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
27static const char* REGEXP_LINEDIR = "^#line ([[:digit:]]+) \"(.*)\"";
28static const char* REGEXP_BLANK_LINE = "^[[:space:]]*$";
29
30regex_t regex_linedir; /**< matches line directives */
31regex_t regex_blank_line; /**< matches blank lines */
32
33
34/** Initialize the regular expressions.
35 * @return true upon success.
36 */
37bool flex_init_regex(void)
38{
39    flex_regcomp(&regex_linedir, REGEXP_LINEDIR, REG_EXTENDED);
40    flex_regcomp(&regex_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 */
50void 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 */
80char   *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 */
102char   *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 */
119int 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 */
137int 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 */
167bool 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