1#include <stdlib.h>
2
3void *bsearch(const void *key, const void *base, size_t nel, size_t width, int (*cmp)(const void *, const void *))
4{
5	void *try;
6	int sign;
7	while (nel > 0) {
8		try = (char *)base + width*(nel/2);
9		sign = cmp(key, try);
10		if (!sign) return try;
11		else if (nel == 1) break;
12		else if (sign < 0)
13			nel /= 2;
14		else {
15			base = try;
16			nel -= nel/2;
17		}
18	}
19	return NULL;
20}
21