/*
Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
The MySQL Connector/J is licensed under the terms of the GPLv2
<http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most MySQL Connectors.
There are special exceptions to the terms and conditions of the GPLv2 as it is applied to
this software, see the FLOSS License Exception
<http://www.mysql.com/about/legal/licensing/foss-exception.html>.
This program is free software; you can redistribute it and/or modify it under the terms
of the GNU General Public License as published by the Free Software Foundation; version 2
of the License.
This program 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 for more details.
You should have received a copy of the GNU General Public License along with this
program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth
Floor, Boston, MA 02110-1301 USA
*/
package com.mysql.jdbc;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.sql.SQLException;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;
/**
* Used to de-compress packets from the MySQL server when protocol-level
* compression is turned on.
*
* @author Mark Matthews
*
* @version $Id: CompressedInputStream.java,v 1.1.2.1 2005/05/13 18:58:37
* mmatthews Exp $
*/
class CompressedInputStream extends InputStream {
/** The packet data after it has been un-compressed */
private byte[] buffer;
/** The connection that is using us (used to read config values) */
private Connection connection;
/** The stream we are reading from the server */
private InputStream in;
/** The ZIP inflater used to un-compress packets */
private Inflater inflater;
/**
* The buffer to read packet headers into
*/
private byte[] packetHeaderBuffer = new byte[7];
/** The position we are reading from */
private int pos = 0;
/**
* Creates a new CompressedInputStream that reads the given stream from the
* server.
*
* @param conn
* DOCUMENT ME!
* @param streamFromServer
*/
public CompressedInputStream(Connection conn, InputStream streamFromServer) {
this.connection = conn;
this.in = streamFromServer;
this.inflater = new Inflater();
}
/**
* @see java.io.InputStream#available()
*/
public int available() throws IOException {
if (this.buffer == null) {
return this.in.available();
}
return this.buffer.length - this.pos + this.in.available();
}
/**
* @see java.io.InputStream#close()
*/
public void close() throws IOException {
this.in.close();
this.buffer = null;
this.inflater = null;
}
/**
* Retrieves and un-compressed (if necessary) the next packet from the
* server.
*
* @throws IOException
* if an I/O error occurs
*/
private void getNextPacketFromServer() throws IOException {
byte[] uncompressedData = null;
int lengthRead = readFully(this.packetHeaderBuffer, 0, 7);
if (lengthRead < 7) {
throw new IOException("Unexpected end of input stream");
}
int compressedPacketLength = ((this.packetHeaderBuffer[0] & 0xff))
+ (((this.packetHeaderBuffer[1] & 0xff)) << 8)
+ (((this.packetHeaderBuffer[2] & 0xff)) << 16);
int uncompressedLength = ((this.packetHeaderBuffer[4] & 0xff))
+ (((this.packetHeaderBuffer[5] & 0xff)) << 8)
+ (((this.packetHeaderBuffer[6] & 0xff)) << 16);
if (this.connection.getTraceProtocol()) {
try {
this.connection.getLog().logTrace(
"Reading compressed packet of length "
+ compressedPacketLength + " uncompressed to "
+ uncompressedLength);
} catch (SQLException sqlEx) {
throw new IOException(sqlEx.toString()); // should never
// happen
}
}
if (uncompressedLength > 0) {
uncompressedData = new byte[uncompressedLength];
byte[] compressedBuffer = new byte[compressedPacketLength];
readFully(compressedBuffer, 0, compressedPacketLength);
try {
this.inflater.reset();
} catch (NullPointerException npe) {
this.inflater = new Inflater();
}
this.inflater.setInput(compressedBuffer);
try {
this.inflater.inflate(uncompressedData);
} catch (DataFormatException dfe) {
throw new IOException(
"Error while uncompressing packet from server.");
}
this.inflater.end();
} else {
if (this.connection.getTraceProtocol()) {
try {
this.connection
.getLog()
.logTrace(
"Packet didn't meet compression threshold, not uncompressing...");
} catch (SQLException sqlEx) {
throw new IOException(sqlEx.toString()); // should never
// happen
}
}
//
// Read data, note this this code is reached when using
// compressed packets that have not been compressed, as well
//
uncompressedData = new byte[compressedPacketLength];
readFully(uncompressedData, 0, compressedPacketLength);
}
if (this.connection.getTraceProtocol()) {
try {
this.connection.getLog().logTrace(
"Uncompressed packet: \n"
+ StringUtils.dumpAsHex(uncompressedData,
compressedPacketLength));
} catch (SQLException sqlEx) {
throw new IOException(sqlEx.toString()); // should never
// happen
}
}
if ((this.buffer != null) && (this.pos < this.buffer.length)) {
if (this.connection.getTraceProtocol()) {
try {
this.connection.getLog().logTrace(
"Combining remaining packet with new: ");
} catch (SQLException sqlEx) {
throw new IOException(sqlEx.toString()); // should never
// happen
}
}
int remaining = this.buffer.length - this.pos;
byte[] newBuffer = new byte[remaining + uncompressedData.length];
int newIndex = 0;
for (int i = this.pos; i < this.buffer.length; i++)
newBuffer[newIndex++] = this.buffer[i];
System.arraycopy(uncompressedData, 0, newBuffer, newIndex,
uncompressedData.length);
uncompressedData = newBuffer;
}
this.pos = 0;
this.buffer = uncompressedData;
return;
}
/**
* Determines if another packet needs to be read from the server to be able
* to read numBytes from the stream.
*
* @param numBytes
* the number of bytes to be read
*
* @throws IOException
* if an I/O error occors.
*/
private void getNextPacketIfRequired(int numBytes) throws IOException {
if ((this.buffer == null)
|| ((this.pos + numBytes) > this.buffer.length)) {
getNextPacketFromServer();
}
}
/**
* @see java.io.InputStream#read()
*/
public int read() throws IOException {
try {
getNextPacketIfRequired(1);
} catch (IOException ioEx) {
return -1;
}
return this.buffer[this.pos++] & 0xff;
}
/**
* @see java.io.InputStream#read(byte)
*/
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
/**
* @see java.io.InputStream#read(byte, int, int)
*/
public int read(byte[] b, int off, int len) throws IOException {
if (b == null) {
throw new NullPointerException();
} else if ((off < 0) || (off > b.length) || (len < 0)
|| ((off + len) > b.length) || ((off + len) < 0)) {
throw new IndexOutOfBoundsException();
}
if (len <= 0) {
return 0;
}
try {
getNextPacketIfRequired(len);
} catch (IOException ioEx) {
return -1;
}
System.arraycopy(this.buffer, this.pos, b, off, len);
this.pos += len;
return len;
}
private final int readFully(byte[] b, int off, int len) throws IOException {
if (len < 0) {
throw new IndexOutOfBoundsException();
}
int n = 0;
while (n < len) {
int count = this.in.read(b, off + n, len - n);
if (count < 0) {
throw new EOFException();
}
n += count;
}
return n;
}
/**
* @see java.io.InputStream#skip(long)
*/
public long skip(long n) throws IOException {
long count = 0;
for (long i = 0; i < n; i++) {
int bytesRead = read();
if (bytesRead == -1) {
break;
}
count++;
}
return count;
}
}