nel/3rdparty/seven_zip/XzCrc64.c

   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 }