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	/*
	* Copyright (c) 1999, 2013, 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 sun.net.www.http;

	import java.io.*;
	import java.util.*;

	import sun.net.*;
	import sun.net.www.*;

	/**
	* A <code>ChunkedInputStream</code> provides a stream for reading a body of
	* a http message that can be sent as a series of chunks, each with its own
	* size indicator. Optionally the last chunk can be followed by trailers
	* containing entity-header fields.
	* <p>
	* A <code>ChunkedInputStream</code> is also <code>Hurryable</code> so it
	* can be hurried to the end of the stream if the bytes are available on
	* the underlying stream.
	*/
	public
	class ChunkedInputStream extends InputStream implements Hurryable {

	/**
	* The underlying stream
	*/
	private InputStream in;

	/**
	* The <code>HttpClient</code> that should be notified when the chunked stream has
	* completed.
	*/
	private HttpClient hc;

	/**
	* The <code>MessageHeader</code> that is populated with any optional trailer
	* that appear after the last chunk.
	*/
	private MessageHeader responses;

	/**
	* The size, in bytes, of the chunk that is currently being read.
	* This size is only valid if the current position in the underlying
	* input stream is inside a chunk (ie: state == STATE_READING_CHUNK).
	*/
	private int chunkSize;

	/**
	* The number of bytes read from the underlying stream for the current
	* chunk. This value is always in the range <code>0</code> through to
	* <code>chunkSize</code>
	*/
	private int chunkRead;

	/**
	* The internal buffer array where chunk data is available for the
	* application to read.
	*/
	private byte chunkData[] = new byte[4096];

	/**
	* The current position in the buffer. It contains the index
	* of the next byte to read from <code>chunkData</code>
	*/
	private int chunkPos;

	/**
	* The index one greater than the index of the last valid byte in the
	* buffer. This value is always in the range <code>0</code> through
	* <code>chunkData.length</code>.
	*/
	private int chunkCount;

	/**
	* The internal buffer where bytes from the underlying stream can be
	* read. It may contain bytes representing chunk-size, chunk-data, or
	* trailer fields.
	*/
	private byte rawData[] = new byte[32];

	/**
	* The current position in the buffer. It contains the index
	* of the next byte to read from <code>rawData</code>
	*/
	private int rawPos;

	/**
	* The index one greater than the index of the last valid byte in the
	* buffer. This value is always in the range <code>0</code> through
	* <code>rawData.length</code>.
	*/
	private int rawCount;

	/**
	* Indicates if an error was encountered when processing the chunked
	* stream.
	*/
	private boolean error;

	/**
	* Indicates if the chunked stream has been closed using the
	* <code>close</code> method.
	*/
	private boolean closed;

	/*
	* Maximum chunk header size of 2KB + 2 bytes for CRLF
	*/
	private final static int MAX_CHUNK_HEADER_SIZE = 2050;

	/**
	* State to indicate that next field should be :-
	* chunk-size [ chunk-extension ] CRLF
	*/
	static final int STATE_AWAITING_CHUNK_HEADER = 1;

	/**
	* State to indicate that we are currently reading the chunk-data.
	*/
	static final int STATE_READING_CHUNK = 2;

	/**
	* Indicates that a chunk has been completely read and the next
	* fields to be examine should be CRLF
	*/
	static final int STATE_AWAITING_CHUNK_EOL = 3;

	/**
	* Indicates that all chunks have been read and the next field
	* should be optional trailers or an indication that the chunked
	* stream is complete.
	*/
	static final int STATE_AWAITING_TRAILERS = 4;

	/**
	* State to indicate that the chunked stream is complete and
	* no further bytes should be read from the underlying stream.
	*/
	static final int STATE_DONE = 5;

	/**
	* Indicates the current state.
	*/
	private int state;


	/**
	* Check to make sure that this stream has not been closed.
	*/
	private void ensureOpen() throws IOException {
	if (closed) {
	throw new IOException("stream is closed");
	}
	}


	/**
	* Ensures there is <code>size</code> bytes available in
	* <code>rawData</code>. This requires that we either
	* shift the bytes in use to the begining of the buffer
	* or allocate a large buffer with sufficient space available.
	*/
	private void ensureRawAvailable(int size) {
	if (rawCount + size > rawData.length) {
	int used = rawCount - rawPos;
	if (used + size > rawData.length) {
	byte tmp[] = new byte[used + size];
	if (used > 0) {
	System.arraycopy(rawData, rawPos, tmp, 0, used);
	}
	rawData = tmp;
	} else {
	if (used > 0) {
	System.arraycopy(rawData, rawPos, rawData, 0, used);
	}
	}
	rawCount = used;
	rawPos = 0;
	}
	}


