From 38e876d964346d3e4b88c52732b7ce5966d796a5 Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Thu, 1 Nov 2018 13:35:40 +0100 Subject: import original 1.85 implementation from openbsd libc --- _db1.85/hash/hash_func.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 _db1.85/hash/hash_func.c (limited to '_db1.85/hash/hash_func.c') diff --git a/_db1.85/hash/hash_func.c b/_db1.85/hash/hash_func.c new file mode 100644 index 0000000..6d96a73 --- /dev/null +++ b/_db1.85/hash/hash_func.c @@ -0,0 +1,78 @@ +/* $OpenBSD: hash_func.c,v 1.11 2016/05/29 20:47:49 guenther Exp $ */ + +/*- + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Margo Seltzer. + * + * 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 + +#include + +/* Chris Torek's hash function. */ +u_int32_t +__default_hash(const void *key, size_t len) +{ + u_int32_t h, loop; + u_int8_t *k; + +#define HASH4a h = (h << 5) - h + *k++; +#define HASH4b h = (h << 5) + h + *k++; +#define HASH4 HASH4b + + h = 0; + k = (u_int8_t *)key; + if (len > 0) { + loop = (len + 8 - 1) >> 3; + + switch (len & (8 - 1)) { + case 0: + do { /* All fall throughs */ + HASH4; + case 7: + HASH4; + case 6: + HASH4; + case 5: + HASH4; + case 4: + HASH4; + case 3: + HASH4; + case 2: + HASH4; + case 1: + HASH4; + } while (--loop); + } + + } + return (h); +} -- cgit v1.2.3