looking-glass/vendor/getopt/getopt.c

/*	$NetBSD: getopt.c,v 1.29 2014/06/05 22:00:22 christos Exp $	*/

/*
* Copyright (c) 1987, 1993, 1994
*	The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int	opterr = 1,		/* if error message should be printed */
optind = 1,		/* index into parent argv vector */
optopt,			/* character checked for validity */
optreset;		/* reset getopt */
char	*optarg;		/* argument associated with option */

#define	BADCH	(int)'?'
#define	BADARG	(int)':'
#define	EMSG	""

                  /*
                  * getopt --
                  *	Parse argc/argv argument vector.
                  */
int
getopt(int nargc, char * const nargv[], const char *ostr)
{
  static char *place = EMSG;	/* option letter processing */
  char *oli;				/* option letter list index */

  if (optreset || *place == 0) {		/* update scanning pointer */
    optreset = 0;
    place = nargv[optind];
    if (optind >= nargc || *place++ != '-') {
      /* Argument is absent or is not an option */
      place = EMSG;
      return (-1);
    }
    optopt = *place++;
    if (optopt == '-' && *place == 0) {
      /* "--" => end of options */
      ++optind;
      place = EMSG;
      return (-1);
    }
    if (optopt == 0) {
      /* Solitary '-', treat as a '-' option
      if the program (eg su) is looking for it. */
      place = EMSG;
      if (strchr(ostr, '-') == NULL)
        return -1;
      optopt = '-';
    }
  }
  else
    optopt = *place++;

  /* See if option letter is one the caller wanted... */
  if (optopt == ':' || (oli = strchr(ostr, optopt)) == NULL) {
    if (*place == 0)
      ++optind;
    if (opterr && *ostr != ':')
      (void)fprintf(stderr,
        "unknown option -- %c\n",
        optopt);
    return (BADCH);
  }

  /* Does this option need an argument? */
  if (oli[1] != ':') {
    /* don't need argument */
    optarg = NULL;
    if (*place == 0)
      ++optind;
  }
  else {
    /* Option-argument is either the rest of this argument or the
    entire next argument. */
    if (*place)
      optarg = place;
    else if (oli[2] == ':')
      /*
      * GNU Extension, for optional arguments if the rest of
      * the argument is empty, we return NULL
      */
      optarg = NULL;
    else if (nargc > ++optind)
      optarg = nargv[optind];
    else {
      /* option-argument absent */
      place = EMSG;
      if (*ostr == ':')
        return (BADARG);
      if (opterr)
        (void)fprintf(stderr,
          "option requires an argument -- %c\n",
          optopt);
      return (BADCH);
    }
    place = EMSG;
    ++optind;
  }
  return (optopt);			/* return option letter */
}