/*

 * 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;

import java.util.HashMap;

import java.util.Map;

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

/**

 * This class represents a reference to an unknown (i.e.,

 * application-specific) attribute of a class.  It is instantiated from the

 * {@link Attribute#readAttribute(java.io.DataInput, ConstantPool)} method.

 * Applications that need to read in application-specific attributes should create an

 * {@link UnknownAttributeReader} implementation and attach it via

 * {@link Attribute#addAttributeReader(String, UnknownAttributeReader)}.

 *

 * @see Attribute

 * @see UnknownAttributeReader

 */

public final class Unknown extends Attribute {

    private byte[] bytes;

    private final String name;

    private static final Map<String, Unknown> unknownAttributes = new HashMap<>();

    /** @return array of unknown attributes, but just one for each kind.

     */

    static Unknown[] getUnknownAttributes() {

        final Unknown[] unknowns = new Unknown[unknownAttributes.size()];

        unknownAttributes.values().toArray(unknowns);

        unknownAttributes.clear();

        return unknowns;

    }

    /**

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

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

     */

    public Unknown(final Unknown c) {

        this(c.getNameIndex(), c.getLength(), c.getBytes(), c.getConstantPool());

    }

    /**

     * Create a non-standard attribute.

     *

     * @param name_index Index in constant pool

     * @param length Content length in bytes

     * @param bytes Attribute contents

     * @param constant_pool Array of constants

     */

    public Unknown(final int name_index, final int length, final byte[] bytes, final ConstantPool constant_pool) {

        super(Const.ATTR_UNKNOWN, name_index, length, constant_pool);

        this.bytes = bytes;

        name = ((ConstantUtf8) constant_pool.getConstant(name_index, Const.CONSTANT_Utf8))

                .getBytes();

        unknownAttributes.put(name, this);

    }

    /**

     * Construct object from input stream.

     *

     * @param name_index Index in constant pool

     * @param length Content length in bytes

     * @param input Input stream

     * @param constant_pool Array of constants

     * @throws IOException

     */

    Unknown(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool)

            throws IOException {

        this(name_index, length, (byte[]) null, constant_pool);

        if (length > 0) {

            bytes = new byte[length];

            input.readFully(bytes);

        }

    }

    /**

     * 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.visitUnknown(this);

    }

    /**

     * Dump unknown bytes to file stream.

     *

     * @param file Output file stream

     * @throws IOException

     */

    @Override

    public void dump( final DataOutputStream file ) throws IOException {

        super.dump(file);

        if (super.getLength() > 0) {

            file.write(bytes, 0, super.getLength());

        }

    }

    /**

     * @return data bytes.

     */

    public byte[] getBytes() {

        return bytes;

    }

    /**

     * @return name of attribute.

     */

    @Override

    public String getName() {

        return name;

    }

    /**

     * @param bytes the bytes to set

     */

    public void setBytes( final byte[] bytes ) {

        this.bytes = bytes;

    }

    /**

     * @return String representation.

     */

    @Override

    public String toString() {

        if (super.getLength() == 0 || bytes == null) {

            return "(Unknown attribute " + name + ")";

        }

        String hex;

        if (super.getLength() > 10) {

            final byte[] tmp = new byte[10];

            System.arraycopy(bytes, 0, tmp, 0, 10);

            hex = Utility.toHexString(tmp) + "... (truncated)";

        } else {

            hex = Utility.toHexString(bytes);

        }

        return "(Unknown attribute " + name + ": " + hex + ")";

    }

    /**

     * @return deep copy of this attribute

     */

    @Override

    public Attribute copy( final ConstantPool _constant_pool ) {

        final Unknown c = (Unknown) clone();

        if (bytes != null) {

            c.bytes = new byte[bytes.length];

            System.arraycopy(bytes, 0, c.bytes, 0, bytes.length);

        }

        c.setConstantPool(_constant_pool);

        return c;

    }

}