Add MurmurHash3_x64_128 implementation

Sources:
92cf3702fc/src/MurmurHash3.h
92cf3702fc/src/MurmurHash3.cpp

Other hash functions and unused implementation details are removed.

extern/CMakeLists.txt

@@ -208,3 +208,5 @@ if (NOT OPENMW_USE_SYSTEM_SQLITE3)
     set(SQLite3_INCLUDE_DIR ${sqlite3_SOURCE_DIR}/ PARENT_SCOPE)
     set(SQLite3_LIBRARY sqlite3 PARENT_SCOPE)
 endif()
+
+add_subdirectory(smhasher)

extern/smhasher/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_library(smhasher STATIC MurmurHash3.cpp)
+target_include_directories(smhasher INTERFACE .)

extern/smhasher/MurmurHash3.cpp

@@ -0,0 +1,148 @@
+//-----------------------------------------------------------------------------
+// MurmurHash3 was written by Austin Appleby, and is placed in the public
+// domain. The author hereby disclaims copyright to this source code.
+
+// Note - The x86 and x64 versions do _not_ produce the same results, as the
+// algorithms are optimized for their respective platforms. You can still
+// compile and run any of them on any platform, but your performance with the
+// non-native version will be less than optimal.
+
+#include "MurmurHash3.h"
+
+//-----------------------------------------------------------------------------
+// Platform-specific functions and macros
+
+// Microsoft Visual Studio
+
+#if defined(_MSC_VER)
+
+#define FORCE_INLINE	__forceinline
+
+#include <stdlib.h>
+
+#define ROTL64(x,y)	_rotl64(x,y)
+
+#define BIG_CONSTANT(x) (x)
+
+// Other compilers
+
+#else	// defined(_MSC_VER)
+
+#define	FORCE_INLINE inline __attribute__((always_inline))
+
+inline uint64_t rotl64 ( uint64_t x, int8_t r )
+{
+  return (x << r) | (x >> (64 - r));
+}
+
+#define ROTL64(x,y)	rotl64(x,y)
+
+#define BIG_CONSTANT(x) (x##LLU)
+
+#endif // !defined(_MSC_VER)
+
+//-----------------------------------------------------------------------------
+// Block read - if your platform needs to do endian-swapping or can only
+// handle aligned reads, do the conversion here
+
+FORCE_INLINE uint64_t getblock64 ( const uint64_t * p, int i )
+{
+  return p[i];
+}
+
+//----------
+
+FORCE_INLINE uint64_t fmix64 ( uint64_t k )
+{
+  k ^= k >> 33;
+  k *= BIG_CONSTANT(0xff51afd7ed558ccd);
+  k ^= k >> 33;
+  k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
+  k ^= k >> 33;
+
+  return k;
+}
+
+//-----------------------------------------------------------------------------
+
+void MurmurHash3_x64_128 ( const void * key, const int len,
+                           const uint32_t seed, void * out )
+{
+  const uint8_t * data = (const uint8_t*)key;
+  const int nblocks = len / 16;
+
+  uint64_t h1 = seed;
+  uint64_t h2 = seed;
+
+  const uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
+  const uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);
+
+  //----------
+  // body
+
+  const uint64_t * blocks = (const uint64_t *)(data);
+
+  for(int i = 0; i < nblocks; i++)
+  {
+    uint64_t k1 = getblock64(blocks,i*2+0);
+    uint64_t k2 = getblock64(blocks,i*2+1);
+
+    k1 *= c1; k1  = ROTL64(k1,31); k1 *= c2; h1 ^= k1;
+
+    h1 = ROTL64(h1,27); h1 += h2; h1 = h1*5+0x52dce729;
+
+    k2 *= c2; k2  = ROTL64(k2,33); k2 *= c1; h2 ^= k2;
+
+    h2 = ROTL64(h2,31); h2 += h1; h2 = h2*5+0x38495ab5;
+  }
+
+  //----------
+  // tail
+
+  const uint8_t * tail = (const uint8_t*)(data + nblocks*16);
+
+  uint64_t k1 = 0;
+  uint64_t k2 = 0;
+
+  switch(len & 15)
+  {
+  case 15: k2 ^= ((uint64_t)tail[14]) << 48;
+  case 14: k2 ^= ((uint64_t)tail[13]) << 40;
+  case 13: k2 ^= ((uint64_t)tail[12]) << 32;
+  case 12: k2 ^= ((uint64_t)tail[11]) << 24;
+  case 11: k2 ^= ((uint64_t)tail[10]) << 16;
+  case 10: k2 ^= ((uint64_t)tail[ 9]) << 8;
+  case  9: k2 ^= ((uint64_t)tail[ 8]) << 0;
+           k2 *= c2; k2  = ROTL64(k2,33); k2 *= c1; h2 ^= k2;
+
+  case  8: k1 ^= ((uint64_t)tail[ 7]) << 56;
+  case  7: k1 ^= ((uint64_t)tail[ 6]) << 48;
+  case  6: k1 ^= ((uint64_t)tail[ 5]) << 40;
+  case  5: k1 ^= ((uint64_t)tail[ 4]) << 32;
+  case  4: k1 ^= ((uint64_t)tail[ 3]) << 24;
+  case  3: k1 ^= ((uint64_t)tail[ 2]) << 16;
+  case  2: k1 ^= ((uint64_t)tail[ 1]) << 8;
+  case  1: k1 ^= ((uint64_t)tail[ 0]) << 0;
+           k1 *= c1; k1  = ROTL64(k1,31); k1 *= c2; h1 ^= k1;
+  };
+
+  //----------
+  // finalization
+
+  h1 ^= len; h2 ^= len;
+
+  h1 += h2;
+  h2 += h1;
+
+  h1 = fmix64(h1);
+  h2 = fmix64(h2);
+
+  h1 += h2;
+  h2 += h1;
+
+  ((uint64_t*)out)[0] = h1;
+  ((uint64_t*)out)[1] = h2;
+}
+
+//-----------------------------------------------------------------------------
+

extern/smhasher/MurmurHash3.h

@@ -0,0 +1,33 @@
+//-----------------------------------------------------------------------------
+// MurmurHash3 was written by Austin Appleby, and is placed in the public
+// domain. The author hereby disclaims copyright to this source code.
+
+#ifndef _MURMURHASH3_H_
+#define _MURMURHASH3_H_
+
+//-----------------------------------------------------------------------------
+// Platform-specific functions and macros
+
+// Microsoft Visual Studio
+
+#if defined(_MSC_VER) && (_MSC_VER < 1600)
+
+typedef unsigned char uint8_t;
+typedef unsigned int uint32_t;
+typedef unsigned __int64 uint64_t;
+
+// Other compilers
+
+#else	// defined(_MSC_VER)
+
+#include <stdint.h>
+
+#endif // !defined(_MSC_VER)
+
+//-----------------------------------------------------------------------------
+
+void MurmurHash3_x64_128 ( const void * key, int len, uint32_t seed, void * out );
+
+//-----------------------------------------------------------------------------
+
+#endif // _MURMURHASH3_H_