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Diffstat (limited to 'src/dpdk_lib18/librte_hash/rte_jhash.h')
| -rwxr-xr-x | src/dpdk_lib18/librte_hash/rte_jhash.h | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/src/dpdk_lib18/librte_hash/rte_jhash.h b/src/dpdk_lib18/librte_hash/rte_jhash.h new file mode 100755 index 00000000..a4bf5a1b --- /dev/null +++ b/src/dpdk_lib18/librte_hash/rte_jhash.h @@ -0,0 +1,253 @@ +/*- + * BSD LICENSE + * + * Copyright(c) 2010-2014 Intel Corporation. All rights reserved. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * 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. + * * Neither the name of Intel Corporation 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 COPYRIGHT HOLDERS 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 COPYRIGHT + * OWNER 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. + */ + +#ifndef _RTE_JHASH_H +#define _RTE_JHASH_H + +/** + * @file + * + * jhash functions. + */ + +#ifdef __cplusplus +extern "C" { +#endif + +#include <stdint.h> + +/* jhash.h: Jenkins hash support. + * + * Copyright (C) 1996 Bob Jenkins (bob_jenkins@burtleburtle.net) + * + * http://burtleburtle.net/bob/hash/ + * + * These are the credits from Bob's sources: + * + * lookup2.c, by Bob Jenkins, December 1996, Public Domain. + * hash(), hash2(), hash3, and mix() are externally useful functions. + * Routines to test the hash are included if SELF_TEST is defined. + * You can use this free for any purpose. It has no warranty. + * + * $FreeBSD$ + */ + +/** @internal Internal function. NOTE: Arguments are modified. */ +#define __rte_jhash_mix(a, b, c) do { \ + a -= b; a -= c; a ^= (c>>13); \ + b -= c; b -= a; b ^= (a<<8); \ + c -= a; c -= b; c ^= (b>>13); \ + a -= b; a -= c; a ^= (c>>12); \ + b -= c; b -= a; b ^= (a<<16); \ + c -= a; c -= b; c ^= (b>>5); \ + a -= b; a -= c; a ^= (c>>3); \ + b -= c; b -= a; b ^= (a<<10); \ + c -= a; c -= b; c ^= (b>>15); \ +} while (0) + +/** The golden ratio: an arbitrary value. */ +#define RTE_JHASH_GOLDEN_RATIO 0x9e3779b9 + +/** + * The most generic version, hashes an arbitrary sequence + * of bytes. No alignment or length assumptions are made about + * the input key. + * + * @param key + * Key to calculate hash of. + * @param length + * Length of key in bytes. + * @param initval + * Initialising value of hash. + * @return + * Calculated hash value. + */ +static inline uint32_t +rte_jhash(const void *key, uint32_t length, uint32_t initval) +{ + uint32_t a, b, c, len; + const uint8_t *k = (const uint8_t *)key; + const uint32_t *k32 = (const uint32_t *)key; + + len = length; + a = b = RTE_JHASH_GOLDEN_RATIO; + c = initval; + + while (len >= 12) { + a += k32[0]; + b += k32[1]; + c += k32[2]; + + __rte_jhash_mix(a,b,c); + + k += (3 * sizeof(uint32_t)), k32 += 3; + len -= (3 * sizeof(uint32_t)); + } + + c += length; + switch (len) { + case 11: c += ((uint32_t)k[10] << 24); + case 10: c += ((uint32_t)k[9] << 16); + case 9 : c += ((uint32_t)k[8] << 8); + case 8 : b += ((uint32_t)k[7] << 24); + case 7 : b += ((uint32_t)k[6] << 16); + case 6 : b += ((uint32_t)k[5] << 8); + case 5 : b += k[4]; + case 4 : a += ((uint32_t)k[3] << 24); + case 3 : a += ((uint32_t)k[2] << 16); + case 2 : a += ((uint32_t)k[1] << 8); + case 1 : a += k[0]; + default: break; + }; + + __rte_jhash_mix(a,b,c); + + return c; +} + +/** + * A special optimized version that handles 1 or more of uint32_ts. + * The length parameter here is the number of uint32_ts in the key. + * + * @param k + * Key to calculate hash of. + * @param length + * Length of key in units of 4 bytes. + * @param initval + * Initialising value of hash. + * @return + * Calculated hash value. + */ +static inline uint32_t +rte_jhash2(const uint32_t *k, uint32_t length, uint32_t initval) +{ + uint32_t a, b, c, len; + + a = b = RTE_JHASH_GOLDEN_RATIO; + c = initval; + len = length; + + while (len >= 3) { + a += k[0]; + b += k[1]; + c += k[2]; + __rte_jhash_mix(a, b, c); + k += 3; len -= 3; + } + + c += length * 4; + + switch (len) { + case 2 : b += k[1]; + case 1 : a += k[0]; + default: break; + }; + + __rte_jhash_mix(a,b,c); + + return c; +} + + +/** + * A special ultra-optimized versions that knows it is hashing exactly + * 3 words. + * + * @param a + * First word to calcuate hash of. + * @param b + * Second word to calcuate hash of. + * @param c + * Third word to calcuate hash of. + * @param initval + * Initialising value of hash. + * @return + * Calculated hash value. + */ +static inline uint32_t +rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval) +{ + a += RTE_JHASH_GOLDEN_RATIO; + b += RTE_JHASH_GOLDEN_RATIO; + c += initval; + + __rte_jhash_mix(a, b, c); + + /* + * NOTE: In particular the "c += length; __rte_jhash_mix(a,b,c);" + * normally done at the end is not done here. + */ + return c; +} + +/** + * A special ultra-optimized versions that knows it is hashing exactly + * 2 words. + * + * @param a + * First word to calcuate hash of. + * @param b + * Second word to calcuate hash of. + * @param initval + * Initialising value of hash. + * @return + * Calculated hash value. + */ +static inline uint32_t +rte_jhash_2words(uint32_t a, uint32_t b, uint32_t initval) +{ + return rte_jhash_3words(a, b, 0, initval); +} + +/** + * A special ultra-optimized versions that knows it is hashing exactly + * 1 word. + * + * @param a + * Word to calcuate hash of. + * @param initval + * Initialising value of hash. + * @return + * Calculated hash value. + */ +static inline uint32_t +rte_jhash_1word(uint32_t a, uint32_t initval) +{ + return rte_jhash_3words(a, 0, 0, initval); +} + +#ifdef __cplusplus +} +#endif + +#endif /* _RTE_JHASH_H */ |