Rerfactor package parsing.

Frameworks/MQTTnet.NetStandard/Serializer/Extensions.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace MQTTnet.Serializer
+{
+    public static class Extensions
+    {
+        public static byte[] ToArray(this ArraySegment<byte> source)
+        {
+            if (source.Array == null)
+            {
+                return null;
+            }
+
+            var buffer = new byte[source.Count];
+            Buffer.BlockCopy(source.Array, source.Offset, buffer, 0, buffer.Length);
+
+            return buffer;
+        }
+    }
+}

Frameworks/MQTTnet.NetStandard/Serializer/MqttFixedHeader.cs

@@ -1,6 +1,6 @@
 namespace MQTTnet.Serializer
 {
-    public struct MqttFixedHeader
+    public class MqttFixedHeader
     {
         public MqttFixedHeader(byte flags, int remainingLength)
         {
@@ -10,6 +10,6 @@
 
         public byte Flags { get; }
 
-        public int RemainingLength { get; }
+        public int RemainingLength { get; set; }
     }
 }

Frameworks/MQTTnet.NetStandard/Serializer/MqttPacketBodyReader.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Text;
+
+namespace MQTTnet.Serializer
+{
+    public class MqttPacketBodyReader
+    {
+        private readonly byte[] _buffer;
+        private int _offset;
+
+        public MqttPacketBodyReader(byte[] buffer)
+        {
+            _buffer = buffer;
+        }
+
+        public int Length => _buffer.Length - _offset;
+
+        public bool EndOfStream => _offset == _buffer.Length;
+
+        public byte ReadByte()
+        {
+            return _buffer[_offset++];
+        }
+
+        public ArraySegment<byte> ReadRemainingData()
+        {
+            return new ArraySegment<byte>(_buffer, _offset, _buffer.Length - _offset);
+        }
+
+        public ushort ReadUInt16()
+        {
+            var msb = _buffer[_offset++];
+            var lsb = _buffer[_offset++];
+            
+            return (ushort)(msb << 8 | lsb);
+        }
+
+        public ArraySegment<byte> ReadWithLengthPrefix()
+        {
+            var length = ReadUInt16();
+
+            var result = new ArraySegment<byte>(_buffer, _offset, length);
+            _offset += length;
+
+            return result;
+        }
+
+        public string ReadStringWithLengthPrefix()
+        {
+            var buffer = ReadWithLengthPrefix();
+            return Encoding.UTF8.GetString(buffer.Array, buffer.Offset, buffer.Count);
+        }
+    }
+}

Frameworks/MQTTnet.NetStandard/Serializer/MqttPacketReader.cs

@@ -1,7 +1,4 @@
-using System;
-using System.IO;
-using System.Text;
-using System.Threading;
+using System.Threading;
 using System.Threading.Tasks;
 using MQTTnet.Channel;
 using MQTTnet.Exceptions;
@@ -23,6 +20,11 @@ namespace MQTTnet.Serializer
                 var bytesRead = await channel.ReadAsync(buffer, 0, buffer.Length - totalBytesRead, cancellationToken).ConfigureAwait(false);
                 if (bytesRead <= 0)
                 {
+                    if (cancellationToken.IsCancellationRequested)
+                    {
+                        return null;
+                    }
+
                     ExceptionHelper.ThrowGracefulSocketClose();
                 }
 
@@ -35,78 +37,20 @@ namespace MQTTnet.Serializer
                 return new MqttFixedHeader(buffer[0], 0);
             }
 
-            var bodyLength = await ReadBodyLengthAsync(channel, buffer[1], cancellationToken);
+            var bodyLength = await ReadBodyLengthAsync(channel, buffer[1], cancellationToken).ConfigureAwait(false);
             return new MqttFixedHeader(buffer[0], bodyLength);
         }
 
-        public static ushort ReadUInt16(this Stream stream)
-        {
-            var buffer = stream.ReadBytes(2);
-
-            var temp = buffer[0];
-            buffer[0] = buffer[1];
-            buffer[1] = temp;
-
-            return BitConverter.ToUInt16(buffer, 0);
-        }
-
-        public static string ReadStringWithLengthPrefix(this Stream stream)
-        {
-            var buffer = stream.ReadWithLengthPrefix();
-            if (buffer.Length == 0)
-            {
-                return string.Empty;
-            }
-
-            return Encoding.UTF8.GetString(buffer, 0, buffer.Length);
-        }
-
-        public static byte[] ReadWithLengthPrefix(this Stream stream)
-        {
-            var length = stream.ReadUInt16();
-            if (length == 0)
-            {
-                return new byte[0];
-            }
-
-            return stream.ReadBytes(length);
-        }
-
-        public static byte[] ReadRemainingData(this Stream stream)
-        {
-            return stream.ReadBytes((int)(stream.Length - stream.Position));
-        }
-
-        private static byte[] ReadBytes(this Stream stream, int count)
-        {
-            var buffer = new byte[count];
-            var readBytes = stream.Read(buffer, 0, count);
-
-            if (readBytes != count)
-            {
-                throw new InvalidOperationException($"Unable to read {count} bytes from the stream.");
-            }
-
-            return buffer;
-        }
-
         private static async Task<int> ReadBodyLengthAsync(IMqttChannel channel, byte initialEncodedByte, CancellationToken cancellationToken)
         {
             // Alorithm taken from https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html.
             var multiplier = 128;
             var value = initialEncodedByte & 127;
             int encodedByte = initialEncodedByte;
-            var buffer = new byte[1];
-            
+
             while ((encodedByte & 128) != 0)
             {
-                var readCount = await channel.ReadAsync(buffer, 0, 1, cancellationToken).ConfigureAwait(false);
-                if (readCount <= 0)
-                {
-                    ExceptionHelper.ThrowGracefulSocketClose();
-                }
-
-                encodedByte = buffer[0];
+                encodedByte = await ReadByteAsync(channel, cancellationToken).ConfigureAwait(false);
 
