diff options
Diffstat (limited to 'libc/stdlib/bsearch.c')
-rw-r--r-- | libc/stdlib/bsearch.c | 67 |
1 files changed, 0 insertions, 67 deletions
diff --git a/libc/stdlib/bsearch.c b/libc/stdlib/bsearch.c deleted file mode 100644 index 8193d27..0000000 --- a/libc/stdlib/bsearch.c +++ /dev/null @@ -1,67 +0,0 @@ -/* - * Copyright (c) 1990 Regents of the University of California. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. - */ - -#include <stdlib.h> - -/* - * Perform a binary search. - * - * The code below is a bit sneaky. After a comparison fails, we - * divide the work in half by moving either left or right. If lim - * is odd, moving left simply involves halving lim: e.g., when lim - * is 5 we look at item 2, so we change lim to 2 so that we will - * look at items 0 & 1. If lim is even, the same applies. If lim - * is odd, moving right again involes halving lim, this time moving - * the base up one item past p: e.g., when lim is 5 we change base - * to item 3 and make lim 2 so that we will look at items 3 and 4. - * If lim is even, however, we have to shrink it by one before - * halving: e.g., when lim is 4, we still looked at item 2, so we - * have to make lim 3, then halve, obtaining 1, so that we will only - * look at item 3. - */ -void * -bsearch(const void *key, const void *base0, size_t nmemb, size_t size, - int (*compar)(const void *, const void *)) -{ - const char *base = base0; - int lim, cmp; - const void *p; - - for (lim = nmemb; lim != 0; lim >>= 1) { - p = base + (lim >> 1) * size; - cmp = (*compar)(key, p); - if (cmp == 0) - return ((void *)p); - if (cmp > 0) { /* key > p: move right */ - base = (char *)p + size; - lim--; - } /* else move left */ - } - return (NULL); -} |