/*
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.flex.swf.io;
import java.io.IOException;
import java.io.InputStream;
import org.apache.flex.utils.DAByteArrayOutputStream;
import SevenZip.Compression.LZMA.Decoder;
/**
* Takes an input stream of LZMA compressed bytes, provides a stream on
* uncompressed data.
*/
public class LZMAInputStream extends InputStream
{
/**
* At the point this function is called, we should have read the 12 byte SWF
* Header already.
*/
public LZMAInputStream(InputStream inputStream) throws IOException
{
decoder = new Decoder();
this.inputStream = inputStream;
initDecode();
}
private final Decoder decoder;
private final InputStream inputStream;
private byte[] buffer = null;
private int readIndex;
@Override
public int read() throws IOException
{
if (readIndex >= buffer.length)
return -1;
else
{
int ret = buffer[readIndex++];
if (ret < 0) // convert signed byte to unsigned byte
ret += 256;
return ret;
}
}
/**
* set up the LZMA decoder, then decompress the entire file into memory
*
* @throws IOException
*/
private void initDecode() throws IOException
{
int propertiesSize = 5;
byte[] properties = new byte[propertiesSize];
if (inputStream.read(properties, 0, propertiesSize) != propertiesSize)
throw new IOException("input .lzma file is too short");
if (!decoder.SetDecoderProperties(properties))
throw new IOException("Incorrect stream properties");
/* swf omits the len field */
DAByteArrayOutputStream os = new DAByteArrayOutputStream();
long outSize = -1;
if (!decoder.Code(inputStream, os, outSize))
throw new IOException("Error in data stream");
os.flush();
readIndex = 0;
buffer = os.getDirectByteArray();
}
}