newlib-cygwin/newlib/libc/string/wcsstr.c

102 lines
2.8 KiB
C

/*
FUNCTION
<<wcsstr>>---find a wide-character substring
SYNOPSIS
#include <wchar.h>
wchar_t *wcsstr(const wchar_t *__restrict <[big]>,
const wchar_t *__restrict <[little]>);
DESCRIPTION
The <<wcsstr>> function locates the first occurrence in the
wide-character string pointed to by <[big]> of the sequence of
wide characters (excluding the terminating null wide character) in the
wide-character string pointed to by <[little]>.
RETURNS
On successful completion, <<wcsstr>> returns a pointer to the located
wide-character string, or a null pointer if the wide-character string
is not found.
If <[little]> points to a wide-character string with zero length,
the function returns <[big]>.
PORTABILITY
<<wcsstr>> is ISO/IEC 9899/AMD1:1995 (ISO C).
*/
/* $NetBSD: wcsstr.c,v 1.1 2000/12/23 23:14:37 itojun Exp $ */
/*-
* Copyright (c)1999 Citrus Project,
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* citrus Id: wcsstr.c,v 1.2 2000/12/21 05:07:25 itojun Exp
*/
#include <_ansi.h>
#include <stddef.h>
#include <wchar.h>
wchar_t *
_DEFUN (wcsstr, (big, little),
const wchar_t *__restrict big,
const wchar_t *__restrict little)
{
const wchar_t *p;
const wchar_t *q;
const wchar_t *r;
if (!*little)
{
/* LINTED interface specification */
return (wchar_t *) big;
}
if (wcslen (big) < wcslen (little))
return NULL;
p = big;
q = little;
while (*p)
{
q = little;
r = p;
while (*q)
{
if (*r != *q)
break;
q++;
r++;
}
if (!*q)
{
/* LINTED interface specification */
return (wchar_t *) p;
}
p++;
}
return NULL;
}