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- /*
- * Copyright (c) 2016-2018 Positive Technologies, https://www.ptsecurity.com,
- * Fast Positive Hash.
- *
- * Portions Copyright (c) 2010-2018 Leonid Yuriev <leo@yuriev.ru>,
- * The 1Hippeus project (t1h).
- *
- * This software is provided 'as-is', without any express or implied
- * warranty. In no event will the authors be held liable for any damages
- * arising from the use of this software.
- *
- * Permission is granted to anyone to use this software for any purpose,
- * including commercial applications, and to alter it and redistribute it
- * freely, subject to the following restrictions:
- *
- * 1. The origin of this software must not be misrepresented; you must not
- * claim that you wrote the original software. If you use this software
- * in a product, an acknowledgement in the product documentation would be
- * appreciated but is not required.
- * 2. Altered source versions must be plainly marked as such, and must not be
- * misrepresented as being the original software.
- * 3. This notice may not be removed or altered from any source distribution.
- */
-
- /*
- * t1ha = { Fast Positive Hash, aka "Позитивный Хэш" }
- * by [Positive Technologies](https://www.ptsecurity.ru)
- *
- * Briefly, it is a 64-bit Hash Function:
- * 1. Created for 64-bit little-endian platforms, in predominantly for x86_64,
- * but portable and without penalties it can run on any 64-bit CPU.
- * 2. In most cases up to 15% faster than City64, xxHash, mum-hash, metro-hash
- * and all others portable hash-functions (which do not use specific
- * hardware tricks).
- * 3. Not suitable for cryptography.
- *
- * The Future will Positive. Всё будет хорошо.
- *
- * ACKNOWLEDGEMENT:
- * The t1ha was originally developed by Leonid Yuriev (Леонид Юрьев)
- * for The 1Hippeus project - zerocopy messaging in the spirit of Sparta!
- */
-
- #include "config.h"
- #include "t1ha_bits.h"
-
- /* xor-mul-xor mixer */
- static __inline uint64_t mix64(uint64_t v, uint64_t p) {
- v *= p;
- return v ^ rot64(v, 41);
- }
-
- static __inline uint64_t final_weak_avalanche(uint64_t a, uint64_t b) {
- /* LY: for performance reason on a some not high-end CPUs
- * I replaced the second mux64() operation by mix64().
- * Unfortunately this approach fails the "strict avalanche criteria",
- * see test results at https://github.com/demerphq/smhasher. */
- return mux64(rot64(a + b, 17), prime_4) + mix64(a ^ b, prime_0);
- }
-
- /* TODO: C++ template in the next version */
- #define T1HA1_BODY(ENDIANNES, ALIGNESS) \
- const uint64_t *v = (const uint64_t *)data; \
- if (unlikely(len > 32)) { \
- uint64_t c = rot64(len, 17) + seed; \
- uint64_t d = len ^ rot64(seed, 17); \
- const uint64_t *detent = \
- (const uint64_t *)((const uint8_t *)data + len - 31); \
- do { \
- const uint64_t w0 = fetch64_##ENDIANNES##_##ALIGNESS(v + 0); \
- const uint64_t w1 = fetch64_##ENDIANNES##_##ALIGNESS(v + 1); \
- const uint64_t w2 = fetch64_##ENDIANNES##_##ALIGNESS(v + 2); \
- const uint64_t w3 = fetch64_##ENDIANNES##_##ALIGNESS(v + 3); \
- v += 4; \
- prefetch(v); \
- \
- const uint64_t d02 = w0 ^ rot64(w2 + d, 17); \
- const uint64_t c13 = w1 ^ rot64(w3 + c, 17); \
- c += a ^ rot64(w0, 41); \
- d -= b ^ rot64(w1, 31); \
- a ^= prime_1 * (d02 + w3); \
- b ^= prime_0 * (c13 + w2); \
- } while (likely(v < detent)); \
- \
- a ^= prime_6 * (rot64(c, 17) + d); \
- b ^= prime_5 * (c + rot64(d, 17)); \
- len &= 31; \
- } \
- \
- switch (len) { \
- default: \
- b += mux64(fetch64_##ENDIANNES##_##ALIGNESS(v++), prime_4); \
- /* fall through */ \
- case 24: \
- case 23: \
- case 22: \
- case 21: \
- case 20: \
- case 19: \
- case 18: \
- case 17: \
- a += mux64(fetch64_##ENDIANNES##_##ALIGNESS(v++), prime_3); \
- /* fall through */ \
- case 16: \
- case 15: \
- case 14: \
- case 13: \
- case 12: \
- case 11: \
- case 10: \
- case 9: \
- b += mux64(fetch64_##ENDIANNES##_##ALIGNESS(v++), prime_2); \
- /* fall through */ \
- case 8: \
- case 7: \
- case 6: \
- case 5: \
- case 4: \
- case 3: \
- case 2: \
- case 1: \
- a += mux64(tail64_##ENDIANNES##_##ALIGNESS(v, len), prime_1); \
- /* fall through */ \
- case 0: \
- return final_weak_avalanche(a, b); \
- }
-
- uint64_t t1ha1_le(const void *data, size_t len, uint64_t seed) {
- uint64_t a = seed;
- uint64_t b = len;
-
- #if T1HA_CONFIG_UNALIGNED_ACCESS == T1HA_CONFIG_UNALIGNED_ACCESS__EFFICIENT
- T1HA1_BODY(le, unaligned);
- #else
- const bool misaligned = (((uintptr_t)data) & (ALIGNMENT_64 - 1)) != 0;
- if (misaligned) {
- T1HA1_BODY(le, unaligned);
- } else {
- T1HA1_BODY(le, aligned);
- }
- #endif
- }
-
- uint64_t t1ha1_be(const void *data, size_t len, uint64_t seed) {
- uint64_t a = seed;
- uint64_t b = len;
-
- #if T1HA_CONFIG_UNALIGNED_ACCESS == T1HA_CONFIG_UNALIGNED_ACCESS__EFFICIENT
- T1HA1_BODY(be, unaligned);
- #else
- const bool misaligned = (((uintptr_t)data) & (ALIGNMENT_64 - 1)) != 0;
- if (misaligned) {
- T1HA1_BODY(be, unaligned);
- } else {
- T1HA1_BODY(be, aligned);
- }
- #endif
- }
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