- /*
- * Copyright 2003,2004 The Apache Software Foundation.
- *
- * Licensed 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 org.apache.commons.io.output;
-
- import java.io.IOException;
- import java.io.OutputStream;
- import java.io.UnsupportedEncodingException;
- import java.util.List;
-
- /**
- * This class implements an output stream in which the data is
- * written into a byte array. The buffer automatically grows as data
- * is written to it.
- * <p>
- * The data can be retrieved using <code>toByteArray()</code> and
- * <code>toString()</code>.
- * <p>
- * Closing a <tt>ByteArrayOutputStream</tt> has no effect. The methods in
- * this class can be called after the stream has been closed without
- * generating an <tt>IOException</tt>.
- * <p>
- * This is an alternative implementation of the java.io.ByteArrayOutputStream
- * class. The original implementation only allocates 32 bytes at the beginning.
- * As this class is designed for heavy duty it starts at 1024 bytes. In contrast
- * to the original it doesn't reallocate the whole memory block but allocates
- * additional buffers. This way no buffers need to be garbage collected and
- * the contents don't have to be copied to the new buffer. This class is
- * designed to behave exactly like the original. The only exception is the
- * deprecated toString(int) method that has been ignored.
- * @author <a href="mailto:jeremias@apache.org">Jeremias Maerki</a>
- * @version $Id: ByteArrayOutputStream.java,v 1.8 2004/04/24 19:24:09 jeremias Exp $
- */
- public class ByteArrayOutputStream extends OutputStream {
-
- private List buffers = new java.util.ArrayList();
- private int currentBufferIndex;
- private int filledBufferSum;
- private byte[] currentBuffer;
- private int count;
-
- /**
- * Creates a new byte array output stream. The buffer capacity is
- * initially 1024 bytes, though its size increases if necessary.
- */
- public ByteArrayOutputStream() {
- this(1024);
- }
-
- /**
- * Creates a new byte array output stream, with a buffer capacity of
- * the specified size, in bytes.
- *
- * @param size the initial size.
- * @exception IllegalArgumentException if size is negative.
- */
- public ByteArrayOutputStream(int size) {
- if (size < 0) {
- throw new IllegalArgumentException(
- "Negative initial size: " + size);
- }
- needNewBuffer(size);
- }
-
- private byte[] getBuffer(int index) {
- return (byte[])buffers.get(index);
- }
-
- private void needNewBuffer(int newcount) {
- if (currentBufferIndex < buffers.size() - 1) {
- //Recycling old buffer
- filledBufferSum += currentBuffer.length;
-
- currentBufferIndex++;
- currentBuffer = getBuffer(currentBufferIndex);
- } else {
- //Creating new buffer
- int newBufferSize;
- if (currentBuffer == null) {
- newBufferSize = newcount;
- filledBufferSum = 0;
- } else {
- newBufferSize = Math.max(
- currentBuffer.length << 1,
- newcount - filledBufferSum);
- filledBufferSum += currentBuffer.length;
- }
-
- currentBufferIndex++;
- currentBuffer = new byte[newBufferSize];
- buffers.add(currentBuffer);
- }
- }
-
- /**
- * @see java.io.OutputStream#write(byte[], int, int)
- */
- public synchronized void write(byte[] b, int off, int len) {
- if ((off < 0)
- || (off > b.length)
- || (len < 0)
- || ((off + len) > b.length)
- || ((off + len) < 0)) {
- throw new IndexOutOfBoundsException();
- } else if (len == 0) {
- return;
- }
- int newcount = count + len;
- int remaining = len;
- int inBufferPos = count - filledBufferSum;
- while (remaining > 0) {
- int part = Math.min(remaining, currentBuffer.length - inBufferPos);
- System.arraycopy(b, off + len - remaining, currentBuffer, inBufferPos, part);
- remaining -= part;
- if (remaining > 0) {
- needNewBuffer(newcount);
- inBufferPos = 0;
- }
- }
- count = newcount;
- }
-
- /**
- * Calls the write(byte[]) method.
- *
- * @see java.io.OutputStream#write(int)
- */
- public synchronized void write(int b) {
- write(new byte[] {(byte)b}, 0, 1);
- }
-
- /**
- * @see java.io.ByteArrayOutputStream#size()
- */
- public int size() {
- return count;
- }
-
- /**
- * Closing a <tt>ByteArrayOutputStream</tt> has no effect. The methods in
- * this class can be called after the stream has been closed without
- * generating an <tt>IOException</tt>.
- * @throws IOException in case an I/O error occurs
- */
- public void close() throws IOException {
- //nop
- }
-
- /**
- * @see java.io.ByteArrayOutputStream#reset()
- */
- public synchronized void reset() {
- count = 0;
- filledBufferSum = 0;
- currentBufferIndex = 0;
- currentBuffer = getBuffer(currentBufferIndex);
- }
-
- /**
- * @see java.io.ByteArrayOutputStream#writeTo(OutputStream)
- */
- public synchronized void writeTo(OutputStream out) throws IOException {
- int remaining = count;
- for (int i = 0; i < buffers.size(); i++) {
- byte[] buf = getBuffer(i);
- int c = Math.min(buf.length, remaining);
- out.write(buf, 0, c);
- remaining -= c;
- if (remaining == 0) {
- break;
- }
- }
- }
-
- /**
- * @see java.io.ByteArrayOutputStream#toByteArray()
- */
- public synchronized byte toByteArray()[] {
- int remaining = count;
- int pos = 0;
- byte newbuf[] = new byte[count];
- for (int i = 0; i < buffers.size(); i++) {
- byte[] buf = getBuffer(i);
- int c = Math.min(buf.length, remaining);
- System.arraycopy(buf, 0, newbuf, pos, c);
- pos += c;
- remaining -= c;
- if (remaining == 0) {
- break;
- }
- }
- return newbuf;
- }
-
- /**
- * @see java.io.ByteArrayOutputStream#toString()
- */
- public String toString() {
- return new String(toByteArray());
- }
-
- /**
- * @see java.io.ByteArrayOutputStream#toString(String)
- */
- public String toString(String enc) throws UnsupportedEncodingException {
- return new String(toByteArray(), enc);
- }
-
- }