dom/canvas/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 namespace {
  13
  14 //-----------------------------------------------------------------------------
  15 // Platform-specific functions and macros
  16
  17 // Microsoft Visual Studio
  18
  19 #if defined(_MSC_VER)
  20
  21 #define FORCE_INLINE    __forceinline
  22
  23 #include <stdlib.h>
  24
  25 #define ROTL32(x,y)     _rotl(x,y)
  26 #define ROTL64(x,y)     _rotl64(x,y)
  27
  28 #define BIG_CONSTANT(x) (x)
  29
  30 // Other compilers
  31
  32 #else   // defined(_MSC_VER)
  33
  34 // We can't do always_inline, becasue -Werror -Wattribute will trigger
  35 // a "might not be able to inline" warning.
  36 //#define       FORCE_INLINE __attribute__((always_inline))
  37 #define FORCE_INLINE inline
  38
  39 inline uint32_t rotl32 ( uint32_t x, int8_t r )
  40 {
  41   return (x << r) | (x >> (32 - r));
  42 }
  43
  44 inline uint64_t rotl64 ( uint64_t x, int8_t r )
  45 {
  46   return (x << r) | (x >> (64 - r));
  47 }
  48
  49 #define ROTL32(x,y)     rotl32(x,y)
  50 #define ROTL64(x,y)     rotl64(x,y)
  51
  52 #define BIG_CONSTANT(x) (x##LLU)
  53
  54 #endif // !defined(_MSC_VER)
  55
  56 //-----------------------------------------------------------------------------
  57 // Block read - if your platform needs to do endian-swapping or can only
  58 // handle aligned reads, do the conversion here
  59
  60 FORCE_INLINE uint32_t getblock ( const uint32_t * p, int i )
  61 {
  62   return p[i];
  63 }
  64
  65 FORCE_INLINE uint64_t getblock ( const uint64_t * p, int i )
  66 {
  67   return p[i];
  68 }
  69
  70 //-----------------------------------------------------------------------------
  71 // Finalization mix - force all bits of a hash block to avalanche
  72
  73 FORCE_INLINE uint32_t fmix ( uint32_t h )
  74 {
  75   h ^= h >> 16;
  76   h *= 0x85ebca6b;
  77   h ^= h >> 13;
  78   h *= 0xc2b2ae35;
  79   h ^= h >> 16;
  80
  81   return h;
  82 }
  83
  84 //----------
  85
  86 FORCE_INLINE uint64_t fmix ( uint64_t k )
  87 {
  88   k ^= k >> 33;
  89   k *= BIG_CONSTANT(0xff51afd7ed558ccd);
  90   k ^= k >> 33;
  91   k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
  92   k ^= k >> 33;
  93
  94   return k;
  95 }
  96
  97 } // unnamed namespace
  98
  99 //-----------------------------------------------------------------------------
 100
 101 void MurmurHash3_x86_32 ( const void * key, int len,
 102                           uint32_t seed, void * out )
 103 {
 104   const uint8_t * data = (const uint8_t*)key;
 105   const int nblocks = len / 4;
 106
 107   uint32_t h1 = seed;
 108
 109   const uint32_t c1 = 0xcc9e2d51;
 110   const uint32_t c2 = 0x1b873593;
 111
 112   //----------
 113   // body
 114
 115   const uint32_t * blocks = (const uint32_t *)(data + nblocks*4);
 116
 117   for(int i = -nblocks; i; i++)
 118   {
 119     uint32_t k1 = getblock(blocks,i);
 120
 121     k1 *= c1;
 122     k1 = ROTL32(k1,15);
 123     k1 *= c2;
 124
 125     h1 ^= k1;
 126     h1 = ROTL32(h1,13);
 127     h1 = h1*5+0xe6546b64;
