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 */
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 */
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 size_t errbuf_sz = 200;
58 char *errbuf;
59 int n;
60
61 errbuf = malloc(errbuf_sz * sizeof(char));
62 if (!errbuf)
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);
66
67 flexfatal (errbuf); /* never returns - no need to free(errbuf) */
68 }
69 }
70
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.
75 */
76 char *regmatch_dup (regmatch_t * m, const char *src)
77 {
78 char *str;
79 size_t len;
80
81 if (m == NULL || m->rm_so < 0 || m->rm_eo < m->rm_so)
82 return NULL;
83 len = (size_t) (m->rm_eo - m->rm_so);
84 str = malloc((len + 1) * sizeof(char));
85 if (!str)
86 flexfatal(_("Unable to allocate a copy of the match"));
87 strncpy (str, src + m->rm_so, len);
88 str[len] = 0;
89 return str;
90 }
91
92 /** Copy the match.
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().
96 * @return dest
97 */
98 char *regmatch_cpy (regmatch_t * m, char *dest, const char *src)
99 {
100 if (m == NULL || m->rm_so < 0) {
101 if (dest)
102 dest[0] = '\0';
103 return dest;
104 }
105
106 snprintf (dest, (size_t) regmatch_len(m), "%s", src + m->rm_so);
107 return dest;
108 }
109
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.
113 */
114 int regmatch_len (regmatch_t * m)
115 {
116 if (m == NULL || m->rm_so < 0) {
117 return 0;
118 }
119
120 return m->rm_eo - m->rm_so;
121 }
122
123
124
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()).
131 */
132 int regmatch_strtol (regmatch_t * m, const char *src, char **endptr,
133 int base)
134 {
135 int n = 0;
136
137 #define bufsz 20
138 char buf[bufsz];
139 char *s;
140
141 if (m == NULL || m->rm_so < 0)
142 return 0;
143
144 if (regmatch_len (m) < bufsz)
145 s = regmatch_cpy (m, buf, src);
146 else
147 s = regmatch_dup (m, src);
148
149 n = (int) strtol (s, endptr, base);
150
151 if (s != buf)
152 free (s);
153
154 return n;
155 }
156
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.
161 */
162 bool regmatch_empty (regmatch_t * m)
163 {
164 return (m == NULL || m->rm_so < 0 || m->rm_so == m->rm_eo);
165 }
166
167 /* vim:set expandtab cindent tabstop=4 softtabstop=4 shiftwidth=4 textwidth=0: */