/*-------------------------------------------------------------------------
 * Filename:      strstr.c
 * Version:       $Id: strstr.c,v 1.2 1999/05/02 20:26:27 erik Exp $
 * Copyright:     Copyright (C) 1996 - 1999, Erik Mouw
 * Author:        Erik Mouw <J.A.K.Mouw@its.tudelft.nl>
 * Description:   strstr() replacement function for brain damaged OSes
 * Created at:    Tue Oct  1 13:27:25 1996
 * Modified by:   Erik Mouw <J.A.K.Mouw@its.tudelft.nl>
 * Modified at:   Sun May  2 16:49:24 1999
 *-----------------------------------------------------------------------*/
/*
 *
 * This will be compiled if your system misses the strstr() function.
 *
 *
 * strstr.c, Copyright (C) 1996 - 1999, Erik Mouw
 *
 * Email:
 *   J.A.K.Mouw@its.tudelft.nl
 *
 * Snail mail:
 *   J.A.K. Mouw
 *   Information and Communication Theory Group
 *   Department of Electrical Engineering
 *   Faculty of Information Technology and Systems
 *   Delft University of Technology
 *   P.O. Box 5031
 *   2600 GA  Delft
 *   The Netherlands
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software (the "Software"), to deal in the
 * Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit
 * persons to whom the Software is furnished to do so, subject to the
 * following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Except as contained in this notice, the name of Erik Mouw shall not
 * be used in advertising or otherwise to promote the sale, use or
 * other dealings in this Software without prior written authorization
 * from Erik Mouw.
 *
 *
 * strstr - locate a substring
 *
 * The strstr() function finds the first occurrence of the substring
 * needle in the string haystack. The terminating `\0' characters are
 * not compared.
 *
 * The strstr() function returns a pointer to the beginning of the
 * substring, or NULL if the substring is not found.
 *
 */

#ident "$Id: strstr.c,v 1.2 1999/05/02 20:26:27 erik Exp $"




#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#if STDC_HEADERS
# include <stdlib.h>
#else
# ifdef HAVE_MALLOC_H
#  include <malloc.h>
# else
#  ifndef NULL
#   define NULL ((void *)0)
#  endif
# endif
#endif








#ifdef __cplusplus
extern "C" char *strstr(const char *haystack, const char *needle)
#else
char *strstr(const char *haystack, const char *needle)
#endif
{
  char *h = (char *)haystack;
  char *n = (char *)needle;
  char *start = (char *)haystack;
  int stop = 0;

  if((*needle == '\0') || (*haystack == '\0'))
    {
      return(NULL);
    }

  while(stop == 0)
    {
      if(*n == '\0')
	{
	  /* we've reached the end of the needle, this is it */
	  return(start);
	}
      else if(*h == '\0')
	{
	  /* end of the haystack, stop */
	  stop = 1;
	}
      else if(*n == *h)
	{
	  /* this looks good, try the next one */
	  n++;
	  h++;
	}
      else
	{
	  /* start all over again */
	  n = (char *) needle;
	  h++;
	  start = h;
	}
    }

  return(NULL);
}