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[toc] / antlr4-cpp-runtime-4.9.2-source / runtime / src / misc / MurmurHash.cpp

diff --git a/antlr4-cpp-runtime-4.9.2-source/runtime/src/misc/MurmurHash.cpp b/antlr4-cpp-runtime-4.9.2-source/runtime/src/misc/MurmurHash.cpp
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+++ b/antlr4-cpp-runtime-4.9.2-source/runtime/src/misc/MurmurHash.cpp
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+/* 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