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460b9539 | 1 | /* |
2 | * This file is part of DisOrder | |
5aff007d | 3 | * Copyright (C) 2004, 2005, 2007, 20008 Richard Kettlewell |
460b9539 | 4 | * |
e7eb3a27 | 5 | * This program is free software: you can redistribute it and/or modify |
460b9539 | 6 | * it under the terms of the GNU General Public License as published by |
e7eb3a27 | 7 | * the Free Software Foundation, either version 3 of the License, or |
460b9539 | 8 | * (at your option) any later version. |
e7eb3a27 RK |
9 | * |
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. | |
14 | * | |
460b9539 | 15 | * You should have received a copy of the GNU General Public License |
e7eb3a27 | 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
460b9539 | 17 | */ |
18 | ||
05b75f8d | 19 | #include "common.h" |
460b9539 | 20 | |
460b9539 | 21 | #include <pcre.h> |
22 | ||
23 | #include "regsub.h" | |
24 | #include "mem.h" | |
25 | #include "vector.h" | |
26 | #include "log.h" | |
27 | ||
28 | #define PREMATCH (-1) /* fictitious pre-match substring */ | |
29 | #define POSTMATCH (-2) /* fictitious post-match substring */ | |
30 | ||
31 | static inline int substring_start(const char attribute((unused)) *subject, | |
32 | const int *ovector, | |
33 | int n) { | |
34 | switch(n) { | |
35 | case PREMATCH: return 0; | |
36 | case POSTMATCH: return ovector[1]; | |
37 | default: return ovector[2 * n]; | |
38 | } | |
39 | } | |
40 | ||
41 | static inline int substring_end(const char *subject, | |
42 | const int *ovector, | |
43 | int n) { | |
44 | switch(n) { | |
45 | case PREMATCH: return ovector[0]; | |
46 | case POSTMATCH: return strlen(subject); | |
47 | default: return ovector[2 * n + 1]; | |
48 | } | |
49 | } | |
50 | ||
51 | static void transform_append(struct dynstr *d, | |
52 | const char *subject, | |
53 | const int *ovector, | |
54 | int n) { | |
55 | int start = substring_start(subject, ovector, n); | |
56 | int end = substring_end(subject, ovector, n); | |
57 | ||
58 | if(start != -1) | |
59 | dynstr_append_bytes(d, subject + start, end - start); | |
60 | } | |
61 | ||
62 | static void replace_core(struct dynstr *d, | |
63 | const char *subject, | |
64 | const char *replace, | |
65 | int rc, | |
66 | const int *ovector) { | |
67 | int substr; | |
68 | ||
69 | while(*replace) { | |
70 | if(*replace == '$') | |
71 | switch(replace[1]) { | |
72 | case '&': | |
73 | transform_append(d, subject, ovector, 0); | |
74 | replace += 2; | |
75 | break; | |
76 | case '1': case '2': case '3': | |
77 | case '4': case '5': case '6': | |
78 | case '7': case '8': case '9': | |
79 | substr = replace[1] - '0'; | |
80 | if(substr < rc) | |
81 | transform_append(d, subject, ovector, substr); | |
82 | replace += 2; | |
83 | break; | |
84 | case '$': | |
85 | dynstr_append(d, '$'); | |
86 | replace += 2; | |
87 | break; | |
88 | default: | |
89 | dynstr_append(d, *replace++); | |
90 | break; | |
91 | } | |
92 | else | |
93 | dynstr_append(d, *replace++); | |
94 | } | |
95 | } | |
96 | ||
97 | unsigned regsub_flags(const char *flags) { | |
98 | unsigned f = 0; | |
99 | ||
100 | while(*flags) { | |
101 | switch(*flags++) { | |
102 | case 'g': f |= REGSUB_GLOBAL; break; | |
103 | case 'i': f |= REGSUB_CASE_INDEPENDENT; break; | |
104 | default: break; | |
105 | } | |
106 | } | |
107 | return f; | |
108 | } | |
109 | ||
110 | int regsub_compile_options(unsigned flags) { | |
111 | int options = 0; | |
112 | ||
113 | if(flags & REGSUB_CASE_INDEPENDENT) | |
114 | options |= PCRE_CASELESS; | |
115 | return options; | |
116 | } | |
117 | ||
118 | const char *regsub(const pcre *re, const char *subject, const char *replace, | |
119 | unsigned flags) { | |
120 | int rc, ovector[99], matches; | |
121 | struct dynstr d; | |
122 | ||
123 | dynstr_init(&d); | |
124 | matches = 0; | |
125 | /* find the next match */ | |
126 | while((rc = pcre_exec(re, 0, subject, strlen(subject), 0, | |
127 | 0, ovector, sizeof ovector / sizeof (int))) > 0) { | |
128 | /* text just before the match */ | |
129 | if(!(flags & REGSUB_REPLACE)) | |
130 | transform_append(&d, subject, ovector, PREMATCH); | |
131 | /* the replacement text */ | |
132 | replace_core(&d, subject, replace, rc, ovector); | |
133 | ++matches; | |
134 | if(!*subject) /* end of subject */ | |
135 | break; | |
136 | if(flags & REGSUB_REPLACE) /* replace subject entirely */ | |
137 | break; | |
138 | /* step over the matched substring */ | |
139 | subject += substring_start(subject, ovector, POSTMATCH); | |
140 | if(!(flags & REGSUB_GLOBAL)) | |
141 | break; | |
142 | } | |
143 | if(rc <= 0 && rc != PCRE_ERROR_NOMATCH) { | |
144 | error(0, "pcre_exec returned %d, subject '%s'", rc, subject); | |
145 | return 0; | |
146 | } | |
147 | if((flags & REGSUB_MUST_MATCH) && matches == 0) | |
148 | return 0; | |
149 | /* append the remainder of the subject */ | |
150 | if(!(flags & REGSUB_REPLACE)) | |
151 | dynstr_append_string(&d, subject); | |
152 | dynstr_terminate(&d); | |
153 | return d.vec; | |
154 | } | |
155 | ||
156 | /* | |
157 | Local Variables: | |
158 | c-basic-offset:2 | |
159 | comment-column:40 | |
160 | End: | |
161 | */ |