 128   }
 129
 130   //----------
 131   // tail
 132
 133   const uint8_t * tail = (const uint8_t*)(data + nblocks*4);
 134
 135   uint32_t k1 = 0;
 136
 137   switch(len & 3)
 138   {
 139   case 3: k1 ^= tail[2] << 16;
 140   case 2: k1 ^= tail[1] << 8;
 141   case 1: k1 ^= tail[0];
 142           k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
 143   };
 144
 145   //----------
 146   // finalization
 147
 148   h1 ^= len;
 149
 150   h1 = fmix(h1);
 151
 152   *(uint32_t*)out = h1;
 153 }
 154
 155 //-----------------------------------------------------------------------------
 156
 157 void MurmurHash3_x86_128 ( const void * key, const int len,
 158                            uint32_t seed, void * out )
 159 {
 160   const uint8_t * data = (const uint8_t*)key;
 161   const int nblocks = len / 16;
 162
 163   uint32_t h1 = seed;
 164   uint32_t h2 = seed;
 165   uint32_t h3 = seed;
 166   uint32_t h4 = seed;
 167
 168   const uint32_t c1 = 0x239b961b;
 169   const uint32_t c2 = 0xab0e9789;
 170   const uint32_t c3 = 0x38b34ae5;
 171   const uint32_t c4 = 0xa1e38b93;
 172
 173   //----------
 174   // body
 175
 176   const uint32_t * blocks = (const uint32_t *)(data + nblocks*16);
 177
 178   for(int i = -nblocks; i; i++)
 179   {
 180     uint32_t k1 = getblock(blocks,i*4+0);
 181     uint32_t k2 = getblock(blocks,i*4+1);
 182     uint32_t k3 = getblock(blocks,i*4+2);
 183     uint32_t k4 = getblock(blocks,i*4+3);
 184
 185     k1 *= c1; k1  = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
 186
 187     h1 = ROTL32(h1,19); h1 += h2; h1 = h1*5+0x561ccd1b;
 188
 189     k2 *= c2; k2  = ROTL32(k2,16); k2 *= c3; h2 ^= k2;
 190
 191     h2 = ROTL32(h2,17); h2 += h3; h2 = h2*5+0x0bcaa747;
 192
 193     k3 *= c3; k3  = ROTL32(k3,17); k3 *= c4; h3 ^= k3;
 194
 195     h3 = ROTL32(h3,15); h3 += h4; h3 = h3*5+0x96cd1c35;
 196
 197     k4 *= c4; k4  = ROTL32(k4,18); k4 *= c1; h4 ^= k4;
 198
 199     h4 = ROTL32(h4,13); h4 += h1; h4 = h4*5+0x32ac3b17;
 200   }
 201
 202   //----------
 203   // tail
 204
 205   const uint8_t * tail = (const uint8_t*)(data + nblocks*16);
 206
 207   uint32_t k1 = 0;
 208   uint32_t k2 = 0;
 209   uint32_t k3 = 0;
 210   uint32_t k4 = 0;
 211
 212   switch(len & 15)
 213   {
 214   case 15: k4 ^= tail[14] << 16;
 215   case 14: k4 ^= tail[13] << 8;
 216   case 13: k4 ^= tail[12] << 0;
 217            k4 *= c4; k4  = ROTL32(k4,18); k4 *= c1; h4 ^= k4;
 218
 219   case 12: k3 ^= tail[11] << 24;
 220   case 11: k3 ^= tail[10] << 16;
 221   case 10: k3 ^= tail[ 9] << 8;
 222   case  9: k3 ^= tail[ 8] << 0;
 223            k3 *= c3; k3  = ROTL32(k3,17); k3 *= c4; h3 ^= k3;
 224
 225   case  8: k2 ^= tail[ 7] << 24;
 226   case  7: k2 ^= tail[ 6] << 16;
 227   case  6: k2 ^= tail[ 5] << 8;
 228   case  5: k2 ^= tail[ 4] << 0;
 229            k2 *= c2; k2  = ROTL32(k2,16); k2 *= c3; h2 ^= k2;
 230
 231   case  4: k1 ^= tail[ 3] << 24;
 232   case  3: k1 ^= tail[ 2] << 16;
 233   case  2: k1 ^= tail[ 1] << 8;
 234   case  1: k1 ^= tail[ 0] << 0;
