAG_ALLCAP;
    }
  }

  // Find out if we can support regions: All languages must support the same
  // regions or none at all.
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    p = lp->lp_slang->sl_regions;
    if (p[0] != 0) {
      if (region_names == NULL)             // first language with regions
        region_names = p;
      else if (STRCMP(region_names, p) != 0) {
        do_region = false;                  // region names are different
        break;
      }
    }
  }

  if (do_region && region_names != NULL) {
    if (pat == NULL) {
      vim_snprintf((char *)IObuff, IOSIZE, "/regions=%s", region_names);
      ml_append(lnum++, IObuff, (colnr_T)0, FALSE);
    }
  } else
    do_region = false;

  // Loop over all files loaded for the entries in 'spelllang'.
  for (int lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
    lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
    slang = lp->lp_slang;
    if (slang->sl_fbyts == NULL)            // reloading failed
      continue;

    if (pat == NULL) {
      vim_snprintf((char *)IObuff, IOSIZE, "# file: %s", slang->sl_fname);
      ml_append(lnum++, IObuff, (colnr_T)0, FALSE);
    }

    // When matching with a pattern and there are no prefixes only use
    // parts of the tree that match "pat".
    if (pat != NULL && slang->sl_pbyts == NULL)
      patlen = (int)STRLEN(pat);
    else
      patlen = -1;

    // round 1: case-folded tree
    // round 2: keep-case tree
    for (round = 1; round <= 2; ++round) {
      if (round == 1) {
        dumpflags &= ~DUMPFLAG_KEEPCASE;
        byts = slang->sl_fbyts;
        idxs = slang->sl_fidxs;
      } else {
        dumpflags |= DUMPFLAG_KEEPCASE;
        byts = slang->sl_kbyts;
        idxs = slang->sl_kidxs;
      }
      if (byts == NULL)
        continue;                       // array is empty

      depth = 0;
      arridx[0] = 0;
      curi[0] = 1;
      while (depth >= 0 && !got_int
             && (pat == NULL || !compl_interrupted)) {
        if (curi[depth] > byts[arridx[depth]]) {
          // Done all bytes at this node, go up one level.
          --depth;
          line_breakcheck();
          ins_compl_check_keys(50);
        } else {
          // Do one more byte at this node.
          n = arridx[depth] + curi[depth];
          ++curi[depth];
          c = byts[n];
          if (c == 0) {
            // End of word, deal with the word.
            // Don't use keep-case words in the fold-case tree,
            // they will appear in the keep-case tree.
            // Only use the word when the region matches.
            flags = (int)idxs[n];
            if ((round == 2 || (flags & WF_KEEPCAP) == 0)
                && (flags & WF_NEEDCOMP) == 0
                && (do_region
                    || (flags & WF_REGION) == 0
                    || (((unsigned)flags >> 16)
                        & lp->lp_region) != 0)) {
              word[depth] = NUL;
              if (!do_region)
                flags &= ~WF_REGION;

              // Dump the basic word if there is no prefix or
              // when it's the first one.
              c = (unsigned)flags >> 24;
              if (c == 0 || curi[depth] == 2) {
                dump_word(slang, word, pat, dir,
                    dumpflags, flags, lnum);
                if (pat == NULL)
                  ++lnum;
              }

              // Apply the prefix, if there is one.
              if (c != 0)
                lnum = dump_prefixes(slang, word, pat, dir,
                    dumpflags, flags, lnum);
            }
          } else {
            // Normal char, go one level deeper.
            word[depth++] = c;
            arridx[depth] = idxs[n];
            curi[depth] = 1;

            // Check if this characters matches with the pattern.
            // If not skip the whole tree below it.
            // Always ignore case here, dump_word() will check
            // proper case later.  This isn't exactly right when
            // length changes for multi-byte characters with
            // ignore case...
            if (depth <= patlen
                && MB_STRNICMP(word, pat, depth) != 0)
              --depth;
          }
        }
      }
    }
  }
}

