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 #include <sys/types.h>
  33 #include <regex.h>
  34
  35 #if ENABLE_NLS
  36 # include <libintl.h>
  37 # define _(Text) gettext (Text)
  38 #else
  39 # define _(Text) Text
  40 #endif
  41
  42 static int
  43 try (response, pattern, match, nomatch, lastp, re)
  44      const char *response;
  45      const char *pattern;
  46      const int match;
  47      const int nomatch;
  48      const char **lastp;
  49      regex_t *re;
  50 {
  51   if (pattern != *lastp)
  52     {
  53       /* The pattern has changed.  */
  54       if (*lastp)
  55         {
  56           /* Free the old compiled pattern.  */
  57           regfree (re);
  58           *lastp = NULL;
  59         }
  60       /* Compile the pattern and cache it for future runs.  */
  61       if (regcomp (re, pattern, REG_EXTENDED) != 0)
  62         return -1;
  63       *lastp = pattern;
  64     }
  65
  66   /* See if the regular expression matches RESPONSE.  */
  67   return regexec (re, response, 0, NULL, 0) == 0 ? match : nomatch;
  68 }
  69
  70
  71 int
  72 rpmatch (response)
  73      const char *response;
  74 {
  75   /* Match against one of the response patterns, compiling the pattern
  76      first if necessary.  */
  77
  78   /* We cache the response patterns and compiled regexps here.  */
  79   static const char *yesexpr, *noexpr;
  80   static regex_t yesre, nore;
  81   int result;
  82
  83   return ((result = try (response, _("^[yY]"), 1, 0,
  84                          &yesexpr, &yesre))
  85           ? result
  86           : try (response, _("^[nN]"), 0, -1, &noexpr, &nore));
  87 }