/* argmatch.c -- find a match for a string in an array
   Copyright (C) 1990, 1997 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 2, 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
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING.
   If not, write to the Free Software Foundation,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Written by David MacKenzie <djm@gnu.ai.mit.edu> */

#if HAVE_CONFIG_H
# include <config.h>
#endif

#include <argmatch.h>

#include <sys/types.h>

#include <stdio.h>
#if HAVE_STRING_H
# include <string.h>
#else
# include <strings.h>
#endif

/* If ARG is an unambiguous match for an element of the
   null-terminated array OPTLIST, return the index in OPTLIST
   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).  */

int
argmatch (const char *arg, const char *const *optlist)
{
  int i;			/* Temporary index in OPTLIST.  */
  size_t arglen;		/* Length of ARG.  */
  int matchind = -1;		/* Index of first nonexact match.  */
  int ambiguous = 0;		/* If nonzero, multiple nonexact match(es).  */

  arglen = strlen (arg);

  /* Test all elements for either exact match or abbreviated matches.  */
  for (i = 0; optlist[i]; i++)
    {
      if (!strncmp (optlist[i], arg, arglen))
	{
	  if (strlen (optlist[i]) == arglen)
	    /* Exact match found.  */
	    return i;
	  else if (matchind == -1)
	    /* First nonexact match found.  */
	    matchind = i;
	  else
	    /* Second nonexact match found.  */
	    ambiguous = 1;
	}
    }
  if (ambiguous)
    return -2;
  else
    return matchind;
}

/* Error reporting for argmatch.
   KIND 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.  */

void
invalid_arg (const char *kind, const char *value, int problem)
{
  const char *fmt = (problem == -1
		     ? "%s: invalid %s `%s'\n"
		     : "%s: ambiguous %s `%s'\n");
  fprintf (stderr, fmt, program_name, kind, value);
}