Refactoring in Asn1.Cmp

1 files changed, 12 insertions, 20 deletions

diff --git a/crypto/src/asn1/cmp/PKIMessage.cs b/crypto/src/asn1/cmp/PKIMessage.cs
index e835b6f16..4b5acad77 100644
--- a/crypto/src/asn1/cmp/PKIMessage.cs
+++ b/crypto/src/asn1/cmp/PKIMessage.cs
@@ -26,22 +26,17 @@ namespace Org.BouncyCastle.Asn1.Cmp
 
         private PkiMessage(Asn1Sequence seq)
         {
-            m_header = PkiHeader.GetInstance(seq[0]);
-            m_body = PkiBody.GetInstance(seq[1]);
+            int count = seq.Count, pos = 0;
+            if (count < 2 || count > 4)
+                throw new ArgumentException("Bad sequence size: " + count, nameof(seq));
 
-            for (int pos = 2; pos < seq.Count; ++pos)
-            {
-                Asn1TaggedObject tObj = Asn1TaggedObject.GetInstance(seq[pos]);
+            m_header = PkiHeader.GetInstance(seq[pos++]);
+            m_body = PkiBody.GetInstance(seq[pos++]);
+            m_protection = Asn1Utilities.ReadOptionalContextTagged(seq, ref pos, 0, true, DerBitString.GetInstance);
+            m_extraCerts = Asn1Utilities.ReadOptionalContextTagged(seq, ref pos, 1, true, Asn1Sequence.GetInstance);
 
-                if (tObj.HasContextTag(0))
-                {
-                    m_protection = DerBitString.GetInstance(tObj, true);
-                }
-                else if (tObj.HasContextTag(1))
-                {
-                    m_extraCerts = Asn1Sequence.GetInstance(tObj, true);
-                }
-            }
+            if (pos != count)
+                throw new ArgumentException("Unexpected elements in sequence", nameof(seq));
         }
 
         /**
@@ -54,13 +49,10 @@ namespace Org.BouncyCastle.Asn1.Cmp
          */
         public PkiMessage(PkiHeader header, PkiBody body, DerBitString protection, CmpCertificate[] extraCerts)
         {
-            m_header = header;
-            m_body = body;
+            m_header = header ?? throw new ArgumentNullException(nameof(header));
+            m_body = body ?? throw new ArgumentNullException(nameof(body));
             m_protection = protection;
-            if (extraCerts != null)
-            {
-                m_extraCerts = new DerSequence(extraCerts);
-            }
+            m_extraCerts = extraCerts == null ? null : DerSequence.FromElements(extraCerts);
         }
 
         public PkiMessage(PkiHeader header, PkiBody body, DerBitString protection)