From: Pablo de Lara Date: Wed, 10 Jun 2015 15:25:24 +0000 (+0100) Subject: hash: add new jhash functions X-Git-Tag: spdx-start~9070 X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=8718219a8737;p=dpdk.git hash: add new jhash functions With the jhash update, two new functions were introduced: - rte_jhash_2hashes: Same as rte_jhash, but takes two seeds and return two hashes (uint32_ts) - rte_jhash2_2hashes: Same as rte_jhash2, but takes two seeds and return two hashes (uint32_ts) Signed-off-by: Pablo de Lara Acked-by: Bruce Richardson [Thomas: fix doxygen typos] --- diff --git a/lib/librte_hash/rte_jhash.h b/lib/librte_hash/rte_jhash.h index 1cb5c444be..62e276cc12 100644 --- a/lib/librte_hash/rte_jhash.h +++ b/lib/librte_hash/rte_jhash.h @@ -300,6 +300,215 @@ rte_jhash2(const uint32_t *k, uint32_t length, uint32_t initval) return c; } +/** + * 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) +{ + 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 defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32) + const uint32_t *k = 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 (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_jhash2, 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_jhash2. + * + * @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_jhash2_2hashes(const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t *pb) +{ + uint32_t a, b, c; + + /* Set up the internal state */ + a = b = c = RTE_JHASH_GOLDEN_RATIO + (((uint32_t)length) << 2) + *pc; + c += *pb; + + /* Handle most of the key */ + while (length > 3) { + a += k[0]; + b += k[1]; + c += k[2]; + + __rte_jhash_mix(a, b, c); + + k += 3; + length -= 3; + } + + /* Handle the last 3 uint32_t's */ + switch (length) { + case 3: + c += k[2]; + /* Fallthrough */ + case 2: + b += k[1]; + /* Fallthrough */ + case 1: + a += k[0]; + __rte_jhash_final(a, b, c); + /* Fallthrough */ + /* case 0: nothing left to add */ + case 0: + break; + }; + + *pc = c; + *pb = b; +} + static inline uint32_t __rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval) {