1 files changed, 153 insertions, 0 deletions
diff --git a/pg/src/main/java/org/spongycastle/openpgp/PGPCompressedData.java b/pg/src/main/java/org/spongycastle/openpgp/PGPCompressedData.java
new file mode 100644
index 00000000..9269dfee
--- /dev/null
+++ b/pg/src/main/java/org/spongycastle/openpgp/PGPCompressedData.java
@@ -0,0 +1,153 @@
+package org.spongycastle.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.spongycastle.apache.bzip2.CBZip2InputStream;
+import org.spongycastle.bcpg.BCPGInputStream;
+import org.spongycastle.bcpg.CompressedDataPacket;
+import org.spongycastle.bcpg.CompressionAlgorithmTags;
+import org.spongycastle.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());
+    }
+}