contrib/flex/regex.c

   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(&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  */
  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  */
  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  */
 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  */
 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  */
 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  */
 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: */