MurmurHash/MurmurHash3.cpp

   1 //-----------------------------------------------------------------------------
   2 // MurmurHash3 was written by Austin Appleby, and is placed in the public
   3 // domain. The author hereby disclaims copyright to this source code.
   4
   5 // Note - The x86 and x64 versions do _not_ produce the same results, as the
   6 // algorithms are optimized for their respective platforms. You can still
   7 // compile and run any of them on any platform, but your performance with the
   8 // non-native version will be less than optimal.
   9
  10 #include "MurmurHash3.h"
  11
  12 //-----------------------------------------------------------------------------
  13 // Platform-specific functions and macros
  14
  15 // Microsoft Visual Studio
  16
  17 #if defined(_MSC_VER)
  18
  19 #define FORCE_INLINE    __forceinline
  20
  21 #include <stdlib.h>
  22
  23 #define ROTL32(x,y)     _rotl(x,y)
  24 #define ROTL64(x,y)     _rotl64(x,y)
  25
  26 #define BIG_CONSTANT(x) (x)
  27
  28 // Other compilers
  29
  30 #else   // defined(_MSC_VER)
  31
  32 #define FORCE_INLINE __attribute__((always_inline))
  33
  34 inline uint32_t rotl32 ( uint32_t x, int8_t r )
  35 {
  36   return (x << r) | (x >> (32 - r));
  37 }
  38
  39 inline uint64_t rotl64 ( uint64_t x, int8_t r )
  40 {
  41   return (x << r) | (x >> (64 - r));
  42 }
  43
  44 #define ROTL32(x,y)     rotl32(x,y)
  45 #define ROTL64(x,y)     rotl64(x,y)
  46
  47 #define BIG_CONSTANT(x) (x##LLU)
  48
  49 #endif // !defined(_MSC_VER)
  50
  51 //-----------------------------------------------------------------------------
  52 // Block read - if your platform needs to do endian-swapping or can only
  53 // handle aligned reads, do the conversion here
  54
  55 FORCE_INLINE uint32_t getblock ( const uint32_t * p, int i )
  56 {
  57   return p[i];
  58 }
  59
  60 FORCE_INLINE uint64_t getblock ( const uint64_t * p, int i )
  61 {
  62   return p[i];
  63 }
  64
  65 //-----------------------------------------------------------------------------
  66 // Finalization mix - force all bits of a hash block to avalanche
  67
  68 FORCE_INLINE uint32_t fmix ( uint32_t h )
  69 {
  70   h ^= h >> 16;
  71   h *= 0x85ebca6b;
  72   h ^= h >> 13;
  73   h *= 0xc2b2ae35;
  74   h ^= h >> 16;
  75
  76   return h;
  77 }
  78
  79 //----------
  80
  81 FORCE_INLINE uint64_t fmix ( uint64_t k )
  82 {
  83   k ^= k >> 33;
  84   k *= BIG_CONSTANT(0xff51afd7ed558ccd);
  85   k ^= k >> 33;
  86   k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
  87   k ^= k >> 33;
  88
  89   return k;
  90 }
  91
  92 //-----------------------------------------------------------------------------
  93
  94 void MurmurHash3_x86_32 ( const void * key, int len,
  95                           uint32_t seed, void * out )
  96 {
  97   const uint8_t * data = (const uint8_t*)key;
  98   const int nblocks = len / 4;
  99
 100   uint32_t h1 = seed;
 101
 102   uint32_t c1 = 0xcc9e2d51;
 103   uint32_t c2 = 0x1b873593;
 104
 105   //----------
 106   // body
 107
 108   const uint32_t * blocks = (const uint32_t *)(data + nblocks*4);
 109
