1 files changed, 43 insertions, 67 deletions

diff --git a/crypto/src/asn1/ocsp/BasicOCSPResponse.cs b/crypto/src/asn1/ocsp/BasicOCSPResponse.cs
index 2637d36bc..fc491f78e 100644
--- a/crypto/src/asn1/ocsp/BasicOCSPResponse.cs
+++ b/crypto/src/asn1/ocsp/BasicOCSPResponse.cs
@@ -1,91 +1,66 @@
 using System;
 
-using Org.BouncyCastle.Asn1;
 using Org.BouncyCastle.Asn1.X509;
-using Org.BouncyCastle.Utilities;
 
 namespace Org.BouncyCastle.Asn1.Ocsp
 {
     public class BasicOcspResponse
         : Asn1Encodable
     {
-        private readonly ResponseData			tbsResponseData;
-        private readonly AlgorithmIdentifier	signatureAlgorithm;
-        private readonly DerBitString			signature;
-        private readonly Asn1Sequence			certs;
-
-		public static BasicOcspResponse GetInstance(
-			Asn1TaggedObject	obj,
-			bool				explicitly)
-		{
-			return GetInstance(Asn1Sequence.GetInstance(obj, explicitly));
-		}
-
-		public static BasicOcspResponse GetInstance(
-			object obj)
-		{
-			if (obj == null || obj is BasicOcspResponse)
-			{
-				return (BasicOcspResponse)obj;
-			}
+        public static BasicOcspResponse GetInstance(object obj)
+        {
+            if (obj == null)
+                return null;
+            if (obj is BasicOcspResponse basicOcspResponse)
+                return basicOcspResponse;
+            return new BasicOcspResponse(Asn1Sequence.GetInstance(obj));
+        }
 
-			if (obj is Asn1Sequence)
-			{
-				return new BasicOcspResponse((Asn1Sequence)obj);
-			}
+        public static BasicOcspResponse GetInstance(Asn1TaggedObject obj, bool explicitly)
+        {
+            return new BasicOcspResponse(Asn1Sequence.GetInstance(obj, explicitly));
+        }
 
-            throw new ArgumentException("unknown object in factory: " + Platform.GetTypeName(obj), "obj");
-		}
+        private readonly ResponseData m_tbsResponseData;
+        private readonly AlgorithmIdentifier m_signatureAlgorithm;
+        private readonly DerBitString m_signature;
+        private readonly Asn1Sequence m_certs;
 
-		public BasicOcspResponse(
-            ResponseData		tbsResponseData,
-            AlgorithmIdentifier	signatureAlgorithm,
-            DerBitString		signature,
-            Asn1Sequence		certs)
+        public BasicOcspResponse(ResponseData tbsResponseData, AlgorithmIdentifier signatureAlgorithm,
+            DerBitString signature, Asn1Sequence certs)
         {
-            this.tbsResponseData = tbsResponseData;
-            this.signatureAlgorithm = signatureAlgorithm;
-            this.signature = signature;
-            this.certs = certs;
+            m_tbsResponseData = tbsResponseData ?? throw new ArgumentNullException(nameof(tbsResponseData));
+            m_signatureAlgorithm = signatureAlgorithm ?? throw new ArgumentNullException(nameof(signatureAlgorithm));
+            m_signature = signature ?? throw new ArgumentNullException(nameof(signature));
+            m_certs = certs;
         }
 
-		private BasicOcspResponse(
-            Asn1Sequence seq)
+        private BasicOcspResponse(Asn1Sequence seq)
         {
-            this.tbsResponseData = ResponseData.GetInstance(seq[0]);
-            this.signatureAlgorithm = AlgorithmIdentifier.GetInstance(seq[1]);
-            this.signature = (DerBitString)seq[2];
+            int count = seq.Count;
+            if (count < 3 || count > 4)
+                throw new ArgumentException("Bad sequence size: " + count, nameof(seq));
+
+            int pos = 0;
+
+            m_tbsResponseData = ResponseData.GetInstance(seq[pos++]);
+            m_signatureAlgorithm = AlgorithmIdentifier.GetInstance(seq[pos++]);
+            m_signature = DerBitString.GetInstance(seq[pos++]);
+            m_certs = Asn1Utilities.ReadOptionalContextTagged(seq, ref pos, 0, true, Asn1Sequence.GetInstance);
 
-			if (seq.Count > 3)
-            {
-                this.certs = Asn1Sequence.GetInstance((Asn1TaggedObject)seq[3], true);
-            }
+            if (pos != count)
+                throw new ArgumentException("Unexpected elements in sequence", nameof(seq));
         }
 
-		public ResponseData TbsResponseData
-		{
-			get { return tbsResponseData; }
-		}
+		public ResponseData TbsResponseData => m_tbsResponseData;
 
-		public AlgorithmIdentifier SignatureAlgorithm
-		{
-			get { return signatureAlgorithm; }
-		}
+		public AlgorithmIdentifier SignatureAlgorithm => m_signatureAlgorithm;
 
-		public DerBitString Signature
-		{
-			get { return signature; }
-		}
+		public DerBitString Signature => m_signature;
 
-        public byte[] GetSignatureOctets()
-        {
-            return signature.GetOctets();
-        }
+        public byte[] GetSignatureOctets() => m_signature.GetOctets();
 
-		public Asn1Sequence Certs
-		{
-			get { return certs; }
-		}
+        public Asn1Sequence Certs => m_certs;
 
 		/**
          * Produce an object suitable for an Asn1OutputStream.
@@ -99,8 +74,9 @@ namespace Org.BouncyCastle.Asn1.Ocsp
          */
         public override Asn1Object ToAsn1Object()
         {
-            Asn1EncodableVector v = new Asn1EncodableVector(tbsResponseData, signatureAlgorithm, signature);
-            v.AddOptionalTagged(true, 0, certs);
+            Asn1EncodableVector v = new Asn1EncodableVector(4);
+            v.Add(m_tbsResponseData, m_signatureAlgorithm, m_signature);
+            v.AddOptionalTagged(true, 0, m_certs);
             return new DerSequence(v);
         }
     }