kvec,typval_encode: Add new vector: the one with preallocated array

src/nvim/eval/typval_encode.h

@@ -168,7 +168,15 @@ typedef struct {
 } MPConvStackVal;
 
 /// Stack used to convert VimL values to messagepack.
-typedef kvec_t(MPConvStackVal) MPConvStack;
+typedef kvec_withinit_t(MPConvStackVal, 8) MPConvStack;
+
+// Defines for MPConvStack
+#define _mp_size kv_size
+#define _mp_init kvi_init
+#define _mp_destroy kvi_destroy
+#define _mp_push kvi_push
+#define _mp_pop kv_pop
+#define _mp_last kv_last
 
 /// Code for checking whether container references itself
 ///
@@ -245,7 +253,7 @@ static int name##_convert_one_value(firstargtype firstargname, \
       _TYPVAL_ENCODE_CHECK_SELF_REFERENCE(tv->vval.v_list, lv_copyID, \
                                           kMPConvList); \
       TYPVAL_ENCODE_CONV_LIST_START(tv->vval.v_list->lv_len); \
-      kv_push(*mpstack, ((MPConvStackVal) { \
+      _mp_push(*mpstack, ((MPConvStackVal) { \
         .type = kMPConvList, \
         .data = { \
           .l = { \
@@ -376,7 +384,7 @@ static int name##_convert_one_value(firstargtype firstargname, \
             _TYPVAL_ENCODE_CHECK_SELF_REFERENCE(val_di->di_tv.vval.v_list, \
                                                 lv_copyID, kMPConvList); \
             TYPVAL_ENCODE_CONV_LIST_START(val_di->di_tv.vval.v_list->lv_len); \
-            kv_push(*mpstack, ((MPConvStackVal) { \
+            _mp_push(*mpstack, ((MPConvStackVal) { \
               .type = kMPConvList, \
               .data = { \
                 .l = { \
@@ -406,7 +414,7 @@ static int name##_convert_one_value(firstargtype firstargname, \
             _TYPVAL_ENCODE_CHECK_SELF_REFERENCE(val_list, lv_copyID, \
                                                 kMPConvPairs); \
             TYPVAL_ENCODE_CONV_DICT_START(val_list->lv_len); \
-            kv_push(*mpstack, ((MPConvStackVal) { \
+            _mp_push(*mpstack, ((MPConvStackVal) { \
               .type = kMPConvPairs, \
               .data = { \
                 .l = { \
@@ -446,7 +454,7 @@ name##_convert_one_value_regular_dict: \
       _TYPVAL_ENCODE_CHECK_SELF_REFERENCE(tv->vval.v_dict, dv_copyID, \
                                           kMPConvDict); \
       TYPVAL_ENCODE_CONV_DICT_START(tv->vval.v_dict->dv_hashtab.ht_used); \
-      kv_push(*mpstack, ((MPConvStackVal) { \
+      _mp_push(*mpstack, ((MPConvStackVal) { \
         .type = kMPConvDict, \
         .data = { \
           .d = { \
@@ -472,18 +480,18 @@ scope int encode_vim_to_##name(firstargtype firstargname, typval_T *const tv, \
 { \
   const int copyID = get_copyID(); \
   MPConvStack mpstack; \
-  kv_init(mpstack); \
+  _mp_init(mpstack); \
   if (name##_convert_one_value(firstargname, &mpstack, tv, copyID, objname) \
       == FAIL) { \
     goto encode_vim_to_##name##_error_ret; \
   } \
-  while (kv_size(mpstack)) { \
+  while (_mp_size(mpstack)) { \
-    MPConvStackVal *cur_mpsv = &kv_A(mpstack, kv_size(mpstack) - 1); \
+    MPConvStackVal *cur_mpsv = &_mp_last(mpstack); \
     typval_T *cur_tv = NULL; \
     switch (cur_mpsv->type) { \
       case kMPConvDict: { \
         if (!cur_mpsv->data.d.todo) { \
-          (void) kv_pop(mpstack); \
+          (void) _mp_pop(mpstack); \
           cur_mpsv->data.d.dict->dv_copyID = copyID - 1; \
           TYPVAL_ENCODE_CONV_DICT_END(); \
           continue; \
@@ -505,7 +513,7 @@ scope int encode_vim_to_##name(firstargtype firstargname, typval_T *const tv, \
       } \
       case kMPConvList: { \
         if (cur_mpsv->data.l.li == NULL) { \
-          (void) kv_pop(mpstack); \
+          (void) _mp_pop(mpstack); \
           cur_mpsv->data.l.list->lv_copyID = copyID - 1; \
           TYPVAL_ENCODE_CONV_LIST_END(); \
           continue; \
@@ -518,7 +526,7 @@ scope int encode_vim_to_##name(firstargtype firstargname, typval_T *const tv, \
       } \
       case kMPConvPairs: { \
         if (cur_mpsv->data.l.li == NULL) { \
-          (void) kv_pop(mpstack); \
+          (void) _mp_pop(mpstack); \
           cur_mpsv->data.l.list->lv_copyID = copyID - 1; \
           TYPVAL_ENCODE_CONV_DICT_END(); \
           continue; \
@@ -545,10 +553,10 @@ scope int encode_vim_to_##name(firstargtype firstargname, typval_T *const tv, \
       goto encode_vim_to_##name##_error_ret; \
     } \
   } \
-  kv_destroy(mpstack); \
+  _mp_destroy(mpstack); \
   return OK; \
 encode_vim_to_##name##_error_ret: \
-  kv_destroy(mpstack); \
+  _mp_destroy(mpstack); \
   return FAIL; \
 }
 

