/*
 * getopt.c
 *
 * a minimal implementation of the getopt() function, written so that
 * test applications that use that function can run on non-POSIX
 * platforms 
 *
 */
/*
 *	
 * Copyright (c) 2001-2017 Cisco Systems, Inc.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 *   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.
 * 
 *   Neither the name of the Cisco Systems, Inc. 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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 <stdlib.h>  /* for NULL */

int optind_s = 0;

char *optarg_s;

#define GETOPT_FOUND_WITHOUT_ARGUMENT    2
#define GETOPT_FOUND_WITH_ARGUMENT       1
#define GETOPT_NOT_FOUND                 0 

static int 
getopt_check_character(char c, const char *string) {
  unsigned int max_string_len = 128;

  while (*string != 0) {
    if (max_string_len == 0) {
      return '?';
    }
    if (*string++ == c) {
      if (*string == ':') {
	return GETOPT_FOUND_WITH_ARGUMENT;
      } else {
	return GETOPT_FOUND_WITHOUT_ARGUMENT;
      }
    }
  }
  return GETOPT_NOT_FOUND;
}

int
getopt_s(int argc, 
       char * const argv[], 
       const char *optstring) {


  while (optind_s + 1 < argc) {
    char *string;
    
    /* move 'string' on to next argument */
    optind_s++;
    string = argv[optind_s];

    if (string == NULL)
      return '?'; /* NULL argument string */

    if (string[0] != '-')
      return -1; /* found an unexpected character */

    switch(getopt_check_character(string[1], optstring)) {
    case GETOPT_FOUND_WITH_ARGUMENT:
      if (optind_s + 1 < argc) {
	optind_s++;
	optarg_s = argv[optind_s];
	return string[1]; 
      } else {
	return '?';  /* argument missing */
      }
    case GETOPT_FOUND_WITHOUT_ARGUMENT:
      return string[1];
    case GETOPT_NOT_FOUND:
    default:
      return '?'; /* didn't find expected character */
      break;
    }
  }

  return -1;
}