/*
 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/util/ByteArrayBuffer.java $
 * $Revision: 496070 $
 * $Date: 2007-01-14 04:18:34 -0800 (Sun, 14 Jan 2007) $
 *
 * ====================================================================
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.util;

/**
 * A resizable byte array.
 *
 * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
 * 
 * @version $Revision: 496070 $
 * 
 * @since 4.0
 */
public final class ByteArrayBuffer  {
    
    private byte[] buffer;
    private int len;

    public ByteArrayBuffer(int capacity) {
        super();
        if (capacity < 0) {
            throw new IllegalArgumentException("Buffer capacity may not be negative");
        }
        this.buffer = new byte[capacity]; 
    }

    private void expand(int newlen) {
        byte newbuffer[] = new byte[Math.max(this.buffer.length << 1, newlen)];
        System.arraycopy(this.buffer, 0, newbuffer, 0, this.len);
        this.buffer = newbuffer;
    }
    
    public void append(final byte[] b, int off, int len) {
        if (b == null) {
            return;
        }
        if ((off < 0) || (off > b.length) || (len < 0) ||
                ((off + len) < 0) || ((off + len) > b.length)) {
            throw new IndexOutOfBoundsException();
        }
        if (len == 0) {
            return;
        }
        int newlen = this.len + len;
        if (newlen > this.buffer.length) {
            expand(newlen);
        }
        System.arraycopy(b, off, this.buffer, this.len, len);
        this.len = newlen;
    }

    public void append(int b) {
        int newlen = this.len + 1;
        if (newlen > this.buffer.length) {
            expand(newlen);
        }
        this.buffer[this.len] = (byte)b;
        this.len = newlen;
    }

    public void append(final char[] b, int off, int len) {
        if (b == null) {
            return;
        }
        if ((off < 0) || (off > b.length) || (len < 0) ||
                ((off + len) < 0) || ((off + len) > b.length)) {
            throw new IndexOutOfBoundsException();
        }
        if (len == 0) {
            return;
        }
        int oldlen = this.len;
        int newlen = oldlen + len;
        if (newlen > this.buffer.length) {
            expand(newlen);
        }
        for (int i1 = off, i2 = oldlen; i2 < newlen; i1++, i2++) {
            this.buffer[i2] = (byte) b[i1];
        }
        this.len = newlen;
    }

    public void append(final CharArrayBuffer b, int off, int len) {
        if (b == null) {
            return;
        }
        append(b.buffer(), off, len);
    }
    
    public void clear() {
        this.len = 0;
    }
    
    public byte[] toByteArray() {
        byte[] b = new byte[this.len]; 
        if (this.len > 0) {
            System.arraycopy(this.buffer, 0, b, 0, this.len);
        }
        return b;
    }
    
    public int byteAt(int i) {
        return this.buffer[i];
    }
    
    public int capacity() {
        return this.buffer.length;
    }
    
    public int length() {
        return this.len;
    }

    public byte[] buffer() {
        return this.buffer;
    }
        
    public void setLength(int len) {
        if (len < 0 || len > this.buffer.length) {
            throw new IndexOutOfBoundsException();
        }
        this.len = len;
    }
    
    public boolean isEmpty() {
        return this.len == 0; 
    }
    
    public boolean isFull() {
        return this.len == this.buffer.length; 
    }
    
}