/*

Copyright (c) 2014-2020, Arvid Norberg

Copyright (c) 2016, Alden Torres

Copyright (c) 2018, Pavel Pimenov

All rights reserved.

Redistribution and use in source and binary forms, with or without

modification, are permitted provided that the following conditions

are met:

    * Redistributions of source code must retain the above copyright

      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above copyright

      notice, this list of conditions and the following disclaimer in

      the documentation and/or other materials provided with the distribution.

    * Neither the name of the author nor the names of its

      contributors may be used to endorse or promote products derived

      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

POSSIBILITY OF SUCH DAMAGE.

*/

#include "libtorrent/config.hpp"

#include "libtorrent/crc32c.hpp"

#include "libtorrent/aux_/cpuid.hpp"

#include "libtorrent/aux_/byteswap.hpp"

#include "libtorrent/aux_/disable_warnings_push.hpp"

#include <boost/crc.hpp>

#if (defined _MSC_VER && _MSC_VER >= 1600 && (defined _M_IX86 || defined _M_X64))

#include <nmmintrin.h>

#endif

#include "libtorrent/aux_/disable_warnings_pop.hpp"

#if TORRENT_HAS_ARM_CRC32

#include <arm_acle.h>

#endif

namespace libtorrent {

  std::uint32_t crc32c_32(std::uint32_t v)

  {

#if TORRENT_HAS_SSE

    if (aux::sse42_support)

    {

      std::uint32_t ret = 0xffffffff;

#ifdef __GNUC__

      // we can't use these because then we'd have to tell

      // -msse4.2 to gcc on the command line

//      return __builtin_ia32_crc32si(ret, v) ^ 0xffffffff;

      asm ("crc32l\t" "(%1), %0"

        : "=r"(ret)

        : "r"(&v), "0"(ret));

      return ret ^ 0xffffffff;

#else

      return _mm_crc32_u32(ret, v) ^ 0xffffffff;

#endif

    }

#endif

#if TORRENT_HAS_ARM_CRC32

    if (aux::arm_crc32c_support)

    {

      std::uint32_t ret = 0xffffffff;

      return __crc32cw(ret, v) ^ 0xffffffff;

    }

#endif

    boost::crc_optimal<32, 0x1EDC6F41, 0xFFFFFFFF, 0xFFFFFFFF, true, true> crc;

    crc.process_bytes(&v, 4);

    return crc.checksum();

  }

  std::uint32_t crc32c(std::uint64_t const* buf, int num_words)

  {

#if TORRENT_HAS_SSE

    if (aux::sse42_support)

    {

#if defined _M_AMD64 || defined __x86_64__ \

  || defined __x86_64 || defined _M_X64 || defined __amd64__

      std::uint64_t ret = 0xffffffff;

      for (int i = 0; i < num_words; ++i)

      {

#ifdef __GNUC__

        // we can't use these because then we'd have to tell

        // -msse4.2 to gcc on the command line

//        ret = __builtin_ia32_crc32di(ret, buf[i]);

        __asm__("crc32q\t" "(%1), %0"

          : "=r"(ret)

          : "r"(buf+i), "0"(ret));

#else

        ret = _mm_crc32_u64(ret, buf[i]);

#endif

      }

      return std::uint32_t(ret) ^ 0xffffffff;

#else

      std::uint32_t ret = 0xffffffff;

      std::uint32_t const* buf0 = reinterpret_cast<std::uint32_t const*>(buf);

      for (int i = 0; i < num_words; ++i)

      {

#ifdef __GNUC__

        // we can't use these because then we'd have to tell

        // -msse4.2 to gcc on the command line

//        ret = __builtin_ia32_crc32si(ret, buf0[i*2]);

//        ret = __builtin_ia32_crc32si(ret, buf0[i*2+1]);

        asm ("crc32l\t" "(%1), %0"

          : "=r"(ret)

          : "r"(buf0+i*2), "0"(ret));

        asm ("crc32l\t" "(%1), %0"

          : "=r"(ret)

          : "r"(buf0+i*2+1), "0"(ret));

#else

        ret = _mm_crc32_u32(ret, buf0[i*2]);

        ret = _mm_crc32_u32(ret, buf0[i*2+1]);

#endif

      }

      return ret ^ 0xffffffff;

#endif // amd64 or x86

    }

#endif // x86 or amd64 and gcc or msvc

#if TORRENT_HAS_ARM_CRC32

    if (aux::arm_crc32c_support)

    {

      std::uint32_t ret = 0xffffffff;

      for (int i = 0; i < num_words; ++i)

      {

        ret = __crc32cd(ret, buf[i]);

      }

      return ret ^ 0xffffffff;

    }

#endif

    boost::crc_optimal<32, 0x1EDC6F41, 0xFFFFFFFF, 0xFFFFFFFF, true, true> crc;

    crc.process_bytes(buf, std::size_t(num_words) * 8);

    return crc.checksum();

  }

}