/*
 * Copyright (C) 2010, 2013 Google Inc.
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.eclipse.jgit.util.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

Input stream that copies data read to another output stream. This stream is primarily useful with a TemporaryBuffer, where any data read or skipped by the caller is also duplicated into the temporary buffer. Later the temporary buffer can then be used instead of the original source stream. During close this stream copies any remaining data from the source stream into the destination stream. /**
 * Input stream that copies data read to another output stream.
 *
 * This stream is primarily useful with a
 * {@link org.eclipse.jgit.util.TemporaryBuffer}, where any data read or skipped
 * by the caller is also duplicated into the temporary buffer. Later the
 * temporary buffer can then be used instead of the original source stream.
 *
 * During close this stream copies any remaining data from the source stream
 * into the destination stream.
 */
public class TeeInputStream extends InputStream {
	private byte[] skipBuffer;

	private InputStream src;

	private OutputStream dst;

	
Initialize a tee input stream.
Params:
src – 
           source stream to consume.
dst –  destination to copy the source to as it is consumed. Typically this is a TemporaryBuffer./**
	 * Initialize a tee input stream.
	 *
	 * @param src
	 *            source stream to consume.
	 * @param dst
	 *            destination to copy the source to as it is consumed. Typically
	 *            this is a {@link org.eclipse.jgit.util.TemporaryBuffer}.
	 */
	public TeeInputStream(InputStream src, OutputStream dst) {
		this.src = src;
		this.dst = dst;
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public int read() throws IOException {
		byte[] b = skipBuffer();
		int n = read(b, 0, 1);
		return n == 1 ? b[0] & 0xff : -1;
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public long skip(long count) throws IOException {
		long skipped = 0;
		long cnt = count;
		final byte[] b = skipBuffer();
		while (0 < cnt) {
			final int n = src.read(b, 0, (int) Math.min(b.length, cnt));
			if (n <= 0)
				break;
			dst.write(b, 0, n);
			skipped += n;
			cnt -= n;
		}
		return skipped;
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public int read(byte[] b, int off, int len) throws IOException {
		if (len == 0)
			return 0;

		int n = src.read(b, off, len);
		if (0 < n)
			dst.write(b, off, n);
		return n;
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public void close() throws IOException {
		byte[] b = skipBuffer();
		for (;;) {
			int n = src.read(b);
			if (n <= 0)
				break;
			dst.write(b, 0, n);
		}
		dst.close();
		src.close();
	}

	private byte[] skipBuffer() {
		if (skipBuffer == null)
			skipBuffer = new byte[2048];
		return skipBuffer;
	}
}