lib/rpmatch.c

   1 /* rpmatch - determine whether string value is affirmation or negative
   2              response according to current locale's data
   3 Copyright (C) 1996 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 #ifdef 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 #ifdef WITH_REGEX
  34 # include <regex.h>
  35 #else
  36 # include <rx.h>
  37 #endif
  38
  39 #if ENABLE_NLS
  40 # include <libintl.h>
  41 # define _(Text) gettext (Text)
  42 #else
  43 # define _(Text) Text
  44 #endif
  45
  46 static int
  47 try (response, pattern, match, nomatch, lastp, re)
  48      const char *response;
  49      const char *pattern;
  50      const int match;
  51      const int nomatch;
  52      const char **lastp;
  53      regex_t *re;
  54 {
  55   if (pattern != *lastp)
  56     {
  57       /* The pattern has changed.  */
  58       if (*lastp)
  59         {
  60           /* Free the old compiled pattern.  */
  61           regfree (re);
  62           *lastp = NULL;
  63         }
  64       /* Compile the pattern and cache it for future runs.  */
  65       if (regcomp (re, pattern, REG_EXTENDED) != 0)
  66         return -1;
  67       *lastp = pattern;
  68     }
  69
  70   /* See if the regular expression matches RESPONSE.  */
  71   return regexec (re, response, 0, NULL, 0) == 0 ? match : nomatch;
  72 }
  73
  74
  75 int
  76 rpmatch (response)
  77      const char *response;
  78 {
  79   /* Match against one of the response patterns, compiling the pattern
  80      first if necessary.  */
  81
  82   /* We cache the response patterns and compiled regexps here.  */
  83   static const char *yesexpr, *noexpr;
  84   static regex_t yesre, nore;
  85   int result;
  86
  87   return ((result = try (response, _("^[yY]"), 1, 0,
  88                          &yesexpr, &yesre))
  89           ? result
  90           : try (response, _("^[nN]"), 0, -1, &noexpr, &nore));
  91 }