 110   for(int i = -nblocks; i; i++)
 111   {
 112     uint32_t k1 = getblock(blocks,i);
 113
 114     k1 *= c1;
 115     k1 = ROTL32(k1,15);
 116     k1 *= c2;
 117
 118     h1 ^= k1;
 119     h1 = ROTL32(h1,13);
 120     h1 = h1*5+0xe6546b64;
 121   }
 122
 123   //----------
 124   // tail
 125
 126   const uint8_t * tail = (const uint8_t*)(data + nblocks*4);
 127
 128   uint32_t k1 = 0;
 129
 130   switch(len & 3)
 131   {
 132   case 3: k1 ^= tail[2] << 16;
 133   case 2: k1 ^= tail[1] << 8;
 134   case 1: k1 ^= tail[0];
 135           k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
 136   };
 137
 138   //----------
 139   // finalization
 140
 141   h1 ^= len;
 142
 143   h1 = fmix(h1);
 144
 145   *(uint32_t*)out = h1;
 146 }
 147
 148 //-----------------------------------------------------------------------------
 149
 150 void MurmurHash3_x86_128 ( const void * key, const int len,
 151                            uint32_t seed, void * out )
 152 {
 153   const uint8_t * data = (const uint8_t*)key;
 154   const int nblocks = len / 16;
 155
 156   uint32_t h1 = seed;
 157   uint32_t h2 = seed;
 158   uint32_t h3 = seed;
 159   uint32_t h4 = seed;
 160
 161   uint32_t c1 = 0x239b961b;
 162   uint32_t c2 = 0xab0e9789;
 163   uint32_t c3 = 0x38b34ae5;
 164   uint32_t c4 = 0xa1e38b93;
 165
 166   //----------
 167   // body
 168
 169   const uint32_t * blocks = (const uint32_t *)(data + nblocks*16);
 170
 171   for(int i = -nblocks; i; i++)
 172   {
 173     uint32_t k1 = getblock(blocks,i*4+0);
 174     uint32_t k2 = getblock(blocks,i*4+1);
 175     uint32_t k3 = getblock(blocks,i*4+2);
 176     uint32_t k4 = getblock(blocks,i*4+3);
 177
 178     k1 *= c1; k1  = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
 179
 180     h1 = ROTL32(h1,19); h1 += h2; h1 = h1*5+0x561ccd1b;
 181
 182     k2 *= c2; k2  = ROTL32(k2,16); k2 *= c3; h2 ^= k2;
 183
 184     h2 = ROTL32(h2,17); h2 += h3; h2 = h2*5+0x0bcaa747;
 185
 186     k3 *= c3; k3  = ROTL32(k3,17); k3 *= c4; h3 ^= k3;
 187
 188     h3 = ROTL32(h3,15); h3 += h4; h3 = h3*5+0x96cd1c35;
 189
 190     k4 *= c4; k4  = ROTL32(k4,18); k4 *= c1; h4 ^= k4;
 191
 192     h4 = ROTL32(h4,13); h4 += h1; h4 = h4*5+0x32ac3b17;
 193   }
 194
 195   //----------
 196   // tail
 197
 198   const uint8_t * tail = (const uint8_t*)(data + nblocks*16);
 199
 200   uint32_t k1 = 0;
 201   uint32_t k2 = 0;
 202   uint32_t k3 = 0;
 203   uint32_t k4 = 0;
 204
 205   switch(len & 15)
 206   {
 207   case 15: k4 ^= tail[14] << 16;
 208   case 14: k4 ^= tail[13] << 8;
 209   case 13: k4 ^= tail[12] << 0;
 210            k4 *= c4; k4  = ROTL32(k4,18); k4 *= c1; h4 ^= k4;
 211
 212   case 12: k3 ^= tail[11] << 24;
 213   case 11: k3 ^= tail[10] << 16;
 214   case 10: k3 ^= tail[ 9] << 8;
 215   case  9: k3 ^= tail[ 8] << 0;
 216            k3 *= c3; k3  = ROTL32(k3,17); k3 *= c4; h3 ^= k3;
 217
 218   case  8: k2 ^= tail[ 7] << 24;
 219   case  7: k2 ^= tail[ 6] << 16;
 220   case  6: k2 ^= tail[ 5] << 8;
 221   case  5: k2 ^= tail[ 4] << 0;
 222            k2 *= c2; k2  = ROTL32(k2,16); k2 *= c3; h2 ^= k2;
 223
 224   case  4: k1 ^= tail[ 3] << 24;
 225   case  3: k1 ^= tail[ 2] << 16;
