Performance optimizations

2026-10-19 02:53:06 +08:00 · 2017-11-25 23:10:48 +01:00
parent 24ab285066
commit 611fabcd01
11 changed files with 105 additions and 88 deletions
@@ -1,4 +1,6 @@
-using MQTTnet.Adapter;
+using System;
+using System.Collections.Generic;
+using MQTTnet.Adapter;
 using MQTTnet.Packets;

 namespace MQTTnet.Serializer
@@ -7,7 +9,7 @@ namespace MQTTnet.Serializer
    {
        MqttProtocolVersion ProtocolVersion { get; set; }

-        byte[] Serialize(MqttBasePacket mqttPacket);
+        IEnumerable<ArraySegment<byte>> Serialize(MqttBasePacket mqttPacket);

        MqttBasePacket Deserialize(ReceivedMqttPacket receivedMqttPacket);
    }
@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using System.Threading;
@@ -30,7 +29,7 @@ namespace MQTTnet.Serializer
            {
                return null;
            }
-
+            
            var fixedHeader = (byte)buffer;
            var controlPacketType = (MqttControlPacketType)(fixedHeader >> 4);
            var bodyLength = ReadBodyLengthFromSource(stream, cancellationToken);
@@ -57,12 +56,22 @@ namespace MQTTnet.Serializer
        public string ReadStringWithLengthPrefix()
        {
            var buffer = ReadWithLengthPrefix();
+            if (buffer.Length == 0)
+            {
+                return string.Empty;
+            }
+
            return Encoding.UTF8.GetString(buffer, 0, buffer.Length);
        }

        public byte[] ReadWithLengthPrefix()
        {
            var length = ReadUInt16();
+            if (length == 0)
+            {
+                return new byte[0];
+            }
+
            return ReadBytes(length);
        }

@@ -78,7 +87,7 @@ namespace MQTTnet.Serializer
            var value = 0;
            byte encodedByte;

-            var readBytes = new List<int>();
+            ////var readBytes = new List<int>();
            do
            {
                if (cancellationToken.IsCancellationRequested)
@@ -87,19 +96,20 @@ namespace MQTTnet.Serializer
                }

                var buffer = stream.ReadByte();
-                readBytes.Add(buffer);
-
                if (buffer == -1)
                {
                    throw new MqttCommunicationException("Connection closed while reading remaining length data.");
                }

+                ////readBytes.Add(buffer);
+
                encodedByte = (byte)buffer;
                value += (byte)(encodedByte & 127) * multiplier;
                multiplier *= 128;
                if (multiplier > 128 * 128 * 128)
                {
-                    throw new MqttProtocolViolationException($"Remaining length is invalid (Data={string.Join(",", readBytes)}).");
+                    //throw new MqttProtocolViolationException($"Remaining length is invalid (Data={string.Join(",", readBytes)}).");
+                    throw new MqttProtocolViolationException("Remaining length is invalid.");
                }
            } while ((encodedByte & 128) != 0);

@@ -1,12 +1,12 @@
-using System;
+using MQTTnet.Adapter;
+using MQTTnet.Exceptions;
+using MQTTnet.Packets;
+using MQTTnet.Protocol;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text;
-using MQTTnet.Adapter;
-using MQTTnet.Exceptions;
-using MQTTnet.Packets;
-using MQTTnet.Protocol;

 namespace MQTTnet.Serializer
 {
@@ -17,25 +17,29 @@ namespace MQTTnet.Serializer

        public MqttProtocolVersion ProtocolVersion { get; set; } = MqttProtocolVersion.V311;

-        public byte[] Serialize(MqttBasePacket packet)
+        public IEnumerable<ArraySegment<byte>> Serialize(MqttBasePacket packet)
        {
            if (packet == null) throw new ArgumentNullException(nameof(packet));

-            using (var stream = new MemoryStream())
+            using (var stream = new MemoryStream(128))
            using (var writer = new MqttPacketWriter(stream))
            {
                var fixedHeader = SerializePacket(packet, writer);
-                var headerBuffer = new List<byte> { fixedHeader };
-                MqttPacketWriter.WriteRemainingLength((int)stream.Length, headerBuffer);
+                var remainingLength = (int)stream.Length;
+                writer.Write(fixedHeader);
+                MqttPacketWriter.WriteRemainingLength(remainingLength, writer);
+                var headerLength = (int)stream.Length - remainingLength;

-                var header = headerBuffer.ToArray();
-                var body = stream.ToArray();
-
-                var buffer = new byte[header.Length + body.Length];
-                Buffer.BlockCopy(header, 0, buffer, 0, header.Length);
-                Buffer.BlockCopy(body, 0, buffer, header.Length, body.Length);
-
-                return buffer;
+#if NET461 || NET452 || NETSTANDARD2_0
+                var buffer = stream.GetBuffer();
+#else
+                var buffer = stream.ToArray();
+#endif
+                return new List<ArraySegment<byte>>
+                {
+                    new ArraySegment<byte>(buffer, remainingLength, headerLength),
+                    new ArraySegment<byte>(buffer, 0, remainingLength)
+                };
            }
        }

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using MQTTnet.Protocol;
@@ -56,11 +55,11 @@ namespace MQTTnet.Serializer
            Write(value);
        }

-        public static void WriteRemainingLength(int length, List<byte> target)
+        public static void WriteRemainingLength(int length, BinaryWriter target)
        {
            if (length == 0)
            {
-                target.Add(0);
+                target.Write((byte)0);
                return;
            }

@@ -75,7 +74,7 @@ namespace MQTTnet.Serializer
                    encodedByte = encodedByte | 128;
                }

-                target.Add((byte)encodedByte);
+                target.Write((byte)encodedByte);
            } while (x > 0);
        }
    }