com.fluxchess.pulse.Move Maven / Gradle / Ivy

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/*
 * Copyright (C) 2013-2019 Phokham Nonava
 *
 * Use of this source code is governed by the MIT license that can be
 * found in the LICENSE file.
 */
package com.fluxchess.pulse;

import static com.fluxchess.pulse.MoveType.NOMOVETYPE;
import static com.fluxchess.pulse.Piece.NOPIECE;
import static com.fluxchess.pulse.PieceType.NOPIECETYPE;
import static com.fluxchess.pulse.Square.NOSQUARE;

/**
 * This class represents a move as a int value. The fields are represented by
 * the following bits.
 * 
 *  0 -  2: type (required)
 *  3 -  9: origin square (required)
 * 10 - 16: target square (required)
 * 17 - 21: origin piece (required)
 * 22 - 26: target piece (optional)
 * 27 - 29: promotion type (optional)
 */
final class Move {

	// These are our bit masks
	private static final int TYPE_SHIFT = 0;
	private static final int TYPE_MASK = MoveType.MASK << TYPE_SHIFT;
	private static final int ORIGIN_SQUARE_SHIFT = 3;
	private static final int ORIGIN_SQUARE_MASK = Square.MASK << ORIGIN_SQUARE_SHIFT;
	private static final int TARGET_SQUARE_SHIFT = 10;
	private static final int TARGET_SQUARE_MASK = Square.MASK << TARGET_SQUARE_SHIFT;
	private static final int ORIGIN_PIECE_SHIFT = 17;
	private static final int ORIGIN_PIECE_MASK = Piece.MASK << ORIGIN_PIECE_SHIFT;
	private static final int TARGET_PIECE_SHIFT = 22;
	private static final int TARGET_PIECE_MASK = Piece.MASK << TARGET_PIECE_SHIFT;
	private static final int PROMOTION_SHIFT = 27;
	private static final int PROMOTION_MASK = PieceType.MASK << PROMOTION_SHIFT;

	// We don't use 0 as a null value to protect against errors.
	static final int NOMOVE = (NOMOVETYPE << TYPE_SHIFT)
			| (NOSQUARE << ORIGIN_SQUARE_SHIFT)
			| (NOSQUARE << TARGET_SQUARE_SHIFT)
			| (NOPIECE << ORIGIN_PIECE_SHIFT)
			| (NOPIECE << TARGET_PIECE_SHIFT)
			| (NOPIECETYPE << PROMOTION_SHIFT);

	private Move() {
	}

	static int valueOf(int type, int originSquare, int targetSquare, int originPiece, int targetPiece, int promotion) {
		int move = 0;

		// Encode type
		move |= type << TYPE_SHIFT;

		// Encode origin square
		move |= originSquare << ORIGIN_SQUARE_SHIFT;

		// Encode target square
		move |= targetSquare << TARGET_SQUARE_SHIFT;

		// Encode origin piece
		move |= originPiece << ORIGIN_PIECE_SHIFT;

		// Encode target piece
		move |= targetPiece << TARGET_PIECE_SHIFT;

		// Encode promotion
		move |= promotion << PROMOTION_SHIFT;

		return move;
	}

	static int getType(int move) {
		return (move & TYPE_MASK) >>> TYPE_SHIFT;
	}

	static int getOriginSquare(int move) {
		return (move & ORIGIN_SQUARE_MASK) >>> ORIGIN_SQUARE_SHIFT;
	}

	static int getTargetSquare(int move) {
		return (move & TARGET_SQUARE_MASK) >>> TARGET_SQUARE_SHIFT;
	}

	static int getOriginPiece(int move) {
		return (move & ORIGIN_PIECE_MASK) >>> ORIGIN_PIECE_SHIFT;
	}

	static int getTargetPiece(int move) {
		return (move & TARGET_PIECE_MASK) >>> TARGET_PIECE_SHIFT;
	}

	static int getPromotion(int move) {
		return (move & PROMOTION_MASK) >>> PROMOTION_SHIFT;
	}
}