 226   case  2: k1 ^= tail[ 1] << 8;
 227   case  1: k1 ^= tail[ 0] << 0;
 228            k1 *= c1; k1  = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
 229   };
 230
 231   //----------
 232   // finalization
 233
 234   h1 ^= len; h2 ^= len; h3 ^= len; h4 ^= len;
 235
 236   h1 += h2; h1 += h3; h1 += h4;
 237   h2 += h1; h3 += h1; h4 += h1;
 238
 239   h1 = fmix(h1);
 240   h2 = fmix(h2);
 241   h3 = fmix(h3);
 242   h4 = fmix(h4);
 243
 244   h1 += h2; h1 += h3; h1 += h4;
 245   h2 += h1; h3 += h1; h4 += h1;
 246
 247   ((uint32_t*)out)[0] = h1;
 248   ((uint32_t*)out)[1] = h2;
 249   ((uint32_t*)out)[2] = h3;
 250   ((uint32_t*)out)[3] = h4;
 251 }
 252
 253 //-----------------------------------------------------------------------------
 254
 255 void MurmurHash3_x64_128 ( const void * key, const int len,
 256                            const uint32_t seed, void * out )
 257 {
 258   const uint8_t * data = (const uint8_t*)key;
 259   const int nblocks = len / 16;
 260
 261   uint64_t h1 = seed;
 262   uint64_t h2 = seed;
 263
 264   uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
 265   uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);
 266
 267   //----------
 268   // body
 269
 270   const uint64_t * blocks = (const uint64_t *)(data);
 271
 272   for(int i = 0; i < nblocks; i++)
 273   {
 274     uint64_t k1 = getblock(blocks,i*2+0);
 275     uint64_t k2 = getblock(blocks,i*2+1);
 276
 277     k1 *= c1; k1  = ROTL64(k1,31); k1 *= c2; h1 ^= k1;
 278
 279     h1 = ROTL64(h1,27); h1 += h2; h1 = h1*5+0x52dce729;
 280
 281     k2 *= c2; k2  = ROTL64(k2,33); k2 *= c1; h2 ^= k2;
 282
 283     h2 = ROTL64(h2,31); h2 += h1; h2 = h2*5+0x38495ab5;
 284   }
 285
 286   //----------
 287   // tail
 288
 289   const uint8_t * tail = (const uint8_t*)(data + nblocks*16);
 290
 291   uint64_t k1 = 0;
 292   uint64_t k2 = 0;
 293
 294   switch(len & 15)
 295   {
 296   case 15: k2 ^= uint64_t(tail[14]) << 48;
 297   case 14: k2 ^= uint64_t(tail[13]) << 40;
 298   case 13: k2 ^= uint64_t(tail[12]) << 32;
 299   case 12: k2 ^= uint64_t(tail[11]) << 24;
 300   case 11: k2 ^= uint64_t(tail[10]) << 16;
 301   case 10: k2 ^= uint64_t(tail[ 9]) << 8;
 302   case  9: k2 ^= uint64_t(tail[ 8]) << 0;
 303            k2 *= c2; k2  = ROTL64(k2,33); k2 *= c1; h2 ^= k2;
 304
 305   case  8: k1 ^= uint64_t(tail[ 7]) << 56;
 306   case  7: k1 ^= uint64_t(tail[ 6]) << 48;
 307   case  6: k1 ^= uint64_t(tail[ 5]) << 40;
 308   case  5: k1 ^= uint64_t(tail[ 4]) << 32;
 309   case  4: k1 ^= uint64_t(tail[ 3]) << 24;
 310   case  3: k1 ^= uint64_t(tail[ 2]) << 16;
 311   case  2: k1 ^= uint64_t(tail[ 1]) << 8;
 312   case  1: k1 ^= uint64_t(tail[ 0]) << 0;
 313            k1 *= c1; k1  = ROTL64(k1,31); k1 *= c2; h1 ^= k1;
 314   };
 315
 316   //----------
 317   // finalization
 318
 319   h1 ^= len; h2 ^= len;
 320
 321   h1 += h2;
 322   h2 += h1;
 323
 324   h1 = fmix(h1);
 325   h2 = fmix(h2);
 326
 327   h1 += h2;
 328   h2 += h1;
 329
 330   ((uint64_t*)out)[0] = h1;
 331   ((uint64_t*)out)[1] = h2;
 332 }
 333
 334 //-----------------------------------------------------------------------------
 335