flex-2.5.33/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=0;
  59
  60         errbuf = (char*)flex_alloc(errbuf_sz *sizeof(char));
  61                 regerror (err, preg, errbuf, errbuf_sz);
  62                 sprintf (errbuf, "regcomp failed: %s\n", errbuf);
  63
  64                 flexfatal (errbuf);
  65         free(errbuf);
  66         }
  67 }
  68
  69 /** Extract a copy of the match, or NULL if no match.
  70  * @param m A match as returned by regexec().
  71  * @param src The source string that was passed to regexec().
  72  * @return The allocated string.
  73  */
  74 char   *regmatch_dup (regmatch_t * m, const char *src)
  75 {
  76         char   *str;
  77         int     len;
  78
  79         if (m == NULL || m->rm_so < 0)
  80                 return NULL;
  81         len = m->rm_eo - m->rm_so;
  82         str = (char *) flex_alloc ((len + 1) * sizeof (char));
  83         strncpy (str, src + m->rm_so, len);
  84         str[len] = 0;
  85         return str;
  86 }
  87
  88 /** Copy the match.
  89  * @param m A match as returned by regexec().
  90  * @param dest The destination buffer.
  91  * @param src The source string that was passed to regexec().
  92  * @return dest
  93  */
  94 char   *regmatch_cpy (regmatch_t * m, char *dest, const char *src)
  95 {
  96         if (m == NULL || m->rm_so < 0) {
  97                 if (dest)
  98                         dest[0] = '\0';
  99                 return dest;
 100         }
 101
 102         snprintf (dest, regmatch_len(m), "%s", src + m->rm_so);
 103     return dest;
 104 }
 105
 106 /** Get the length in characters of the match.
 107  * @param m A match as returned by regexec().
 108  * @param src The source string that was passed to regexec().
 109  * @return The length of the match.
 110  */
 111 int regmatch_len (regmatch_t * m)
 112 {
 113         if (m == NULL || m->rm_so < 0) {
 114                 return 0;
 115         }
 116
 117         return m->rm_eo - m->rm_so;
 118 }
 119
 120
 121
 122 /** Convert a regmatch_t object to an integer using the strtol() function.
 123  * @param m A match as returned by regexec().
 124  * @param src The source string that was passed to regexec().
 125  * @param endptr Same as the second argument to strtol().
 126  * @param base   Same as the third argument to strtol().
 127  * @return The converted integer or error (Return value is the same as for strtol()).
 128  */
 129 int regmatch_strtol (regmatch_t * m, const char *src, char **endptr,
 130                      int base)
 131 {
 132         int     n = 0;
 133
 134 #define bufsz 20
 135         char    buf[bufsz];
 136         char   *s;
 137
 138         if (m == NULL || m->rm_so < 0)
 139                 return 0;
 140
 141         if (regmatch_len (m) < bufsz)
 142                 s = regmatch_cpy (m, buf, src);
 143         else
 144                 s = regmatch_dup (m, src);
 145
 146         n = strtol (s, endptr, base);
 147
 148         if (s != buf)
 149                 free (s);
 150
 151         return n;
 152 }
 153
 154 /** Check for empty or non-existent match.
 155  * @param m A match as returned by regexec().
 156  * @return false if match length is non-zero.
 157  * Note that reg_empty returns true even if match did not occur at all.
 158  */
 159 bool regmatch_empty (regmatch_t * m)
 160 {
 161         return (m == NULL || m->rm_so < 0 || m->rm_so == m->rm_eo);
 162 }
 163
 164 /* vim:set expandtab cindent tabstop=4 softtabstop=4 shiftwidth=4 textwidth=0: */