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
30 #define PREMATCH (-1) /* fictitious pre-match substring */
31 #define POSTMATCH (-2) /* fictitious post-match substring */
33 static inline int substring_start(const char attribute((unused)) *subject,
37 case PREMATCH: return 0;
38 case POSTMATCH: return ovector[1];
39 default: return ovector[2 * n];
43 static inline int substring_end(const char *subject,
47 case PREMATCH: return ovector[0];
48 case POSTMATCH: return strlen(subject);
49 default: return ovector[2 * n + 1];
53 static void transform_append(struct dynstr *d,
57 int start = substring_start(subject, ovector, n);
58 int end = substring_end(subject, ovector, n);
61 dynstr_append_bytes(d, subject + start, end - start);
64 static void replace_core(struct dynstr *d,
75 transform_append(d, subject, ovector, 0);
78 case '1': case '2': case '3':
79 case '4': case '5': case '6':
80 case '7': case '8': case '9':
81 substr = replace[1] - '0';
83 transform_append(d, subject, ovector, substr);
87 dynstr_append(d, '$');
91 dynstr_append(d, *replace++);
95 dynstr_append(d, *replace++);
99 unsigned regsub_flags(const char *flags) {
104 case 'g': f |= REGSUB_GLOBAL; break;
105 case 'i': f |= REGSUB_CASE_INDEPENDENT; break;
112 int regsub_compile_options(unsigned flags) {
115 if(flags & REGSUB_CASE_INDEPENDENT)
116 options |= PCRE_CASELESS;
120 const char *regsub(const pcre *re, const char *subject, const char *replace,
122 int rc, ovector[99], matches;
127 /* find the next match */
128 while((rc = pcre_exec(re, 0, subject, strlen(subject), 0,
129 0, ovector, sizeof ovector / sizeof (int))) > 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 != PCRE_ERROR_NOMATCH) {
146 error(0, "pcre_exec 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);