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 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 # include <regex.h>
  35 # include <libintl.h>
  36 # define _(Text) gettext (Text)
  37
  38 static int
  39 try (const char *response, const char *pattern, const int match,
  40      const int nomatch, const char **lastp, regex_t *re)
  41 {
  42   if (pattern != *lastp)
  43     {
  44       /* The pattern has changed.  */
  45       if (*lastp)
  46         {
  47           /* Free the old compiled pattern.  */
  48           regfree (re);
  49           *lastp = NULL;
  50         }
  51       /* Compile the pattern and cache it for future runs.  */
  52       if (regcomp (re, pattern, REG_EXTENDED) != 0)
  53         return -1;
  54       *lastp = pattern;
  55     }
  56
  57   /* See if the regular expression matches RESPONSE.  */
  58   return regexec (re, response, 0, NULL, 0) == 0 ? match : nomatch;
  59 }
  60 #endif
  61
  62
  63 int
  64 rpmatch (const char *response)
  65 {
  66 #if ENABLE_NLS
  67   /* Match against one of the response patterns, compiling the pattern
  68      first if necessary.  */
  69
  70   /* We cache the response patterns and compiled regexps here.  */
  71   static const char *yesexpr, *noexpr;
  72   static regex_t yesre, nore;
  73   int result;
  74
  75   return ((result = try (response, _("^[yY]"), 1, 0,
  76                          &yesexpr, &yesre))
  77           ? result
  78           : try (response, _("^[nN]"), 0, -1, &noexpr, &nore));
  79 #else
  80   /* Test against "^[yY]" and "^[nN]", hardcoded to avoid requiring regex */
  81   return (*response == 'y' || *response == 'Y' ? 1
  82           : *response == 'n' || *response == 'N' ? 0 : -1);
  83 #endif
  84 }