1 /* argmatch.c -- find a match for a string in an array
2
3 Copyright (C) 1990, 1998-1999, 2001-2007, 2009-2021 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 <stdbool.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31
32 #define _(msgid) gettext (msgid)
33
34 #include "error.h"
35 #include "quotearg.h"
36 #include "getprogname.h"
37
38 #if USE_UNLOCKED_IO
39 # include "unlocked-io.h"
40 #endif
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 /* Non failing version of argmatch call this function after failing. */
50 #ifndef ARGMATCH_DIE
51 # include "exitfail.h"
52 # define ARGMATCH_DIE exit (exit_failure)
53 #endif
54
55 #ifdef ARGMATCH_DIE_DECL
56 ARGMATCH_DIE_DECL;
57 #endif
58
59 static void
60 __argmatch_die (void)
61 {
62 ARGMATCH_DIE;
63 }
64
65 /* Used by XARGMATCH and XARGCASEMATCH. See description in argmatch.h.
66 Default to __argmatch_die, but allow caller to change this at run-time. */
67 argmatch_exit_fn argmatch_die = __argmatch_die;
68
69
70 /* If ARG is an unambiguous match for an element of the
71 NULL-terminated array ARGLIST, return the index in ARGLIST
72 of the matched element, else -1 if it does not match any element
73 or -2 if it is ambiguous (is a prefix of more than one element).
74
75 If VALLIST is none null, use it to resolve ambiguities limited to
76 synonyms, i.e., for
77 "yes", "yop" -> 0
78 "no", "nope" -> 1
79 "y" is a valid argument, for 0, and "n" for 1. */
80
81 ptrdiff_t
82 argmatch (const char *arg, const char *const *arglist,
83 const void *vallist, size_t valsize)
84 {
85 size_t i; /* Temporary index in ARGLIST. */
86 size_t arglen; /* Length of ARG. */
87 ptrdiff_t matchind = -1; /* Index of first nonexact match. */
88 bool ambiguous = false; /* If true, multiple nonexact match(es). */
89
90 arglen = strlen (arg);
91
92 /* Test all elements for either exact match or abbreviated matches. */
93 for (i = 0; arglist[i]; i++)
94 {
95 if (!strncmp (arglist[i], arg, arglen))
96 {
97 if (strlen (arglist[i]) == arglen)
98 /* Exact match found. */
99 return i;
100 else if (matchind == -1)
101 /* First nonexact match found. */
102 matchind = i;
103 else
104 {
105 /* Second nonexact match found. */
106 if (vallist == NULL
107 || memcmp ((char const *) vallist + valsize * matchind,
108 (char const *) vallist + valsize * i, valsize))
109 {
110 /* There is a real ambiguity, or we could not
111 disambiguate. */
112 ambiguous = true;
113 }
114 }
115 }
116 }
117 if (ambiguous)
118 return -2;
119 else
120 return matchind;
121 }
122
123 /* Error reporting for argmatch.
124 CONTEXT is a description of the type of entity that was being matched.
125 VALUE is the invalid value that was given.
126 PROBLEM is the return value from argmatch. */
127
128 void
129 argmatch_invalid (const char *context, const char *value, ptrdiff_t problem)
130 {
131 char const *format = (problem == -1
132 ? _("invalid argument %s for %s")
133 : _("ambiguous argument %s for %s"));
134
135 error (0, 0, format, quotearg_n_style (0, ARGMATCH_QUOTING_STYLE, value),
136 quote_n (1, context));
137 }
138
139 /* List the valid arguments for argmatch.
140 ARGLIST is the same as in argmatch.
141 VALLIST is a pointer to an array of values.
142 VALSIZE is the size of the elements of VALLIST */
143 void
144 argmatch_valid (const char *const *arglist,
145 const void *vallist, size_t valsize)
146 {
147 size_t i;
148 const char *last_val = NULL;
149
150 /* We try to put synonyms on the same line. The assumption is that
151 synonyms follow each other */
152 fputs (_("Valid arguments are:"), stderr);
153 for (i = 0; arglist[i]; i++)
154 if ((i == 0)
155 || memcmp (last_val, (char const *) vallist + valsize * i, valsize))
156 {
157 fprintf (stderr, "\n - %s", quote (arglist[i]));
158 last_val = (char const *) vallist + valsize * i;
159 }
160 else
161 {
162 fprintf (stderr, ", %s", quote (arglist[i]));
163 }
164 putc ('\n', stderr);
165 }
166
167 /* Never failing versions of the previous functions.
168
169 CONTEXT is the context for which argmatch is called (e.g.,
170 "--version-control", or "$VERSION_CONTROL" etc.). Upon failure,
171 calls the (supposed never to return) function EXIT_FN. */
172
173 ptrdiff_t
174 __xargmatch_internal (const char *context,
175 const char *arg, const char *const *arglist,
176 const void *vallist, size_t valsize,
177 argmatch_exit_fn exit_fn)
178 {
179 ptrdiff_t res = argmatch (arg, arglist, vallist, valsize);
180 if (res >= 0)
181 /* Success. */
182 return res;
183
184 /* We failed. Explain why. */
185 argmatch_invalid (context, arg, res);
186 argmatch_valid (arglist, vallist, valsize);
187 (*exit_fn) ();
188
189 return -1; /* To please the compilers. */
190 }
191
192 /* Look for VALUE in VALLIST, an array of objects of size VALSIZE and
193 return the first corresponding argument in ARGLIST */
194 const char *
195 argmatch_to_argument (const void *value,
196 const char *const *arglist,
197 const void *vallist, size_t valsize)
198 {
199 size_t i;
200
201 for (i = 0; arglist[i]; i++)
202 if (!memcmp (value, (char const *) vallist + valsize * i, valsize))
203 return arglist[i];
204 return NULL;
205 }
206
207 #ifdef TEST
208 /*
209 * Based on "getversion.c" by David MacKenzie <djm@gnu.ai.mit.edu>
210 */
211
212 /* When to make backup files. */
213 enum backup_type
214 {
215 /* Never make backups. */
216 no_backups,
217
218 /* Make simple backups of every file. */
219 simple_backups,
220
221 /* Make numbered backups of files that already have numbered backups,
222 and simple backups of the others. */
223 numbered_existing_backups,
224
225 /* Make numbered backups of every file. */
226 numbered_backups
227 };
228
229 /* Two tables describing arguments (keys) and their corresponding
230 values */
231 static const char *const backup_args[] =
232 {
233 "no", "none", "off",
234 "simple", "never",
235 "existing", "nil",
236 "numbered", "t",
237 0
238 };
239
240 static const enum backup_type backup_vals[] =
241 {
242 no_backups, no_backups, no_backups,
243 simple_backups, simple_backups,
244 numbered_existing_backups, numbered_existing_backups,
245 numbered_backups, numbered_backups
246 };
247
248 int
249 main (int argc, const char *const *argv)
250 {
251 const char *cp;
252 enum backup_type backup_type = no_backups;
253
254 if (argc > 2)
255 {
256 fprintf (stderr, "Usage: %s [VERSION_CONTROL]\n", getprogname ());
257 exit (1);
258 }
259
260 if ((cp = getenv ("VERSION_CONTROL")))
261 backup_type = XARGMATCH ("$VERSION_CONTROL", cp,
262 backup_args, backup_vals);
263
264 if (argc == 2)
265 backup_type = XARGMATCH (getprogname (), argv[1],
266 backup_args, backup_vals);
267
268 printf ("The version control is '%s'\n",
269 ARGMATCH_TO_ARGUMENT (&backup_type, backup_args, backup_vals));
270
271 return 0;
272 }
273 #endif