1 /* argmatch.c -- find a match for a string in an array
2
3 Copyright (C) 1990, 1998-1999, 2001-2007, 2009-2023 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 <https://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 <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30
31 #define _(msgid) gettext (msgid)
32
33 #include "error.h"
34 #include "quotearg.h"
35
36 #if USE_UNLOCKED_IO
37 # include "unlocked-io.h"
38 #endif
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 # include "exitfail.h"
50 # define ARGMATCH_DIE exit (exit_failure)
51 #endif
52
53 #ifdef ARGMATCH_DIE_DECL
54 ARGMATCH_DIE_DECL;
55 #endif
56
57 static void
58 __argmatch_die (void)
59 {
60 ARGMATCH_DIE;
61 }
62
63 /* Used by XARGMATCH. See description in argmatch.h.
64 Default to __argmatch_die, but allow caller to change this at run-time. */
65 argmatch_exit_fn argmatch_die = __argmatch_die;
66
67
68 /* If ARG is an unambiguous match for an element of the
69 NULL-terminated array ARGLIST, return the index in ARGLIST
70 of the matched element, else -1 if it does not match any element
71 or -2 if it is ambiguous (is a prefix of more than one element).
72
73 If VALLIST is none null, use it to resolve ambiguities limited to
74 synonyms, i.e., for
75 "yes", "yop" -> 0
76 "no", "nope" -> 1
77 "y" is a valid argument, for 0, and "n" for 1. */
78
79 ptrdiff_t
80 argmatch (const char *arg, const char *const *arglist,
81 const void *vallist, size_t valsize)
82 {
83 size_t i; /* Temporary index in ARGLIST. */
84 size_t arglen; /* Length of ARG. */
85 ptrdiff_t matchind = -1; /* Index of first nonexact match. */
86 bool ambiguous = false; /* If true, multiple nonexact match(es). */
87
88 arglen = strlen (arg);
89
90 /* Test all elements for either exact match or abbreviated matches. */
91 for (i = 0; arglist[i]; i++)
92 {
93 if (!strncmp (arglist[i], arg, arglen))
94 {
95 if (strlen (arglist[i]) == arglen)
96 /* Exact match found. */
97 return i;
98 else if (matchind == -1)
99 /* First nonexact match found. */
100 matchind = i;
101 else
102 {
103 /* Second nonexact match found. */
104 if (vallist == NULL
105 || memcmp ((char const *) vallist + valsize * matchind,
106 (char const *) vallist + valsize * i, valsize))
107 {
108 /* There is a real ambiguity, or we could not
109 disambiguate. */
110 ambiguous = true;
111 }
112 }
113 }
114 }
115 if (ambiguous)
116 return -2;
117 else
118 return matchind;
119 }
120
121 ptrdiff_t
122 argmatch_exact (const char *arg, const char *const *arglist)
123 {
124 size_t i;
125
126 /* Test elements for exact match. */
127 for (i = 0; arglist[i]; i++)
128 {
129 if (!strcmp (arglist[i], arg))
130 return i;
131 }
132
133 return -1;
134 }
135
136 /* Error reporting for argmatch.
137 CONTEXT is a description of the type of entity that was being matched.
138 VALUE is the invalid value that was given.
139 PROBLEM is the return value from argmatch. */
140
141 void
142 argmatch_invalid (const char *context, const char *value, ptrdiff_t problem)
143 {
144 char const *format = (problem == -1
145 ? _("invalid argument %s for %s")
146 : _("ambiguous argument %s for %s"));
147
148 error (0, 0, format, quotearg_n_style (0, ARGMATCH_QUOTING_STYLE, value),
149 quote_n (1, context));
150 }
151
152 /* List the valid arguments for argmatch.