// Dumps one word: apply case modifications and append a line to the buffer.
// When "lnum" is zero add insert mode completion.
static void dump_word(slang_T *slang, char_u *word, char_u *pat, int *dir, int dumpflags, int wordflags, linenr_T lnum)
{
  bool keepcap = false;
  char_u      *p;
  char_u      *tw;
  char_u cword[MAXWLEN];
  char_u badword[MAXWLEN + 10];
  int i;
  int flags = wordflags;

  if (dumpflags & DUMPFLAG_ONECAP)
    flags |= WF_ONECAP;
  if (dumpflags & DUMPFLAG_ALLCAP)
    flags |= WF_ALLCAP;

  if ((dumpflags & DUMPFLAG_KEEPCASE) == 0 && (flags & WF_CAPMASK) != 0) {
    // Need to fix case according to "flags".
    make_case_word(word, cword, flags);
    p = cword;
  } else {
    p = word;
    if ((dumpflags & DUMPFLAG_KEEPCASE)
        && ((captype(word, NULL) & WF_KEEPCAP) == 0
            || (flags & WF_FIXCAP) != 0))
      keepcap = true;
  }
  tw = p;

  if (pat == NULL) {
    // Add flags and regions after a slash.
    if ((flags & (WF_BANNED | WF_RARE | WF_REGION)) || keepcap) {
      STRCPY(badword, p);
      STRCAT(badword, "/");
      if (keepcap)
        STRCAT(badword, "=");
      if (flags & WF_BANNED)
        STRCAT(badword, "!");
      else if (flags & WF_RARE)
        STRCAT(badword, "?");
      if (flags & WF_REGION)
        for (i = 0; i < 7; ++i)
          if (flags & (0x10000 << i))
            sprintf((char *)badword + STRLEN(badword), "%d", i + 1);
      p = badword;
    }

    if (dumpflags & DUMPFLAG_COUNT) {
      hashitem_T  *hi;

      // Include the word count for ":spelldump!".
      hi = hash_find(&slang->sl_wordcount, tw);
      if (!HASHITEM_EMPTY(hi)) {
        vim_snprintf((char *)IObuff, IOSIZE, "%s\t%d",
            tw, HI2WC(hi)->wc_count);
        p = IObuff;
      }
    }

    ml_append(lnum, p, (colnr_T)0, FALSE);
  } else if (((dumpflags & DUMPFLAG_ICASE)
              ? MB_STRNICMP(p, pat, STRLEN(pat)) == 0
              : STRNCMP(p, pat, STRLEN(pat)) == 0)
             && ins_compl_add_infercase(p, (int)STRLEN(p),
                 p_ic, NULL, *dir, 0) == OK)
    // if dir was BACKWARD then honor it just once
    *dir = FORWARD;
}

// For ":spelldump": Find matching prefixes for "word".  Prepend each to
// "word" and append a line to the buffer.
// When "lnum" is zero add insert mode completion.
// Return the updated line number.
static linenr_T
dump_prefixes (
    slang_T *slang,
    char_u *word,          // case-folded word
    char_u *pat,
    int *dir,
    int dumpflags,
    int flags,                  // flags with prefix ID
    linenr_T startlnum
)
{
  idx_T arridx[MAXWLEN];
  int curi[MAXWLEN];
  char_u prefix[MAXWLEN];
  char_u word_up[MAXWLEN];
  bool has_word_up = false;
  int c;
  char_u      *byts;
  idx_T       *idxs;
  linenr_T lnum = startlnum;
  int depth;
  int n;
  int len;
  int i;

