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 Free Software
   4    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 "quotearg.h"
  39 #include "quote.h"
  40 #include "unlocked-io.h"
  41
  42 /* When reporting an invalid argument, show nonprinting characters
  43    by using the quoting style ARGMATCH_QUOTING_STYLE.  Do not use
  44    literal_quoting_style.  */
  45 #ifndef ARGMATCH_QUOTING_STYLE
  46 # define ARGMATCH_QUOTING_STYLE locale_quoting_style
  47 #endif
  48
  49 #ifndef EXIT_FAILURE
  50 # define EXIT_FAILURE 1
  51 #endif
  52
  53 /* Non failing version of argmatch call this function after failing. */
  54 #ifndef ARGMATCH_DIE
  55 # define ARGMATCH_DIE exit (EXIT_FAILURE)
  56 #endif
  57
  58 #ifdef ARGMATCH_DIE_DECL
  59 ARGMATCH_DIE_DECL;
  60 #endif
  61
  62 static void
  63 __argmatch_die (void)
  64 {
  65   ARGMATCH_DIE;
  66 }
  67
  68 /* Used by XARGMATCH and XARGCASEMATCH.  See description in argmatch.h.
  69    Default to __argmatch_die, but allow caller to change this at run-time. */
  70 argmatch_exit_fn argmatch_die = __argmatch_die;
  71
  72 \f
  73 /* If ARG is an unambiguous match for an element of the
  74    null-terminated array ARGLIST, return the index in ARGLIST
  75    of the matched element, else -1 if it does not match any element
  76    or -2 if it is ambiguous (is a prefix of more than one element).
  77
  78    If VALLIST is none null, use it to resolve ambiguities limited to
  79    synonyms, i.e., for
  80      "yes", "yop" -> 0
  81      "no", "nope" -> 1
  82    "y" is a valid argument, for `0', and "n" for `1'.  */
  83
  84 int
  85 argmatch (const char *arg, const char *const *arglist,
  86           const char *vallist, size_t valsize)
  87 {
  88   int i;                        /* Temporary index in ARGLIST.  */
  89   size_t arglen;                /* Length of ARG.  */
  90   int matchind = -1;            /* Index of first nonexact match.  */
  91   int ambiguous = 0;            /* If nonzero, multiple nonexact match(es).  */
  92
  93   arglen = strlen (arg);
  94
  95   /* Test all elements for either exact match or abbreviated matches.  */
  96   for (i = 0; arglist[i]; i++)
  97     {
  98       if (!strncmp (arglist[i], arg, arglen))
  99         {
 100           if (strlen (arglist[i]) == arglen)
 101             /* Exact match found.  */
 102             return i;
 103           else if (matchind == -1)
 104             /* First nonexact match found.  */
 105             matchind = i;
 106           else
 107             {
 108               /* Second nonexact match found.  */
 109               if (vallist == NULL
 110                   || memcmp (vallist + valsize * matchind,
 111                              vallist + valsize * i, valsize))
 112                 {
 113                   /* There is a real ambiguity, or we could not
 114                      disambiguate. */
 115                   ambiguous = 1;
 116                 }
 117             }
 118         }
 119     }
 120   if (ambiguous)
 121     return -2;
 122   else
 123     return matchind;
 124 }
 125
 126 /* Error reporting for argmatch.
 127    CONTEXT is a description of the type of entity that was being matched.
 128    VALUE is the invalid value that was given.
 129    PROBLEM is the return value from argmatch.  */
 130
 131 void
 132 argmatch_invalid (const char *context, const char *value, int problem)
 133 {
 134   char const *format = (problem == -1
 135                         ? _("invalid argument %s for %s")
 136                         : _("ambiguous argument %s for %s"));
 137
 138   error (0, 0, format, quotearg_n_style (0, ARGMATCH_QUOTING_STYLE, value),
 139          quote_n (1, context));
 140 }
 141
 142 /* List the valid arguments for argmatch.
