diff options
Diffstat (limited to 'lib/librte_hash/rte_jhash.h')
| -rw-r--r-- | lib/librte_hash/rte_jhash.h | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/lib/librte_hash/rte_jhash.h b/lib/librte_hash/rte_jhash.h new file mode 100644 index 00000000..207478c2 --- /dev/null +++ b/lib/librte_hash/rte_jhash.h @@ -0,0 +1,410 @@ +/*- + * BSD LICENSE + * + * Copyright(c) 2010-2015 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> +#include <string.h> +#include <limits.h> + +#include <rte_log.h> +#include <rte_byteorder.h> + +/* jhash.h: Jenkins hash support. + * + * Copyright (C) 2006 Bob Jenkins (bob_jenkins@burtleburtle.net) + * + * http://burtleburtle.net/bob/hash/ + * + * These are the credits from Bob's sources: + * + * lookup3.c, by Bob Jenkins, May 2006, Public Domain. + * + * These are functions for producing 32-bit hashes for hash table lookup. + * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final() + * 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's in + * the public domain. It has no warranty. + * + * $FreeBSD$ + */ + +#define rot(x, k) (((x) << (k)) | ((x) >> (32-(k)))) + +/** @internal Internal function. NOTE: Arguments are modified. */ +#define __rte_jhash_mix(a, b, c) do { \ + a -= c; a ^= rot(c, 4); c += b; \ + b -= a; b ^= rot(a, 6); a += c; \ + c -= b; c ^= rot(b, 8); b += a; \ + a -= c; a ^= rot(c, 16); c += b; \ + b -= a; b ^= rot(a, 19); a += c; \ + c -= b; c ^= rot(b, 4); b += a; \ +} while (0) + +#define __rte_jhash_final(a, b, c) do { \ + c ^= b; c -= rot(b, 14); \ + a ^= c; a -= rot(c, 11); \ + b ^= a; b -= rot(a, 25); \ + c ^= b; c -= rot(b, 16); \ + a ^= c; a -= rot(c, 4); \ + b ^= a; b -= rot(a, 14); \ + c ^= b; c -= rot(b, 24); \ +} while (0) + +/** The golden ratio: an arbitrary value. */ +#define RTE_JHASH_GOLDEN_RATIO 0xdeadbeef + +#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN +#define BIT_SHIFT(x, y, k) (((x) >> (k)) | ((uint64_t)(y) << (32-(k)))) +#else +#define BIT_SHIFT(x, y, k) (((uint64_t)(x) << (k)) | ((y) >> (32-(k)))) +#endif + +#define LOWER8b_MASK rte_le_to_cpu_32(0xff) +#define LOWER16b_MASK rte_le_to_cpu_32(0xffff) +#define LOWER24b_MASK rte_le_to_cpu_32(0xffffff) + +static inline void +__rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc, + uint32_t *pb, unsigned check_align) +{ + uint32_t a, b, c; + + /* Set up the internal state */ + a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + *pc; + c += *pb; + + /* + * Check key alignment. For x86 architecture, first case is always optimal + * If check_align is not set, first case will be used + */ +#if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32) + const uint32_t *k = (const uint32_t *)key; + const uint32_t s = 0; +#else + const uint32_t *k = (uint32_t *)((uintptr_t)key & (uintptr_t)~3); + const uint32_t s = ((uintptr_t)key & 3) * CHAR_BIT; +#endif + if (!check_align || s == 0) { + while (length > 12) { + a += k[0]; + b += k[1]; + c += k[2]; + + __rte_jhash_mix(a, b, c); + + k += 3; + length -= 12; + } + + switch (length) { + case 12: + c += k[2]; b += k[1]; a += k[0]; break; + case 11: + c += k[2] & LOWER24b_MASK; b += k[1]; a += k[0]; break; + case 10: + c += k[2] & LOWER16b_MASK; b += k[1]; a += k[0]; break; + case 9: + c += k[2] & LOWER8b_MASK; b += k[1]; a += k[0]; break; + case 8: + b += k[1]; a += k[0]; break; + case 7: + b += k[1] & LOWER24b_MASK; a += k[0]; break; + case 6: + b += k[1] & LOWER16b_MASK; a += k[0]; break; + case 5: + b += k[1] & LOWER8b_MASK; a += k[0]; break; + case 4: + a += k[0]; break; + case 3: + a += k[0] & LOWER24b_MASK; break; + case 2: + a += k[0] & LOWER16b_MASK; break; + case 1: + a += k[0] & LOWER8b_MASK; break; + /* zero length strings require no mixing */ + case 0: + *pc = c; + *pb = b; + return; + }; + } else { + /* all but the last block: affect some 32 bits of (a, b, c) */ + while (length > 12) { + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s); + c += BIT_SHIFT(k[2], k[3], s); + __rte_jhash_mix(a, b, c); + + k += 3; + length -= 12; + } + + /* last block: affect all 32 bits of (c) */ + switch (length) { + case 12: + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s); + c += BIT_SHIFT(k[2], k[3], s); + break; + case 11: + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s); + c += BIT_SHIFT(k[2], k[3], s) & LOWER24b_MASK; + break; + case 10: + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s); + c += BIT_SHIFT(k[2], k[3], s) & LOWER16b_MASK; + break; + case 9: + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s); + c += BIT_SHIFT(k[2], k[3], s) & LOWER8b_MASK; + break; + case 8: + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s); + break; + case 7: + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s) & LOWER24b_MASK; + break; + case 6: + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s) & LOWER16b_MASK; + break; + case 5: + a += BIT_SHIFT(k[0], k[1], s); + b += BIT_SHIFT(k[1], k[2], s) & LOWER8b_MASK; + break; + case 4: + a += BIT_SHIFT(k[0], k[1], s); + break; + case 3: + a += BIT_SHIFT(k[0], k[1], s) & LOWER24b_MASK; + break; + case 2: + a += BIT_SHIFT(k[0], k[1], s) & LOWER16b_MASK; + break; + case 1: + a += BIT_SHIFT(k[0], k[1], s) & LOWER8b_MASK; + break; + /* zero length strings require no mixing */ + case 0: + *pc = c; + *pb = b; + return; + } + } + + __rte_jhash_final(a, b, c); + + *pc = c; + *pb = b; +} + +/** + * Same as rte_jhash, but takes two seeds and return two uint32_ts. + * pc and pb must be non-null, and *pc and *pb must both be initialized + * with seeds. If you pass in (*pb)=0, the output (*pc) will be + * the same as the return value from rte_jhash. + * + * @param key + * Key to calculate hash of. + * @param length + * Length of key in bytes. + * @param pc + * IN: seed OUT: primary hash value. + * @param pb + * IN: second seed OUT: secondary hash value. + */ +static inline void +rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc, uint32_t *pb) +{ + __rte_jhash_2hashes(key, length, pc, pb, 1); +} + +/** + * Same as rte_jhash_32b, but takes two seeds and return two uint32_ts. + * pc and pb must be non-null, and *pc and *pb must both be initialized + * with seeds. If you pass in (*pb)=0, the output (*pc) will be + * the same as the return value from rte_jhash_32b. + * + * @param k + * Key to calculate hash of. + * @param length + * Length of key in units of 4 bytes. + * @param pc + * IN: seed OUT: primary hash value. + * @param pb + * IN: second seed OUT: secondary hash value. + */ +static inline void +rte_jhash_32b_2hashes(const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t *pb) +{ + __rte_jhash_2hashes((const void *) k, (length << 2), pc, pb, 0); +} + +/** + * 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 initval2 = 0; + + rte_jhash_2hashes(key, length, &initval, &initval2); + + return initval; +} + +/** + * 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_jhash_32b(const uint32_t *k, uint32_t length, uint32_t initval) +{ + uint32_t initval2 = 0; + + rte_jhash_32b_2hashes(k, length, &initval, &initval2); + + return initval; +} + +static inline uint32_t +__rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval) +{ + a += RTE_JHASH_GOLDEN_RATIO + initval; + b += RTE_JHASH_GOLDEN_RATIO + initval; + c += RTE_JHASH_GOLDEN_RATIO + initval; + + __rte_jhash_final(a, b, c); + + return c; +} + +/** + * A special ultra-optimized versions that knows it is hashing exactly + * 3 words. + * + * @param a + * First word to calculate hash of. + * @param b + * Second word to calculate hash of. + * @param c + * Third word to calculate 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) +{ + return __rte_jhash_3words(a + 12, b + 12, c + 12, initval); +} + +/** + * A special ultra-optimized versions that knows it is hashing exactly + * 2 words. + * + * @param a + * First word to calculate hash of. + * @param b + * Second word to calculate 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 + 8, b + 8, 8, initval); +} + +/** + * A special ultra-optimized versions that knows it is hashing exactly + * 1 word. + * + * @param a + * Word to calculate 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 + 4, 4, 4, initval); +} + +#ifdef __cplusplus +} +#endif + +#endif /* _RTE_JHASH_H */ |