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