external/bsd/flex/dist/regex.c

   1 /*      $NetBSD: regex.c,v 1.1.1.2 2013/04/06 14:05:44 christos Exp $   */
   2
   3 /** regex - regular expression functions related to POSIX regex lib. */
   4
   5 /*  This file is part of flex. */
   6
   7 /*  Redistribution and use in source and binary forms, with or without */
   8 /*  modification, are permitted provided that the following conditions */
   9 /*  are met: */
  10
  11 /*  1. Redistributions of source code must retain the above copyright */
  12 /*     notice, this list of conditions and the following disclaimer. */
  13 /*  2. Redistributions in binary form must reproduce the above copyright */
  14 /*     notice, this list of conditions and the following disclaimer in the */
  15 /*     documentation and/or other materials provided with the distribution. */
  16
  17 /*  Neither the name of the University nor the names of its contributors */
  18 /*  may be used to endorse or promote products derived from this software */
  19 /*  without specific prior written permission. */
  20
  21 /*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */
  22 /*  IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */
  23 /*  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
  24 /*  PURPOSE. */
  25
  26 #include "flexdef.h"
  27
  28
  29 static const char* REGEXP_LINEDIR = "^#line ([[:digit:]]+) \"(.*)\"";
  30 static const char* REGEXP_BLANK_LINE = "^[[:space:]]*$";
  31
  32 regex_t regex_linedir; /**< matches line directives */
  33 regex_t regex_blank_line; /**< matches blank lines */
  34
  35
  36 /** Initialize the regular expressions.
  37  * @return true upon success.
  38  */
  39 bool flex_init_regex(void)
  40 {
  41     flex_regcomp(&regex_linedir, REGEXP_LINEDIR, REG_EXTENDED);
  42     flex_regcomp(&regex_blank_line, REGEXP_BLANK_LINE, REG_EXTENDED);
  43
  44     return true;
  45 }
  46
  47 /** Compiles a regular expression or dies trying.
  48  * @param preg  Same as for regcomp().
  49  * @param regex Same as for regcomp().
  50  * @param cflags Same as for regcomp().
  51  */
  52 void flex_regcomp(regex_t *preg, const char *regex, int cflags)
  53 {
  54     int err;
  55
  56         memset (preg, 0, sizeof (regex_t));
  57
  58         if ((err = regcomp (preg, regex, cflags)) != 0) {
  59         const int errbuf_sz = 200;
  60         char *errbuf, *rxerr;
  61
  62                 errbuf = (char*)flex_alloc(errbuf_sz *sizeof(char));
  63                 if (!errbuf)
  64                         flexfatal(_("Unable to allocate buffer to report regcomp"));
  65                 rxerr = (char*)flex_alloc(errbuf_sz *sizeof(char));
  66                 if (!rxerr)
  67                         flexfatal(_("Unable to allocate buffer for regerror"));
  68                 regerror (err, preg, rxerr, errbuf_sz);
  69                 snprintf (errbuf, errbuf_sz, "regcomp for \"%s\" failed: %s", regex, rxerr);
  70
  71                 flexfatal (errbuf);
  72         free(errbuf);
  73         free(rxerr);
  74         }
  75 }
  76
  77 /** Extract a copy of the match, or NULL if no match.
  78  * @param m A match as returned by regexec().
  79  * @param src The source string that was passed to regexec().
  80  * @return The allocated string.
  81  */
  82 char   *regmatch_dup (regmatch_t * m, const char *src)
  83 {
  84         char   *str;
  85         int     len;
  86
  87         if (m == NULL || m->rm_so < 0)
  88                 return NULL;
  89         len = m->rm_eo - m->rm_so;
  90         str = (char *) flex_alloc ((len + 1) * sizeof (char));
  91         if (!str)
  92                 flexfatal(_("Unable to allocate a copy of the match"));
  93         strncpy (str, src + m->rm_so, len);
  94         str[len] = 0;
  95         return str;
  96 }
  97
  98 /** Copy the match.
  99  * @param m A match as returned by regexec().
 100  * @param dest The destination buffer.
 101  * @param src The source string that was passed to regexec().
 102  * @return dest
 103  */
 104 char   *regmatch_cpy (regmatch_t * m, char *dest, const char *src)
 105 {
 106         if (m == NULL || m->rm_so < 0) {
 107                 if (dest)
 108                         dest[0] = '\0';
 109                 return dest;
 110         }
 111
 112         snprintf (dest, regmatch_len(m), "%s", src + m->rm_so);
 113     return dest;
 114 }
 115
 116 /** Get the length in characters of the match.
 117  * @param m A match as returned by regexec().
 118  * @param src The source string that was passed to regexec().
 119  * @return The length of the match.
 120  */
 121 int regmatch_len (regmatch_t * m)
 122 {
 123         if (m == NULL || m->rm_so < 0) {
 124                 return 0;
 125         }
 126
 127         return m->rm_eo - m->rm_so;
 128 }
 129
 130
 131
 132 /** Convert a regmatch_t object to an integer using the strtol() function.
 133  * @param m A match as returned by regexec().
 134  * @param src The source string that was passed to regexec().
 135  * @param endptr Same as the second argument to strtol().
 136  * @param base   Same as the third argument to strtol().
 137  * @return The converted integer or error (Return value is the same as for strtol()).
 138  */
 139 int regmatch_strtol (regmatch_t * m, const char *src, char **endptr,
 140                      int base)
 141 {
 142         int     n = 0;
 143
 144 #define bufsz 20
 145         char    buf[bufsz];
 146         char   *s;
 147
 148         if (m == NULL || m->rm_so < 0)
 149                 return 0;
 150
 151         if (regmatch_len (m) < bufsz)
 152                 s = regmatch_cpy (m, buf, src);
 153         else
 154                 s = regmatch_dup (m, src);
 155
 156         n = strtol (s, endptr, base);
 157
 158         if (s != buf)
 159                 free (s);
 160
 161         return n;
 162 }
 163
 164 /** Check for empty or non-existent match.
 165  * @param m A match as returned by regexec().
 166  * @return false if match length is non-zero.
 167  * Note that reg_empty returns true even if match did not occur at all.
 168  */
 169 bool regmatch_empty (regmatch_t * m)
 170 {
 171         return (m == NULL || m->rm_so < 0 || m->rm_so == m->rm_eo);
 172 }
 173
 174 /* vim:set expandtab cindent tabstop=4 softtabstop=4 shiftwidth=4 textwidth=0: */