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1 | /* |
2 | * This file is part of DisOrder |
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3 | * Copyright (C) 2004, 2005, 2007, 20008 Richard Kettlewell |
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4 | * |
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 2 of the License, or |
8 | * (at your option) any later version. |
9 | * |
10 | * This program is distributed in the hope that it will be useful, but |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | * General Public License for more details. |
14 | * |
15 | * You should have received a copy of the GNU General Public License |
16 | * along with this program; if not, write to the Free Software |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
18 | * USA |
19 | */ |
20 | |
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21 | #include "common.h" |
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22 | |
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23 | #include <pcre.h> |
24 | |
25 | #include "regsub.h" |
26 | #include "mem.h" |
27 | #include "vector.h" |
28 | #include "log.h" |
29 | |
30 | #define PREMATCH (-1) /* fictitious pre-match substring */ |
31 | #define POSTMATCH (-2) /* fictitious post-match substring */ |
32 | |
33 | static inline int substring_start(const char attribute((unused)) *subject, |
34 | const int *ovector, |
35 | int n) { |
36 | switch(n) { |
37 | case PREMATCH: return 0; |
38 | case POSTMATCH: return ovector[1]; |
39 | default: return ovector[2 * n]; |
40 | } |
41 | } |
42 | |
43 | static inline int substring_end(const char *subject, |
44 | const int *ovector, |
45 | int n) { |
46 | switch(n) { |
47 | case PREMATCH: return ovector[0]; |
48 | case POSTMATCH: return strlen(subject); |
49 | default: return ovector[2 * n + 1]; |
50 | } |
51 | } |
52 | |
53 | static void transform_append(struct dynstr *d, |
54 | const char *subject, |
55 | const int *ovector, |
56 | int n) { |
57 | int start = substring_start(subject, ovector, n); |
58 | int end = substring_end(subject, ovector, n); |
59 | |
60 | if(start != -1) |
61 | dynstr_append_bytes(d, subject + start, end - start); |
62 | } |
63 | |
64 | static void replace_core(struct dynstr *d, |
65 | const char *subject, |
66 | const char *replace, |
67 | int rc, |
68 | const int *ovector) { |
69 | int substr; |
70 | |
71 | while(*replace) { |
72 | if(*replace == '$') |
73 | switch(replace[1]) { |
74 | case '&': |
75 | transform_append(d, subject, ovector, 0); |
76 | replace += 2; |
77 | break; |
78 | case '1': case '2': case '3': |
79 | case '4': case '5': case '6': |
80 | case '7': case '8': case '9': |
81 | substr = replace[1] - '0'; |
82 | if(substr < rc) |
83 | transform_append(d, subject, ovector, substr); |
84 | replace += 2; |
85 | break; |
86 | case '$': |
87 | dynstr_append(d, '$'); |
88 | replace += 2; |
89 | break; |
90 | default: |
91 | dynstr_append(d, *replace++); |
92 | break; |
93 | } |
94 | else |
95 | dynstr_append(d, *replace++); |
96 | } |
97 | } |
98 | |
99 | unsigned regsub_flags(const char *flags) { |
100 | unsigned f = 0; |
101 | |
102 | while(*flags) { |
103 | switch(*flags++) { |
104 | case 'g': f |= REGSUB_GLOBAL; break; |
105 | case 'i': f |= REGSUB_CASE_INDEPENDENT; break; |
106 | default: break; |
107 | } |
108 | } |
109 | return f; |
110 | } |
111 | |
112 | int regsub_compile_options(unsigned flags) { |
113 | int options = 0; |
114 | |
115 | if(flags & REGSUB_CASE_INDEPENDENT) |
116 | options |= PCRE_CASELESS; |
117 | return options; |
118 | } |
119 | |
120 | const char *regsub(const pcre *re, const char *subject, const char *replace, |
121 | unsigned flags) { |
122 | int rc, ovector[99], matches; |
123 | struct dynstr d; |
124 | |
125 | dynstr_init(&d); |
126 | matches = 0; |
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); |
135 | ++matches; |
136 | if(!*subject) /* end of subject */ |
137 | break; |
138 | if(flags & REGSUB_REPLACE) /* replace subject entirely */ |
139 | break; |
140 | /* step over the matched substring */ |
141 | subject += substring_start(subject, ovector, POSTMATCH); |
142 | if(!(flags & REGSUB_GLOBAL)) |
143 | break; |
144 | } |
145 | if(rc <= 0 && rc != PCRE_ERROR_NOMATCH) { |
146 | error(0, "pcre_exec returned %d, subject '%s'", rc, subject); |
147 | return 0; |
148 | } |
149 | if((flags & REGSUB_MUST_MATCH) && matches == 0) |
150 | return 0; |
151 | /* append the remainder of the subject */ |
152 | if(!(flags & REGSUB_REPLACE)) |
153 | dynstr_append_string(&d, subject); |
154 | dynstr_terminate(&d); |
155 | return d.vec; |
156 | } |
157 | |
158 | /* |
159 | Local Variables: |
160 | c-basic-offset:2 |
161 | comment-column:40 |
162 | End: |
163 | */ |