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/***

 * ASM: a very small and fast Java bytecode manipulation framework

 * Copyright (c) 2000-2005 INRIA, France Telecom

 * All rights reserved.

 *

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

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. 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.

 * 3. Neither the name of the copyright holders 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.

 */

package org.objectweb.asm.tree.analysis;

import java.util.ArrayList;

import java.util.List;

import org.objectweb.asm.Label;

import org.objectweb.asm.tree.JumpInsnNode;

/**

 * A method subroutine (corresponds to a JSR instruction).

 *

 * @author Eric Bruneton

 */

class Subroutine {

    Label start;

    boolean[] access;

    List callers;

    private Subroutine() {

    }

    public Subroutine(

        final Label start,

        final int maxLocals,

        final JumpInsnNode caller)

    {

        this.start = start;

        this.access = new boolean[maxLocals];

        this.callers = new ArrayList();

        callers.add(caller);

    }

    public Subroutine copy() {

        Subroutine result = new Subroutine();

        result.start = start;

        result.access = new boolean[access.length];

        System.arraycopy(access, 0, result.access, 0, access.length);

        result.callers = new ArrayList(callers);

        return result;

    }

    public boolean merge(final Subroutine subroutine, boolean checkOverlap)

            throws AnalyzerException

    {

        if (checkOverlap && subroutine.start != start) {

            throw new AnalyzerException("Overlapping sub routines");

        }

        boolean changes = false;

        for (int i = 0; i < access.length; ++i) {

            if (subroutine.access[i] && !access[i]) {

                access[i] = true;

                changes = true;

            }

        }

        for (int i = 0; i < subroutine.callers.size(); ++i) {

            Object caller = subroutine.callers.get(i);

            if (!callers.contains(caller)) {

                callers.add(caller);

                changes = true;

            }

        }

        return changes;

    }

}