	/**
	* Close the underlying input stream by either returning it to the
	* keep alive cache or closing the stream.
	* <p>
	* As a chunked stream is inheritly persistent (see HTTP 1.1 RFC) the
	* underlying stream can be returned to the keep alive cache if the
	* stream can be completely read without error.
	*/
	private void closeUnderlying() throws IOException {
	if (in == null) {
	return;
	}

	if (!error && state == STATE_DONE) {
	hc.finished();
	} else {
	if (!hurry()) {
	hc.closeServer();
	}
	}

	in = null;
	}

	/**
	* Attempt to read the remainder of a chunk directly into the
	* caller's buffer.
	* <p>
	* Return the number of bytes read.
	*/
	private int fastRead(byte[] b, int off, int len) throws IOException {

	// assert state == STATE_READING_CHUNKS;

	int remaining = chunkSize - chunkRead;
	int cnt = (remaining < len) ? remaining : len;
	if (cnt > 0) {
	int nread;
	try {
	nread = in.read(b, off, cnt);
	} catch (IOException e) {
	error = true;
	throw e;
	}
	if (nread > 0) {
	chunkRead += nread;
	if (chunkRead >= chunkSize) {
	state = STATE_AWAITING_CHUNK_EOL;
	}
	return nread;
	}
	error = true;
	throw new IOException("Premature EOF");
	} else {
	return 0;
	}
	}

	/**
	* Process any outstanding bytes that have already been read into
	* <code>rawData</code>.
	* <p>
	* The parsing of the chunked stream is performed as a state machine with
	* <code>state</code> representing the current state of the processing.
	* <p>
	* Returns when either all the outstanding bytes in rawData have been
	* processed or there is insufficient bytes available to continue
	* processing. When the latter occurs <code>rawPos</code> will not have
	* been updated and thus the processing can be restarted once further
	* bytes have been read into <code>rawData</code>.
	*/
	private void processRaw() throws IOException {
	int pos;
	int i;

	while (state != STATE_DONE) {

	switch (state) {

	/**
	* We are awaiting a line with a chunk header
	*/
	case STATE_AWAITING_CHUNK_HEADER:
	/*
	* Find \n to indicate end of chunk header. If not found when there is
	* insufficient bytes in the raw buffer to parse a chunk header.
	*/
	pos = rawPos;
	while (pos < rawCount) {
	if (rawData[pos] == '\n') {
	break;
	}
	pos++;
	if ((pos - rawPos) >= MAX_CHUNK_HEADER_SIZE) {
	error = true;
	throw new IOException("Chunk header too long");
	}
	}
	if (pos >= rawCount) {
	return;
	}

	/*
	* Extract the chunk size from the header (ignoring extensions).
	*/
	String header = new String(rawData, rawPos, pos-rawPos+1, "US-ASCII");
	for (i=0; i < header.length(); i++) {
	if (Character.digit(header.charAt(i), 16) == -1)
	break;
	}
	try {
	chunkSize = Integer.parseInt(header.substring(0, i), 16);
	} catch (NumberFormatException e) {
	error = true;
	throw new IOException("Bogus chunk size");
	}

	/*
	* Chunk has been parsed so move rawPos to first byte of chunk
	* data.
	*/
	rawPos = pos + 1;
	chunkRead = 0;

	/*
	* A chunk size of 0 means EOF.
	*/
	if (chunkSize > 0) {
	state = STATE_READING_CHUNK;
	} else {
	state = STATE_AWAITING_TRAILERS;
	}
	break;


	/**
	* We are awaiting raw entity data (some may have already been
	* read). chunkSize is the size of the chunk; chunkRead is the
	* total read from the underlying stream to date.
	*/
	case STATE_READING_CHUNK :
	/* no data available yet */
	if (rawPos >= rawCount) {
	return;
	}

	/*
	* Compute the number of bytes of chunk data available in the
	* raw buffer.
	*/
	int copyLen = Math.min( chunkSize-chunkRead, rawCount-rawPos );

	/*
	* Expand or compact chunkData if needed.
	*/
	if (chunkData.length < chunkCount + copyLen) {
	int cnt = chunkCount - chunkPos;
	if (chunkData.length < cnt + copyLen) {
	byte tmp[] = new byte[cnt + copyLen];
	System.arraycopy(chunkData, chunkPos, tmp, 0, cnt);
	chunkData = tmp;
	} else {
	System.arraycopy(chunkData, chunkPos, chunkData, 0, cnt);
	}
	chunkPos = 0;
	chunkCount = cnt;
	}

	/*
	* Copy the chunk data into chunkData so that it's available
	* to the read methods.
	*/
	System.arraycopy(rawData, rawPos, chunkData, chunkCount, copyLen);
	rawPos += copyLen;
	chunkCount += copyLen;
	chunkRead += copyLen;

