source: trunk/minix/lib/ansi/bsearch.c@ 9

/*
 * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 */
/* $Header: /cvsup/minix/src/lib/ansi/bsearch.c,v 1.1.1.1 2005/04/21 14:56:04 beng Exp $ */

#include        <stdlib.h>

void *
bsearch(register const void *key, register const void *base,
        register size_t nmemb, register size_t size,
        int (*compar)(const void *, const void *))
{
        register const void *mid_point;
        register int  cmp;

        while (nmemb > 0) {
                mid_point = (char *)base + size * (nmemb >> 1);
                if ((cmp = (*compar)(key, mid_point)) == 0)
                        return (void *)mid_point;
                if (cmp >= 0) {
                        base  = (char *)mid_point + size;
                        nmemb = (nmemb - 1) >> 1;
                } else
                        nmemb >>= 1;
        }
        return (void *)NULL;
}