1 files changed, 109 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..4ed3a400d
--- /dev/null
+++ b/crypto/src/asn1/x509/AlgorithmIdentifier.cs
@@ -0,0 +1,109 @@
+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;
+
+            // TODO: delete
+            if (obj is DerObjectIdentifier)
+                return new AlgorithmIdentifier((DerObjectIdentifier) obj);
+
+            // TODO: delete
+            if (obj is string)
+                return new AlgorithmIdentifier((string) obj);
+
+            return new AlgorithmIdentifier(Asn1Sequence.GetInstance(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);
+        }
+    }
+}