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Diffstat (limited to 'deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/misc/MurmurHash.cpp')
-rw-r--r-- | deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/misc/MurmurHash.cpp | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/misc/MurmurHash.cpp b/deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/misc/MurmurHash.cpp new file mode 100644 index 0000000000..d073079c5e --- /dev/null +++ b/deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/misc/MurmurHash.cpp @@ -0,0 +1,127 @@ +/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved. + * Use of this file is governed by the BSD 3-clause license that + * can be found in the LICENSE.txt file in the project root. + */ + +#include "misc/MurmurHash.h" + +using namespace antlr4::misc; + +// A variation of the MurmurHash3 implementation +// (https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp) Here +// we unrolled the loop used there into individual calls to update(), as we +// usually hash object fields instead of entire buffers. + +// Platform-specific functions and macros + +// Microsoft Visual Studio + +#if defined(_MSC_VER) + +#define FORCE_INLINE __forceinline + +#include <stdlib.h> + +#define ROTL32(x, y) _rotl(x, y) +#define ROTL64(x, y) _rotl64(x, y) + +#define BIG_CONSTANT(x) (x) + +#else // defined(_MSC_VER) + +// Other compilers + +#define FORCE_INLINE inline __attribute__((always_inline)) + +inline uint32_t rotl32(uint32_t x, int8_t r) { + return (x << r) | (x >> (32 - r)); +} + +inline uint64_t rotl64(uint64_t x, int8_t r) { + return (x << r) | (x >> (64 - r)); +} + +#define ROTL32(x, y) rotl32(x, y) +#define ROTL64(x, y) rotl64(x, y) + +#define BIG_CONSTANT(x) (x##LLU) + +#endif // !defined(_MSC_VER) + +size_t MurmurHash::initialize() { return initialize(DEFAULT_SEED); } + +size_t MurmurHash::initialize(size_t seed) { return seed; } + +#if defined(_WIN32) || defined(_WIN64) +#if _WIN64 +#define ENVIRONMENT64 +#else +#define ENVIRONMENT32 +#endif +#endif + +#if defined(__GNUC__) +#if defined(__x86_64__) || defined(__ppc64__) +#define ENVIRONMENT64 +#else +#define ENVIRONMENT32 +#endif +#endif + +#if defined(ENVIRONMENT32) + +size_t MurmurHash::update(size_t hash, size_t value) { + static const size_t c1 = 0xCC9E2D51; + static const size_t c2 = 0x1B873593; + + size_t k1 = value; + k1 *= c1; + k1 = ROTL32(k1, 15); + k1 *= c2; + + hash ^= k1; + hash = ROTL32(hash, 13); + hash = hash * 5 + 0xE6546B64; + + return hash; +} + +size_t MurmurHash::finish(size_t hash, size_t entryCount) { + hash ^= entryCount * 4; + hash ^= hash >> 16; + hash *= 0x85EBCA6B; + hash ^= hash >> 13; + hash *= 0xC2B2AE35; + hash ^= hash >> 16; + return hash; +} + +#else + +size_t MurmurHash::update(size_t hash, size_t value) { + static const size_t c1 = BIG_CONSTANT(0x87c37b91114253d5); + static const size_t c2 = BIG_CONSTANT(0x4cf5ad432745937f); + + size_t k1 = value; + k1 *= c1; + k1 = ROTL64(k1, 31); + k1 *= c2; + + hash ^= k1; + hash = ROTL64(hash, 27); + hash = hash * 5 + 0x52dce729; + + return hash; +} + +size_t MurmurHash::finish(size_t hash, size_t entryCount) { + hash ^= entryCount * 8; + hash ^= hash >> 33; + hash *= 0xff51afd7ed558ccd; + hash ^= hash >> 33; + hash *= 0xc4ceb9fe1a85ec53; + hash ^= hash >> 33; + return hash; +} + +#endif |