| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef LIBTEXTCLASSIFIER_UTIL_HASH_FARMHASH_H_ |
| #define LIBTEXTCLASSIFIER_UTIL_HASH_FARMHASH_H_ |
| |
| #include <assert.h> |
| #include <stdint.h> |
| #include <stdlib.h> |
| #include <string.h> // for memcpy and memset |
| #include <utility> |
| |
| #ifndef NAMESPACE_FOR_HASH_FUNCTIONS |
| #define NAMESPACE_FOR_HASH_FUNCTIONS tc2farmhash |
| #endif |
| |
| namespace NAMESPACE_FOR_HASH_FUNCTIONS { |
| |
| #if defined(FARMHASH_UINT128_T_DEFINED) |
| inline uint64_t Uint128Low64(const uint128_t x) { |
| return static_cast<uint64_t>(x); |
| } |
| inline uint64_t Uint128High64(const uint128_t x) { |
| return static_cast<uint64_t>(x >> 64); |
| } |
| inline uint128_t Uint128(uint64_t lo, uint64_t hi) { |
| return lo + (((uint128_t)hi) << 64); |
| } |
| #else |
| typedef std::pair<uint64_t, uint64_t> uint128_t; |
| inline uint64_t Uint128Low64(const uint128_t x) { return x.first; } |
| inline uint64_t Uint128High64(const uint128_t x) { return x.second; } |
| inline uint128_t Uint128(uint64_t lo, uint64_t hi) { return uint128_t(lo, hi); } |
| #endif |
| |
| |
| // BASIC STRING HASHING |
| |
| // Hash function for a byte array. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| size_t Hash(const char* s, size_t len); |
| |
| // Hash function for a byte array. Most useful in 32-bit binaries. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| uint32_t Hash32(const char* s, size_t len); |
| |
| // Hash function for a byte array. For convenience, a 32-bit seed is also |
| // hashed into the result. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| uint32_t Hash32WithSeed(const char* s, size_t len, uint32_t seed); |
| |
| // Hash 128 input bits down to 64 bits of output. |
| // Hash function for a byte array. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| uint64_t Hash64(const char* s, size_t len); |
| |
| // Hash function for a byte array. For convenience, a 64-bit seed is also |
| // hashed into the result. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| uint64_t Hash64WithSeed(const char* s, size_t len, uint64_t seed); |
| |
| // Hash function for a byte array. For convenience, two seeds are also |
| // hashed into the result. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| uint64_t Hash64WithSeeds(const char* s, size_t len, |
| uint64_t seed0, uint64_t seed1); |
| |
| // Hash function for a byte array. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| uint128_t Hash128(const char* s, size_t len); |
| |
| // Hash function for a byte array. For convenience, a 128-bit seed is also |
| // hashed into the result. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| uint128_t Hash128WithSeed(const char* s, size_t len, uint128_t seed); |
| |
| // BASIC NON-STRING HASHING |
| |
| // This is intended to be a reasonably good hash function. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| inline uint64_t Hash128to64(uint128_t x) { |
| // Murmur-inspired hashing. |
| const uint64_t kMul = 0x9ddfea08eb382d69ULL; |
| uint64_t a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul; |
| a ^= (a >> 47); |
| uint64_t b = (Uint128High64(x) ^ a) * kMul; |
| b ^= (b >> 47); |
| b *= kMul; |
| return b; |
| } |
| |
| // FINGERPRINTING (i.e., good, portable, forever-fixed hash functions) |
| |
| // Fingerprint function for a byte array. Most useful in 32-bit binaries. |
| uint32_t Fingerprint32(const char* s, size_t len); |
| |
| // Fingerprint function for a byte array. |
| uint64_t Fingerprint64(const char* s, size_t len); |
| |
| // Fingerprint function for a byte array. |
| uint128_t Fingerprint128(const char* s, size_t len); |
| |
| // This is intended to be a good fingerprinting primitive. |
| // See below for more overloads. |
| inline uint64_t Fingerprint(uint128_t x) { |
| // Murmur-inspired hashing. |
| const uint64_t kMul = 0x9ddfea08eb382d69ULL; |
| uint64_t a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul; |
| a ^= (a >> 47); |
| uint64_t b = (Uint128High64(x) ^ a) * kMul; |
| b ^= (b >> 44); |
| b *= kMul; |
| b ^= (b >> 41); |
| b *= kMul; |
| return b; |
