lib/argmatch.c

   1 /* argmatch.c -- find a match for a string in an array
   2
   3    Copyright (C) 1990, 1998, 1999, 2001, 2002, 2003, 2004 Free
   4    Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software Foundation,
  18    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 /* Written by David MacKenzie <djm@ai.mit.edu>
  21    Modified by Akim Demaille <demaille@inf.enst.fr> */
  22
  23 #if HAVE_CONFIG_H
  24 # include <config.h>
  25 #endif
  26
  27 /* Specification.  */
  28 #include "argmatch.h"
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include "gettext.h"
  35 #define _(msgid) gettext (msgid)
  36
  37 #include "error.h"
  38 #include "exit.h"
  39 #include "quotearg.h"
  40 #include "quote.h"
  41 #include "unlocked-io.h"
  42
  43 /* When reporting an invalid argument, show nonprinting characters
  44    by using the quoting style ARGMATCH_QUOTING_STYLE.  Do not use
  45    literal_quoting_style.  */
  46 #ifndef ARGMATCH_QUOTING_STYLE
  47 # define ARGMATCH_QUOTING_STYLE locale_quoting_style
  48 #endif
  49
  50 /* Non failing version of argmatch call this function after failing. */
  51 #ifndef ARGMATCH_DIE
  52 # include "exitfail.h"
  53 # define ARGMATCH_DIE exit (exit_failure)
  54 #endif
  55
  56 #ifdef ARGMATCH_DIE_DECL
  57 ARGMATCH_DIE_DECL;
  58 #endif
  59
  60 static void
  61 __argmatch_die (void)
  62 {
  63   ARGMATCH_DIE;
  64 }
  65
  66 /* Used by XARGMATCH and XARGCASEMATCH.  See description in argmatch.h.
  67    Default to __argmatch_die, but allow caller to change this at run-time. */
  68 argmatch_exit_fn argmatch_die = __argmatch_die;
  69
  70 \f
  71 /* If ARG is an unambiguous match for an element of the
  72    null-terminated array ARGLIST, return the index in ARGLIST
  73    of the matched element, else -1 if it does not match any element
  74    or -2 if it is ambiguous (is a prefix of more than one element).
  75
  76    If VALLIST is none null, use it to resolve ambiguities limited to
  77    synonyms, i.e., for
  78      "yes", "yop" -> 0
  79      "no", "nope" -> 1
  80    "y" is a valid argument, for `0', and "n" for `1'.  */
  81
  82 int
  83 argmatch (const char *arg, const char *const *arglist,
  84           const char *vallist, size_t valsize)
  85 {
  86   int i;                        /* Temporary index in ARGLIST.  */
  87   size_t arglen;                /* Length of ARG.  */
  88   int matchind = -1;            /* Index of first nonexact match.  */
  89   int ambiguous = 0;            /* If nonzero, multiple nonexact match(es).  */
  90
  91   arglen = strlen (arg);
  92
  93   /* Test all elements for either exact match or abbreviated matches.  */
  94   for (i = 0; arglist[i]; i++)
  95     {
  96       if (!strncmp (arglist[i], arg, arglen))
  97         {
  98           if (strlen (arglist[i]) == arglen)
  99             /* Exact match found.  */
 100             return i;
 101           else if (matchind == -1)
 102             /* First nonexact match found.  */
 103             matchind = i;
 104           else
 105             {
 106               /* Second nonexact match found.  */
 107               if (vallist == NULL
 108                   || memcmp (vallist + valsize * matchind,
 109                              vallist + valsize * i, valsize))
 110                 {
 111                   /* There is a real ambiguity, or we could not
 112                      disambiguate. */
 113                   ambiguous = 1;
 114                 }
 115             }
 116         }
 117     }
 118   if (ambiguous)
 119     return -2;
 120   else
 121     return matchind;
 122 }
 123
 124 /* Error reporting for argmatch.
 125    CONTEXT is a description of the type of entity that was being matched.
 126    VALUE is the invalid value that was given.
 127    PROBLEM is the return value from argmatch.  */
 128
 129 void
 130 argmatch_invalid (const char *context, const char *value, int problem)
 131 {
 132   char const *format = (problem == -1
 133                         ? _("invalid argument %s for %s")
 134                         : _("ambiguous argument %s for %s"));
 135
 136   error (0, 0, format, quotearg_n_style (0, ARGMATCH_QUOTING_STYLE, value),
 137          quote_n (1, context));
 138 }
 139
 140 /* List the valid arguments for argmatch.
