ack/lang/cem/libcc.ansi/stdlib/bsearch.c

/*
 * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 */
/* $Id$ */

#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;
}