1/* XzCrc64.c -- CRC64 calculation
 22015-03-01 : 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 CRC_NUM_TABLES 4
13#else
14  #define CRC_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
32typedef UInt64 (MY_FAST_CALL *CRC_FUNC)(UInt64 v, const void *data, size_t size, const UInt64 *table);
33
34static CRC_FUNC g_Crc64Update;
35UInt64 g_Crc64Table[256 * CRC_NUM_TABLES];
36
37UInt64 MY_FAST_CALL Crc64Update(UInt64 v, const void *data, size_t size)
38{
39  return g_Crc64Update(v, data, size, g_Crc64Table);
40}
41
42UInt64 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
47void 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 & ~((r & 1) - 1));
56    g_Crc64Table[i] = r;
57  }
58  for (; i < 256 * CRC_NUM_TABLES; i++)
59  {
60    UInt64 r = g_Crc64Table[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 * CRC_NUM_TABLES - 1; i >= 256; i--)
78      {
79        UInt64 x = g_Crc64Table[i - 256];
80        g_Crc64Table[i] = CRC_UINT64_SWAP(x);
81      }
82      g_Crc64Update = XzCrc64UpdateT1_BeT4;
83    }
84  }
85  #endif
86}