1 files changed, 165 insertions, 0 deletions
diff --git a/pkix/src/main/java/org/spongycastle/cms/CMSCompressedDataStreamGenerator.java b/pkix/src/main/java/org/spongycastle/cms/CMSCompressedDataStreamGenerator.java
new file mode 100644
index 00000000..47af9b4f
--- /dev/null
+++ b/pkix/src/main/java/org/spongycastle/cms/CMSCompressedDataStreamGenerator.java
@@ -0,0 +1,165 @@
+package org.spongycastle.cms;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+import org.spongycastle.asn1.ASN1Integer;
+import org.spongycastle.asn1.ASN1ObjectIdentifier;
+import org.spongycastle.asn1.BERSequenceGenerator;
+import org.spongycastle.asn1.cms.CMSObjectIdentifiers;
+import org.spongycastle.operator.OutputCompressor;
+
+/**
+ * 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, new ZlibCompressor());
+ *      
+ *      cOut.write(data);
+ *      
+ *      cOut.close();
+ * </pre>
+ */
+public class CMSCompressedDataStreamGenerator
+{
+    public static final String  ZLIB    = "1.2.840.113549.1.9.16.3.8";
+
+    private int _bufferSize;
+    
+    /**
+     * base constructor
+     */
+    public CMSCompressedDataStreamGenerator()
+    {
+    }
+
+    /**
+     * Set the underlying string size for encapsulated data
+     *
+     * @param bufferSize length of octet strings to buffer the data.
+     */
+    public void setBufferSize(
+        int bufferSize)
+    {
+        _bufferSize = bufferSize;
+    }
+
+    /**
+     * Open a compressing output stream with the PKCS#7 content type OID of "data".
+     *
+     * @param out the stream to encode to.
+     * @param compressor the type of compressor to use.
+     * @return an output stream to write the data be compressed to.
+     * @throws IOException
+     */
+    public OutputStream open(
+        OutputStream out,
+        OutputCompressor compressor)
+        throws IOException
+    {
+        return open(CMSObjectIdentifiers.data, out, compressor);
+    }
+
+    /**
+     * Open a compressing output stream.
+     *
+     * @param contentOID the content type OID.
+     * @param out the stream to encode to.
+     * @param compressor the type of compressor to use.
+     * @return an output stream to write the data be compressed to.
+     * @throws IOException
+     */
+    public OutputStream open(
+        ASN1ObjectIdentifier contentOID,
+        OutputStream out,
+        OutputCompressor compressor)
+        throws IOException
+    {
+        BERSequenceGenerator sGen = new BERSequenceGenerator(out);
+
+        sGen.addObject(CMSObjectIdentifiers.compressedData);
+
+        //
+        // Compressed Data
+        //
+        BERSequenceGenerator cGen = new BERSequenceGenerator(sGen.getRawOutputStream(), 0, true);
+
+        cGen.addObject(new ASN1Integer(0));
+
+        //
+        // AlgorithmIdentifier
+        //
+        cGen.addObject(compressor.getAlgorithmIdentifier());
+
+        //
+        // Encapsulated ContentInfo
+        //
+        BERSequenceGenerator eiGen = new BERSequenceGenerator(cGen.getRawOutputStream());
+
+        eiGen.addObject(contentOID);
+
+        OutputStream octetStream = CMSUtils.createBEROctetOutputStream(
+            eiGen.getRawOutputStream(), 0, true, _bufferSize);
+
+        return new CmsCompressedOutputStream(
+            compressor.getOutputStream(octetStream), sGen, cGen, eiGen);
+    }
+
+    private class CmsCompressedOutputStream
+        extends OutputStream
+    {
+        private OutputStream _out;
+        private BERSequenceGenerator _sGen;
+        private BERSequenceGenerator _cGen;
+        private BERSequenceGenerator _eiGen;
+        
+        CmsCompressedOutputStream(
+            OutputStream 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();
+        }
+    }
+}