Sucessfulyl parsed our very first BFBS GSE Frame.

skyscraper8/GS/GSE-BFBS/BfbsGseReader.cs

@@ -5,6 +5,7 @@ using System.Text;
 using System.Threading.Tasks;
 using skyscraper5.Mpeg2;
 using skyscraper8.GSE;
+using skyscraper8.GSE.GSE;
 using skyscraper8.Skyscraper.IO;
 using skyscraper8.Skyscraper.Scraper;
 
@@ -15,6 +16,8 @@ namespace skyscraper8.GS.GSE_BFBS
 		private readonly byte _misId;
 		private readonly ISubTsHandler _subTsHandler;
 
+		private GseLabel lastLabel;
+
 		public BfbsGseReader(byte misId, ISubTsHandler subTsHandler)
 		{
 			_misId = misId;
@@ -32,6 +35,82 @@ namespace skyscraper8.GS.GSE_BFBS
 
 
 			StreamlikeSpan span = new StreamlikeSpan(readOnlySpan);
+
+			while (span.GetAvailableBytes() >= 1)
+			{
+				byte byteA = span.ReadUInt8();
+				bool startIndicator = (byteA & 0x80) != 0;
+				bool endIndicator = (byteA & 0x40) != 0;
+				int labelTypeIndicator = (byteA & 0x30) >> 4;
+				if (!startIndicator && !endIndicator && labelTypeIndicator == 0)
+				{
+					//padding bits, packet has ended.
+					return;
+				}
+				else
+				{
+					int gseLength = (byteA & 0x0f) << 8;
+					gseLength += span.ReadUInt8();
+
+					byte? fragId = null;
+					if (!startIndicator || !endIndicator)
+					{
+						fragId = span.ReadUInt8();
+						gseLength -= 1;
+					}
+
+					ushort? totalLength = null;
+					if ((startIndicator) && !endIndicator)
+					{
+						totalLength = span.ReadUInt16BE();
+						gseLength -= 2;
+					}
+
+					GseLabel label = null;
+					ushort? protocolType = null;
+					if (startIndicator)
+					{
+						protocolType = span.ReadUInt16BE();
+						gseLength -= 2;
+						if (labelTypeIndicator == 0)
+						{
+							label = new _6byteLabel(span.ReadBytes(6));
+							gseLength -= 6;
+						}
+						else if (labelTypeIndicator == 1)
+						{
+							label = new _3byteLabel(span.ReadBytes(3));
+							gseLength -= 3;
+						}
+						else if (labelTypeIndicator == 2)
+						{
+							label = BroadcastLabel.GetInstance();
+						}
+						else if (labelTypeIndicator == 3)
+						{
+							label = lastLabel;
+						}
+					}
+
+					if (!startIndicator && endIndicator)
+						gseLength -= 4;
+
+					ReadOnlySpan<byte> gseDataBytes = span.ReadBytes(gseLength);
+
+					if (!startIndicator && endIndicator)
+					{
+						uint crc32 = span.ReadUInt32BE();
+						throw new NotImplementedException("crc32");
+					}
+
+					HandleGseFrame(startIndicator, endIndicator, fragId, totalLength, label, protocolType,
+						gseDataBytes);
+				}
+			}
+		}
+
+		private void HandleGseFrame(bool startIndicator, bool endIndicator, byte? fragId, ushort? totalLength, GseLabel label, ushort? protocolType, ReadOnlySpan<byte> gseDataBytes)
+		{
 			throw new NotImplementedException();
 		}
 	}

skyscraper8/GS/GSE/GseLabel.cs

@@ -29,16 +29,29 @@ public class _3byteLabel : GseLabel
 {
     public _3byteLabel(byte[] buffer)
     {
-        Label = buffer;
+        this.buffer = buffer;
     }
-    
-    public byte[] Label { get; private set; }
 
-    override public string ToString()
+    private byte[] buffer;
+
+    public byte GroupId => buffer[0];
+
+    public ushort LogonId
     {
-        return BitConverter.ToString(Label);
+        get
+        {
+            ushort result = buffer[1];
+            result <<= 8;
+            result += buffer[2];
+            return result;
+        }
     }
-    
+
+    public override string ToString()
+    {
+        return $"{nameof(GroupId)}: {GroupId}, {nameof(LogonId)}: {LogonId}";
+    }
+
     override public int Length => 3;
 }
 

skyscraper8/Skyscraper/IO/StreamlikeSpan.cs

@@ -69,6 +69,57 @@ namespace skyscraper8.Skyscraper.IO
 		public bool CanWrite => true;
 		public long Length => internalLength;
 		public long Position => internalPosition;
+
+		public byte ReadUInt8()
+		{
+			byte result = _readOnlySpan[internalPosition];
+			internalPosition++;
+			return result;
+		}
+
+		public ushort ReadUInt16BE()
+		{
+			ushort a = _readOnlySpan[internalPosition];
+			a <<= 8;
+			a += _readOnlySpan[internalPosition + 1];
+			internalPosition += 2;
+			return a;
+		}
+
+		public byte[] ReadBytes(int i)
+		{
+			byte[] buffer = new byte[i];
+			if (Read(buffer, 0, i) != i)
+			{
+				throw new IOException(String.Format("Failed to read {0} bytes", i));
+			}
+			return buffer;
+		}
+
+		public ReadOnlySpan<byte> ReadSpan(int length)
+		{
+			ReadOnlySpan<byte> buffer = _readOnlySpan.Slice(internalPosition, length);
+			internalPosition += length;
+			return buffer;
+		}
+
+		public uint ReadUInt32BE()
+		{
+			uint result = _readOnlySpan[internalPosition];
+			result <<= 8;
+			result += _readOnlySpan[internalPosition + 1];
+			result <<= 8;
+			result += _readOnlySpan[internalPosition + 2];
+			result <<= 8;
+			result += _readOnlySpan[internalPosition + 3];
+			internalPosition += 4;
+			return result;
+		}
+
+		public int GetAvailableBytes()
+		{
+			return internalLength - internalPosition;
+		}
 	}
 
 	class TelepathyStream : Stream