src/nvim/lib/kvec.h

@@ -38,6 +38,7 @@
 #define NVIM_LIB_KVEC_H
 
 #include <stdlib.h>
+#include <string.h>
 
 #include "nvim/memory.h"
 
@@ -96,4 +97,97 @@
          : 0)), \
      (v).items[(i)])
 
+/// Type of a vector with a few first members allocated on stack
+///
+/// Is compatible with #kv_A, #kv_pop, #kv_size, #kv_max, #kv_last.
+/// Is not compatible with #kv_resize, #kv_resize_full, #kv_copy, #kv_push,
+/// #kv_pushp, #kv_a, #kv_destroy.
+///
+/// @param[in]  type  Type of vector elements.
+/// @param[in]  init_size  Number of the elements in the initial array.
+#define kvec_withinit_t(type, INIT_SIZE) \
+    struct { \
+      size_t size; \
+      size_t capacity; \
+      type *items; \
+      type init_array[INIT_SIZE]; \
+    }
+
+/// Initialize vector with preallocated array
+///
+/// @param[out]  v  Vector to initialize.
+#define kvi_init(v) \
+    ((v).capacity = ARRAY_SIZE((v).init_array), \
+     (v).size = 0, \
+     (v).items = (v).init_array)
+
+/// Move data to a new destination and free source
+static inline void *_memcpy_free(void *const restrict dest,
+                                 void *const restrict src,
+                                 const size_t size)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_NONNULL_RET FUNC_ATTR_ALWAYS_INLINE
+{
+  memcpy(dest, src, size);
+  xfree(src);
+  return dest;
+}
+
+/// Resize vector with preallocated array
+///
+/// @param[out]  v  Vector to resize.
+/// @param[in]  s  New size.
+#define kvi_resize(v, s) \
+    ((v).capacity = ((s) > ARRAY_SIZE((v).init_array) \
+                     ? (s) \
+                     : ARRAY_SIZE((v).init_array)), \
+     (v).items = ((v).capacity == ARRAY_SIZE((v).init_array) \
+                  ? ((v).items == (v).init_array \
+                     ? (v).items \
+                     : _memcpy_free((v).init_array, (v).items, \
+                                    (v).size * sizeof((v).items[0]))) \
+                  : ((v).items == (v).init_array \
+                     ? memcpy(xmalloc((v).capacity * sizeof((v).items[0])), \
+                              (v).items, \
+                              (v).size * sizeof((v).items[0])) \
+                     : xrealloc((v).items, \
+                                (v).capacity * sizeof((v).items[0])))))
+
+/// Resize vector with preallocated array when it is full
+///
+/// @param[out]  v  Vector to resize.
+#define kvi_resize_full(v) \
+    /* ARRAY_SIZE((v).init_array) is the minimal capacity of this vector. */ \
+    /* Thus when vector is full capacity may not be zero and it is safe */ \
+    /* not to bother with checking whether (v).capacity is 0. But now */ \
+    /* capacity is not guaranteed to have size that is a power of 2. */ \
+    kvi_resize(v, ((v).capacity == ARRAY_SIZE((v).init_array) \
+                   ? ((v).capacity++, kv_roundup32((v).capacity)) \
+                   : (v).capacity << 1))
+
+/// Get location where to store new element to a vector with preallocated array
+///
+/// @param[in,out]  v  Vector to push to.
+///
+/// @return Pointer to the place where new value should be stored.
+#define kvi_pushp(v) \
+    ((((v).size == (v).capacity) ? (kvi_resize_full(v), 0) : 0), \
+     ((v).items + ((v).size++)))
+
+/// Push value to a vector with preallocated array
+///
+/// @param[out]  v  Vector to push to.
+/// @param[in]  x  Value to push.
+#define kvi_push(v, x) \
+    (*kvi_pushp(v) = (x))
+
+/// Free array of elements of a vector with preallocated array if needed
+///
+/// @param[out]  v  Vector to free.
+#define kvi_destroy(v) \
+    do { \
+      if ((v).items != (v).init_array) { \
+        xfree((v).items); \
+      } \
+    } while (0)
+
 #endif  // NVIM_LIB_KVEC_H