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/* argmatch.c -- find a match for a string in an array
Copyright (C) 1990, 1998-1999, 2001-2007, 2009-2012 Free Software
Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <>. */
/* Written by David MacKenzie <>
Modified by Akim Demaille <> */
#include <config.h>
/* Specification. */
#include "argmatch.h"
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "gettext.h"
#define _(msgid) gettext (msgid)
#include "error.h"
#include "quotearg.h"
#include "quote.h"
# include "unlocked-io.h"
/* When reporting an invalid argument, show nonprinting characters
by using the quoting style ARGMATCH_QUOTING_STYLE. Do not use
literal_quoting_style. */
# define ARGMATCH_QUOTING_STYLE locale_quoting_style
/* Non failing version of argmatch call this function after failing. */
# include "exitfail.h"
# define ARGMATCH_DIE exit (exit_failure)
static void
__argmatch_die (void)
/* Used by XARGMATCH and XARGCASEMATCH. See description in argmatch.h.
Default to __argmatch_die, but allow caller to change this at run-time. */
argmatch_exit_fn argmatch_die = __argmatch_die;
/* If ARG is an unambiguous match for an element of the
NULL-terminated array ARGLIST, return the index in ARGLIST
of the matched element, else -1 if it does not match any element
or -2 if it is ambiguous (is a prefix of more than one element).
If VALLIST is none null, use it to resolve ambiguities limited to
synonyms, i.e., for
"yes", "yop" -> 0
"no", "nope" -> 1
"y" is a valid argument, for 0, and "n" for 1. */
argmatch (const char *arg, const char *const *arglist,
const char *vallist, size_t valsize)
size_t i; /* Temporary index in ARGLIST. */
size_t arglen; /* Length of ARG. */
ptrdiff_t matchind = -1; /* Index of first nonexact match. */
bool ambiguous = false; /* If true, multiple nonexact match(es). */
arglen = strlen (arg);
/* Test all elements for either exact match or abbreviated matches. */
for (i = 0; arglist[i]; i++)
if (!strncmp (arglist[i], arg, arglen))
if (strlen (arglist[i]) == arglen)
/* Exact match found. */
return i;
else if (matchind == -1)
/* First nonexact match found. */
matchind = i;
/* Second nonexact match found. */
if (vallist == NULL
|| memcmp (vallist + valsize * matchind,
vallist + valsize * i, valsize))
/* There is a real ambiguity, or we could not
disambiguate. */
ambiguous = true;
if (ambiguous)
return -2;
return matchind;
/* Error reporting for argmatch.
CONTEXT is a description of the type of entity that was being matched.
VALUE is the invalid value that was given.
PROBLEM is the return value from argmatch. */
argmatch_invalid (const char *context, const char *value, ptrdiff_t problem)
char const *format = (problem == -1
? _("invalid argument %s for %s")
: _("ambiguous argument %s for %s"));
error (0, 0, format, quotearg_n_style (0, ARGMATCH_QUOTING_STYLE, value),
quote_n (1, context));
/* List the valid arguments for argmatch.
ARGLIST is the same as in argmatch.
VALLIST is a pointer to an array of values.
VALSIZE is the size of the elements of VALLIST */
argmatch_valid (const char *const *arglist,
const char *vallist, size_t valsize)
size_t i;
const char *last_val = NULL;
/* We try to put synonyms on the same line. The assumption is that
synonyms follow each other */
fputs (_("Valid arguments are:"), stderr);
for (i = 0; arglist[i]; i++)
if ((i == 0)
|| memcmp (last_val, vallist + valsize * i, valsize))
fprintf (stderr, "\n - %s", quote (arglist[i]));
last_val = vallist + valsize * i;
fprintf (stderr, ", %s", quote (arglist[i]));
putc ('\n', stderr);
/* Never failing versions of the previous functions.
CONTEXT is the context for which argmatch is called (e.g.,
"--version-control", or "$VERSION_CONTROL" etc.). Upon failure,
calls the (supposed never to return) function EXIT_FN. */
__xargmatch_internal (const char *context,
const char *arg, const char *const *arglist,
const char *vallist, size_t valsize,
argmatch_exit_fn exit_fn)
ptrdiff_t res = argmatch (arg, arglist, vallist, valsize);
if (res >= 0)
/* Success. */
return res;
/* We failed. Explain why. */
argmatch_invalid (context, arg, res);
argmatch_valid (arglist, vallist, valsize);
(*exit_fn) ();
return -1; /* To please the compilers. */
/* Look for VALUE in VALLIST, an array of objects of size VALSIZE and
return the first corresponding argument in ARGLIST */
const char *
argmatch_to_argument (const char *value,
const char *const *arglist,
const char *vallist, size_t valsize)
size_t i;
for (i = 0; arglist[i]; i++)
if (!memcmp (value, vallist + valsize * i, valsize))
return arglist[i];
return NULL;
#ifdef TEST
* Based on "getversion.c" by David MacKenzie <>
char *program_name;
/* When to make backup files. */
enum backup_type
/* Never make backups. */
/* Make simple backups of every file. */
/* Make numbered backups of files that already have numbered backups,
and simple backups of the others. */
/* Make numbered backups of every file. */
/* Two tables describing arguments (keys) and their corresponding
values */
static const char *const backup_args[] =
"no", "none", "off",
"simple", "never",
"existing", "nil",
"numbered", "t",
static const enum backup_type backup_vals[] =
no_backups, no_backups, no_backups,
simple_backups, simple_backups,
numbered_existing_backups, numbered_existing_backups,
numbered_backups, numbered_backups
main (int argc, const char *const *argv)
const char *cp;
enum backup_type backup_type = no_backups;
program_name = (char *) argv[0];
if (argc > 2)
fprintf (stderr, "Usage: %s [VERSION_CONTROL]\n", program_name);
exit (1);
if ((cp = getenv ("VERSION_CONTROL")))
backup_type = XARGMATCH ("$VERSION_CONTROL", cp,
backup_args, backup_vals);
if (argc == 2)
backup_type = XARGMATCH (program_name, argv[1],
backup_args, backup_vals);
printf ("The version control is '%s'\n",
ARGMATCH_TO_ARGUMENT (backup_type, backup_args, backup_vals));
return 0;