  // If the word starts with a lower-case letter make the word with an
  // upper-case letter in word_up[].
  c = PTR2CHAR(word);
  if (SPELL_TOUPPER(c) != c) {
    onecap_copy(word, word_up, true);
    has_word_up = true;
  }

  byts = slang->sl_pbyts;
  idxs = slang->sl_pidxs;
  if (byts != NULL) {           // array not is empty
    // Loop over all prefixes, building them byte-by-byte in prefix[].
    // When at the end of a prefix check that it supports "flags".
    depth = 0;
    arridx[0] = 0;
    curi[0] = 1;
    while (depth >= 0 && !got_int) {
      n = arridx[depth];
      len = byts[n];
      if (curi[depth] > len) {
        // Done all bytes at this node, go up one level.
        --depth;
        line_breakcheck();
      } else {
        // Do one more byte at this node.
        n += curi[depth];
        ++curi[depth];
        c = byts[n];
        if (c == 0) {
          // End of prefix, find out how many IDs there are.
          for (i = 1; i < len; ++i)
            if (byts[n + i] != 0)
              break;
          curi[depth] += i - 1;

          c = valid_word_prefix(i, n, flags, word, slang, false);
          if (c != 0) {
            STRLCPY(prefix + depth, word, MAXWLEN - depth);
            dump_word(slang, prefix, pat, dir, dumpflags,
                (c & WF_RAREPFX) ? (flags | WF_RARE)
                : flags, lnum);
            if (lnum != 0)
              ++lnum;
          }

          // Check for prefix that matches the word when the
          // first letter is upper-case, but only if the prefix has
          // a condition.
          if (has_word_up) {
            c = valid_word_prefix(i, n, flags, word_up, slang,
                true);
            if (c != 0) {
              STRLCPY(prefix + depth, word_up, MAXWLEN - depth);
              dump_word(slang, prefix, pat, dir, dumpflags,
                  (c & WF_RAREPFX) ? (flags | WF_RARE)
                  : flags, lnum);
              if (lnum != 0)
                ++lnum;
            }
          }
        } else {
          // Normal char, go one level deeper.
          prefix[depth++] = c;
          arridx[depth] = idxs[n];
          curi[depth] = 1;
        }
      }
    }
  }

  return lnum;
}

// Move "p" to the end of word "start".
// Uses the spell-checking word characters.
char_u *spell_to_word_end(char_u *start, win_T *win)
{
  char_u  *p = start;

  while (*p != NUL && spell_iswordp(p, win))
    mb_ptr_adv(p);
  return p;
}

// For Insert mode completion CTRL-X s:
// Find start of the word in front of column "startcol".
// We don't check if it is badly spelled, with completion we can only change
// the word in front of the cursor.
// Returns the column number of the word.
int spell_word_start(int startcol)
{
  char_u      *line;
  char_u      *p;
  int col = 0;

  if (no_spell_checking(curwin))
    return startcol;

  // Find a word character before "startcol".
  line = get_cursor_line_ptr();
  for (p = line + startcol; p > line; ) {
    mb_ptr_back(line, p);
    if (spell_iswordp_nmw(p, curwin))
      break;
  }

  // Go back to start of the word.
  while (p > line) {
    col = (int)(p - line);
    mb_ptr_back(line, p);
    if (!spell_iswordp(p, curwin))
      break;
    col = 0;
  }

  return col;
}

// Need to check for 'spellcapcheck' now, the word is removed before
// expand_spelling() is called.  Therefore the ugly global variable.
static bool spell_expand_need_cap;

void spell_expand_check_cap(colnr_T col)
{
  spell_expand_need_cap = check_need_cap(curwin->w_cursor.lnum, col);
}

// Get list of spelling suggestions.
// Used for Insert mode completion CTRL-X ?.
// Returns the number of matches.  The matches are in "matchp[]", array of
// allocated strings.
int expand_spelling(linenr_T lnum, char_u *pat, char_u ***matchp)
{
  garray_T ga;

  spell_suggest_list(&ga, pat, 100, spell_expand_need_cap, true);
  *matchp = ga.ga_data;
  return ga.ga_len;
}