 141    ARGLIST is the same as in argmatch.
 142    VALLIST is a pointer to an array of values.
 143    VALSIZE is the size of the elements of VALLIST */
 144 void
 145 argmatch_valid (const char *const *arglist,
 146                 const char *vallist, size_t valsize)
 147 {
 148   int i;
 149   const char *last_val = NULL;
 150
 151   /* We try to put synonyms on the same line.  The assumption is that
 152      synonyms follow each other */
 153   fprintf (stderr, _("Valid arguments are:"));
 154   for (i = 0; arglist[i]; i++)
 155     if ((i == 0)
 156         || memcmp (last_val, vallist + valsize * i, valsize))
 157       {
 158         fprintf (stderr, "\n  - `%s'", arglist[i]);
 159         last_val = vallist + valsize * i;
 160       }
 161     else
 162       {
 163         fprintf (stderr, ", `%s'", arglist[i]);
 164       }
 165   putc ('\n', stderr);
 166 }
 167
 168 /* Never failing versions of the previous functions.
 169
 170    CONTEXT is the context for which argmatch is called (e.g.,
 171    "--version-control", or "$VERSION_CONTROL" etc.).  Upon failure,
 172    calls the (supposed never to return) function EXIT_FN. */
 173
 174 int
 175 __xargmatch_internal (const char *context,
 176                       const char *arg, const char *const *arglist,
 177                       const char *vallist, size_t valsize,
 178                       argmatch_exit_fn exit_fn)
 179 {
 180   int res = argmatch (arg, arglist, vallist, valsize);
 181   if (res >= 0)
 182     /* Success. */
 183     return res;
 184
 185   /* We failed.  Explain why. */
 186   argmatch_invalid (context, arg, res);
 187   argmatch_valid (arglist, vallist, valsize);
 188   (*exit_fn) ();
 189
 190   return -1; /* To please the compilers. */
 191 }
 192
 193 /* Look for VALUE in VALLIST, an array of objects of size VALSIZE and
 194    return the first corresponding argument in ARGLIST */
 195 const char *
 196 argmatch_to_argument (const char *value,
 197                       const char *const *arglist,
 198                       const char *vallist, size_t valsize)
 199 {
 200   int i;
 201
 202   for (i = 0; arglist[i]; i++)
 203     if (!memcmp (value, vallist + valsize * i, valsize))
 204       return arglist[i];
 205   return NULL;
 206 }
 207
 208 #ifdef TEST
 209 /*
 210  * Based on "getversion.c" by David MacKenzie <djm@gnu.ai.mit.edu>
 211  */
 212 char *program_name;
 213
 214 /* When to make backup files.  */
 215 enum backup_type
 216 {
 217   /* Never make backups.  */
 218   none,
 219
 220   /* Make simple backups of every file.  */
 221   simple,
 222
 223   /* Make numbered backups of files that already have numbered backups,
 224      and simple backups of the others.  */
 225   numbered_existing,
 226
 227   /* Make numbered backups of every file.  */
 228   numbered
 229 };
 230
 231 /* Two tables describing arguments (keys) and their corresponding
 232    values */
 233 static const char *const backup_args[] =
 234 {
 235   "no", "none", "off",
 236   "simple", "never",
 237   "existing", "nil",
 238   "numbered", "t",
 239   0
 240 };
 241
 242 static const enum backup_type backup_vals[] =
 243 {
 244   none, none, none,
 245   simple, simple,
 246   numbered_existing, numbered_existing,
 247   numbered, numbered
 248 };
 249
 250 int
 251 main (int argc, const char *const *argv)
 252 {
 253   const char *cp;
 254   enum backup_type backup_type = none;
 255
 256   program_name = (char *) argv[0];
 257
 258   if (argc > 2)
 259     {
 260       fprintf (stderr, "Usage: %s [VERSION_CONTROL]\n", program_name);
 261       exit (1);
 262     }
 263
 264   if ((cp = getenv ("VERSION_CONTROL")))
 265     backup_type = XARGMATCH ("$VERSION_CONTROL", cp,
 266                              backup_args, backup_vals);
 267
 268   if (argc == 2)
 269     backup_type = XARGMATCH (program_name, argv[1],
 270                              backup_args, backup_vals);
 271
 272   printf ("The version control is `%s'\n",
 273           ARGMATCH_TO_ARGUMENT (backup_type, backup_args, backup_vals));
 274
 275   return 0;
 276 }
 277 #endif