 143    ARGLIST is the same as in argmatch.
 144    VALLIST is a pointer to an array of values.
 145    VALSIZE is the size of the elements of VALLIST */
 146 void
 147 argmatch_valid (const char *const *arglist,
 148                 const char *vallist, size_t valsize)
 149 {
 150   int i;
 151   const char *last_val = NULL;
 152
 153   /* We try to put synonyms on the same line.  The assumption is that
 154      synonyms follow each other */
 155   fprintf (stderr, _("Valid arguments are:"));
 156   for (i = 0; arglist[i]; i++)
 157     if ((i == 0)
 158         || memcmp (last_val, vallist + valsize * i, valsize))
 159       {
 160         fprintf (stderr, "\n  - `%s'", arglist[i]);
 161         last_val = vallist + valsize * i;
 162       }
 163     else
 164       {
 165         fprintf (stderr, ", `%s'", arglist[i]);
 166       }
 167   putc ('\n', stderr);
 168 }
 169
 170 /* Never failing versions of the previous functions.
 171
 172    CONTEXT is the context for which argmatch is called (e.g.,
 173    "--version-control", or "$VERSION_CONTROL" etc.).  Upon failure,
 174    calls the (supposed never to return) function EXIT_FN. */
 175
 176 int
 177 __xargmatch_internal (const char *context,
 178                       const char *arg, const char *const *arglist,
 179                       const char *vallist, size_t valsize,
 180                       argmatch_exit_fn exit_fn)
 181 {
 182   int res = argmatch (arg, arglist, vallist, valsize);
 183   if (res >= 0)
 184     /* Success. */
 185     return res;
 186
 187   /* We failed.  Explain why. */
 188   argmatch_invalid (context, arg, res);
 189   argmatch_valid (arglist, vallist, valsize);
 190   (*exit_fn) ();
 191
 192   return -1; /* To please the compilers. */
 193 }
 194
 195 /* Look for VALUE in VALLIST, an array of objects of size VALSIZE and
 196    return the first corresponding argument in ARGLIST */
 197 const char *
 198 argmatch_to_argument (const char *value,
 199                       const char *const *arglist,
 200                       const char *vallist, size_t valsize)
 201 {
 202   int i;
 203
 204   for (i = 0; arglist[i]; i++)
 205     if (!memcmp (value, vallist + valsize * i, valsize))
 206       return arglist[i];
 207   return NULL;
 208 }
 209
 210 #ifdef TEST
 211 /*
 212  * Based on "getversion.c" by David MacKenzie <djm@gnu.ai.mit.edu>
 213  */
 214 char *program_name;
 215 extern const char *getenv ();
 216
 217 /* When to make backup files.  */
 218 enum backup_type
 219 {
 220   /* Never make backups.  */
 221   none,
 222
 223   /* Make simple backups of every file.  */
 224   simple,
 225
 226   /* Make numbered backups of files that already have numbered backups,
 227      and simple backups of the others.  */
 228   numbered_existing,
 229
 230   /* Make numbered backups of every file.  */
 231   numbered
 232 };
 233
 234 /* Two tables describing arguments (keys) and their corresponding
 235    values */
 236 static const char *const backup_args[] =
 237 {
 238   "no", "none", "off",
 239   "simple", "never",
 240   "existing", "nil",
 241   "numbered", "t",
 242   0
 243 };
 244
 245 static const enum backup_type backup_vals[] =
 246 {
 247   none, none, none,
 248   simple, simple,
 249   numbered_existing, numbered_existing,
 250   numbered, numbered
 251 };
 252
 253 int
 254 main (int argc, const char *const *argv)
 255 {
 256   const char *cp;
 257   enum backup_type backup_type = none;
 258
 259   program_name = (char *) argv[0];
 260
 261   if (argc > 2)
 262     {
 263       fprintf (stderr, "Usage: %s [VERSION_CONTROL]\n", program_name);
 264       exit (1);
 265     }
 266
 267   if ((cp = getenv ("VERSION_CONTROL")))
 268     backup_type = XARGMATCH ("$VERSION_CONTROL", cp,
 269                              backup_args, backup_vals);
 270
 271   if (argc == 2)
 272     backup_type = XARGMATCH (program_name, argv[1],
 273                              backup_args, backup_vals);
 274
 275   printf ("The version control is `%s'\n",
 276           ARGMATCH_TO_ARGUMENT (backup_type, backup_args, backup_vals));
 277
 278   return 0;
 279 }
 280 #endif