1 /* $OpenBSD: regsub.c,v 1.5 2020/04/09 14:23:34 nicm Exp $ */ 2 3 /* 4 * Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com> 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 26 static void 27 regsub_copy(char **buf, size_t *len, const char *text, size_t start, size_t end) 28 { 29 size_t add = end - start; 30 31 *buf = xrealloc(*buf, (*len) + add + 1); 32 memcpy((*buf) + *len, text + start, add); 33 (*len) += add; 34 } 35 36 static void 37 regsub_expand(char **buf, size_t *len, const char *with, const char *text, 38 regmatch_t *m, u_int n) 39 { 40 const char *cp; 41 u_int i; 42 43 for (cp = with; *cp != '\0'; cp++) { 44 if (*cp == '\\') { 45 cp++; 46 if (*cp >= '0' && *cp <= '9') { 47 i = *cp - '0'; 48 if (i < n && m[i].rm_so != m[i].rm_eo) { 49 regsub_copy(buf, len, text, m[i].rm_so, 50 m[i].rm_eo); 51 continue; 52 } 53 } 54 } 55 *buf = xrealloc(*buf, (*len) + 2); 56 (*buf)[(*len)++] = *cp; 57 } 58 } 59 60 char * 61 regsub(const char *pattern, const char *with, const char *text, int flags) 62 { 63 regex_t r; 64 regmatch_t m[10]; 65 ssize_t start, end, last, len = 0; 66 int empty = 0; 67 char *buf = NULL; 68 69 if (*text == '\0') 70 return (xstrdup("")); 71 if (regcomp(&r, pattern, flags) != 0) 72 return (NULL); 73 74 start = 0; 75 last = 0; 76 end = strlen(text); 77 78 while (start <= end) { 79 if (regexec(&r, text + start, nitems(m), m, 0) != 0) { 80 regsub_copy(&buf, &len, text, start, end); 81 break; 82 } 83 84 /* 85 * Append any text not part of this match (from the end of the 86 * last match). 87 */ 88 regsub_copy(&buf, &len, text, last, m[0].rm_so + start); 89 90 /* 91 * If the last match was empty and this one isn't (it is either 92 * later or has matched text), expand this match. If it is 93 * empty, move on one character and try again from there. 94 */ 95 if (empty || 96 start + m[0].rm_so != last || 97 m[0].rm_so != m[0].rm_eo) { 98 regsub_expand(&buf, &len, with, text + start, m, 99 nitems(m)); 100 101 last = start + m[0].rm_eo; 102 start += m[0].rm_eo; 103 empty = 0; 104 } else { 105 last = start + m[0].rm_eo; 106 start += m[0].rm_eo + 1; 107 empty = 1; 108 } 109 110 /* Stop now if anchored to start. */ 111 if (*pattern == '^') { 112 regsub_copy(&buf, &len, text, start, end); 113 break; 114 } 115 } 116 buf[len] = '\0'; 117 118 regfree(&r); 119 return (buf); 120 } 121