/*
 *      dnsutl - utilities to make DNS easier to configure
 *      Copyright (C) 1999, 2006, 2007 Peter Miller
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation; either version 3 of the License, or
 *      (at your option) any later version.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU General Public License for more details.
 *
 *      You should have received a copy of the GNU General Public License
 *      along with this program. If not, see
 *      <http://www.gnu.org/licenses/>.
 */

#include <ac/stddef.h>
#include <sys/types.h>
#include <ac/rxposix.h>

#include <error.h>
#include <regu_expr.h>


int
regular_expression_match(const char *formal, const char *actual)
{
#if defined(HAVE_REGCOMP) && defined(HAVE_REGEXEC)
    /* use POSIX regular expressions */
    regex_t         reg;
    int             n;

    n = regcomp(&reg, formal, REG_NOSUB | REG_EXTENDED);
    if (n)
    {
        char            errbuf[100];
      bomb:
        regerror(n, &reg, errbuf, sizeof(errbuf));
        fatal("pattern \"%s\" error: %s", formal, errbuf);
    }
    n = regexec(&reg, actual, 0, (regmatch_t *) 0, 0);
    switch (n)
    {
    case 0:
        regfree(&reg);
        return 1;

    case REG_NOMATCH:
        regfree(&reg);
        return 0;

    default:
        goto bomb;
    }
#else  /* !posix */
#if defined(HAVE_REGCMP) && defined(HAVE_REGEX)
    /* use ancient BSD regular expressions */
    int             n;
    char            *magic;

    magic = regcmp(formal, (char *)0);
    if (!magic)
    {
        fatal("pattern \"%s\" error", formal);
    }
    n = regex(magic, actual);
    free(magic);
    return (n != 0);
#else  /* !bsd */
#if defined(HAVE_RE_COMP) && defined(HAVE_RE_EXEC)
    /* use BSD 4.2 regular expressions */
    int             n;
    char            *s;

    s = re_comp(formal);
    if (s)
    {
        fatal("pattern \"%s\" error: %s", formal, s);
    }
    n = re_exec(actual);
    if (n < 0)
        fatal("pattern \"%s\" error", formal);
    return n;
#else  /* !sun */
#error "Can't find any Regular Expression functions!"
    fatal("no regular expressions available");
#endif /* !sun */
#endif /* !bsd */
#endif /* !posix */
}