minix/lib/libc/ansi/bsearch.c

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2005-04-21 16:53:53 +02:00
/*
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
#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;
}