Pissing about with TZX support

Core/Io/TzxBlocks.cs

@@ -51,5 +51,65 @@ namespace Core.Io
         public int DataLength { get; set; }
 
         public byte[] Data { get; set; } = Array.Empty<byte>();
+        // ID 0x30: Text Description
+        public class TextDescriptionBlock : TzxBlock
+        {
+            public override int BlockId => 0x30;
+            public string Description { get; set; } = string.Empty;
+        }
+
+        // ID 0x20: Pause / Stop the Tape
+        public class PauseBlock : TzxBlock
+        {
+            public override int BlockId => 0x20;
+            public ushort PauseDurationMs { get; set; } // 0 means "Stop the tape"
+        }
+
+        // ID 0x21: Group Start (Used to group blocks in UI tape browsers)
+        public class GroupStartBlock : TzxBlock
+        {
+            public override int BlockId => 0x21;
+            public string GroupName { get; set; } = string.Empty;
+        }
+
+        // ID 0x22: Group End
+        public class GroupEndBlock : TzxBlock
+        {
+            public override int BlockId => 0x22;
+        }
+
+        // ID 0x12: Pure Tone Block
+        public class PureToneBlock : TzxBlock
+        {
+            public override int BlockId => 0x12;
+            public ushort PulseLength { get; set; }
+            public ushort PulseCount { get; set; }
+        }
+        // ID 0x13: Pulse Sequence Block
+        public class PulseSequenceBlock : TzxBlock
+        {
+            public override int BlockId => 0x13;
+
+            // Number of pulses (1 to 255)
+            public int PulseCount { get; set; }
+
+            // The exact T-State lengths of each pulse
+            public ushort[] Pulses { get; set; } = Array.Empty<ushort>();
+        }
+        // ID 0x14: Pure Data Block
+        public class PureDataBlock : TzxBlock
+        {
+            public override int BlockId => 0x14;
+
+            public ushort ZeroBitPulseLength { get; set; }
+            public ushort OneBitPulseLength { get; set; }
+            public byte UsedBitsInLastByte { get; set; }
+            public ushort PauseAfterMs { get; set; }
+
+            // The return of the 24-bit integer!
+            public int DataLength { get; set; }
+
+            public byte[] Data { get; set; } = Array.Empty<byte>();
+        }
     }
 }