/*
 * Copyright (c) 2007, 2008, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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 com.sun.tools.classfile;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Objects;

 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/**
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class ClassReader {
    ClassReader(ClassFile classFile, InputStream in, Attribute.Factory attributeFactory) throws IOException {
        this.classFile = Objects.requireNonNull(classFile);
        this.attributeFactory = Objects.requireNonNull(attributeFactory);
        this.in = new DataInputStream(new BufferedInputStream(in));
    }

    ClassFile getClassFile() {
        return classFile;
    }

    ConstantPool getConstantPool() {
        return classFile.constant_pool;
    }

    public Attribute readAttribute() throws IOException {
        int name_index = readUnsignedShort();
        int length = readInt();
        byte[] data = new byte[length];
        readFully(data);

        DataInputStream prev = in;
        in = new DataInputStream(new ByteArrayInputStream(data));
        try {
            return attributeFactory.createAttribute(this, name_index, data);
        } finally {
            in = prev;
        }
    }

    public void readFully(byte[] b) throws IOException {
        in.readFully(b);
    }

    public int readUnsignedByte() throws IOException {
        return in.readUnsignedByte();
    }

    public int readUnsignedShort() throws IOException {
        return in.readUnsignedShort();
    }

    public int readInt() throws IOException {
        return in.readInt();
    }

    public long readLong() throws IOException {
        return in.readLong();
    }

    public float readFloat() throws IOException {
        return in.readFloat();
    }

    public double readDouble() throws IOException {
        return in.readDouble();
    }

    public String readUTF() throws IOException {
        return in.readUTF();
    }

    private DataInputStream in;
    private ClassFile classFile;
    private Attribute.Factory attributeFactory;
}