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package org.bouncycastle.openpgp;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterInputStream;
import org.bouncycastle.apache.bzip2.CBZip2InputStream;
import org.bouncycastle.bcpg.BCPGInputStream;
import org.bouncycastle.bcpg.CompressedDataPacket;
import org.bouncycastle.bcpg.CompressionAlgorithmTags;
import org.bouncycastle.bcpg.PacketTags;
/**
* A PGP compressed data object.
*/
public class PGPCompressedData
implements CompressionAlgorithmTags
{
CompressedDataPacket data;
/**
* Construct a compressed data object, reading a single {@link PacketTags#COMPRESSED_DATA}
* packet from the stream.
*
* @param pIn a PGP input stream, with a compressed data packet as the current packet.
* @throws IOException if an error occurs reading the packet from the stream.
*/
public PGPCompressedData(
BCPGInputStream pIn)
throws IOException
{
data = (CompressedDataPacket)pIn.readPacket();
}
/**
* Return the {@link CompressionAlgorithmTags compression algorithm} used for this packet.
*
* @return the compression algorithm code
*/
public int getAlgorithm()
{
return data.getAlgorithm();
}
/**
* Return the raw input stream contained in the object.
* <p/>
* Note that this stream is shared with the decompression stream, so consuming the returned
* stream will affect decompression.
*
* @return the raw data in the compressed data packet.
*/
public InputStream getInputStream()
{
return data.getInputStream();
}
/**
* Return an input stream that decompresses and returns data in the compressed packet.
*
* @return a stream over the uncompressed data.
* @throws PGPException if an error occurs constructing the decompression stream.
*/
public InputStream getDataStream()
throws PGPException
{
if (this.getAlgorithm() == UNCOMPRESSED)
{
return this.getInputStream();
}
if (this.getAlgorithm() == ZIP)
{
return new InflaterInputStream(this.getInputStream(), new Inflater(true))
{
// If the "nowrap" inflater option is used the stream can
// apparently overread - we override fill() and provide
// an extra byte for the end of the input stream to get
// around this.
//
// Totally weird...
//
protected void fill() throws IOException
{
if (eof)
{
throw new EOFException("Unexpected end of ZIP input stream");
}
len = this.in.read(buf, 0, buf.length);
if (len == -1)
{
buf[0] = 0;
len = 1;
eof = true;
}
inf.setInput(buf, 0, len);
}
private boolean eof = false;
};
}
if (this.getAlgorithm() == ZLIB)
{
return new InflaterInputStream(this.getInputStream())
{
// If the "nowrap" inflater option is used the stream can
// apparently overread - we override fill() and provide
// an extra byte for the end of the input stream to get
// around this.
//
// Totally weird...
//
protected void fill() throws IOException
{
if (eof)
{
throw new EOFException("Unexpected end of ZIP input stream");
}
len = this.in.read(buf, 0, buf.length);
if (len == -1)
{
buf[0] = 0;
len = 1;
eof = true;
}
inf.setInput(buf, 0, len);
}
private boolean eof = false;
};
}
if (this.getAlgorithm() == BZIP2)
{
try
{
return new CBZip2InputStream(this.getInputStream());
}
catch (IOException e)
{
throw new PGPException("I/O problem with stream: " + e, e);
}
}
throw new PGPException("can't recognise compression algorithm: " + this.getAlgorithm());
}
}
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