2 * This file is part of DisOrder
3 * Copyright (C) 2004, 2005, 2007, 20008 Richard Kettlewell
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 /** @file lib/regsub.c
19 * @brief Regexp substitution
29 #define PREMATCH (-1) /* fictitious pre-match substring */
30 #define POSTMATCH (-2) /* fictitious post-match substring */
32 static inline size_t substring_start(const char attribute((unused)) *subject,
33 const size_t *ovector,
36 case PREMATCH: return 0;
37 case POSTMATCH: return ovector[1];
38 default: return ovector[2 * n];
42 static inline size_t substring_end(const char *subject,
43 const size_t *ovector,
46 case PREMATCH: return ovector[0];
47 case POSTMATCH: return strlen(subject);
48 default: return ovector[2 * n + 1];
52 static void transform_append(struct dynstr *d,
54 const size_t *ovector,
56 int start = substring_start(subject, ovector, n);
57 int end = substring_end(subject, ovector, n);
60 dynstr_append_bytes(d, subject + start, end - start);
63 static void replace_core(struct dynstr *d,
67 const size_t *ovector) {
74 transform_append(d, subject, ovector, 0);
77 case '1': case '2': case '3':
78 case '4': case '5': case '6':
79 case '7': case '8': case '9':
80 substr = replace[1] - '0';
82 transform_append(d, subject, ovector, substr);
86 dynstr_append(d, '$');
90 dynstr_append(d, *replace++);
94 dynstr_append(d, *replace++);
98 unsigned regsub_flags(const char *flags) {
103 case 'g': f |= REGSUB_GLOBAL; break;
104 case 'i': f |= REGSUB_CASE_INDEPENDENT; break;
111 int regsub_compile_options(unsigned flags) {
114 if(flags & REGSUB_CASE_INDEPENDENT)
115 options |= RXF_CASELESS;
119 const char *regsub(const regexp *re, const char *subject,
120 const char *replace, unsigned flags) {
127 /* find the next match */
128 while((rc = regexp_match(re, subject, strlen(subject), 0,
129 ovector, sizeof ovector / sizeof (ovector[0]))) > 0) {
130 /* text just before the match */
131 if(!(flags & REGSUB_REPLACE))
132 transform_append(&d, subject, ovector, PREMATCH);
133 /* the replacement text */
134 replace_core(&d, subject, replace, rc, ovector);
136 if(!*subject) /* end of subject */
138 if(flags & REGSUB_REPLACE) /* replace subject entirely */
140 /* step over the matched substring */
141 subject += substring_start(subject, ovector, POSTMATCH);
142 if(!(flags & REGSUB_GLOBAL))
145 if(rc <= 0 && rc != RXERR_NOMATCH) {
146 disorder_error(0, "regexp_match returned %d, subject '%s'", rc, subject);
149 if((flags & REGSUB_MUST_MATCH) && matches == 0)
151 /* append the remainder of the subject */
152 if(!(flags & REGSUB_REPLACE))
153 dynstr_append_string(&d, subject);
154 dynstr_terminate(&d);