1 /** regex - regular expression functions related to POSIX regex lib. */
3 /* This file is part of flex. */
5 /* Redistribution and use in source and binary forms, with or without */
6 /* modification, are permitted provided that the following conditions */
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. */
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. */
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 */
27 static const char* REGEXP_LINEDIR = "^#line ([[:digit:]]+) \"(.*)\"";
28 static const char* REGEXP_BLANK_LINE = "^[[:space:]]*$";
30 regex_t regex_linedir; /**< matches line directives */
31 regex_t regex_blank_line; /**< matches blank lines */
34 /** Initialize the regular expressions.
35 * @return true upon success.
37 bool flex_init_regex(void)
39 flex_regcomp(®ex_linedir, REGEXP_LINEDIR, REG_EXTENDED);
40 flex_regcomp(®ex_blank_line, REGEXP_BLANK_LINE, REG_EXTENDED);
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().
50 void flex_regcomp(regex_t *preg, const char *regex, int cflags)
54 memset (preg, 0, sizeof (regex_t));
56 if ((err = regcomp (preg, regex, cflags)) != 0) {
57 const size_t errbuf_sz = 200;
61 errbuf = malloc(errbuf_sz * sizeof(char));
63 flexfatal(_("Unable to allocate buffer to report regcomp"));
64 n = snprintf(errbuf, errbuf_sz, "regcomp for \"%s\" failed: ", regex);
65 regerror(err, preg, errbuf+n, errbuf_sz-(size_t)n);
67 flexfatal (errbuf); /* never returns - no need to free(errbuf) */
71 /** Extract a copy of the match, or NULL if no match.
72 * @param m A match as returned by regexec().
73 * @param src The source string that was passed to regexec().
74 * @return The allocated string.
76 char *regmatch_dup (regmatch_t * m, const char *src)
81 if (m == NULL || m->rm_so < 0 || m->rm_eo < m->rm_so)
83 len = (size_t) (m->rm_eo - m->rm_so);
84 str = malloc((len + 1) * sizeof(char));
86 flexfatal(_("Unable to allocate a copy of the match"));
87 strncpy (str, src + m->rm_so, len);
93 * @param m A match as returned by regexec().
94 * @param dest The destination buffer.
95 * @param src The source string that was passed to regexec().
98 char *regmatch_cpy (regmatch_t * m, char *dest, const char *src)
100 if (m == NULL || m->rm_so < 0) {
106 snprintf (dest, (size_t) regmatch_len(m), "%s", src + m->rm_so);
110 /** Get the length in characters of the match.
111 * @param m A match as returned by regexec().
112 * @return The length of the match.
114 int regmatch_len (regmatch_t * m)
116 if (m == NULL || m->rm_so < 0) {
120 return m->rm_eo - m->rm_so;
125 /** Convert a regmatch_t object to an integer using the strtol() function.
126 * @param m A match as returned by regexec().
127 * @param src The source string that was passed to regexec().
128 * @param endptr Same as the second argument to strtol().
129 * @param base Same as the third argument to strtol().
130 * @return The converted integer or error (Return value is the same as for strtol()).
132 int regmatch_strtol (regmatch_t * m, const char *src, char **endptr,
141 if (m == NULL || m->rm_so < 0)
144 if (regmatch_len (m) < bufsz)
145 s = regmatch_cpy (m, buf, src);
147 s = regmatch_dup (m, src);
149 n = (int) strtol (s, endptr, base);
157 /** Check for empty or non-existent match.
158 * @param m A match as returned by regexec().
159 * @return false if match length is non-zero.
160 * Note that reg_empty returns true even if match did not occur at all.
162 bool regmatch_empty (regmatch_t * m)
164 return (m == NULL || m->rm_so < 0 || m->rm_so == m->rm_eo);
167 /* vim:set expandtab cindent tabstop=4 softtabstop=4 shiftwidth=4 textwidth=0: */