perf: reuse fast character size calculation algorithm from getvcol()

src/nvim/plines.h

@@ -4,26 +4,96 @@
 #include <stdint.h>  // IWYU pragma: keep
 
 #include "nvim/marktree_defs.h"
+#include "nvim/mbyte_defs.h"
 #include "nvim/pos_defs.h"  // IWYU pragma: keep
 #include "nvim/types_defs.h"
 
-/// Argument for lbr_chartabsize().
+typedef bool CSType;
+
+enum {
+  kCharsizeRegular,
+  kCharsizeFast,
+};
+
+/// Argument for char size functions.
 typedef struct {
-  win_T *cts_win;
-  char *cts_line;                ///< start of the line
-  char *cts_ptr;                 ///< current position in line
-  int cts_vcol;                  ///< virtual column at current position
-  int indent_width;              ///< width of showbreak and breakindent on wrapped lines
-                                 ///  INT_MIN if not yet calculated
+  win_T *win;
+  char *line;                ///< start of the line
 
-  int virt_row;                  ///< line number, -1 if no virtual text
-  int cts_cur_text_width_left;   ///< width of virtual text left of cursor
-  int cts_cur_text_width_right;  ///< width of virtual text right of cursor
+  bool use_tabstop;          ///< use tabstop for tab insted of counting it as ^I
+  int indent_width;          ///< width of showbreak and breakindent on wrapped lines
+                             ///  INT_MIN if not yet calculated
 
-  int cts_max_head_vcol;         ///< see win_lbr_chartabsize()
-  MarkTreeIter cts_iter[1];
-} chartabsize_T;
+  int virt_row;              ///< line number, -1 if no virtual text
+  int cur_text_width_left;   ///< width of virtual text left of cursor
+  int cur_text_width_right;  ///< width of virtual text right of cursor
+
+  int max_head_vcol;         ///< see charsize_regular()
+  MarkTreeIter iter[1];
+} CharsizeArg;
+
+typedef struct {
+  int width;
+  int head;  // size of breakindent etc. before the character (included in width)
+} CharSize;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "plines.h.generated.h"
 #endif
+
+static inline CharSize win_charsize(CSType cstype, int vcol, char *ptr, int32_t chr,
+                                    CharsizeArg *arg)
+  REAL_FATTR_NONNULL_ALL REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_ALWAYS_INLINE;
+
+/// Get the number of cells taken up on the screen by the given character at vcol.
+/// "arg->cur_text_width_left" and "arg->cur_text_width_right" are set
+/// to the extra size for inline virtual text.
+///
+/// When "arg->max_head_vcol" is positive, only count in "head" the size
+/// of 'showbreak'/'breakindent' before "arg->max_head_vcol".
+/// When "arg->max_head_vcol" is negative, only count in "head" the size
+/// of 'showbreak'/'breakindent' before where cursor should be placed.
+static inline CharSize win_charsize(CSType cstype, int vcol, char *ptr, int32_t chr,
+                                    CharsizeArg *arg)
+{
+  if (cstype == kCharsizeFast) {
+    return charsize_fast(arg, vcol, chr);
+  } else {
+    return charsize_regular(arg, ptr, vcol, chr);
+  }
+}
+
+static inline int linetabsize_str(char *s)
+  REAL_FATTR_NONNULL_ALL REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_ALWAYS_INLINE;
+
+/// Return the number of characters the string 's' will take on the screen,
+/// taking into account the size of a tab.
+///
+/// @param s
+///
+/// @return Number of characters the string will take on the screen.
+static inline int linetabsize_str(char *s)
+{
+  return linetabsize_col(0, s);
+}
+
+static inline int win_linetabsize(win_T *wp, linenr_T lnum, char *line, colnr_T len)
+  REAL_FATTR_NONNULL_ALL REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_ALWAYS_INLINE;
+
+/// Like linetabsize_str(), but for a given window instead of the current one.
+///
+/// @param wp
+/// @param line
+/// @param len
+///
+/// @return Number of characters the string will take on the screen.
+static inline int win_linetabsize(win_T *wp, linenr_T lnum, char *line, colnr_T len)
+{
+  CharsizeArg arg;
+  CSType const cstype = init_charsize_arg(&arg, wp, lnum, line);
+  if (cstype == kCharsizeFast) {
+    return linesize_fast(&arg, 0, len);
+  } else {
+    return linesize_regular(&arg, 0, len);
+  }
+}