/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.sun.org.apache.bcel.internal.classfile;

import java.io.DataInput;

import java.io.DataOutputStream;

import java.io.IOException;

/**

 * This class represents a (PC offset, line number) pair, i.e., a line number in

 * the source that corresponds to a relative address in the byte code. This

 * is used for debugging purposes.

 *

 * @see     LineNumberTable

 */

public final class LineNumber implements Cloneable, Node {

    /** Program Counter (PC) corresponds to line */

    private short startPc;

    /** number in source file */

    private short lineNumber;

    /**

     * Initialize from another object.

     *

     * @param c the object to copy

     */

    public LineNumber(final LineNumber c) {

        this(c.getStartPC(), c.getLineNumber());

    }

    /**

     * Construct object from file stream.

     *

     * @param file Input stream

     * @throws IOException if an I/O Exception occurs in readUnsignedShort

     */

    LineNumber(final DataInput file) throws IOException {

        this(file.readUnsignedShort(), file.readUnsignedShort());

    }

    /**

     * @param startPc Program Counter (PC) corresponds to

     * @param lineNumber line number in source file

     */

    public LineNumber(final int startPc, final int lineNumber) {

        this.startPc = (short) startPc;

        this.lineNumber = (short)lineNumber;

    }

    /**

     * Called by objects that are traversing the nodes of the tree implicitely

     * defined by the contents of a Java class. I.e., the hierarchy of methods,

     * fields, attributes, etc. spawns a tree of objects.

     *

     * @param v Visitor object

     */

    @Override

    public void accept( final Visitor v ) {

        v.visitLineNumber(this);

    }

    /**

     * Dump line number/pc pair to file stream in binary format.

     *

     * @param file Output file stream

     * @throws IOException if an I/O Exception occurs in writeShort

     */

    public void dump( final DataOutputStream file ) throws IOException {

        file.writeShort(startPc);

        file.writeShort(lineNumber);

    }

    /**

     * @return Corresponding source line

     */

    public int getLineNumber() {

        return 0xffff & lineNumber;

    }

    /**

     * @return PC in code

     */

    public int getStartPC() {

        return  0xffff & startPc;

    }

    /**

     * @param lineNumber the source line number

     */

    public void setLineNumber( final int lineNumber ) {

        this.lineNumber = (short) lineNumber;

    }

    /**

     * @param startPc the pc for this line number

     */

    public void setStartPC( final int startPc ) {

        this.startPc = (short) startPc;

    }

    /**

     * @return String representation

     */

    @Override

    public String toString() {

        return "LineNumber(" + startPc + ", " + lineNumber + ")";

    }

    /**

     * @return deep copy of this object

     */

    public LineNumber copy() {

        try {

            return (LineNumber) clone();

        } catch (final CloneNotSupportedException e) {

            // TODO should this throw?

        }

        return null;

    }

}