1/*- 2 * Copyright (c) 2014 Dag-Erling Smørgrav 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/hash.h> 28#include <sys/endian.h> 29#include <sys/stdint.h> 30#include <sys/types.h> 31 32#define rol32(i32, n) ((i32) << (n) | (i32) >> (32 - (n))) 33 34/* 35 * $FreeBSD$ 36 * Simple implementation of the Murmur3-32 hash function optimized for 37 * aligned sequences of 32-bit words. If len is not a multiple of 4, it 38 * will be rounded down, droping trailer bytes. 39 */ 40uint32_t 41murmur3_aligned_32(const void *data, size_t len, uint32_t seed) 42{ 43 const uint32_t *data32; 44 uint32_t hash, k; 45 size_t res; 46 47 /* initialize */ 48 len -= len % sizeof(*data32); 49 res = len; 50 data32 = data; 51 hash = seed; 52 53 /* iterate */ 54 for (res = 0; res < len; res += sizeof(*data32), data32++) { 55 k = le32toh(*data32); 56 k *= 0xcc9e2d51; 57 k = rol32(k, 15); 58 k *= 0x1b873593; 59 hash ^= k; 60 hash = rol32(hash, 13); 61 hash *= 5; 62 hash += 0xe6546b64; 63 } 64 65 /* finalize */ 66 hash ^= (uint32_t)len; 67 hash ^= hash >> 16; 68 hash *= 0x85ebca6b; 69 hash ^= hash >> 13; 70 hash *= 0xc2b2ae35; 71 hash ^= hash >> 16; 72 return (hash); 73} 74 75