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vim-patch:9.2.0152: concatenating strings is slow (#38286)

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Problem:  concatenating strings is slow
Solution: Use grow_string_tv() to grow the existing string buffer in
          place when possible (Yasuhiro Matsumoto).

closes: vim/vim#19642

16d421a4d9

Co-authored-by: Yasuhiro Matsumoto <mattn.jp@gmail.com>
This commit is contained in:
zeertzjq
2026-03-14 08:14:34 +08:00
committed by GitHub
parent fd1e019e90
commit d3bca3b7fa
2 changed files with 29 additions and 2 deletions
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22
src/nvim/eval.c
View File

@@ -2267,6 +2267,23 @@ static int eval_addlist(typval_T *tv1, typval_T *tv2)
return OK;
}
/// Append string "s2" to the string in "tv1".
/// Returns OK if "tv1" was grown in place, FAIL otherwise.
int grow_string_tv(typval_T *tv1, const char *s2)
{
if (tv1->v_type != VAR_STRING || tv1->vval.v_string == NULL) {
return FAIL;
}
size_t len1 = strlen(tv1->vval.v_string);
size_t len2 = strlen(s2);
char *p = xrealloc(tv1->vval.v_string, len1 + len2 + 1);
memmove(p + len1, s2, len2 + 1);
tv1->vval.v_string = p;
return OK;
}
/// Concatenate strings "tv1" and "tv2" and store the result in "tv1".
static int eval_concat_str(typval_T *tv1, typval_T *tv2)
{
@@ -2281,6 +2298,11 @@ static int eval_concat_str(typval_T *tv1, typval_T *tv2)
return FAIL;
}
// When possible, grow the existing string in place to avoid alloc/free.
if (grow_string_tv(tv1, s2) == OK) {
return OK;
}
char *p = concat_str(s1, s2);
tv_clear(tv1);
tv1->v_type = VAR_STRING;

9
src/nvim/eval/executor.c
View File

@@ -129,10 +129,15 @@ static int tv_op_string(typval_T *tv1, const typval_T *tv2, const char *op)
return FAIL;
}
char numbuf[NUMBUFLEN];
const char *s2 = tv_get_string_buf(tv2, numbuf);
if (grow_string_tv(tv1, s2) == OK) {
return OK;
}
// str .= str
const char *tvs = tv_get_string(tv1);
char numbuf[NUMBUFLEN];
char *const s = concat_str(tvs, tv_get_string_buf(tv2, numbuf));
char *const s = concat_str(tvs, s2);
tv_clear(tv1);
tv1->v_type = VAR_STRING;
tv1->vval.v_string = s;