1/* argmatch.c -- find a match for a string in an array
2
3   Copyright (C) 1990, 1998-1999, 2001-2007, 2009-2012 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 3 of the License, or
9   (at your option) 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, see <http://www.gnu.org/licenses/>.  */
18
19/* Written by David MacKenzie <djm@ai.mit.edu>
20   Modified by Akim Demaille <demaille@inf.enst.fr> */
21
22#include <config.h>
23
24/* Specification.  */
25#include "argmatch.h"
26
27#include <stdbool.h>
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
39#if USE_UNLOCKED_IO
40# include "unlocked-io.h"
41#endif
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
57ARGMATCH_DIE_DECL;
58#endif
59
60static 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. */
68argmatch_exit_fn argmatch_die = __argmatch_die;
69
70
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
82ptrdiff_t
83argmatch (const char *arg, const char *const *arglist,
84          const char *vallist, size_t valsize)
85{
86  size_t i;                     /* Temporary index in ARGLIST.  */
87  size_t arglen;                /* Length of ARG.  */
88  ptrdiff_t matchind = -1;      /* Index of first nonexact match.  */
89  bool ambiguous = false;       /* If true, 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 = true;
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
129void
130argmatch_invalid (const char *context, const char *value, ptrdiff_t 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 */
144void
145argmatch_valid (const char *const *arglist,
146                const char *vallist, size_t valsize)
147{
148  size_t 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  fputs (_("Valid arguments are:"), stderr);
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", quote (arglist[i]));
159        last_val = vallist + valsize * i;
160      }
161    else
162      {
163        fprintf (stderr, ", %s", quote (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
174ptrdiff_t
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  ptrdiff_t 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 */
195const char *
196argmatch_to_argument (const char *value,
197                      const char *const *arglist,
198                      const char *vallist, size_t valsize)
199{
200  size_t 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 */
212char *program_name;
213
214/* When to make backup files.  */
215enum backup_type
216{
217  /* Never make backups.  */
218  no_backups,
219
220  /* Make simple backups of every file.  */
221  simple_backups,
222
223  /* Make numbered backups of files that already have numbered backups,
224     and simple backups of the others.  */
225  numbered_existing_backups,
226
227  /* Make numbered backups of every file.  */
228  numbered_backups
229};
230
231/* Two tables describing arguments (keys) and their corresponding
232   values */
233static const char *const backup_args[] =
234{
235  "no", "none", "off",
236  "simple", "never",
237  "existing", "nil",
238  "numbered", "t",
239  0
240};
241
242static const enum backup_type backup_vals[] =
243{
244  no_backups, no_backups, no_backups,
245  simple_backups, simple_backups,
246  numbered_existing_backups, numbered_existing_backups,
247  numbered_backups, numbered_backups
248};
249
250int
251main (int argc, const char *const *argv)
252{
253  const char *cp;
254  enum backup_type backup_type = no_backups;
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
278