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
57 ARGMATCH_DIE_DECL;
58 #endif
59 
60 static void
__argmatch_die(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 
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 ptrdiff_t
argmatch(const char * arg,const char * const * arglist,const char * vallist,size_t valsize)83 argmatch (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 
129 void
argmatch_invalid(const char * context,const char * value,ptrdiff_t problem)130 argmatch_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 */
144 void
argmatch_valid(const char * const * arglist,const char * vallist,size_t valsize)145 argmatch_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 
174 ptrdiff_t
__xargmatch_internal(const char * context,const char * arg,const char * const * arglist,const char * vallist,size_t valsize,argmatch_exit_fn exit_fn)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 */
195 const char *
argmatch_to_argument(const char * value,const char * const * arglist,const char * vallist,size_t valsize)196 argmatch_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  */
212 char *program_name;
213 
214 /* When to make backup files.  */
215 enum 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 */
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   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 
250 int
main(int argc,const char * const * argv)251 main (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