text: /* 7zCrcOpt.c -- CRC32 calculation
  2015-03-01 : Igor Pavlov : Public domain */
  
  #include "Precomp.h"
  
  #include "CpuArch.h"
  
  #ifndef MY_CPU_BE
  
  #define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
  
  UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
  {
    const Byte *p = (const Byte *)data;
    for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
      v = CRC_UPDATE_BYTE_2(v, *p);
    for (; size >= 4; size -= 4, p += 4)
    {
      v ^= *(const UInt32 *)p;
      v =
            table[0x300 + ((v      ) & 0xFF)]
          ^ table[0x200 + ((v >>  8) & 0xFF)]
          ^ table[0x100 + ((v >> 16) & 0xFF)]
          ^ table[0x000 + ((v >> 24))];
    }
    for (; size > 0; size--, p++)
      v = CRC_UPDATE_BYTE_2(v, *p);
    return v;
  }
  
  UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
  {
    const Byte *p = (const Byte *)data;
    for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
      v = CRC_UPDATE_BYTE_2(v, *p);
    for (; size >= 8; size -= 8, p += 8)
    {
      UInt32 d;
      v ^= *(const UInt32 *)p;
      v =
            table[0x700 + ((v      ) & 0xFF)]
          ^ table[0x600 + ((v >>  8) & 0xFF)]
          ^ table[0x500 + ((v >> 16) & 0xFF)]
          ^ table[0x400 + ((v >> 24))];
      d = *((const UInt32 *)p + 1);
      v ^=
            table[0x300 + ((d      ) & 0xFF)]
          ^ table[0x200 + ((d >>  8) & 0xFF)]
          ^ table[0x100 + ((d >> 16) & 0xFF)]
          ^ table[0x000 + ((d >> 24))];
    }
    for (; size > 0; size--, p++)
      v = CRC_UPDATE_BYTE_2(v, *p);
    return v;
  }
  
  #endif
  
  
  #ifndef MY_CPU_LE
  
  #define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24))
  
  #define CRC_UPDATE_BYTE_2_BE(crc, b) (table[(((crc) >> 24) ^ (b))] ^ ((crc) << 8))
  
  UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
  {
    const Byte *p = (const Byte *)data;
    table += 0x100;
    v = CRC_UINT32_SWAP(v);
    for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
      v = CRC_UPDATE_BYTE_2_BE(v, *p);
    for (; size >= 4; size -= 4, p += 4)
    {
      v ^= *(const UInt32 *)p;
      v =
            table[0x000 + ((v      ) & 0xFF)]
          ^ table[0x100 + ((v >>  8) & 0xFF)]
          ^ table[0x200 + ((v >> 16) & 0xFF)]
          ^ table[0x300 + ((v >> 24))];
    }
    for (; size > 0; size--, p++)
      v = CRC_UPDATE_BYTE_2_BE(v, *p);
    return CRC_UINT32_SWAP(v);
  }
  
  UInt32 MY_FAST_CALL CrcUpdateT1_BeT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
  {
    const Byte *p = (const Byte *)data;
    table += 0x100;
    v = CRC_UINT32_SWAP(v);
    for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
      v = CRC_UPDATE_BYTE_2_BE(v, *p);
    for (; size >= 8; size -= 8, p += 8)
    {
      UInt32 d;
      v ^= *(const UInt32 *)p;
      v =
            table[0x400 + ((v      ) & 0xFF)]
          ^ table[0x500 + ((v >>  8) & 0xFF)]
          ^ table[0x600 + ((v >> 16) & 0xFF)]
          ^ table[0x700 + ((v >> 24))];
      d = *((const UInt32 *)p + 1);
      v ^=
            table[0x000 + ((d      ) & 0xFF)]
          ^ table[0x100 + ((d >>  8) & 0xFF)]
          ^ table[0x200 + ((d >> 16) & 0xFF)]
          ^ table[0x300 + ((d >> 24))];
    }
    for (; size > 0; size--, p++)
      v = CRC_UPDATE_BYTE_2_BE(v, *p);
    return CRC_UINT32_SWAP(v);
  }
  
  #endif
  