1 files changed, 75 insertions, 0 deletions
diff --git a/crypto/src/bcpg/sig/Features.cs b/crypto/src/bcpg/sig/Features.cs
new file mode 100644
index 000000000..29584239a
--- /dev/null
+++ b/crypto/src/bcpg/sig/Features.cs
@@ -0,0 +1,75 @@
+using System;
+
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Bcpg.Sig
+{
+    /**
+    * packet giving signature expiration time.
+    */
+    public class Features
+        : SignatureSubpacket
+    {
+        /** Identifier for the modification detection feature */
+        public static readonly byte FEATURE_MODIFICATION_DETECTION = 1;
+
+        private static byte[] FeatureToByteArray(byte feature)
+        {
+            return new byte[]{ feature };
+        }
+
+        public Features(
+            bool    critical,
+            bool    isLongLength,
+            byte[]  data)
+            : base(SignatureSubpacketTag.Features, critical, isLongLength, data)
+        {
+        }
+
+        public Features(bool critical, byte feature)
+            : base(SignatureSubpacketTag.Features, critical, false, FeatureToByteArray(feature))
+        {
+        }
+
+        /**
+         * Returns if modification detection is supported.
+         */
+        public bool SupportsModificationDetection
+        {
+            get { return SupportsFeature(FEATURE_MODIFICATION_DETECTION); }
+        }
+
+        /**
+         * Returns if a particular feature is supported.
+         */
+        public bool SupportsFeature(byte feature)
+        {
+            return Array.IndexOf(data, feature) >= 0;
+        }
+
+        /**
+         * Sets support for a particular feature.
+         */
+        private void SetSupportsFeature(byte feature, bool support)
+        {
+            if (feature == 0)
+                throw new ArgumentException("cannot be 0", "feature");
+
+            int i = Array.IndexOf(data, feature);
+            if ((i >= 0) == support)
+                return;
+
+            if (support)
+            {
+                data = Arrays.Append(data, feature);
+            }
+            else
+            {
+                byte[] temp = new byte[data.Length - 1];
+                Array.Copy(data, 0, temp, 0, i);
+                Array.Copy(data, i + 1, temp, i, temp.Length - i);
+                data = temp;
+            }
+        }
+    }
+}