/*

 */

/*

 * 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;

import com.sun.org.apache.bcel.internal.Const;

/**

 * This class represents a local variable within a method. It contains its

 * scope, name, signature and index on the method's frame.

 *

 * @see     LocalVariableTable

 */

public final class LocalVariable implements Cloneable, Node {

    private int start_pc; // Range in which the variable is valid

    private int length;

    private int name_index; // Index in constant pool of variable name

    private int signature_index; // Index of variable signature

    private int index; /* Variable is `index'th local variable on

     * this method's frame.

     */

    private ConstantPool constant_pool;

    /**

     * Initialize from another object. Note that both objects use the same

     * references (shallow copy). Use copy() for a physical copy.

     */

    public LocalVariable(final LocalVariable c) {

        this(c.getStartPC(), c.getLength(), c.getNameIndex(), c.getSignatureIndex(), c.getIndex(),

                c.getConstantPool());

    }

    /**

     * Construct object from file stream.

     * @param file Input stream

     * @throws IOException

     */

    LocalVariable(final DataInput file, final ConstantPool constant_pool) throws IOException {

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

                .readUnsignedShort(), file.readUnsignedShort(), constant_pool);

    }

    /**

     * @param start_pc Range in which the variable

     * @param length ... is valid

     * @param name_index Index in constant pool of variable name

     * @param signature_index Index of variable's signature

     * @param index Variable is `index'th local variable on the method's frame

     * @param constant_pool Array of constants

     */

    public LocalVariable(final int start_pc, final int length, final int name_index, final int signature_index, final int index,

            final ConstantPool constant_pool) {

        this.start_pc = start_pc;

        this.length = length;

        this.name_index = name_index;

        this.signature_index = signature_index;

        this.index = index;

        this.constant_pool = constant_pool;

    }

    /**

     * 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.visitLocalVariable(this);

    }

    /**

     * Dump local variable to file stream in binary format.

     *

     * @param file Output file stream

     * @throws IOException

     */

    public final void dump( final DataOutputStream file ) throws IOException {

        file.writeShort(start_pc);

        file.writeShort(length);

        file.writeShort(name_index);

        file.writeShort(signature_index);

        file.writeShort(index);

    }

    /**

     * @return Constant pool used by this object.

     */

    public final ConstantPool getConstantPool() {

        return constant_pool;

    }

    /**

     * @return Variable is valid within getStartPC() .. getStartPC()+getLength()

     */

    public final int getLength() {

        return length;

    }

    /**

     * @return Variable name.

     */

    public final String getName() {

        ConstantUtf8 c;

        c = (ConstantUtf8) constant_pool.getConstant(name_index, Const.CONSTANT_Utf8);

        return c.getBytes();

    }

    /**

     * @return Index in constant pool of variable name.

     */

    public final int getNameIndex() {

        return name_index;

    }

    /**

     * @return Signature.

     */

    public final String getSignature() {

        ConstantUtf8 c;

        c = (ConstantUtf8) constant_pool.getConstant(signature_index, Const.CONSTANT_Utf8);

        return c.getBytes();

    }

    /**

     * @return Index in constant pool of variable signature.

     */

    public final int getSignatureIndex() {

        return signature_index;

    }

    /**

     * @return index of register where variable is stored

     */

    public final int getIndex() {

        return index;

    }

    /**

     * @return Start of range where he variable is valid

     */

    public final int getStartPC() {

        return start_pc;

    }

    /*

     * Helper method shared with LocalVariableTypeTable

     */

    final String toStringShared( final boolean typeTable ) {

        final String name = getName();

        final String signature = Utility.signatureToString(getSignature(), false);

        final String label = "LocalVariable" + (typeTable ? "Types" : "" );

        return label + "(start_pc = " + start_pc + ", length = " + length + ", index = "

                + index + ":" + signature + " " + name + ")";

    }

    /**

     * @param constant_pool Constant pool to be used for this object.

     */

    public final void setConstantPool( final ConstantPool constant_pool ) {

        this.constant_pool = constant_pool;

    }

    /**

     * @param length the length of this local variable

     */

    public final void setLength( final int length ) {

        this.length = length;

    }

    /**

     * @param name_index the index into the constant pool for the name of this variable

     */

    public final void setNameIndex( final int name_index ) { // TODO unused

        this.name_index = name_index;

    }

    /**

     * @param signature_index the index into the constant pool for the signature of this variable

     */

    public final void setSignatureIndex( final int signature_index ) { // TODO unused

        this.signature_index = signature_index;

    }

    /**

     * @param index the index in the local variable table of this variable

     */

    public final void setIndex( final int index ) { // TODO unused

        this.index = index;

    }

    /**

     * @param start_pc Specify range where the local variable is valid.

     */

    public final void setStartPC( final int start_pc ) { // TODO unused

        this.start_pc = start_pc;

    }

    /**

     * @return string representation.

     */

    @Override

    public final String toString() {

        return toStringShared(false);

    }

    /**

     * @return deep copy of this object

     */

    public LocalVariable copy() {

        try {

            return (LocalVariable) clone();

        } catch (final CloneNotSupportedException e) {

            // TODO should this throw?

        }

        return null;

    }

}