perf(substitute): don't reallocate new_start every time (#24997)

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zeertzjq 2023-09-03 12:32:58 +08:00 committed by GitHub
parent 087ef52997
commit 0e11bf0e1a
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@ -3177,21 +3177,21 @@ static bool sub_joining_lines(exarg_T *eap, char *pat, const char *sub, const ch
/// Slightly more memory that is strictly necessary is allocated to reduce the
/// frequency of memory (re)allocation.
///
/// @param[in,out] new_start pointer to the memory for the replacement text
/// @param[in] needed_len amount of memory needed
/// @param[in,out] new_start pointer to the memory for the replacement text
/// @param[in,out] new_start_len pointer to length of new_start
/// @param[in] needed_len amount of memory needed
///
/// @returns pointer to the end of the allocated memory
static char *sub_grow_buf(char **new_start, int needed_len)
FUNC_ATTR_NONNULL_ARG(1) FUNC_ATTR_NONNULL_RET
static char *sub_grow_buf(char **new_start, int *new_start_len, int needed_len)
FUNC_ATTR_NONNULL_ALL FUNC_ATTR_NONNULL_RET
{
int new_start_len = 0;
char *new_end;
if (*new_start == NULL) {
// Get some space for a temporary buffer to do the
// substitution into (and some extra space to avoid
// too many calls to xmalloc()/free()).
new_start_len = needed_len + 50;
*new_start = xmalloc((size_t)new_start_len);
*new_start_len = needed_len + 50;
*new_start = xmalloc((size_t)(*new_start_len));
**new_start = NUL;
new_end = *new_start;
} else {
@ -3200,9 +3200,9 @@ static char *sub_grow_buf(char **new_start, int needed_len)
// extra to avoid too many calls to xmalloc()/free()).
size_t len = strlen(*new_start);
needed_len += (int)len;
if (needed_len > new_start_len) {
new_start_len = needed_len + 50;
*new_start = xrealloc(*new_start, (size_t)new_start_len);
if (needed_len > *new_start_len) {
*new_start_len = needed_len + 50;
*new_start = xrealloc(*new_start, (size_t)(*new_start_len));
}
new_end = *new_start + len;
}
@ -3527,6 +3527,7 @@ static int do_sub(exarg_T *eap, const proftime_T timeout, const long cmdpreview_
colnr_T matchcol;
colnr_T prev_matchcol = MAXCOL;
char *new_end, *new_start = NULL;
int new_start_len = 0;
char *p1;
bool did_sub = false;
int lastone;
@ -3572,7 +3573,8 @@ static int do_sub(exarg_T *eap, const proftime_T timeout, const long cmdpreview_
// accordingly.
//
// The new text is built up in new_start[]. It has some extra
// room to avoid using xmalloc()/free() too often.
// room to avoid using xmalloc()/free() too often. new_start_len is
// the length of the allocated memory at new_start.
//
// Make a copy of the old line, so it won't be taken away when
// updating the screen or handling a multi-line match. The "old_"
@ -3952,7 +3954,7 @@ static int do_sub(exarg_T *eap, const proftime_T timeout, const long cmdpreview_
nmatch_tl += nmatch - 1;
}
size_t copy_len = (size_t)(regmatch.startpos[0].col - copycol);
new_end = sub_grow_buf(&new_start,
new_end = sub_grow_buf(&new_start, &new_start_len,
(colnr_T)strlen(p1) - regmatch.endpos[0].col
+ (colnr_T)copy_len + sublen + 1);