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sortix--sortix/libc/wchar/wcsstr.cpp

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2013-09-16 08:41:16 -04:00
/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013.
This file is part of the Sortix C Library.
The Sortix 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 3 of the License, or (at your
option) any later version.
The Sortix 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 Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
wchar/wcsstr.cpp
Locate a wide substring.
*******************************************************************************/
#include <wchar.h>
// TODO: This simple and hacky implementation runs in O(N^2) even though this
// problem can be solved in O(N).
extern "C"
wchar_t* wcsstr(const wchar_t* restrict haystack,
const wchar_t* restrict needle)
{
if ( !needle[0] )
return (wchar_t*) haystack;
for ( size_t i = 0; haystack[i]; i++ )
{
bool diff = false;
for ( size_t j = 0; needle[j]; j++ )
{
if ( (diff = haystack[i+j] != needle[j]) )
break;
}
if ( diff )
continue;
return (wchar_t*) haystack + i;
}
return NULL;
}