1/* 7zCrcOpt.c -- CRC32 calculation
  22015-03-01 : Igor Pavlov : Public domain */
  3
  4#include "Precomp.h"
  5
  6#include "CpuArch.h"
  7
  8#ifndef MY_CPU_BE
  9
 10#define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
 11
 12UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
 13{
 14  const Byte *p = (const Byte *)data;
 15  for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
 16    v = CRC_UPDATE_BYTE_2(v, *p);
 17  for (; size >= 4; size -= 4, p += 4)
 18  {
 19    v ^= *(const UInt32 *)p;
 20    v =
 21          table[0x300 + ((v      ) & 0xFF)]
 22        ^ table[0x200 + ((v >>  8) & 0xFF)]
 23        ^ table[0x100 + ((v >> 16) & 0xFF)]
 24        ^ table[0x000 + ((v >> 24))];
 25  }
 26  for (; size > 0; size--, p++)
 27    v = CRC_UPDATE_BYTE_2(v, *p);
 28  return v;
 29}
 30
 31UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
 32{
 33  const Byte *p = (const Byte *)data;
 34  for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
 35    v = CRC_UPDATE_BYTE_2(v, *p);
 36  for (; size >= 8; size -= 8, p += 8)
 37  {
 38    UInt32 d;
 39    v ^= *(const UInt32 *)p;
 40    v =
 41          table[0x700 + ((v      ) & 0xFF)]
 42        ^ table[0x600 + ((v >>  8) & 0xFF)]
 43        ^ table[0x500 + ((v >> 16) & 0xFF)]
 44        ^ table[0x400 + ((v >> 24))];
 45    d = *((const UInt32 *)p + 1);
 46    v ^=
 47          table[0x300 + ((d      ) & 0xFF)]
 48        ^ table[0x200 + ((d >>  8) & 0xFF)]
 49        ^ table[0x100 + ((d >> 16) & 0xFF)]
 50        ^ table[0x000 + ((d >> 24))];
 51  }
 52  for (; size > 0; size--, p++)
 53    v = CRC_UPDATE_BYTE_2(v, *p);
 54  return v;
 55}
 56
 57#endif
 58
 59
 60#ifndef MY_CPU_LE
 61
 62#define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24))
 63
 64#define CRC_UPDATE_BYTE_2_BE(crc, b) (table[(((crc) >> 24) ^ (b))] ^ ((crc) << 8))
 65
 66UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
 67{
 68  const Byte *p = (const Byte *)data;
 69  table += 0x100;
 70  v = CRC_UINT32_SWAP(v);
 71  for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
 72    v = CRC_UPDATE_BYTE_2_BE(v, *p);
 73  for (; size >= 4; size -= 4, p += 4)
 74  {
 75    v ^= *(const UInt32 *)p;
 76    v =
 77          table[0x000 + ((v      ) & 0xFF)]
 78        ^ table[0x100 + ((v >>  8) & 0xFF)]
 79        ^ table[0x200 + ((v >> 16) & 0xFF)]
 80        ^ table[0x300 + ((v >> 24))];
 81  }
 82  for (; size > 0; size--, p++)
 83    v = CRC_UPDATE_BYTE_2_BE(v, *p);
 84  return CRC_UINT32_SWAP(v);
 85}
 86
 87UInt32 MY_FAST_CALL CrcUpdateT1_BeT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
 88{
 89  const Byte *p = (const Byte *)data;
 90  table += 0x100;
 91  v = CRC_UINT32_SWAP(v);
 92  for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
 93    v = CRC_UPDATE_BYTE_2_BE(v, *p);
 94  for (; size >= 8; size -= 8, p += 8)
 95  {
 96    UInt32 d;
 97    v ^= *(const UInt32 *)p;
 98    v =
 99          table[0x400 + ((v      ) & 0xFF)]
100        ^ table[0x500 + ((v >>  8) & 0xFF)]
101        ^ table[0x600 + ((v >> 16) & 0xFF)]
102        ^ table[0x700 + ((v >> 24))];
103    d = *((const UInt32 *)p + 1);
104    v ^=
105          table[0x000 + ((d      ) & 0xFF)]
106        ^ table[0x100 + ((d >>  8) & 0xFF)]
107        ^ table[0x200 + ((d >> 16) & 0xFF)]
108        ^ table[0x300 + ((d >> 24))];
109  }
110  for (; size > 0; size--, p++)
111    v = CRC_UPDATE_BYTE_2_BE(v, *p);
112  return CRC_UINT32_SWAP(v);
113}
114
115#endif