1 files changed, 110 insertions, 0 deletions
diff --git a/crypto/src/asn1/x509/AlgorithmIdentifier.cs b/crypto/src/asn1/x509/AlgorithmIdentifier.cs
new file mode 100644
index 000000000..caf9e77c9
--- /dev/null
+++ b/crypto/src/asn1/x509/AlgorithmIdentifier.cs
@@ -0,0 +1,110 @@
+using System;
+
+namespace Org.BouncyCastle.Asn1.X509
+{
+    public class AlgorithmIdentifier
+        : Asn1Encodable
+    {
+        private readonly DerObjectIdentifier	objectID;
+        private readonly Asn1Encodable			parameters;
+		private readonly bool					parametersDefined;
+
+		public static AlgorithmIdentifier GetInstance(
+            Asn1TaggedObject	obj,
+            bool				explicitly)
+        {
+            return GetInstance(Asn1Sequence.GetInstance(obj, explicitly));
+        }
+
+		public static AlgorithmIdentifier GetInstance(
+            object obj)
+        {
+            if (obj == null || obj is AlgorithmIdentifier)
+                return (AlgorithmIdentifier) obj;
+
+			if (obj is DerObjectIdentifier)
+                return new AlgorithmIdentifier((DerObjectIdentifier) obj);
+
+			if (obj is string)
+                return new AlgorithmIdentifier((string) obj);
+
+			if (obj is Asn1Sequence)
+                return new AlgorithmIdentifier((Asn1Sequence) obj);
+
+			throw new ArgumentException("unknown object in factory: " + obj.GetType().Name, "obj");
+		}
+
+		public AlgorithmIdentifier(
+            DerObjectIdentifier objectID)
+        {
+            this.objectID = objectID;
+        }
+
+		public AlgorithmIdentifier(
+            string objectID)
+        {
+            this.objectID = new DerObjectIdentifier(objectID);
+        }
+
+		public AlgorithmIdentifier(
+            DerObjectIdentifier	objectID,
+            Asn1Encodable		parameters)
+        {
+            this.objectID = objectID;
+            this.parameters = parameters;
+			this.parametersDefined = true;
+        }
+
+		internal AlgorithmIdentifier(
+            Asn1Sequence seq)
+        {
+			if (seq.Count < 1 || seq.Count > 2)
+				throw new ArgumentException("Bad sequence size: " + seq.Count);
+
+			this.objectID = DerObjectIdentifier.GetInstance(seq[0]);
+			this.parametersDefined = (seq.Count == 2);
+
+			if (parametersDefined)
+            {
+                this.parameters = seq[1];
+            }
+        }
+
+		public virtual DerObjectIdentifier ObjectID
+		{
+			get { return objectID; }
+		}
+
+		public Asn1Encodable Parameters
+		{
+			get { return parameters; }
+		}
+
+		/**
+         * Produce an object suitable for an Asn1OutputStream.
+         * <pre>
+         *      AlgorithmIdentifier ::= Sequence {
+         *                            algorithm OBJECT IDENTIFIER,
+         *                            parameters ANY DEFINED BY algorithm OPTIONAL }
+         * </pre>
+         */
+        public override Asn1Object ToAsn1Object()
+        {
+			Asn1EncodableVector v = new Asn1EncodableVector(objectID);
+
+			if (parametersDefined)
+			{
+				if (parameters != null)
+				{
+					v.Add(parameters);
+				}
+				else
+				{
+					v.Add(DerNull.Instance);
+				}
+			}
+
+			return new DerSequence(v);
+        }
+    }
+}