                 value += (byte)(encodedByte & 127) * multiplier;
                 if (multiplier > 128 * 128 * 128)
@@ -119,5 +63,17 @@ namespace MQTTnet.Serializer
 
             return value;
         }
+
+        private static async Task<byte> ReadByteAsync(IMqttChannel channel, CancellationToken cancellationToken)
+        {
+            var buffer = new byte[1];
+            var readCount = await channel.ReadAsync(buffer, 0, 1, cancellationToken).ConfigureAwait(false);
+            if (readCount <= 0)
+            {
+                ExceptionHelper.ThrowGracefulSocketClose();
+            }
+
+            return buffer[0];
+        }
     }
 }

Frameworks/MQTTnet.NetStandard/Serializer/MqttPacketSerializer.cs

@@ -104,7 +104,7 @@ namespace MQTTnet.Serializer
             }
         }
 
-        private static MqttBasePacket DeserializeUnsubAck(Stream body)
+        private static MqttBasePacket DeserializeUnsubAck(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -114,7 +114,7 @@ namespace MQTTnet.Serializer
             };
         }
 
-        private static MqttBasePacket DeserializePubComp(Stream body)
+        private static MqttBasePacket DeserializePubComp(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -124,7 +124,7 @@ namespace MQTTnet.Serializer
             };
         }
 
-        private static MqttBasePacket DeserializePubRel(Stream body)
+        private static MqttBasePacket DeserializePubRel(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -134,7 +134,7 @@ namespace MQTTnet.Serializer
             };
         }
 
-        private static MqttBasePacket DeserializePubRec(Stream body)
+        private static MqttBasePacket DeserializePubRec(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -144,7 +144,7 @@ namespace MQTTnet.Serializer
             };
         }
 
-        private static MqttBasePacket DeserializePubAck(Stream body)
+        private static MqttBasePacket DeserializePubAck(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -154,7 +154,7 @@ namespace MQTTnet.Serializer
             };
         }
 
-        private static MqttBasePacket DeserializeUnsubscribe(Stream body)
+        private static MqttBasePacket DeserializeUnsubscribe(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -163,7 +163,7 @@ namespace MQTTnet.Serializer
                 PacketIdentifier = body.ReadUInt16(),
             };
 
-            while (body.Position != body.Length)
+            while (!body.EndOfStream)
             {
                 packet.TopicFilters.Add(body.ReadStringWithLengthPrefix());
             }
@@ -171,7 +171,7 @@ namespace MQTTnet.Serializer
             return packet;
         }
 
-        private static MqttBasePacket DeserializeSubscribe(Stream body)
+        private static MqttBasePacket DeserializeSubscribe(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -180,7 +180,7 @@ namespace MQTTnet.Serializer
                 PacketIdentifier = body.ReadUInt16()
             };
 
-            while (body.Position != body.Length)
+            while (!body.EndOfStream)
             {
                 packet.TopicFilters.Add(new TopicFilter(
                     body.ReadStringWithLengthPrefix(),
@@ -213,7 +213,7 @@ namespace MQTTnet.Serializer
                 PacketIdentifier = packetIdentifier,
                 Retain = retain,
                 Topic = topic,
-                Payload = body.ReadRemainingData(),
+                Payload = body.ReadRemainingData().ToArray(),
                 QualityOfServiceLevel = qualityOfServiceLevel,
                 Dup = dup
             };
@@ -221,7 +221,7 @@ namespace MQTTnet.Serializer
             return packet;
         }
 
-        private static MqttBasePacket DeserializeConnect(Stream body)
+        private static MqttBasePacket DeserializeConnect(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -279,7 +279,7 @@ namespace MQTTnet.Serializer
                 packet.WillMessage = new MqttApplicationMessage
                 {
                     Topic = body.ReadStringWithLengthPrefix(),
-                    Payload = body.ReadWithLengthPrefix(),
+                    Payload = body.ReadWithLengthPrefix().ToArray(),
                     QualityOfServiceLevel = (MqttQualityOfServiceLevel)willQoS,
                     Retain = willRetain
                 };
@@ -299,7 +299,7 @@ namespace MQTTnet.Serializer
             return packet;
         }
 
-        private static MqttBasePacket DeserializeSubAck(Stream body)
+        private static MqttBasePacket DeserializeSubAck(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -308,7 +308,7 @@ namespace MQTTnet.Serializer
                 PacketIdentifier = body.ReadUInt16()
             };
 
-            while (body.Position != body.Length)
+            while (!body.EndOfStream)
             {
                 packet.SubscribeReturnCodes.Add((MqttSubscribeReturnCode)body.ReadByte());
             }
@@ -316,7 +316,7 @@ namespace MQTTnet.Serializer
             return packet;
         }
 
-        private MqttBasePacket DeserializeConnAck(Stream body)
+        private MqttBasePacket DeserializeConnAck(MqttPacketBodyReader body)
         {
             ThrowIfBodyIsEmpty(body);
 
@@ -614,7 +614,7 @@ namespace MQTTnet.Serializer
             return MqttPacketWriter.BuildFixedHeader(type);
         }
 
-        private static void ThrowIfBodyIsEmpty(Stream body)
+        private static void ThrowIfBodyIsEmpty(MqttPacketBodyReader body)
         {
             if (body == null || body.Length == 0)
             {