1 files changed, 107 insertions, 0 deletions
diff --git a/crypto/src/asn1/DERGenerator.cs b/crypto/src/asn1/DERGenerator.cs
new file mode 100644
index 000000000..aab40fefa
--- /dev/null
+++ b/crypto/src/asn1/DERGenerator.cs
@@ -0,0 +1,107 @@
+using System.IO;
+
+using Org.BouncyCastle.Utilities.IO;
+
+namespace Org.BouncyCastle.Asn1
+{
+    public abstract class DerGenerator
+        : Asn1Generator
+    {
+        private bool _tagged = false;
+        private bool _isExplicit;
+        private int _tagNo;
+
+		protected DerGenerator(
+            Stream outStream)
+            : base(outStream)
+		{
+        }
+
+        protected DerGenerator(
+            Stream outStream,
+            int tagNo,
+            bool isExplicit)
+            : base(outStream)
+        {
+            _tagged = true;
+            _isExplicit = isExplicit;
+            _tagNo = tagNo;
+        }
+
+		private static void WriteLength(
+            Stream	outStr,
+            int		length)
+        {
+            if (length > 127)
+            {
+                int size = 1;
+                int val = length;
+
+				while ((val >>= 8) != 0)
+                {
+                    size++;
+                }
+
+				outStr.WriteByte((byte)(size | 0x80));
+
+				for (int i = (size - 1) * 8; i >= 0; i -= 8)
+                {
+                    outStr.WriteByte((byte)(length >> i));
+                }
+            }
+            else
+            {
+                outStr.WriteByte((byte)length);
+            }
+        }
+
+		internal static void WriteDerEncoded(
+            Stream	outStream,
+            int		tag,
+            byte[]	bytes)
+        {
+            outStream.WriteByte((byte) tag);
+            WriteLength(outStream, bytes.Length);
+            outStream.Write(bytes, 0, bytes.Length);
+        }
+
+		internal void WriteDerEncoded(
+            int		tag,
+            byte[]	bytes)
+        {
+            if (_tagged)
+            {
+                int tagNum = _tagNo | Asn1Tags.Tagged;
+
+                if (_isExplicit)
+                {
+                    int newTag = _tagNo | Asn1Tags.Constructed | Asn1Tags.Tagged;
+					MemoryStream bOut = new MemoryStream();
+                    WriteDerEncoded(bOut, tag, bytes);
+                    WriteDerEncoded(Out, newTag, bOut.ToArray());
+                }
+                else
+                {
+					if ((tag & Asn1Tags.Constructed) != 0)
+					{
+						tagNum |= Asn1Tags.Constructed;
+					}
+
+					WriteDerEncoded(Out, tagNum, bytes);
+                }
+            }
+            else
+            {
+                WriteDerEncoded(Out, tag, bytes);
+            }
+        }
+
+		internal static void WriteDerEncoded(
+            Stream	outStr,
+            int		tag,
+            Stream	inStr)
+        {
+			WriteDerEncoded(outStr, tag, Streams.ReadAll(inStr));
+        }
+    }
+}