/* argmatch.c -- find a match for a string in an array
   Copyright (C) 1990 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 1, 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; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

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

/* MS-DOS port (c) 1990 by Thorsten Ohl, ohl@gnu.ai.mit.edu
   This port is also distributed under the terms of the
   GNU General Public License as published by the
   Free Software Foundation.

   Please note that this file is not identical to the
   original GNU release, you should have received this
   code as patch to the official release.

   $Header: e:/gnu/fileutil/RCS/argmatch.c 1.4.0.2 90/09/19 12:27:25 tho Exp $
 */

#include <stdio.h>
#ifdef STDC_HEADERS
#include <string.h>
#endif

#ifdef MSDOS
int argmatch (char *arg, char **optlist);
void invalid_arg (char *kind, char *value, int problem);
#endif /* MSDOS */

extern char *program_name;

/* 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 (arg, optlist)
     char *arg;
     char **optlist;
{
  int i;			/* Temporary index in OPTLIST. */
  int 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 (kind, value, problem)
     char *kind;
     char *value;
     int problem;
{
  fprintf (stderr, "%s: ", program_name);
  if (problem == -1)
    fprintf (stderr, "invalid");
  else				/* Assume -2. */
    fprintf (stderr, "ambiguous");
  fprintf (stderr, " %s `%s'\n", kind, value);
}
