Initial Commit

iTechSharp/srcbc/cms/CMSCompressedDataParser.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections;
+using System.IO;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Org.BouncyCastle.Utilities.Zlib;
+
+namespace Org.BouncyCastle.Cms
+{
+    /**
+    * Class for reading a CMS Compressed Data stream.
+    * <pre>
+    *     CMSCompressedDataParser cp = new CMSCompressedDataParser(inputStream);
+    *
+    *     process(cp.GetContent().GetContentStream());
+    * </pre>
+    *  Note: this class does not introduce buffering - if you are processing large files you should create
+    *  the parser with:
+    *  <pre>
+    *      CMSCompressedDataParser     ep = new CMSCompressedDataParser(new BufferedInputStream(inputStream, bufSize));
+    *  </pre>
+    *  where bufSize is a suitably large buffer size.
+    */
+    public class CmsCompressedDataParser
+        : CmsContentInfoParser
+    {
+        public CmsCompressedDataParser(
+            byte[] compressedData)
+            : this(new MemoryStream(compressedData, false))
+        {
+        }
+
+        public CmsCompressedDataParser(
+            Stream compressedData)
+            : base(compressedData)
+        {
+        }
+
+		public CmsTypedStream GetContent()
+        {
+            try
+            {
+                CompressedDataParser comData = new CompressedDataParser((Asn1SequenceParser)this.contentInfo.GetContent(Asn1Tags.Sequence));
+                ContentInfoParser content = comData.GetEncapContentInfo();
+
+                Asn1OctetStringParser bytes = (Asn1OctetStringParser)content.GetContent(Asn1Tags.OctetString);
+
+                return new CmsTypedStream(content.ContentType.ToString(), new ZInflaterInputStream(bytes.GetOctetStream()));
+            }
+            catch (IOException e)
+            {
+                throw new CmsException("IOException reading compressed content.", e);
+            }
+        }
+    }
+}