package org.bouncycastle.cms;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.DeflaterOutputStream;
import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.BERConstructedOctetString;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.cms.CMSObjectIdentifiers;
import org.bouncycastle.asn1.cms.CompressedData;
import org.bouncycastle.asn1.cms.ContentInfo;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
/**
* General class for generating a compressed CMS message.
* <p>
* A simple example of usage.
* <p>
* <pre>
* CMSCompressedDataGenerator fact = new CMSCompressedDataGenerator();
*
* CMSCompressedData data = fact.generate(content, algorithm);
* </pre>
*/
public class CMSCompressedDataGenerator
{
public static final String ZLIB = "1.2.840.113549.1.9.16.3.8";
/**
* base constructor
*/
public CMSCompressedDataGenerator()
{
}
private DERObject makeObj(
byte[] encoding)
throws IOException
{
if (encoding == null)
{
return null;
}
ByteArrayInputStream bIn = new ByteArrayInputStream(encoding);
ASN1InputStream aIn = new ASN1InputStream(bIn);
return aIn.readObject();
}
private AlgorithmIdentifier makeAlgId(
String oid,
byte[] params)
throws IOException
{
if (params != null)
{
return new AlgorithmIdentifier(
new DERObjectIdentifier(oid), makeObj(params));
}
else
{
return new AlgorithmIdentifier(new DERObjectIdentifier(oid));
}
}
/**
* generate an object that contains an CMS Compressed Data
*/
public CMSCompressedData generate(
CMSProcessable content,
String compressionOID)
throws CMSException
{
AlgorithmIdentifier comAlgId;
ASN1OctetString comOcts;
try
{
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
DeflaterOutputStream zOut = new DeflaterOutputStream(bOut);
content.write(zOut);
zOut.close();
comAlgId = makeAlgId(compressionOID, null);
comOcts = new BERConstructedOctetString(bOut.toByteArray());
}
catch (IOException e)
{
throw new CMSException("exception encoding data.", e);
}
ContentInfo comContent = new ContentInfo(
CMSObjectIdentifiers.data, comOcts);
ContentInfo contentInfo = new ContentInfo(
CMSObjectIdentifiers.compressedData,
new CompressedData(comAlgId, comContent));
return new CMSCompressedData(contentInfo);
}
}