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/* Copyright (C) 1991, 1992 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., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <stddef.h>
#include <string.h>
/* Return the first ocurrence of NEEDLE in HAYSTACK. */
char *
DEFUN(strstr, (haystack, needle),
CONST char *CONST haystack AND
CONST char *CONST needle)
{
register CONST char *CONST needle_end = strchr(needle, '\0');
register CONST char *CONST haystack_end = strchr(haystack, '\0');
register CONST size_t needle_len = needle_end - needle;
register CONST size_t needle_last = needle_len - 1;
register CONST char *begin;
if (needle_len == 0)
return (char *) haystack; /* ANSI 4.11.5.7, line 25. */
if ((size_t) (haystack_end - haystack) < needle_len)
return NULL;
for (begin = &haystack[needle_last]; begin < haystack_end; ++begin)
{
register CONST char *n = &needle[needle_last];
register CONST char *h = begin;
do
if (*h != *n)
goto loop; /* continue for loop */
while (--n >= needle && --h >= haystack);
return (char *) h;
loop:;
}
return NULL;
}
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