/*
* Copyright (c) 2004, 2011, 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.*;
/**
* OutputStream that sends the output to the underlying stream using chunked
* encoding as specified in RFC 2068.
*/
public class ChunkedOutputStream extends PrintStream {
/* Default chunk size (including chunk header) if not specified */
static final int DEFAULT_CHUNK_SIZE = 4096;
private static final byte[] CRLF = {'\r', '\n'};
private static final int CRLF_SIZE = CRLF.length;
private static final byte[] FOOTER = CRLF;
private static final int FOOTER_SIZE = CRLF_SIZE;
private static final byte[] EMPTY_CHUNK_HEADER = getHeader(0);
private static final int EMPTY_CHUNK_HEADER_SIZE = getHeaderSize(0);
/* internal buffer */
private byte buf[];
/* size of data (excluding footers and headers) already stored in buf */
private int size;
/* current index in buf (i.e. buf[count] */
private int count;
/* number of bytes to be filled up to complete a data chunk
* currently being built */
private int spaceInCurrentChunk;
/* underlying stream */
private PrintStream out;
/* the chunk size we use */
private int preferredChunkDataSize;
private int preferedHeaderSize;
private int preferredChunkGrossSize;
/* header for a complete Chunk */
private byte[] completeHeader;
/* return the size of the header for a particular chunk size */
private static int getHeaderSize(int size) {
return (Integer.toHexString(size)).length() + CRLF_SIZE;
}
/* return a header for a particular chunk size */
private static byte[] getHeader(int size){
try {
String hexStr = Integer.toHexString(size);
byte[] hexBytes = hexStr.getBytes("US-ASCII");
byte[] header = new byte[getHeaderSize(size)];
for (int i=0; i<hexBytes.length; i++)
header[i] = hexBytes[i];
header[hexBytes.length] = CRLF[0];
header[hexBytes.length+1] = CRLF[1];
return header;
} catch (java.io.UnsupportedEncodingException e) {
/* This should never happen */
throw new InternalError(e.getMessage(), e);
}
}
public ChunkedOutputStream(PrintStream o) {
this(o, DEFAULT_CHUNK_SIZE);
}
public ChunkedOutputStream(PrintStream o, int size) {
super(o);
out = o;
if (size <= 0) {
size = DEFAULT_CHUNK_SIZE;
}
/* Adjust the size to cater for the chunk header - eg: if the
* preferred chunk size is 1k this means the chunk size should
* be 1017 bytes (differs by 7 from preferred size because of
* 3 bytes for chunk size in hex and CRLF (header) and CRLF (footer)).
*
* If headerSize(adjusted_size) is shorter then headerSize(size)
* then try to use the extra byte unless headerSize(adjusted_size+1)
* increases back to headerSize(size)
*/
if (size > 0) {
int adjusted_size = size - getHeaderSize(size) - FOOTER_SIZE;
if (getHeaderSize(adjusted_size+1) < getHeaderSize(size)){
adjusted_size++;
}
size = adjusted_size;
}
if (size > 0) {
preferredChunkDataSize = size;
} else {
preferredChunkDataSize = DEFAULT_CHUNK_SIZE -
getHeaderSize(DEFAULT_CHUNK_SIZE) - FOOTER_SIZE;
}
preferedHeaderSize = getHeaderSize(preferredChunkDataSize);
preferredChunkGrossSize = preferedHeaderSize + preferredChunkDataSize
+ FOOTER_SIZE;
completeHeader = getHeader(preferredChunkDataSize);
/* start with an initial buffer */
buf = new byte[preferredChunkGrossSize];
reset();
}
/*
* Flush a buffered, completed chunk to an underlying stream. If the data in
* the buffer is insufficient to build up a chunk of "preferredChunkSize"
* then the data do not get flushed unless flushAll is true. If flushAll is
* true then the remaining data builds up a last chunk which size is smaller
* than preferredChunkSize, and then the last chunk gets flushed to
* underlying stream. If flushAll is true and there is no data in a buffer
* at all then an empty chunk (containing a header only) gets flushed to
* underlying stream.