	/*
	* If all the chunk has been copied into chunkData then the next
	* token should be CRLF.
	*/
	if (chunkSize - chunkRead <= 0) {
	state = STATE_AWAITING_CHUNK_EOL;
	} else {
	return;
	}
	break;


	/**
	* Awaiting CRLF after the chunk
	*/
	case STATE_AWAITING_CHUNK_EOL:
	/* not available yet */
	if (rawPos + 1 >= rawCount) {
	return;
	}

	if (rawData[rawPos] != '\r') {
	error = true;
	throw new IOException("missing CR");
	}
	if (rawData[rawPos+1] != '\n') {
	error = true;
	throw new IOException("missing LF");
	}
	rawPos += 2;

	/*
	* Move onto the next chunk
	*/
	state = STATE_AWAITING_CHUNK_HEADER;
	break;


	/**
	* Last chunk has been read so not we're waiting for optional
	* trailers.
	*/
	case STATE_AWAITING_TRAILERS:

	/*
	* Do we have an entire line in the raw buffer?
	*/
	pos = rawPos;
	while (pos < rawCount) {
	if (rawData[pos] == '\n') {
	break;
	}
	pos++;
	}
	if (pos >= rawCount) {
	return;
	}

	if (pos == rawPos) {
	error = true;
	throw new IOException("LF should be proceeded by CR");
	}
	if (rawData[pos-1] != '\r') {
	error = true;
	throw new IOException("LF should be proceeded by CR");
	}

	/*
	* Stream done so close underlying stream.
	*/
	if (pos == (rawPos + 1)) {

	state = STATE_DONE;
	closeUnderlying();

	return;
	}

	/*
	* Extract any tailers and append them to the message
	* headers.
	*/
	String trailer = new String(rawData, rawPos, pos-rawPos, "US-ASCII");
	i = trailer.indexOf(':');
	if (i == -1) {
	throw new IOException("Malformed tailer - format should be key:value");
	}
	String key = (trailer.substring(0, i)).trim();
	String value = (trailer.substring(i+1, trailer.length())).trim();

	responses.add(key, value);

	/*
	* Move onto the next trailer.
	*/
	rawPos = pos+1;
	break;

	} /* switch */
	}
	}


	/**
	* Reads any available bytes from the underlying stream into
	* <code>rawData</code> and returns the number of bytes of
	* chunk data available in <code>chunkData</code> that the
	* application can read.
	*/
	private int readAheadNonBlocking() throws IOException {

	/*
	* If there's anything available on the underlying stream then we read
	* it into the raw buffer and process it. Processing ensures that any
	* available chunk data is made available in chunkData.
	*/
	int avail = in.available();
	if (avail > 0) {

	/* ensure that there is space in rawData to read the available */
	ensureRawAvailable(avail);

	int nread;
	try {
	nread = in.read(rawData, rawCount, avail);
	} catch (IOException e) {
	error = true;
	throw e;
	}
	if (nread < 0) {
	error = true; /* premature EOF ? */
	return -1;
	}
	rawCount += nread;

	/*
	* Process the raw bytes that have been read.
	*/
	processRaw();
	}

	/*
	* Return the number of chunked bytes available to read
	*/
	return chunkCount - chunkPos;
	}

	/**
	* Reads from the underlying stream until there is chunk data
	* available in <code>chunkData</code> for the application to
	* read.
	*/
	private int readAheadBlocking() throws IOException {

	do {
	/*
	* All of chunked response has been read to return EOF.
	*/
	if (state == STATE_DONE) {
	return -1;
	}

	/*
	* We must read into the raw buffer so make sure there is space
	* available. We use a size of 32 to avoid too much chunk data
	* being read into the raw buffer.
	*/
	ensureRawAvailable(32);
	int nread;
	try {
	nread = in.read(rawData, rawCount, rawData.length-rawCount);
	} catch (IOException e) {
	error = true;
	throw e;
	}

	/**
	* If we hit EOF it means there's a problem as we should never
	* attempt to read once the last chunk and trailers have been
	* received.
	*/
	if (nread < 0) {
	error = true;
	throw new IOException("Premature EOF");
	}

	/**
	* Process the bytes from the underlying stream
	*/
	rawCount += nread;
	processRaw();

	} while (chunkCount <= 0);

	/*
	* Return the number of chunked bytes available to read
	*/
	return chunkCount - chunkPos;
	}

	/**
	* Read ahead in either blocking or non-blocking mode. This method
	* is typically used when we run out of available bytes in
	* <code>chunkData</code> or we need to determine how many bytes
	* are available on the input stream.
	*/
	private int readAhead(boolean allowBlocking) throws IOException {

