external/bsd/flex/dist/regex.c

   1 /*      $NetBSD$        */
   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=0;
  61
  62         errbuf = (char*)flex_alloc(errbuf_sz *sizeof(char));
  63                 regerror (err, preg, errbuf, errbuf_sz);
  64                 snprintf (errbuf, errbuf_sz, "regcomp failed: %s\n", errbuf);
  65
  66                 flexfatal (errbuf);
  67         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         int     len;
  80
  81         if (m == NULL || m->rm_so < 0)
  82                 return NULL;
  83         len = m->rm_eo - m->rm_so;
  84         str = (char *) flex_alloc ((len + 1) * sizeof (char));
  85         strncpy (str, src + m->rm_so, len);
  86         str[len] = 0;
  87         return str;
  88 }
  89
  90 /** Copy the match.
  91  * @param m A match as returned by regexec().
  92  * @param dest The destination buffer.
  93  * @param src The source string that was passed to regexec().
  94  * @return dest
  95  */
  96 char   *regmatch_cpy (regmatch_t * m, char *dest, const char *src)
  97 {
  98         if (m == NULL || m->rm_so < 0) {
  99                 if (dest)
 100                         dest[0] = '\0';
 101                 return dest;
 102         }
 103
 104         snprintf (dest, regmatch_len(m), "%s", src + m->rm_so);
 105     return dest;
 106 }
 107
 108 /** Get the length in characters of the match.
 109  * @param m A match as returned by regexec().
 110  * @param src The source string that was passed to regexec().
 111  * @return The length of the match.
 112  */
 113 int regmatch_len (regmatch_t * m)
 114 {
 115         if (m == NULL || m->rm_so < 0) {
 116                 return 0;
 117         }
 118
 119         return m->rm_eo - m->rm_so;
 120 }
 121
 122
 123
 124 /** Convert a regmatch_t object to an integer using the strtol() function.
 125  * @param m A match as returned by regexec().
 126  * @param src The source string that was passed to regexec().
 127  * @param endptr Same as the second argument to strtol().
 128  * @param base   Same as the third argument to strtol().
 129  * @return The converted integer or error (Return value is the same as for strtol()).
 130  */
 131 int regmatch_strtol (regmatch_t * m, const char *src, char **endptr,
 132                      int base)
 133 {
 134         int     n = 0;
 135
 136 #define bufsz 20
 137         char    buf[bufsz];
 138         char   *s;
 139
 140         if (m == NULL || m->rm_so < 0)
 141                 return 0;
 142
 143         if (regmatch_len (m) < bufsz)
 144                 s = regmatch_cpy (m, buf, src);
 145         else
 146                 s = regmatch_dup (m, src);
 147
 148         n = strtol (s, endptr, base);
 149
 150         if (s != buf)
 151                 free (s);
 152
 153         return n;
 154 }
 155
 156 /** Check for empty or non-existent match.
 157  * @param m A match as returned by regexec().
 158  * @return false if match length is non-zero.
 159  * Note that reg_empty returns true even if match did not occur at all.
 160  */
 161 bool regmatch_empty (regmatch_t * m)
 162 {
 163         return (m == NULL || m->rm_so < 0 || m->rm_so == m->rm_eo);
 164 }
 165
 166 /* vim:set expandtab cindent tabstop=4 softtabstop=4 shiftwidth=4 textwidth=0: */