kolibrios/programs/develop/open watcom/trunk/clib/search/bsrch_s.c

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/****************************************************************************
*
* Open Watcom Project
*
* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
* ========================================================================
*
* This file contains Original Code and/or Modifications of Original
* Code as defined in and that are subject to the Sybase Open Watcom
* Public License version 1.0 (the 'License'). You may not use this file
* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
* provided with the Original Code and Modifications, and is also
* available at www.sybase.com/developer/opensource.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
* NON-INFRINGEMENT. Please see the License for the specific language
* governing rights and limitations under the License.
*
* ========================================================================
*
* Description: Implementation of bsearch_s() - bounds-checking bsearch().
*
****************************************************************************/
#include "variety.h"
#include "saferlib.h"
#undef __INLINE_FUNCTIONS__
#include <stddef.h>
#include <stdlib.h>
#include "extfunc.h"
typedef int bcomp();
#ifdef _M_IX86
#pragma aux (__outside_CLIB) bcomp;
#endif
_WCRTLINK void * bsearch_s( const void * key, const void * base,
rsize_t nmemb, rsize_t size,
int (*compar)( const void *k, const void *y, void *context ),
void *context )
/***********************************************************************/
{
char *low;
char *high;
char *mid;
int cond;
bcomp *comp = compar;
/* runtime-constraints */
// nmemb <= RSIZE_MAX
// size <= RSIZE_MAX
// if nmemb > 0 then key, base, compar not NULL
if( __check_constraint_maxsize( nmemb ) &&
__check_constraint_maxsize( size ) &&
( (nmemb == 0) || __check_constraint_nullptr( key ) &&
__check_constraint_nullptr( base ) &&
__check_constraint_nullptr( compar )) ) {
if( nmemb == 0 ) { /* empty array - nothing to do */
return( NULL );
}
low = (char *) base;
high = low + (nmemb - 1) * size;
while( low < high ) {
mid = low + ( (high - low) / size / 2 ) * size;
cond = (*comp)( key, mid, context );
if( cond == 0 ) return( mid );
if( cond < 0 ) { /* key < mid */
high = mid;
} else { /* key > mid */
low = mid + size;
}
}
if (low == high) return( (*comp)( key, low, context ) ? NULL : low );
}
return( NULL );
}