position-compress-fixed.h

Go to the documentation of this file.

// Hoover Chess Utilities / PGN reader
// Copyright (C) 2021-2025  Sami Kiminki
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
#ifndef HOOVER_CHESS_UTILS__PGN_READER__POSITION_COMPRESS_FIXED_H_INCLUDED
#define HOOVER_CHESS_UTILS__PGN_READER__POSITION_COMPRESS_FIXED_H_INCLUDED
 
#include <array>
#include <bit>
#include <cstdint>
 
 
namespace hoover_chess_utils::pgn_reader
{
 
class ChessBoard;
 
 
enum class CompressedPosition_PieceEncoding
{
    WHITE_KING_NOT_IN_TURN     = 0U,
 
    WHITE_BISHOP               = 1U,
 
    WHITE_ROOK_CANNOT_CASTLE   = 2U,
 
    WHITE_QUEEN                = 3U, // note: BISHOP | ROOK_CANNOT_CASTLE
 
    WHITE_KNIGHT               = 4U,
 
    WHITE_PAWN                 = 5U,
 
    WHITE_ROOK_CAN_CASTLE      = 6U, // note: ROOK_CANNOT_CASTLE | 4
 
    WHITE_KING_IN_TURN         = 7U,
 
    EP_PAWN                    = 8U,
 
    BLACK_BISHOP               = 9U,
 
    BLACK_ROOK_CANNOT_CASTLE   = 10U,
 
    BLACK_QUEEN                = 11U, // note: BISHOP | ROOK_CANNOT_CASTLE
 
    BLACK_KNIGHT               = 12U,
 
    BLACK_PAWN                 = 13U,
 
    BLACK_ROOK_CAN_CASTLE      = 14U, // note: ROOK_CANNOT_CASTLE | 4
 
    BLACK_KING                 = 15U,
};
 
struct CompressedPosition_FixedLength
{
    std::uint64_t occupancy;
 
    std::array<std::uint32_t, 4U> dataPlanes;
};
 
inline auto operator <=> (const CompressedPosition_FixedLength &lhs, const CompressedPosition_FixedLength &rhs) noexcept
{
    using RawCompareType = std::array<std::uint64_t, 3U>;
    static_assert(sizeof(RawCompareType) == sizeof(CompressedPosition_FixedLength));
 
    const RawCompareType *p1 { std::bit_cast<const RawCompareType *>(&lhs) };
    const RawCompareType *p2 { std::bit_cast<const RawCompareType *>(&rhs) };
 
    return *p1 <=> *p2;
}
 
inline bool operator == (const CompressedPosition_FixedLength &lhs, const CompressedPosition_FixedLength &rhs) noexcept
{
    using RawCompareType = std::array<std::uint64_t, 3U>;
    static_assert(sizeof(RawCompareType) == sizeof(CompressedPosition_FixedLength));
 
    const RawCompareType *p1 { std::bit_cast<const RawCompareType *>(&lhs) };
    const RawCompareType *p2 { std::bit_cast<const RawCompareType *>(&rhs) };
 
    return *p1 == *p2;
}
 
class PositionCompressor_FixedLength
{
private:
    PositionCompressor_FixedLength() = delete;
    ~PositionCompressor_FixedLength() = delete;
 
public:
    static void compress(const ChessBoard &board, CompressedPosition_FixedLength &out_compressedPosition);
 
    static void decompress(const CompressedPosition_FixedLength &compressedPosition, std::uint8_t halfMoveClock, std::uint32_t moveNum, pgn_reader::ChessBoard &out_board);
};
 
 
}
 
#endif