lib/argmatch.c

   1 /* argmatch.c -- find a match for a string in an array
   2    Copyright (C) 1990, 1998, 1999, 2001, 2002 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by David MacKenzie <djm@ai.mit.edu>
  19    Modified by Akim Demaille <demaille@inf.enst.fr> */
  20
  21 #if HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 /* Specification.  */
  26 #include "argmatch.h"
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31
  32 #include "gettext.h"
  33 #define _(msgid) gettext (msgid)
  34
  35 #include "error.h"
  36 #include "quotearg.h"
  37 #include "quote.h"
  38 #include "unlocked-io.h"
  39
  40 /* When reporting an invalid argument, show nonprinting characters
  41    by using the quoting style ARGMATCH_QUOTING_STYLE.  Do not use
  42    literal_quoting_style.  */
  43 #ifndef ARGMATCH_QUOTING_STYLE
  44 # define ARGMATCH_QUOTING_STYLE locale_quoting_style
  45 #endif
  46
  47 /* Non failing version of argmatch call this function after failing. */
  48 #ifndef ARGMATCH_DIE
  49 # define ARGMATCH_DIE exit (EXIT_FAILURE)
  50 #endif
  51
  52 #ifdef ARGMATCH_DIE_DECL
  53 ARGMATCH_DIE_DECL;
  54 #endif
  55
  56 static void
  57 __argmatch_die (void)
  58 {
  59   ARGMATCH_DIE;
  60 }
  61
  62 /* Used by XARGMATCH and XARGCASEMATCH.  See description in argmatch.h.
  63    Default to __argmatch_die, but allow caller to change this at run-time. */
  64 argmatch_exit_fn argmatch_die = __argmatch_die;
  65
  66 \f
  67 /* If ARG is an unambiguous match for an element of the
  68    null-terminated array ARGLIST, return the index in ARGLIST
  69    of the matched element, else -1 if it does not match any element
  70    or -2 if it is ambiguous (is a prefix of more than one element).
  71
  72    If VALLIST is none null, use it to resolve ambiguities limited to
  73    synonyms, i.e., for
  74      "yes", "yop" -> 0
  75      "no", "nope" -> 1
  76    "y" is a valid argument, for `0', and "n" for `1'.  */
  77
  78 int
  79 argmatch (const char *arg, const char *const *arglist,
  80           const char *vallist, size_t valsize)
  81 {
  82   int i;                        /* Temporary index in ARGLIST.  */
  83   size_t arglen;                /* Length of ARG.  */
  84   int matchind = -1;            /* Index of first nonexact match.  */
  85   int ambiguous = 0;            /* If nonzero, multiple nonexact match(es).  */
  86
  87   arglen = strlen (arg);
  88
  89   /* Test all elements for either exact match or abbreviated matches.  */
  90   for (i = 0; arglist[i]; i++)
  91     {
  92       if (!strncmp (arglist[i], arg, arglen))
  93         {
  94           if (strlen (arglist[i]) == arglen)
  95             /* Exact match found.  */
  96             return i;
  97           else if (matchind == -1)
  98             /* First nonexact match found.  */
  99             matchind = i;
 100           else
 101             {
 102               /* Second nonexact match found.  */
 103               if (vallist == NULL
 104                   || memcmp (vallist + valsize * matchind,
 105                              vallist + valsize * i, valsize))
 106                 {
 107                   /* There is a real ambiguity, or we could not
 108                      disambiguate. */
 109                   ambiguous = 1;
 110                 }
 111             }
 112         }
 113     }
 114   if (ambiguous)
 115     return -2;
 116   else
 117     return matchind;
 118 }
 119
 120 /* Error reporting for argmatch.
 121    CONTEXT is a description of the type of entity that was being matched.
 122    VALUE is the invalid value that was given.
 123    PROBLEM is the return value from argmatch.  */
 124
 125 void
 126 argmatch_invalid (const char *context, const char *value, int problem)
 127 {
 128   char const *format = (problem == -1
 129                         ? _("invalid argument %s for %s")
 130                         : _("ambiguous argument %s for %s"));
 131
 132   error (0, 0, format, quotearg_n_style (0, ARGMATCH_QUOTING_STYLE, value),
 133          quote_n (1, context));
 134 }
 135
 136 /* List the valid arguments for argmatch.
