/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.graalvm.compiler.nodes.calc;

import java.nio.ByteOrder;

import org.graalvm.compiler.core.common.type.StampFactory;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.graph.spi.CanonicalizerTool;

import org.graalvm.compiler.nodeinfo.NodeCycles;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.ConstantNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.spi.Lowerable;

import org.graalvm.compiler.nodes.spi.LoweringTool;

import jdk.vm.ci.meta.JavaKind;

/**

 * Produces the platform dependent first or second half of a long or double value as an int.

 */

@NodeInfo(cycles = NodeCycles.CYCLES_2)

public final class UnpackEndianHalfNode extends UnaryNode implements Lowerable {

    public static final NodeClass<UnpackEndianHalfNode> TYPE = NodeClass.create(UnpackEndianHalfNode.class);

    private final boolean firstHalf;

    protected UnpackEndianHalfNode(ValueNode value, boolean firstHalf) {

        super(TYPE, StampFactory.forKind(JavaKind.Int), value);

        assert value.getStackKind() == JavaKind.Double || value.getStackKind() == JavaKind.Long : "unexpected kind " + value.getStackKind();

        this.firstHalf = firstHalf;

    }

    @SuppressWarnings("unused")

    public static ValueNode create(ValueNode value, boolean firstHalf, NodeView view) {

        if (value.isConstant() && value.asConstant().isDefaultForKind()) {

            return ConstantNode.defaultForKind(JavaKind.Int);

        }

        return new UnpackEndianHalfNode(value, firstHalf);

    }

    public boolean isFirstHalf() {

        return firstHalf;

    }

    @Override

    public Node canonical(CanonicalizerTool tool, ValueNode forValue) {

            return ConstantNode.defaultForKind(stamp.getStackKind());

        }

        return this;

    }

    @Override

    public void lower(LoweringTool tool) {

        tool.getLowerer().lower(this, tool);

    }

    public void lower(ByteOrder byteOrder) {

        ValueNode result = value;

        if (value.getStackKind() == JavaKind.Double) {

            result = graph().unique(new ReinterpretNode(JavaKind.Long, value));

        }

        if ((byteOrder == ByteOrder.BIG_ENDIAN) == firstHalf) {

            result = graph().unique(new UnsignedRightShiftNode(result, ConstantNode.forInt(32, graph())));

        }

        result = IntegerConvertNode.convert(result, StampFactory.forKind(JavaKind.Int), graph(), NodeView.DEFAULT);

        replaceAtUsagesAndDelete(result);

    }

}