1 /* $NetBSD: regex.c,v 1.3 2014/10/30 18:44:05 christos Exp $ */
2
3 /** regex - regular expression functions related to POSIX regex lib. */
4
5 /* This file is part of flex. */
6
7 /* Redistribution and use in source and binary forms, with or without */
8 /* modification, are permitted provided that the following conditions */
9 /* are met: */
10
11 /* 1. Redistributions of source code must retain the above copyright */
12 /* notice, this list of conditions and the following disclaimer. */
13 /* 2. Redistributions in binary form must reproduce the above copyright */
14 /* notice, this list of conditions and the following disclaimer in the */
15 /* documentation and/or other materials provided with the distribution. */
16
17 /* Neither the name of the University nor the names of its contributors */
18 /* may be used to endorse or promote products derived from this software */
19 /* without specific prior written permission. */
20
21 /* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */
22 /* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */
23 /* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
24 /* PURPOSE. */
25 #include "flexdef.h"
26 __RCSID("$NetBSD: regex.c,v 1.3 2014/10/30 18:44:05 christos Exp $");
27
28 static const char* REGEXP_LINEDIR = "^#line ([[:digit:]]+) \"(.*)\"";
29 static const char* REGEXP_BLANK_LINE = "^[[:space:]]*$";
30
31 regex_t regex_linedir; /**< matches line directives */
32 regex_t regex_blank_line; /**< matches blank lines */
33
34
35 /** Initialize the regular expressions.
36 * @return true upon success.
37 */
flex_init_regex(void)38 bool flex_init_regex(void)
39 {
40 flex_regcomp(®ex_linedir, REGEXP_LINEDIR, REG_EXTENDED);
41 flex_regcomp(®ex_blank_line, REGEXP_BLANK_LINE, REG_EXTENDED);
42
43 return true;
44 }
45
46 /** Compiles a regular expression or dies trying.
47 * @param preg Same as for regcomp().
48 * @param regex Same as for regcomp().
49 * @param cflags Same as for regcomp().
50 */
flex_regcomp(regex_t * preg,const char * regex,int cflags)51 void flex_regcomp(regex_t *preg, const char *regex, int cflags)
52 {
53 int err;
54
55 memset (preg, 0, sizeof (regex_t));
56
57 if ((err = regcomp (preg, regex, cflags)) != 0) {
58 const int errbuf_sz = 200;
59 char *errbuf, *rxerr;
60
61 errbuf = (char*)flex_alloc(errbuf_sz *sizeof(char));
62 if (!errbuf)
63 flexfatal(_("Unable to allocate buffer to report regcomp"));
64 rxerr = (char*)flex_alloc(errbuf_sz *sizeof(char));
65 if (!rxerr)
66 flexfatal(_("Unable to allocate buffer for regerror"));
67 regerror (err, preg, rxerr, errbuf_sz);
68 snprintf (errbuf, errbuf_sz, "regcomp for \"%s\" failed: %s", regex, rxerr);
69
70 flexfatal (errbuf);
71 free(errbuf);
72 free(rxerr);
73 }
74 }
75
76 /** Extract a copy of the match, or NULL if no match.
77 * @param m A match as returned by regexec().
78 * @param src The source string that was passed to regexec().
79 * @return The allocated string.
80 */
regmatch_dup(regmatch_t * m,const char * src)81 char *regmatch_dup (regmatch_t * m, const char *src)
82 {
83 char *str;
84 int len;
85
86 if (m == NULL || m->rm_so < 0)
87 return NULL;
88 len = m->rm_eo - m->rm_so;
89 str = (char *) flex_alloc ((len + 1) * sizeof (char));
90 if (!str)
91 flexfatal(_("Unable to allocate a copy of the match"));
92 strncpy (str, src + m->rm_so, len);
93 str[len] = 0;
94 return str;
95 }
96
97 /** Copy the match.
98 * @param m A match as returned by regexec().
99 * @param dest The destination buffer.
100 * @param src The source string that was passed to regexec().
101 * @return dest
102 */
regmatch_cpy(regmatch_t * m,char * dest,const char * src)103 char *regmatch_cpy (regmatch_t * m, char *dest, const char *src)
104 {
105 if (m == NULL || m->rm_so < 0) {
106 if (dest)
107 dest[0] = '\0';
108 return dest;
109 }
110
111 snprintf (dest, regmatch_len(m), "%s", src + m->rm_so);
112 return dest;
113 }
114
115 /** Get the length in characters of the match.
116 * @param m A match as returned by regexec().
117 * @param src The source string that was passed to regexec().
118 * @return The length of the match.
119 */
regmatch_len(regmatch_t * m)120 int regmatch_len (regmatch_t * m)
121 {
122 if (m == NULL || m->rm_so < 0) {
123 return 0;
124 }
125
126 return m->rm_eo - m->rm_so;
127 }
128
129
130
131 /** Convert a regmatch_t object to an integer using the strtol() function.
132 * @param m A match as returned by regexec().
133 * @param src The source string that was passed to regexec().
134 * @param endptr Same as the second argument to strtol().
135 * @param base Same as the third argument to strtol().
136 * @return The converted integer or error (Return value is the same as for strtol()).
137 */
regmatch_strtol(regmatch_t * m,const char * src,char ** endptr,int base)138 int regmatch_strtol (regmatch_t * m, const char *src, char **endptr,
139 int base)
140 {
141 int n = 0;
142
143 #define bufsz 20
144 char buf[bufsz];
145 char *s;
146
147 if (m == NULL || m->rm_so < 0)
148 return 0;
149
150 if (regmatch_len (m) < bufsz)
151 s = regmatch_cpy (m, buf, src);
152 else
153 s = regmatch_dup (m, src);
154
155 n = strtol (s, endptr, base);
156
157 if (s != buf)
158 free (s);
159
160 return n;
161 }
162
163 /** Check for empty or non-existent match.
164 * @param m A match as returned by regexec().
165 * @return false if match length is non-zero.
166 * Note that reg_empty returns true even if match did not occur at all.
167 */
regmatch_empty(regmatch_t * m)168 bool regmatch_empty (regmatch_t * m)
169 {
170 return (m == NULL || m->rm_so < 0 || m->rm_so == m->rm_eo);
171 }
172
173 /* vim:set expandtab cindent tabstop=4 softtabstop=4 shiftwidth=4 textwidth=0: */
174