2 * Copyright 2006 Bob Jenkins
4 * Derived from public domain source, see
5 * <http://burtleburtle.net/bob/c/lookup3.c>:
7 * "lookup3.c, by Bob Jenkins, May 2006, Public Domain.
9 * These are functions for producing 32-bit hashes for hash table lookup...
10 * ...You can use this free for any purpose. It's in the public domain.
11 * It has no warranty."
13 * Copyright (c) 2014-2016 Solarflare Communications Inc.
14 * All rights reserved.
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions are met:
19 * 1. Redistributions of source code must retain the above copyright notice,
20 * this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright notice,
22 * this list of conditions and the following disclaimer in the documentation
23 * and/or other materials provided with the distribution.
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
26 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
27 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
29 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
30 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
31 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
32 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
33 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
34 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
48 /* Hash initial value */
49 #define EFX_HASH_INITIAL_VALUE 0xdeadbeef
52 * Rotate a 32-bit value left
54 * Allow platform to provide an intrinsic or optimised routine and
55 * fall-back to a simple shift based implementation.
57 #if EFSYS_HAS_ROTL_DWORD
59 #define EFX_HASH_ROTATE(_value, _shift) \
60 EFSYS_ROTL_DWORD(_value, _shift)
64 #define EFX_HASH_ROTATE(_value, _shift) \
65 (((_value) << (_shift)) | ((_value) >> (32 - (_shift))))
69 /* Mix three 32-bit values reversibly */
70 #define EFX_HASH_MIX(_a, _b, _c) \
73 _a ^= EFX_HASH_ROTATE(_c, 4); \
76 _b ^= EFX_HASH_ROTATE(_a, 6); \
79 _c ^= EFX_HASH_ROTATE(_b, 8); \
82 _a ^= EFX_HASH_ROTATE(_c, 16); \
85 _b ^= EFX_HASH_ROTATE(_a, 19); \
88 _c ^= EFX_HASH_ROTATE(_b, 4); \
90 _NOTE(CONSTANTCONDITION) \
93 /* Final mixing of three 32-bit values into one (_c) */
94 #define EFX_HASH_FINALISE(_a, _b, _c) \
97 _c -= EFX_HASH_ROTATE(_b, 14); \
99 _a -= EFX_HASH_ROTATE(_c, 11); \
101 _b -= EFX_HASH_ROTATE(_a, 25); \
103 _c -= EFX_HASH_ROTATE(_b, 16); \
105 _a -= EFX_HASH_ROTATE(_c, 4); \
107 _b -= EFX_HASH_ROTATE(_a, 14); \
109 _c -= EFX_HASH_ROTATE(_b, 24); \
110 _NOTE(CONSTANTCONDITION) \
114 /* Produce a 32-bit hash from 32-bit aligned input */
115 __checkReturn uint32_t
117 __in_ecount(count) uint32_t const *input,
125 /* Set up the initial internal state */
126 a = b = c = EFX_HASH_INITIAL_VALUE +
127 (((uint32_t)count) * sizeof (uint32_t)) + init;
129 /* Handle all but the last three dwords of the input */
134 EFX_HASH_MIX(a, b, c);
140 /* Handle the left-overs */
150 EFX_HASH_FINALISE(a, b, c);
154 /* Should only get here if count parameter was zero */
161 #if EFSYS_IS_BIG_ENDIAN
163 /* Produce a 32-bit hash from arbitrarily aligned input */
164 __checkReturn uint32_t
166 __in_ecount(length) uint8_t const *input,
174 /* Set up the initial internal state */
175 a = b = c = EFX_HASH_INITIAL_VALUE + (uint32_t)length + init;
177 /* Handle all but the last twelve bytes of the input */
178 while (length > 12) {
179 a += ((uint32_t)input[0]) << 24;
180 a += ((uint32_t)input[1]) << 16;
181 a += ((uint32_t)input[2]) << 8;
182 a += ((uint32_t)input[3]);
183 b += ((uint32_t)input[4]) << 24;
184 b += ((uint32_t)input[5]) << 16;
185 b += ((uint32_t)input[6]) << 8;
186 b += ((uint32_t)input[7]);
187 c += ((uint32_t)input[8]) << 24;
188 c += ((uint32_t)input[9]) << 16;
189 c += ((uint32_t)input[10]) << 8;
190 c += ((uint32_t)input[11]);
191 EFX_HASH_MIX(a, b, c);
196 /* Handle the left-overs */
199 c += ((uint32_t)input[11]);
202 c += ((uint32_t)input[10]) << 8;
205 c += ((uint32_t)input[9]) << 16;
208 c += ((uint32_t)input[8]) << 24;
211 b += ((uint32_t)input[7]);
214 b += ((uint32_t)input[6]) << 8;
217 b += ((uint32_t)input[5]) << 16;
220 b += ((uint32_t)input[4]) << 24;
223 a += ((uint32_t)input[3]);
226 a += ((uint32_t)input[2]) << 8;
229 a += ((uint32_t)input[1]) << 16;
232 a += ((uint32_t)input[0]) << 24;
233 EFX_HASH_FINALISE(a, b, c);
237 /* Should only get here if length parameter was zero */
244 #elif EFSYS_IS_LITTLE_ENDIAN
246 /* Produce a 32-bit hash from arbitrarily aligned input */
247 __checkReturn uint32_t
249 __in_ecount(length) uint8_t const *input,
257 /* Set up the initial internal state */
258 a = b = c = EFX_HASH_INITIAL_VALUE + (uint32_t)length + init;
260 /* Handle all but the last twelve bytes of the input */
261 while (length > 12) {
262 a += ((uint32_t)input[0]);
263 a += ((uint32_t)input[1]) << 8;
264 a += ((uint32_t)input[2]) << 16;
265 a += ((uint32_t)input[3]) << 24;
266 b += ((uint32_t)input[4]);
267 b += ((uint32_t)input[5]) << 8;
268 b += ((uint32_t)input[6]) << 16;
269 b += ((uint32_t)input[7]) << 24;
270 c += ((uint32_t)input[8]);
271 c += ((uint32_t)input[9]) << 8;
272 c += ((uint32_t)input[10]) << 16;
273 c += ((uint32_t)input[11]) << 24;
274 EFX_HASH_MIX(a, b, c);
279 /* Handle the left-overs */
282 c += ((uint32_t)input[11]) << 24;
285 c += ((uint32_t)input[10]) << 16;
288 c += ((uint32_t)input[9]) << 8;
291 c += ((uint32_t)input[8]);
294 b += ((uint32_t)input[7]) << 24;
297 b += ((uint32_t)input[6]) << 16;
300 b += ((uint32_t)input[5]) << 8;
303 b += ((uint32_t)input[4]);
306 a += ((uint32_t)input[3]) << 24;
309 a += ((uint32_t)input[2]) << 16;
312 a += ((uint32_t)input[1]) << 8;
315 a += ((uint32_t)input[0]);
316 EFX_HASH_FINALISE(a, b, c);
320 /* Should only get here if length parameter was zero */
329 #error "Neither of EFSYS_IS_{BIG,LITTLE}_ENDIAN is set"