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XzCrc64.c (2236B)

      1 /* XzCrc64.c -- CRC64 calculation
      2 2017-05-23 : Igor Pavlov : Public domain */
      3 
      4 #include "Precomp.h"
      5 
      6 #include "XzCrc64.h"
      7 #include "CpuArch.h"
      8 
      9 #define kCrc64Poly UINT64_CONST(0xC96C5795D7870F42)
     10 
     11 #ifdef MY_CPU_LE
     12  #define CRC64_NUM_TABLES 4
     13 #else
     14  #define CRC64_NUM_TABLES 5
     15  #define CRC_UINT64_SWAP(v) \
     16      ((v >> 56) \
     17    | ((v >> 40) & ((UInt64)0xFF <<  8)) \
     18    | ((v >> 24) & ((UInt64)0xFF << 16)) \
     19    | ((v >>  8) & ((UInt64)0xFF << 24)) \
     20    | ((v <<  8) & ((UInt64)0xFF << 32)) \
     21    | ((v << 24) & ((UInt64)0xFF << 40)) \
     22    | ((v << 40) & ((UInt64)0xFF << 48)) \
     23    | ((v << 56)))
     24 
     25  UInt64 MY_FAST_CALL XzCrc64UpdateT1_BeT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
     26 #endif
     27 
     28 #ifndef MY_CPU_BE
     29  UInt64 MY_FAST_CALL XzCrc64UpdateT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
     30 #endif
     31 
     32 typedef UInt64 (MY_FAST_CALL *CRC64_FUNC)(UInt64 v, const void *data, size_t size, const UInt64 *table);
     33 
     34 static CRC64_FUNC g_Crc64Update;
     35 UInt64 g_Crc64Table[256 * CRC64_NUM_TABLES];
     36 
     37 UInt64 MY_FAST_CALL Crc64Update(UInt64 v, const void *data, size_t size)
     38 {
     39  return g_Crc64Update(v, data, size, g_Crc64Table);
     40 }
     41 
     42 UInt64 MY_FAST_CALL Crc64Calc(const void *data, size_t size)
     43 {
     44  return g_Crc64Update(CRC64_INIT_VAL, data, size, g_Crc64Table) ^ CRC64_INIT_VAL;
     45 }
     46 
     47 void MY_FAST_CALL Crc64GenerateTable()
     48 {
     49  UInt32 i;
     50  for (i = 0; i < 256; i++)
     51  {
     52    UInt64 r = i;
     53    unsigned j;
     54    for (j = 0; j < 8; j++)
     55      r = (r >> 1) ^ (kCrc64Poly & ((UInt64)0 - (r & 1)));
     56    g_Crc64Table[i] = r;
     57  }
     58  for (i = 256; i < 256 * CRC64_NUM_TABLES; i++)
     59  {
     60    UInt64 r = g_Crc64Table[(size_t)i - 256];
     61    g_Crc64Table[i] = g_Crc64Table[r & 0xFF] ^ (r >> 8);
     62  }
     63  
     64  #ifdef MY_CPU_LE
     65 
     66  g_Crc64Update = XzCrc64UpdateT4;
     67 
     68  #else
     69  {
     70    #ifndef MY_CPU_BE
     71    UInt32 k = 1;
     72    if (*(const Byte *)&k == 1)
     73      g_Crc64Update = XzCrc64UpdateT4;
     74    else
     75    #endif
     76    {
     77      for (i = 256 * CRC64_NUM_TABLES - 1; i >= 256; i--)
     78      {
     79        UInt64 x = g_Crc64Table[(size_t)i - 256];
     80        g_Crc64Table[i] = CRC_UINT64_SWAP(x);
     81      }
     82      g_Crc64Update = XzCrc64UpdateT1_BeT4;
     83    }
     84  }
     85  #endif
     86 }