package org.bouncycastle.cms;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.DeflaterOutputStream;
import org.bouncycastle.asn1.cms.CMSObjectIdentifiers;
import org.bouncycastle.asn1.BERSequenceGenerator;
import org.bouncycastle.asn1.DERInteger;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.DERSequenceGenerator;
import org.bouncycastle.asn1.BEROctetStringGenerator;
/**
* General class for generating a compressed CMS message stream.
* <p>
* A simple example of usage.
* </p>
* <pre>
* CMSCompressedDataStreamGenerator gen = new CMSCompressedDataStreamGenerator();
*
* OutputStream cOut = gen.open(outputStream, CMSCompressedDataStreamGenerator.ZLIB);
*
* cOut.write(data);
*
* cOut.close();
* </pre>
*/
public class CMSCompressedDataStreamGenerator
{
public static final String ZLIB = "1.2.840.113549.1.9.16.3.8";
/**
* base constructor
*/
public CMSCompressedDataStreamGenerator()
{
}
public OutputStream open(
OutputStream out,
String compressionOID)
throws IOException
{
return open(out, CMSObjectIdentifiers.data.getId(), compressionOID);
}
public OutputStream open(
OutputStream out,
String contentOID,
String compressionOID)
throws IOException
{
BERSequenceGenerator sGen = new BERSequenceGenerator(out);
sGen.addObject(CMSObjectIdentifiers.compressedData);
//
// Compressed Data
//
BERSequenceGenerator cGen = new BERSequenceGenerator(sGen.getRawOutputStream(), 0, true);
cGen.addObject(new DERInteger(0));
//
// AlgorithmIdentifier
//
DERSequenceGenerator algGen = new DERSequenceGenerator(cGen.getRawOutputStream());
algGen.addObject(new DERObjectIdentifier(ZLIB));
algGen.close();
//
// Encapsulated ContentInfo
//
BERSequenceGenerator eiGen = new BERSequenceGenerator(cGen.getRawOutputStream());
eiGen.addObject(new DERObjectIdentifier(contentOID));
BEROctetStringGenerator octGen = new BEROctetStringGenerator(eiGen.getRawOutputStream(), 0, true);
return new CmsCompressedOutputStream(new DeflaterOutputStream(octGen.getOctetOutputStream()), sGen, cGen, eiGen);
}
private class CmsCompressedOutputStream
extends OutputStream
{
private DeflaterOutputStream _out;
private BERSequenceGenerator _sGen;
private BERSequenceGenerator _cGen;
private BERSequenceGenerator _eiGen;
CmsCompressedOutputStream(
DeflaterOutputStream out,
BERSequenceGenerator sGen,
BERSequenceGenerator cGen,
BERSequenceGenerator eiGen)
{
_out = out;
_sGen = sGen;
_cGen = cGen;
_eiGen = eiGen;
}
public void write(
int b)
throws IOException
{
_out.write(b);
}
public void write(
byte[] bytes,
int off,
int len)
throws IOException
{
_out.write(bytes, off, len);
}
public void write(
byte[] bytes)
throws IOException
{
_out.write(bytes);
}
public void close()
throws IOException
{
_out.close();
_eiGen.close();
_cGen.close();
_sGen.close();
}
}
}