/* Copyright (C) 1995-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

/*

 * The original strstr() file contains the following comment:

 *

 * My personal strstr() implementation that beats most other algorithms.

 * Until someone tells me otherwise, I assume that this is the

 * fastest implementation of strstr() in C.

 * I deliberately chose not to comment it.  You should have at least

 * as much fun trying to understand it, as I had to write it :-).

 *

 * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de */

#include <wchar.h>

wchar_t *

wcsstr (const wchar_t *haystack, const wchar_t *needle)

{

  wchar_t b, c;

  if ((b = *needle) != L'\0')

    {

      haystack--;				/* possible ANSI violation */

      do

	if ((c = *++haystack) == L'\0')

	  goto ret0;

      while (c != b);

      if (!(c = *++needle))

	goto foundneedle;

      ++needle;

      goto jin;

      for (;;)

	{

	  wchar_t a;

	  const wchar_t *rhaystack, *rneedle;

	  do

	    {

	      if (!(a = *++haystack))

		goto ret0;

	      if (a == b)

		break;

	      if ((a = *++haystack) == L'\0')

		goto ret0;

shloop:	      ;

	    }

	  while (a != b);

jin:	  if (!(a = *++haystack))

	    goto ret0;

	  if (a != c)

	    goto shloop;

	  if (*(rhaystack = haystack-- + 1) == (a = *(rneedle = needle)))

	    do

	      {

		if (a == L'\0')

		  goto foundneedle;

		if (*++rhaystack != (a = *++needle))

		  break;

		if (a == L'\0')

		  goto foundneedle;

	      }

	    while (*++rhaystack == (a = *++needle));

	  needle = rneedle;		  /* took the register-poor approach */

	  if (a == L'\0')

	    break;

	}

    }

foundneedle:

  return (wchar_t*) haystack;

ret0:

  return NULL;

}

/* This alias is for backward compatibility with drafts of the ISO C

   standard.  Unfortunately the Unix(TM) standard requires this name.  */

weak_alias (wcsstr, wcswcs)