/*

 * Copyright (c) 1999, 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.javac.util;

import java.io.*;

/** A byte buffer is a flexible array which grows when elements are

 *  appended. There are also methods to append names to byte buffers

 *  and to convert byte buffers to names.

 *

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public class ByteBuffer {

    /** An array holding the bytes in this buffer; can be grown.

     */

    public byte[] elems;

    /** The current number of defined bytes in this buffer.

     */

    public int length;

    /** Create a new byte buffer.

     */

    public ByteBuffer() {

        this(64);

    }

    /** Create a new byte buffer with an initial elements array

     *  of given size.

     */

    public ByteBuffer(int initialSize) {

        elems = new byte[initialSize];

        length = 0;

    }

    private void copy(int size) {

        byte[] newelems = new byte[size];

        System.arraycopy(elems, 0, newelems, 0, elems.length);

        elems = newelems;

    }

    /** Append byte to this buffer.

     */

    public void appendByte(int b) {

        if (length >= elems.length) copy(elems.length * 2);

        elems[length++] = (byte)b;

    }

    /** Append `len' bytes from byte array,

     *  starting at given `start' offset.

     */

    public void appendBytes(byte[] bs, int start, int len) {

        while (length + len > elems.length) copy(elems.length * 2);

        System.arraycopy(bs, start, elems, length, len);

        length += len;

    }

    /** Append all bytes from given byte array.

     */

    public void appendBytes(byte[] bs) {

        appendBytes(bs, 0, bs.length);

    }

    /** Append a character as a two byte number.

     */

    public void appendChar(int x) {

        while (length + 1 >= elems.length) copy(elems.length * 2);

        elems[length  ] = (byte)((x >>  8) & 0xFF);

        elems[length+1] = (byte)((x      ) & 0xFF);

        length = length + 2;

    }

    /** Append an integer as a four byte number.

     */

    public void appendInt(int x) {

        while (length + 3 >= elems.length) copy(elems.length * 2);

        elems[length  ] = (byte)((x >> 24) & 0xFF);

        elems[length+1] = (byte)((x >> 16) & 0xFF);

        elems[length+2] = (byte)((x >>  8) & 0xFF);

        elems[length+3] = (byte)((x      ) & 0xFF);

        length = length + 4;

    }

    /** Append a long as an eight byte number.

     */

    public void appendLong(long x) {

        ByteArrayOutputStream buffer = new ByteArrayOutputStream(8);

        DataOutputStream bufout = new DataOutputStream(buffer);

        try {

            bufout.writeLong(x);

            appendBytes(buffer.toByteArray(), 0, 8);

        } catch (IOException e) {

            throw new AssertionError("write");

        }

    }

    /** Append a float as a four byte number.

     */

    public void appendFloat(float x) {

        ByteArrayOutputStream buffer = new ByteArrayOutputStream(4);

        DataOutputStream bufout = new DataOutputStream(buffer);

        try {

            bufout.writeFloat(x);

            appendBytes(buffer.toByteArray(), 0, 4);

        } catch (IOException e) {

            throw new AssertionError("write");

        }

    }

    /** Append a double as a eight byte number.

     */

    public void appendDouble(double x) {

        ByteArrayOutputStream buffer = new ByteArrayOutputStream(8);

        DataOutputStream bufout = new DataOutputStream(buffer);

        try {

            bufout.writeDouble(x);

            appendBytes(buffer.toByteArray(), 0, 8);

        } catch (IOException e) {

            throw new AssertionError("write");

        }

    }

    /** Append a name.

     */

    public void appendName(Name name) {

        appendBytes(name.getByteArray(), name.getByteOffset(), name.getByteLength());

    }

    /** Reset to zero length.

     */

    public void reset() {

        length = 0;

    }

    /** Convert contents to name.

     */

    public Name toName(Names names) {

        return names.fromUtf(elems, 0, length);

    }

}