| } |
| |
| // This is intended to be a good fingerprinting primitive. |
| inline uint64_t Fingerprint(uint64_t x) { |
| // Murmur-inspired hashing. |
| const uint64_t kMul = 0x9ddfea08eb382d69ULL; |
| uint64_t b = x * kMul; |
| b ^= (b >> 44); |
| b *= kMul; |
| b ^= (b >> 41); |
| b *= kMul; |
| return b; |
| } |
| |
| #ifndef FARMHASH_NO_CXX_STRING |
| |
| // Convenience functions to hash or fingerprint C++ strings. |
| // These require that Str::data() return a pointer to the first char |
| // (as a const char*) and that Str::length() return the string's length; |
| // they work with std::string, for example. |
| |
| // Hash function for a byte array. Most useful in 32-bit binaries. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| template <typename Str> |
| inline size_t Hash(const Str& s) { |
| assert(sizeof(s[0]) == 1); |
| return Hash(s.data(), s.length()); |
| } |
| |
| // Hash function for a byte array. Most useful in 32-bit binaries. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| template <typename Str> |
| inline uint32_t Hash32(const Str& s) { |
| assert(sizeof(s[0]) == 1); |
| return Hash32(s.data(), s.length()); |
| } |
| |
| // Hash function for a byte array. For convenience, a 32-bit seed is also |
| // hashed into the result. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| template <typename Str> |
| inline uint32_t Hash32WithSeed(const Str& s, uint32_t seed) { |
| assert(sizeof(s[0]) == 1); |
| return Hash32WithSeed(s.data(), s.length(), seed); |
| } |
| |
| // Hash 128 input bits down to 64 bits of output. |
| // Hash function for a byte array. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| template <typename Str> |
| inline uint64_t Hash64(const Str& s) { |
| assert(sizeof(s[0]) == 1); |
| return Hash64(s.data(), s.length()); |
| } |
| |
| // Hash function for a byte array. For convenience, a 64-bit seed is also |
| // hashed into the result. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| template <typename Str> |
| inline uint64_t Hash64WithSeed(const Str& s, uint64_t seed) { |
| assert(sizeof(s[0]) == 1); |
| return Hash64WithSeed(s.data(), s.length(), seed); |
| } |
| |
| // Hash function for a byte array. For convenience, two seeds are also |
| // hashed into the result. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| template <typename Str> |
| inline uint64_t Hash64WithSeeds(const Str& s, uint64_t seed0, uint64_t seed1) { |
| assert(sizeof(s[0]) == 1); |
| return Hash64WithSeeds(s.data(), s.length(), seed0, seed1); |
| } |
| |
| // Hash function for a byte array. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| template <typename Str> |
| inline uint128_t Hash128(const Str& s) { |
| assert(sizeof(s[0]) == 1); |
| return Hash128(s.data(), s.length()); |
| } |
| |
| // Hash function for a byte array. For convenience, a 128-bit seed is also |
| // hashed into the result. |
| // May change from time to time, may differ on different platforms, may differ |
| // depending on NDEBUG. |
| template <typename Str> |
| inline uint128_t Hash128WithSeed(const Str& s, uint128_t seed) { |
| assert(sizeof(s[0]) == 1); |
| return Hash128(s.data(), s.length(), seed); |
| } |
| |
| // FINGERPRINTING (i.e., good, portable, forever-fixed hash functions) |
| |
| // Fingerprint function for a byte array. Most useful in 32-bit binaries. |
| template <typename Str> |
| inline uint32_t Fingerprint32(const Str& s) { |
| assert(sizeof(s[0]) == 1); |
| return Fingerprint32(s.data(), s.length()); |
| } |
| |
| // Fingerprint 128 input bits down to 64 bits of output. |
| // Fingerprint function for a byte array. |
| template <typename Str> |
| inline uint64_t Fingerprint64(const Str& s) { |
| assert(sizeof(s[0]) == 1); |
| return Fingerprint64(s.data(), s.length()); |
| } |
| |
| // Fingerprint function for a byte array. |
| template <typename Str> |
| inline uint128_t Fingerprint128(const Str& s) { |
| assert(sizeof(s[0]) == 1); |
| return Fingerprint128(s.data(), s.length()); |
| } |
| |
| #endif |
| |
| } // namespace NAMESPACE_FOR_HASH_FUNCTIONS |
| |
| #endif // LIBTEXTCLASSIFIER_UTIL_HASH_FARMHASH_H_ |