/* 7zCrcOpt.c -- CRC32 calculation

2017-04-03 : 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