153 ARGLIST is the same as in argmatch.
154 VALLIST is a pointer to an array of values.
155 VALSIZE is the size of the elements of VALLIST */
156 void
157 argmatch_valid (const char *const *arglist,
158 const void *vallist, size_t valsize)
159 {
160 size_t i;
161 const char *last_val = NULL;
162
163 /* We try to put synonyms on the same line. The assumption is that
164 synonyms follow each other */
165 fputs (_("Valid arguments are:"), stderr);
166 for (i = 0; arglist[i]; i++)
167 if ((i == 0)
168 || memcmp (last_val, (char const *) vallist + valsize * i, valsize))
169 {
170 fprintf (stderr, "\n - %s", quote (arglist[i]));
171 last_val = (char const *) vallist + valsize * i;
172 }
173 else
174 {
175 fprintf (stderr, ", %s", quote (arglist[i]));
176 }
177 putc ('\n', stderr);
178 }
179
180 /* Never failing versions of the previous functions.
181
182 CONTEXT is the context for which argmatch is called (e.g.,
183 "--version-control", or "$VERSION_CONTROL" etc.). Upon failure,
184 calls the (supposed never to return) function EXIT_FN. */
185
186 ptrdiff_t
187 __xargmatch_internal (const char *context,
188 const char *arg, const char *const *arglist,
189 const void *vallist, size_t valsize,
190 argmatch_exit_fn exit_fn,
191 bool allow_abbreviation)
192 {
193 ptrdiff_t res;
194
195 if (allow_abbreviation)
196 res = argmatch (arg, arglist, vallist, valsize);
197 else
198 res = argmatch_exact (arg, arglist);
199
200 if (res >= 0)
201 /* Success. */
202 return res;
203
204 /* We failed. Explain why. */
205 argmatch_invalid (context, arg, res);
206 argmatch_valid (arglist, vallist, valsize);
207 (*exit_fn) ();
208
209 return -1; /* To please the compilers. */
210 }
211
212 /* Look for VALUE in VALLIST, an array of objects of size VALSIZE and
213 return the first corresponding argument in ARGLIST */
214 const char *
215 argmatch_to_argument (const void *value,
216 const char *const *arglist,
217 const void *vallist, size_t valsize)
218 {
219 size_t i;
220
221 for (i = 0; arglist[i]; i++)
222 if (!memcmp (value, (char const *) vallist + valsize * i, valsize))
223 return arglist[i];
224 return NULL;
225 }
226
227 #ifdef TEST
228 /*
229 * Based on "getversion.c" by David MacKenzie <djm@gnu.ai.mit.edu>
230 */
231
232 /* When to make backup files. */
233 enum backup_type
234 {
235 /* Never make backups. */
236 no_backups,
237
238 /* Make simple backups of every file. */
239 simple_backups,
240
241 /* Make numbered backups of files that already have numbered backups,
242 and simple backups of the others. */
243 numbered_existing_backups,
244
245 /* Make numbered backups of every file. */
246 numbered_backups
247 };
248
249 /* Two tables describing arguments (keys) and their corresponding
250 values */
251 static const char *const backup_args[] =
252 {
253 "no", "none", "off",
254 "simple", "never",
255 "existing", "nil",
256 "numbered", "t",
257 0
258 };
259
260 static const enum backup_type backup_vals[] =
261 {
262 no_backups, no_backups, no_backups,
263 simple_backups, simple_backups,
264 numbered_existing_backups, numbered_existing_backups,
265 numbered_backups, numbered_backups
266 };
267
268 int
269 main (int argc, const char *const *argv)
270 {
271 const char *cp;
272 enum backup_type backup_type = no_backups;
273
274 if (argc > 2)
275 {
276 fprintf (stderr, "Usage: %s [VERSION_CONTROL]\n", getprogname ());
277 exit (1);
278 }
279
280 if ((cp = getenv ("VERSION_CONTROL")))
281 backup_type = XARGMATCH ("$VERSION_CONTROL", cp,
282 backup_args, backup_vals);
283
284 if (argc == 2)
285 backup_type = XARGMATCH (getprogname (), argv[1],
286 backup_args, backup_vals);
287
288 printf ("The version control is '%s'\n",
289 ARGMATCH_TO_ARGUMENT (&backup_type, backup_args, backup_vals));
290
291 return 0;
292 }
293 #endif