001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.activemq.util;
018
019import java.io.OutputStream;
020
021
022/**
023 * Very similar to the java.io.ByteArrayOutputStream but this version 
024 * is not thread safe and the resulting data is returned in a ByteSequence
025 * to avoid an extra byte[] allocation.
026 */
027public class ByteArrayOutputStream extends OutputStream {
028
029    byte buffer[];
030    int size;
031
032    public ByteArrayOutputStream() {
033        this(1028);
034    }
035    public ByteArrayOutputStream(int capacity) {
036        buffer = new byte[capacity];
037    }
038
039    public void write(int b) {
040        int newsize = size + 1;
041        checkCapacity(newsize);
042        buffer[size] = (byte) b;
043        size = newsize;
044    }
045
046    public void write(byte b[], int off, int len) {
047        int newsize = size + len;
048        checkCapacity(newsize);
049        System.arraycopy(b, off, buffer, size, len);
050        size = newsize;
051    }
052    
053    /**
054     * Ensures the the buffer has at least the minimumCapacity specified. 
055     * @param minimumCapacity
056     */
057    private void checkCapacity(int minimumCapacity) {
058        if (minimumCapacity > buffer.length) {
059            byte b[] = new byte[Math.max(buffer.length << 1, minimumCapacity)];
060            System.arraycopy(buffer, 0, b, 0, size);
061            buffer = b;
062        }
063    }
064
065    public void reset() {
066        size = 0;
067    }
068
069    public ByteSequence toByteSequence() {
070        return new ByteSequence(buffer, 0, size);
071    }
072    
073    public byte[] toByteArray() {
074        byte rc[] = new byte[size];
075        System.arraycopy(buffer, 0, rc, 0, size);
076        return rc;
077    }
078    
079    public int size() {
080        return size;
081    }
082
083    public boolean endsWith(final byte[] array) {
084        int i = 0;
085        int start = size - array.length;
086        if (start < 0) {
087            return false;
088        }
089        while (start < size) {
090            if (buffer[start++] != array[i++]) {
091                return false;
092            }
093        }
094        return true;
095    }
096}