lib/rpmatch.c

   1 /* Determine whether string value is affirmation or negative response
   2    according to current locale's data.
   3    Copyright (C) 1996, 1998, 2000 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 #if HAVE_CONFIG_H
  20 # include <config.h>
  21 #endif
  22
  23 #if STDC_HEADERS || _LIBC
  24 # include <stddef.h>
  25 # include <stdlib.h>
  26 #else
  27 # ifndef NULL
  28 #  define NULL 0
  29 # endif
  30 #endif
  31
  32 #if ENABLE_NLS
  33 # include <sys/types.h>
  34 # if HAVE_LIMITS_H
  35 #  include <limits.h>
  36 # endif
  37 # include <regex.h>
  38 # include <libintl.h>
  39 # define _(Text) gettext (Text)
  40
  41 static int
  42 try (const char *response, const char *pattern, const int match,
  43      const int nomatch, const char **lastp, regex_t *re)
  44 {
  45   if (pattern != *lastp)
  46     {
  47       /* The pattern has changed.  */
  48       if (*lastp)
  49         {
  50           /* Free the old compiled pattern.  */
  51           regfree (re);
  52           *lastp = NULL;
  53         }
  54       /* Compile the pattern and cache it for future runs.  */
  55       if (regcomp (re, pattern, REG_EXTENDED) != 0)
  56         return -1;
  57       *lastp = pattern;
  58     }
  59
  60   /* See if the regular expression matches RESPONSE.  */
  61   return regexec (re, response, 0, NULL, 0) == 0 ? match : nomatch;
  62 }
  63 #endif
  64
  65
  66 int
  67 rpmatch (const char *response)
  68 {
  69 #if ENABLE_NLS
  70   /* Match against one of the response patterns, compiling the pattern
  71      first if necessary.  */
  72
  73   /* We cache the response patterns and compiled regexps here.  */
  74   static const char *yesexpr, *noexpr;
  75   static regex_t yesre, nore;
  76   int result;
  77
  78   return ((result = try (response, _("^[yY]"), 1, 0,
  79                          &yesexpr, &yesre))
  80           ? result
  81           : try (response, _("^[nN]"), 0, -1, &noexpr, &nore));
  82 #else
  83   /* Test against "^[yY]" and "^[nN]", hardcoded to avoid requiring regex */
  84   return (*response == 'y' || *response == 'Y' ? 1
  85           : *response == 'n' || *response == 'N' ? 0 : -1);
  86 #endif
  87 }