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	/*
	* Copyright (c) 2000, 2012, 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 javax.imageio.stream;

	import java.io.File;
	import java.io.IOException;
	import java.io.OutputStream;
	import java.io.RandomAccessFile;
	import java.nio.file.Files;
	import com.sun.imageio.stream.StreamCloser;

	/**
	* An implementation of <code>ImageOutputStream</code> that writes its
	* output to a regular <code>OutputStream</code>. A file is used to
	* cache data until it is flushed to the output stream.
	*
	*/
	public class FileCacheImageOutputStream extends ImageOutputStreamImpl {

	private OutputStream stream;

	private File cacheFile;

	private RandomAccessFile cache;

	// Pos after last (rightmost) byte written
	private long maxStreamPos = 0L;

	/** The CloseAction that closes the stream in
	* the StreamCloser's shutdown hook */
	private final StreamCloser.CloseAction closeAction;

	/**
	* Constructs a <code>FileCacheImageOutputStream</code> that will write
	* to a given <code>outputStream</code>.
	*
	* <p> A temporary file is used as a cache. If
	* <code>cacheDir</code>is non-<code>null</code> and is a
	* directory, the file will be created there. If it is
	* <code>null</code>, the system-dependent default temporary-file
	* directory will be used (see the documentation for
	* <code>File.createTempFile</code> for details).
	*
	* @param stream an <code>OutputStream</code> to write to.
	* @param cacheDir a <code>File</code> indicating where the
	* cache file should be created, or <code>null</code> to use the
	* system directory.
	*
	* @exception IllegalArgumentException if <code>stream</code>
	* is <code>null</code>.
	* @exception IllegalArgumentException if <code>cacheDir</code> is
	* non-<code>null</code> but is not a directory.
	* @exception IOException if a cache file cannot be created.
	*/
	public FileCacheImageOutputStream(OutputStream stream, File cacheDir)
	throws IOException {
	if (stream == null) {
	throw new IllegalArgumentException("stream == null!");
	}
	if ((cacheDir != null) && !(cacheDir.isDirectory())) {
	throw new IllegalArgumentException("Not a directory!");
	}
	this.stream = stream;
	if (cacheDir == null)
	this.cacheFile = Files.createTempFile("imageio", ".tmp").toFile();
	else
	this.cacheFile = Files.createTempFile(cacheDir.toPath(), "imageio", ".tmp")
	.toFile();
	this.cache = new RandomAccessFile(cacheFile, "rw");

	this.closeAction = StreamCloser.createCloseAction(this);
	StreamCloser.addToQueue(closeAction);
	}

	public int read() throws IOException {
	checkClosed();
	bitOffset = 0;
	int val = cache.read();
	if (val != -1) {
	++streamPos;
	}
	return val;
	}

	public int read(byte[] b, int off, int len) throws IOException {
	checkClosed();

	if (b == null) {
	throw new NullPointerException("b == null!");
	}
	if (off < 0 \|\| len < 0 \|\| off + len > b.length \|\| off + len < 0) {
	throw new IndexOutOfBoundsException
	("off < 0 \|\| len < 0 \|\| off+len > b.length \|\| off+len < 0!");
	}

	bitOffset = 0;

	if (len == 0) {
	return 0;
	}

	int nbytes = cache.read(b, off, len);
	if (nbytes != -1) {
	streamPos += nbytes;
	}
	return nbytes;
	}

	public void write(int b) throws IOException {
	flushBits(); // this will call checkClosed() for us
	cache.write(b);
	++streamPos;
	maxStreamPos = Math.max(maxStreamPos, streamPos);
	}

	public void write(byte[] b, int off, int len) throws IOException {
	flushBits(); // this will call checkClosed() for us
	cache.write(b, off, len);
	streamPos += len;
	maxStreamPos = Math.max(maxStreamPos, streamPos);
	}

	public long length() {
	try {
	checkClosed();
	return cache.length();
	} catch (IOException e) {
	return -1L;
	}
	}

	/**
	* Sets the current stream position and resets the bit offset to
	* 0. It is legal to seek past the end of the file; an
	* <code>EOFException</code> will be thrown only if a read is
	* performed. The file length will not be increased until a write
	* is performed.
	*
	* @exception IndexOutOfBoundsException if <code>pos</code> is smaller
	* than the flushed position.
	* @exception IOException if any other I/O error occurs.
	*/
	public void seek(long pos) throws IOException {
	checkClosed();

	if (pos < flushedPos) {
	throw new IndexOutOfBoundsException();
	}

	cache.seek(pos);
	this.streamPos = cache.getFilePointer();
	maxStreamPos = Math.max(maxStreamPos, streamPos);
	this.bitOffset = 0;
	}

	/**
	* Returns <code>true</code> since this
	* <code>ImageOutputStream</code> caches data in order to allow
	* seeking backwards.
	*
	* @return <code>true</code>.
	*
	* @see #isCachedMemory
	* @see #isCachedFile
	*/
	public boolean isCached() {
	return true;
	}

	/**
	* Returns <code>true</code> since this
	* <code>ImageOutputStream</code> maintains a file cache.
	*
	* @return <code>true</code>.
	*
	* @see #isCached
	* @see #isCachedMemory
	*/
	public boolean isCachedFile() {
	return true;
	}

	/**
	* Returns <code>false</code> since this
	* <code>ImageOutputStream</code> does not maintain a main memory
	* cache.
	*
	* @return <code>false</code>.
	*
	* @see #isCached
	* @see #isCachedFile
	*/
	public boolean isCachedMemory() {
	return false;
	}

	/**
	* Closes this <code>FileCacheImageOutputStream</code>. All
	* pending data is flushed to the output, and the cache file
	* is closed and removed. The destination <code>OutputStream</code>
	* is not closed.
	*
	* @exception IOException if an error occurs.
	*/
	public void close() throws IOException {
	maxStreamPos = cache.length();

	seek(maxStreamPos);
	flushBefore(maxStreamPos);
	super.close();
	cache.close();
	cache = null;
	cacheFile.delete();
	cacheFile = null;
	stream.flush();
	stream = null;
	StreamCloser.removeFromQueue(closeAction);
	}

	public void flushBefore(long pos) throws IOException {
	long oFlushedPos = flushedPos;
	super.flushBefore(pos); // this will call checkClosed() for us

	long flushBytes = flushedPos - oFlushedPos;
	if (flushBytes > 0) {
	int bufLen = 512;
	byte[] buf = new byte[bufLen];
	cache.seek(oFlushedPos);
	while (flushBytes > 0) {
	int len = (int)Math.min(flushBytes, bufLen);
	cache.readFully(buf, 0, len);
	stream.write(buf, 0, len);
	flushBytes -= len;
	}
	stream.flush();
	}
	}
	}

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