Quelle regex.c Sprache: C

/** regex - regular expression functions related to POSIX regex lib. */

/*  This file is part of flex. */

/*  Redistribution and use in source and binary forms, with or without */
/*  modification, are permitted provided that the following conditions */
/*  are met: */

/*  1. Redistributions of source code must retain the above copyright */
/*     notice, this list of conditions and the following disclaimer. */
/*  2. Redistributions in binary form must reproduce the above copyright */
/*     notice, this list of conditions and the following disclaimer in the */
/*     documentation and/or other materials provided with the distribution. */

/*  Neither the name of the University nor the names of its contributors */
/*  may be used to endorse or promote products derived from this software */
/*  without specific prior written permission. */

/*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */
/*  IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */
/*  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
/*  PURPOSE. */

#include "flexdef.h"

static const char* REGEXP_LINEDIR = "^#line ([[:digit:]]+) \"(.*)\"";
static const char* REGEXP_BLANK_LINE = "^[[:space:]]*$";

regex_t regex_linedir; /**< matches line directives */
regex_t regex_blank_line; /**< matches blank lines */

/** Initialize the regular expressions.
* @return true upon success.
*/
bool flex_init_regex(void)
{
    flex_regcomp(®ex_linedir, REGEXP_LINEDIR, REG_EXTENDED);
    flex_regcomp(®ex_blank_line, REGEXP_BLANK_LINE, REG_EXTENDED);

    return true;
}

/** Compiles a regular expression or dies trying.
* @param preg  Same as for regcomp().
* @param regex Same as for regcomp().
* @param cflags Same as for regcomp().
*/
void flex_regcomp(regex_t *preg, const char *regex, int cflags)
{
    int err;

memset (preg, 0, sizeof (regex_t));

if ((err = regcomp (preg, regex, cflags)) != 0) {
        const int errbuf_sz = 200;
        char *errbuf, *rxerr;

  errbuf = (char*)flex_alloc(errbuf_sz *sizeof(char));
  if (!errbuf)
   flexfatal(_("Unable to allocate buffer to report regcomp"));
  rxerr = (char*)flex_alloc(errbuf_sz *sizeof(char));
  if (!rxerr)
   flexfatal(_("Unable to allocate buffer for regerror"));
  regerror (err, preg, rxerr, errbuf_sz);
  snprintf (errbuf, errbuf_sz, "regcomp for \"%s\" failed: %s", regex, rxerr);

  flexfatal (errbuf);
        free(errbuf);
        free(rxerr);
}
}

/** Extract a copy of the match, or NULL if no match.
* @param m A match as returned by regexec().
* @param src The source string that was passed to regexec().
* @return The allocated string.
*/
char   *regmatch_dup (regmatch_t * m, const char *src)
{
char   *str;
int     len;

if (m == NULL || m->rm_so < 0)
  return NULL;
len = m->rm_eo - m->rm_so;
str = (char *) flex_alloc ((len + 1) * sizeof (char));
if (!str)
  flexfatal(_("Unable to allocate a copy of the match"));
strncpy (str, src + m->rm_so, len);
str[len] = 0;
return str;
}

/** Copy the match.
* @param m A match as returned by regexec().
* @param dest The destination buffer.
* @param src The source string that was passed to regexec().
* @return dest
*/
char   *regmatch_cpy (regmatch_t * m, char *dest, const char *src)
{
if (m == NULL || m->rm_so < 0) {
  if (dest)
   dest[0] = '\0';
  return dest;
}

snprintf (dest, regmatch_len(m), "%s", src + m->rm_so);
    return dest;
}

/** Get the length in characters of the match.
* @param m A match as returned by regexec().
* @return The length of the match.
*/
int regmatch_len (regmatch_t * m)
{
if (m == NULL || m->rm_so < 0) {
  return 0;
}

return m->rm_eo - m->rm_so;
}

/** Convert a regmatch_t object to an integer using the strtol() function.
* @param m A match as returned by regexec().
* @param src The source string that was passed to regexec().
* @param endptr Same as the second argument to strtol().
* @param base   Same as the third argument to strtol().
* @return The converted integer or error (Return value is the same as for strtol()).
*/
int regmatch_strtol (regmatch_t * m, const char *src, char **endptr,
       int base)
{
int     n = 0;

#define bufsz 20
char    buf[bufsz];
char   *s;

if (m == NULL || m->rm_so < 0)
  return 0;

if (regmatch_len (m) < bufsz)
  s = regmatch_cpy (m, buf, src);
else
  s = regmatch_dup (m, src);

n = strtol (s, endptr, base);

if (s != buf)
  free (s);

return n;
}

/** Check for empty or non-existent match.
* @param m A match as returned by regexec().
* @return false if match length is non-zero.
* Note that reg_empty returns true even if match did not occur at all.
*/
bool regmatch_empty (regmatch_t * m)
{
return (m == NULL || m->rm_so < 0 || m->rm_so == m->rm_eo);
}

/* vim:set expandtab cindent tabstop=4 softtabstop=4 shiftwidth=4 textwidth=0: */

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