1/* $OpenBSD$ */
2
3/*
4 * Copyright (c) 2019 Nicholas Marriott <[email protected]>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
15 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
16 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <sys/types.h>
20
21#include <regex.h>
22#include <string.h>
23
24#include "tmux.h"
25
26static void
27regsub_copy(char **buf, size_t *len, const char *text, size_t start,
28 size_t end)
29{
30 size_t add = end - start;
31
32 *buf = xrealloc(*buf, (*len) + add + 1);
33 memcpy((*buf) + *len, text + start, add);
34 (*len) += add;
35}
36
37static void
38regsub_expand(char **buf, size_t *len, const char *with, const char *text,
39 regmatch_t *m, u_int n)
40{
41 const char *cp;
42 u_int i;
43
44 for (cp = with; *cp != '\0'; cp++) {
45 if (*cp == '\\') {
46 cp++;
47 if (*cp >= '0' && *cp <= '9') {
48 i = *cp - '0';
49 if (i < n && m[i].rm_so != m[i].rm_eo) {
50 regsub_copy(buf, len, text, m[i].rm_so,
51 m[i].rm_eo);
52 continue;
53 }
54 }
55 }
56 *buf = xrealloc(*buf, (*len) + 2);
57 (*buf)[(*len)++] = *cp;
58 }
59}
60
61char *
62regsub(const char *pattern, const char *with, const char *text, int flags)
63{
64 regex_t r;
65 regmatch_t m[10];
66 ssize_t start, end, last, len = 0;
67 int empty = 0;
68 char *buf = NULL;
69
70 if (*text == '\0')
71 return (xstrdup(""));
72 if (regcomp(&r, pattern, flags) != 0)
73 return (NULL);
74
75 start = 0;
76 last = 0;
77 end = strlen(text);
78
79 while (start <= end) {
80 if (regexec(&r, text + start, nitems(m), m, 0) != 0) {
81 regsub_copy(&buf, &len, text, start, end);
82 break;
83 }
84
85 /*
86 * Append any text not part of this match (from the end of the
87 * last match).
88 */
89 regsub_copy(&buf, &len, text, last, m[0].rm_so + start);
90
91 /*
92 * If the last match was empty and this one isn't (it is either
93 * later or has matched text), expand this match. If it is
94 * empty, move on one character and try again from there.
95 */
96 if (empty ||
97 start + m[0].rm_so != last ||
98 m[0].rm_so != m[0].rm_eo) {
99 regsub_expand(&buf, &len, with, text + start, m,
100 nitems(m));
101
102 last = start + m[0].rm_eo;
103 start += m[0].rm_eo;
104 empty = 0;
105 } else {
106 last = start + m[0].rm_eo;
107 start += m[0].rm_eo + 1;
108 empty = 1;
109 }
110
111 /* Stop now if anchored to start. */
112 if (*pattern == '^') {
113 regsub_copy(&buf, &len, text, start, end);
114 break;
115 }
116 }
117 buf[len] = '\0';
118
119 regfree(&r);
120 return (buf);
121}
122