adtools/clib2

/*
 * $Id: stdlib_bsearch.c,v 1.4 2006-01-08 12:04:25 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
 */

#ifndef _STDLIB_NULL_POINTER_CHECK_H
#include "stdlib_null_pointer_check.h"
#endif /* _STDLIB_NULL_POINTER_CHECK_H */

/****************************************************************************/

#ifndef _STDLIB_HEADERS_H
#include "stdlib_headers.h"
#endif /* _STDLIB_HEADERS_H */

/****************************************************************************/

void *
bsearch(const void *key, const void *base, size_t count, size_t size, int (*compare)(const void * key,const void * value))
{
    void * result = NULL;

    ENTER();

    SHOWPOINTER(key);
    SHOWPOINTER(base);
    SHOWVALUE(count);
    SHOWVALUE(size);
    SHOWPOINTER(compare);

    if(count > 0 && size > 0)
    {
        void * current;
        size_t lower = 0;
        size_t upper = count;
        size_t position;
        int delta;

        assert( key != NULL && base != NULL && compare != NULL );

        #if defined(CHECK_FOR_NULL_POINTERS)
        {
            if(key == NULL || base == NULL || compare == NULL)
            {
                SHOWMSG("invalid parameters");

                __set_errno(EFAULT);
                goto out;
            }
        }
        #endif /* CHECK_FOR_NULL_POINTERS */

        while(lower < upper)
        {
            position = (lower + upper) / 2;

            current = (void *)(((ULONG)base) + (position * size));

            delta = (*compare)(key, current);
            if(delta == 0)
            {
                result = current;
                break;
            }

            if(delta < 0)
                upper = position;
            else
                lower = position + 1;
        }
    }

 out:

    RETURN(result);
    return(result);
}