tmux/regsub.c

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/* $OpenBSD$ */
/*
* Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <regex.h>
#include <string.h>
#include "tmux.h"
static void
regsub_copy(char **buf, size_t *len, const char *text, size_t start,
size_t end)
{
size_t add = end - start;
*buf = xrealloc(*buf, (*len) + add + 1);
memcpy((*buf) + *len, text + start, add);
(*len) += add;
}
static void
regsub_expand(char **buf, size_t *len, const char *with, const char *text,
regmatch_t *m, u_int n)
{
const char *cp;
u_int i;
for (cp = with; *cp != '\0'; cp++) {
if (*cp == '\\') {
cp++;
if (*cp >= '0' && *cp <= '9') {
i = *cp - '0';
if (i < n && m[i].rm_so != m[i].rm_eo) {
regsub_copy(buf, len, text, m[i].rm_so,
m[i].rm_eo);
continue;
}
}
}
*buf = xrealloc(*buf, (*len) + 2);
(*buf)[(*len)++] = *cp;
}
}
char *
regsub(const char *pattern, const char *with, const char *text, int flags)
{
regex_t r;
regmatch_t m[10];
ssize_t start, end, last, len = 0;
int empty = 0;
char *buf = NULL;
if (*text == '\0')
return (xstrdup(""));
if (regcomp(&r, pattern, flags) != 0)
return (NULL);
start = 0;
last = 0;
end = strlen(text);
while (start <= end) {
m[0].rm_so = start;
m[0].rm_eo = end;
if (regexec(&r, text, nitems(m), m, REG_STARTEND) != 0) {
regsub_copy(&buf, &len, text, start, end);
break;
}
/*
* Append any text not part of this match (from the end of the
* last match).
*/
regsub_copy(&buf, &len, text, last, m[0].rm_so);
/*
* If the last match was empty and this one isn't (it is either
* later or has matched text), expand this match. If it is
* empty, move on one character and try again from there.
*/
if (empty || m[0].rm_so != last || m[0].rm_so != m[0].rm_eo) {
regsub_expand(&buf, &len, with, text, m, nitems(m));
last = m[0].rm_eo;
start = m[0].rm_eo;
empty = 0;
} else {
last = m[0].rm_eo;
start = m[0].rm_eo + 1;
empty = 1;
}
/* Stop now if anchored to start. */
if (*pattern == '^') {
regsub_copy(&buf, &len, text, start, end);
break;
}
}
buf[len] = '\0';
regfree(&r);
return (buf);
}