 137    ARGLIST is the same as in argmatch.
 138    VALLIST is a pointer to an array of values.
 139    VALSIZE is the size of the elements of VALLIST */
 140 void
 141 argmatch_valid (const char *const *arglist,
 142                 const char *vallist, size_t valsize)
 143 {
 144   int i;
 145   const char *last_val = NULL;
 146
 147   /* We try to put synonyms on the same line.  The assumption is that
 148      synonyms follow each other */
 149   fprintf (stderr, _("Valid arguments are:"));
 150   for (i = 0; arglist[i]; i++)
 151     if ((i == 0)
 152         || memcmp (last_val, vallist + valsize * i, valsize))
 153       {
 154         fprintf (stderr, "\n  - `%s'", arglist[i]);
 155         last_val = vallist + valsize * i;
 156       }
 157     else
 158       {
 159         fprintf (stderr, ", `%s'", arglist[i]);
 160       }
 161   putc ('\n', stderr);
 162 }
 163
 164 /* Never failing versions of the previous functions.
 165
 166    CONTEXT is the context for which argmatch is called (e.g.,
 167    "--version-control", or "$VERSION_CONTROL" etc.).  Upon failure,
 168    calls the (supposed never to return) function EXIT_FN. */
 169
 170 int
 171 __xargmatch_internal (const char *context,
 172                       const char *arg, const char *const *arglist,
 173                       const char *vallist, size_t valsize,
 174                       argmatch_exit_fn exit_fn)
 175 {
 176   int res = argmatch (arg, arglist, vallist, valsize);
 177   if (res >= 0)
 178     /* Success. */
 179     return res;
 180
 181   /* We failed.  Explain why. */
 182   argmatch_invalid (context, arg, res);
 183   argmatch_valid (arglist, vallist, valsize);
 184   (*exit_fn) ();
 185
 186   return -1; /* To please the compilers. */
 187 }
 188
 189 /* Look for VALUE in VALLIST, an array of objects of size VALSIZE and
 190    return the first corresponding argument in ARGLIST */
 191 const char *
 192 argmatch_to_argument (const char *value,
 193                       const char *const *arglist,
 194                       const char *vallist, size_t valsize)
 195 {
 196   int i;
 197
 198   for (i = 0; arglist[i]; i++)
 199     if (!memcmp (value, vallist + valsize * i, valsize))
 200       return arglist[i];
 201   return NULL;
 202 }
 203
 204 #ifdef TEST
 205 /*
 206  * Based on "getversion.c" by David MacKenzie <djm@gnu.ai.mit.edu>
 207  */
 208 char *program_name;
 209 extern const char *getenv ();
 210
 211 /* When to make backup files.  */
 212 enum backup_type
 213 {
 214   /* Never make backups.  */
 215   none,
 216
 217   /* Make simple backups of every file.  */
 218   simple,
 219
 220   /* Make numbered backups of files that already have numbered backups,
 221      and simple backups of the others.  */
 222   numbered_existing,
 223
 224   /* Make numbered backups of every file.  */
 225   numbered
 226 };
 227
 228 /* Two tables describing arguments (keys) and their corresponding
 229    values */
 230 static const char *const backup_args[] =
 231 {
 232   "no", "none", "off",
 233   "simple", "never",
 234   "existing", "nil",
 235   "numbered", "t",
 236   0
 237 };
 238
 239 static const enum backup_type backup_vals[] =
 240 {
 241   none, none, none,
 242   simple, simple,
 243   numbered_existing, numbered_existing,
 244   numbered, numbered
 245 };
 246
 247 int
 248 main (int argc, const char *const *argv)
 249 {
 250   const char *cp;
 251   enum backup_type backup_type = none;
 252
 253   program_name = (char *) argv[0];
 254
 255   if (argc > 2)
 256     {
 257       fprintf (stderr, "Usage: %s [VERSION_CONTROL]\n", program_name);
 258       exit (1);
 259     }
 260
 261   if ((cp = getenv ("VERSION_CONTROL")))
 262     backup_type = XARGMATCH ("$VERSION_CONTROL", cp,
 263                              backup_args, backup_vals);
 264
 265   if (argc == 2)
 266     backup_type = XARGMATCH (program_name, argv[1],
 267                              backup_args, backup_vals);
 268
 269   printf ("The version control is `%s'\n",
 270           ARGMATCH_TO_ARGUMENT (backup_type, backup_args, backup_vals));
 271
 272   return 0;
 273 }
 274 #endif