 235            k1 *= c1; k1  = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
 236   };
 237
 238   //----------
 239   // finalization
 240
 241   h1 ^= len; h2 ^= len; h3 ^= len; h4 ^= len;
 242
 243   h1 += h2; h1 += h3; h1 += h4;
 244   h2 += h1; h3 += h1; h4 += h1;
 245
 246   h1 = fmix(h1);
 247   h2 = fmix(h2);
 248   h3 = fmix(h3);
 249   h4 = fmix(h4);
 250
 251   h1 += h2; h1 += h3; h1 += h4;
 252   h2 += h1; h3 += h1; h4 += h1;
 253
 254   ((uint32_t*)out)[0] = h1;
 255   ((uint32_t*)out)[1] = h2;
 256   ((uint32_t*)out)[2] = h3;
 257   ((uint32_t*)out)[3] = h4;
 258 }
 259
 260 //-----------------------------------------------------------------------------
 261
 262 void MurmurHash3_x64_128 ( const void * key, const int len,
 263                            const uint32_t seed, void * out )
 264 {
 265   const uint8_t * data = (const uint8_t*)key;
 266   const int nblocks = len / 16;
 267
 268   uint64_t h1 = seed;
 269   uint64_t h2 = seed;
 270
 271   const uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
 272   const uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);
 273
 274   //----------
 275   // body
 276
 277   const uint64_t * blocks = (const uint64_t *)(data);
 278
 279   for(int i = 0; i < nblocks; i++)
 280   {
 281     uint64_t k1 = getblock(blocks,i*2+0);
 282     uint64_t k2 = getblock(blocks,i*2+1);
 283
 284     k1 *= c1; k1  = ROTL64(k1,31); k1 *= c2; h1 ^= k1;
 285
 286     h1 = ROTL64(h1,27); h1 += h2; h1 = h1*5+0x52dce729;
 287
 288     k2 *= c2; k2  = ROTL64(k2,33); k2 *= c1; h2 ^= k2;
 289
 290     h2 = ROTL64(h2,31); h2 += h1; h2 = h2*5+0x38495ab5;
 291   }
 292
 293   //----------
 294   // tail
 295
 296   const uint8_t * tail = (const uint8_t*)(data + nblocks*16);
 297
 298   uint64_t k1 = 0;
 299   uint64_t k2 = 0;
 300
 301   switch(len & 15)
 302   {
 303   case 15: k2 ^= uint64_t(tail[14]) << 48;
 304   case 14: k2 ^= uint64_t(tail[13]) << 40;
 305   case 13: k2 ^= uint64_t(tail[12]) << 32;
 306   case 12: k2 ^= uint64_t(tail[11]) << 24;
 307   case 11: k2 ^= uint64_t(tail[10]) << 16;
 308   case 10: k2 ^= uint64_t(tail[ 9]) << 8;
 309   case  9: k2 ^= uint64_t(tail[ 8]) << 0;
 310            k2 *= c2; k2  = ROTL64(k2,33); k2 *= c1; h2 ^= k2;
 311
 312   case  8: k1 ^= uint64_t(tail[ 7]) << 56;
 313   case  7: k1 ^= uint64_t(tail[ 6]) << 48;
 314   case  6: k1 ^= uint64_t(tail[ 5]) << 40;
 315   case  5: k1 ^= uint64_t(tail[ 4]) << 32;
 316   case  4: k1 ^= uint64_t(tail[ 3]) << 24;
 317   case  3: k1 ^= uint64_t(tail[ 2]) << 16;
 318   case  2: k1 ^= uint64_t(tail[ 1]) << 8;
 319   case  1: k1 ^= uint64_t(tail[ 0]) << 0;
 320            k1 *= c1; k1  = ROTL64(k1,31); k1 *= c2; h1 ^= k1;
 321   };
 322
 323   //----------
 324   // finalization
 325
 326   h1 ^= len; h2 ^= len;
 327
 328   h1 += h2;
 329   h2 += h1;
 330
 331   h1 = fmix(h1);
 332   h2 = fmix(h2);
 333
 334   h1 += h2;
 335   h2 += h1;
 336
 337   ((uint64_t*)out)[0] = h1;
 338   ((uint64_t*)out)[1] = h2;
 339 }
 340
 341 //-----------------------------------------------------------------------------