*/
private void flush(boolean flushAll) {
if (spaceInCurrentChunk == 0) {
/* flush a completed chunk to underlying stream */
out.write(buf, 0, preferredChunkGrossSize);
out.flush();
reset();
} else if (flushAll){
/* complete the last chunk and flush it to underlying stream */
if (size > 0){
/* adjust a header start index in case the header of the last
* chunk is shorter then preferedHeaderSize */
int adjustedHeaderStartIndex = preferedHeaderSize -
getHeaderSize(size);
/* write header */
System.arraycopy(getHeader(size), 0, buf,
adjustedHeaderStartIndex, getHeaderSize(size));
/* write footer */
buf[count++] = FOOTER[0];
buf[count++] = FOOTER[1];
//send the last chunk to underlying stream
out.write(buf, adjustedHeaderStartIndex, count - adjustedHeaderStartIndex);
} else {
//send an empty chunk (containing just a header) to underlying stream
out.write(EMPTY_CHUNK_HEADER, 0, EMPTY_CHUNK_HEADER_SIZE);
}
out.flush();
reset();
}
}
@Override
public boolean checkError() {
return out.checkError();
}
/* Check that the output stream is still open */
private void ensureOpen() {
if (out == null)
setError();
}
/*
* Writes data from b[] to an internal buffer and stores the data as data
* chunks of a following format: {Data length in Hex}{CRLF}{data}{CRLF}
* The size of the data is preferredChunkSize. As soon as a completed chunk
* is read from b[] a process of reading from b[] suspends, the chunk gets
* flushed to the underlying stream and then the reading process from b[]
* continues. When there is no more sufficient data in b[] to build up a
* chunk of preferredChunkSize size the data get stored as an incomplete
* chunk of a following format: {space for data length}{CRLF}{data}
* The size of the data is of course smaller than preferredChunkSize.
*/
@Override
public synchronized void write(byte b[], int off, int len) {
ensureOpen();
if ((off < 0) || (off > b.length) || (len < 0) ||
((off + len) > b.length) || ((off + len) < 0)) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return;
}
/* if b[] contains enough data then one loop cycle creates one complete
* data chunk with a header, body and a footer, and then flushes the
* chunk to the underlying stream. Otherwise, the last loop cycle
* creates incomplete data chunk with empty header and with no footer
* and stores this incomplete chunk in an internal buffer buf[]
*/
int bytesToWrite = len;
int inputIndex = off; /* the index of the byte[] currently being written */
do {
/* enough data to complete a chunk */
if (bytesToWrite >= spaceInCurrentChunk) {
/* header */
for (int i=0; i<completeHeader.length; i++)
buf[i] = completeHeader[i];
/* data */
System.arraycopy(b, inputIndex, buf, count, spaceInCurrentChunk);
inputIndex += spaceInCurrentChunk;
bytesToWrite -= spaceInCurrentChunk;
count += spaceInCurrentChunk;
/* footer */
buf[count++] = FOOTER[0];
buf[count++] = FOOTER[1];
spaceInCurrentChunk = 0; //chunk is complete
flush(false);
if (checkError()){
break;
}
}
/* not enough data to build a chunk */
else {
/* header */
/* do not write header if not enough bytes to build a chunk yet */
/* data */
System.arraycopy(b, inputIndex, buf, count, bytesToWrite);
count += bytesToWrite;
size += bytesToWrite;
spaceInCurrentChunk -= bytesToWrite;
bytesToWrite = 0;
/* footer */
/* do not write header if not enough bytes to build a chunk yet */
}
} while (bytesToWrite > 0);
}
@Override
public synchronized void write(int _b) {
byte b[] = {(byte)_b};
write(b, 0, 1);
}
public synchronized void reset() {
count = preferedHeaderSize;
size = 0;
spaceInCurrentChunk = preferredChunkDataSize;
}
public int size() {
return size;
}
@Override
public synchronized void close() {
ensureOpen();
/* if we have buffer a chunked send it */
if (size > 0) {
flush(true);
}
/* send a zero length chunk */
flush(true);
/* don't close the underlying stream */
out = null;
}
@Override
public synchronized void flush() {
ensureOpen();
if (size > 0) {
flush(true);
}
}
}