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/* Copyright (C) 1995, 1996, 1997 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/*
* 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 (haystack, needle)
const wchar_t *haystack;
const wchar_t *needle;
{
register 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 (;;)
{
register wchar_t a;
register 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;
}
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