rpmatch.c   [plain text]

/* Determine whether string value is affirmation or negative response
   according to current locale's data.

   Copyright (C) 1996, 1998, 2000, 2002, 2003, 2006 Free Software
   Foundation, Inc.

   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 2, 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
   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, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#include <config.h>

#include <stddef.h>
#include <stdlib.h>

# include <sys/types.h>
# include <limits.h>
# include <regex.h>
# include "gettext.h"
# define _(msgid) gettext (msgid)

static int
try (const char *response, const char *pattern, const int match,
     const int nomatch, const char **lastp, regex_t *re)
  if (pattern != *lastp)
      /* The pattern has changed.  */
      if (*lastp)
	  /* 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;

  /* See if the regular expression matches RESPONSE.  */
  return regexec (re, response, 0, NULL, 0) == 0 ? match : nomatch;

rpmatch (const char *response)
  /* Match against one of the response patterns, compiling the pattern
     first if necessary.  */

  /* We cache the response patterns and compiled regexps here.  */
  static const char *yesexpr, *noexpr;
  static regex_t yesre, nore;
  int result;

  return ((result = try (response, _("^[yY]"), 1, 0,
			 &yesexpr, &yesre))
	  ? result
	  : try (response, _("^[nN]"), 0, -1, &noexpr, &nore));
  /* Test against "^[yY]" and "^[nN]", hardcoded to avoid requiring regex */
  return (*response == 'y' || *response == 'Y' ? 1
	  : *response == 'n' || *response == 'N' ? 0 : -1);