More Span-based Stream methods

1 files changed, 52 insertions, 0 deletions

diff --git a/crypto/src/asn1/ConstructedOctetStream.cs b/crypto/src/asn1/ConstructedOctetStream.cs
index 12aa14e74..d005f9fe7 100644
--- a/crypto/src/asn1/ConstructedOctetStream.cs
+++ b/crypto/src/asn1/ConstructedOctetStream.cs
@@ -1,3 +1,4 @@
+using System;
 using System.IO;
 
 using Org.BouncyCastle.Utilities;
@@ -22,6 +23,9 @@ namespace Org.BouncyCastle.Asn1
 		{
 			Streams.ValidateBufferArguments(buffer, offset, count);
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+			return Read(buffer.AsSpan(offset, count));
+#else
 			if (count < 1)
                 return 0;
 
@@ -63,8 +67,56 @@ namespace Org.BouncyCastle.Asn1
 					m_currentStream = next.GetOctetStream();
 				}
 			}
+#endif
 		}
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+		public override int Read(Span<byte> buffer)
+		{
+			if (buffer.IsEmpty)
+                return 0;
+
+			if (m_currentStream == null)
+			{
+				if (!m_first)
+					return 0;
+
+                Asn1OctetStringParser next = GetNextParser();
+                if (next == null)
+                    return 0;
+
+				m_first = false;
+				m_currentStream = next.GetOctetStream();
+			}
+
+			int totalRead = 0;
+
+			for (;;)
+			{
+				int numRead = m_currentStream.Read(buffer[totalRead..]);
+
+				if (numRead > 0)
+				{
+					totalRead += numRead;
+
+					if (totalRead == buffer.Length)
+						return totalRead;
+				}
+				else
+				{
+                    Asn1OctetStringParser next = GetNextParser();
+                    if (next == null)
+					{
+						m_currentStream = null;
+						return totalRead;
+					}
+
+					m_currentStream = next.GetOctetStream();
+				}
+			}
+		}
+#endif
+
 		public override int ReadByte()
 		{
 			if (m_currentStream == null)