/* Determine whether string value is affirmation or negative response

   according to current locale's data.

   This file is part of the GNU C Library.

   Copyright (C) 1996-2018 Free Software Foundation, Inc.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <langinfo.h>

#include <stdlib.h>

#include <regex.h>

/* Match against one of the response patterns, compiling the pattern

   first if necessary.  */

static int

try (const char *response,

     const int tag, const int match, const int nomatch,

     const char **lastp, regex_t *re)

{

  const char *pattern = nl_langinfo (tag);

  if (pattern != *lastp)

    {

      /* The pattern has changed.  */

      if (*lastp != NULL)

        {

          /* Free the old compiled pattern.  */

          __regfree (re);

          *lastp = NULL;

        }

      /* Compile the pattern and cache it for future runs.  */

      if (__regcomp (re, pattern, REG_EXTENDED) != 0)

        return -1;

      *lastp = pattern;

    }

  /* Try the pattern.  */

  return __regexec (re, response, 0, NULL, 0) == 0 ? match : nomatch;

}

int

rpmatch (const char *response)

{

  /* We cache the response patterns and compiled regexps here.  */

  static const char *yesexpr, *noexpr;

  static regex_t yesre, nore;

  return (try (response, YESEXPR, 1, 0, &yesexpr, &yesre) ?:

	  try (response, NOEXPR, 0, -1, &noexpr, &nore));

}