	/*
	* Last chunk already received - return EOF
	*/
	if (state == STATE_DONE) {
	return -1;
	}

	/*
	* Reset position/count if data in chunkData is exhausted.
	*/
	if (chunkPos >= chunkCount) {
	chunkCount = 0;
	chunkPos = 0;
	}

	/*
	* Read ahead blocking or non-blocking
	*/
	if (allowBlocking) {
	return readAheadBlocking();
	} else {
	return readAheadNonBlocking();
	}
	}

	/**
	* Creates a <code>ChunkedInputStream</code> and saves its arguments, for
	* later use.
	*
	* @param in the underlying input stream.
	* @param hc the HttpClient
	* @param responses the MessageHeader that should be populated with optional
	* trailers.
	*/
	public ChunkedInputStream(InputStream in, HttpClient hc, MessageHeader responses) throws IOException {

	/* save arguments */
	this.in = in;
	this.responses = responses;
	this.hc = hc;

	/*
	* Set our initial state to indicate that we are first starting to
	* look for a chunk header.
	*/
	state = STATE_AWAITING_CHUNK_HEADER;
	}

	/**
	* See
	* the general contract of the <code>read</code>
	* method of <code>InputStream</code>.
	*
	* @return the next byte of data, or <code>-1</code> if the end of the
	* stream is reached.
	* @exception IOException if an I/O error occurs.
	* @see java.io.FilterInputStream#in
	*/
	public synchronized int read() throws IOException {
	ensureOpen();
	if (chunkPos >= chunkCount) {
	if (readAhead(true) <= 0) {
	return -1;
	}
	}
	return chunkData[chunkPos++] & 0xff;
	}


	/**
	* Reads bytes from this stream into the specified byte array, starting at
	* the given offset.
	*
	* @param b destination buffer.
	* @param off offset at which to start storing bytes.
	* @param len maximum number of bytes to read.
	* @return the number of bytes read, or <code>-1</code> if the end of
	* the stream has been reached.
	* @exception IOException if an I/O error occurs.
	*/
	public synchronized int read(byte b[], int off, int len)
	throws IOException
	{
	ensureOpen();
	if ((off < 0) \|\| (off > b.length) \|\| (len < 0) \|\|
	((off + len) > b.length) \|\| ((off + len) < 0)) {
	throw new IndexOutOfBoundsException();
	} else if (len == 0) {
	return 0;
	}

	int avail = chunkCount - chunkPos;
	if (avail <= 0) {
	/*
	* Optimization: if we're in the middle of the chunk read
	* directly from the underlying stream into the caller's
	* buffer
	*/
	if (state == STATE_READING_CHUNK) {
	return fastRead( b, off, len );
	}

	/*
	* We're not in the middle of a chunk so we must read ahead
	* until there is some chunk data available.
	*/
	avail = readAhead(true);
	if (avail < 0) {
	return -1; /* EOF */
	}
	}
	int cnt = (avail < len) ? avail : len;
	System.arraycopy(chunkData, chunkPos, b, off, cnt);
	chunkPos += cnt;

	return cnt;
	}

	/**
	* Returns the number of bytes that can be read from this input
	* stream without blocking.
	*
	* @return the number of bytes that can be read from this input
	* stream without blocking.
	* @exception IOException if an I/O error occurs.
	* @see java.io.FilterInputStream#in
	*/
	public synchronized int available() throws IOException {
	ensureOpen();

	int avail = chunkCount - chunkPos;
	if(avail > 0) {
	return avail;
	}

	avail = readAhead(false);

	if (avail < 0) {
	return 0;
	} else {
	return avail;
	}
	}

	/**
	* Close the stream by either returning the connection to the
	* keep alive cache or closing the underlying stream.
	* <p>
	* If the chunked response hasn't been completely read we
	* try to "hurry" to the end of the response. If this is
	* possible (without blocking) then the connection can be
	* returned to the keep alive cache.
	*
	* @exception IOException if an I/O error occurs.
	*/
	public synchronized void close() throws IOException {
	if (closed) {
	return;
	}
	closeUnderlying();
	closed = true;
	}

	/**
	* Hurry the input stream by reading everything from the underlying
	* stream. If the last chunk (and optional trailers) can be read without
	* blocking then the stream is considered hurried.
	* <p>
	* Note that if an error has occurred or we can't get to last chunk
	* without blocking then this stream can't be hurried and should be
	* closed.
	*/
	public synchronized boolean hurry() {
	if (in == null \|\| error) {
	return false;
	}

	try {
	readAhead(false);
	} catch (Exception e) {
	return false;
	}

	if (error) {
	return false;
	}

	return (state == STATE_DONE);
	}

	}

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