propper buffering in place

2026-10-18 18:43:10 +08:00 · 2017-09-10 18:20:25 +02:00
parent 644bcfba27
commit 9cde49f5f8
14 changed files with 227 additions and 131 deletions
@@ -0,0 +1,77 @@
+using System.Threading.Tasks;
+using MQTTnet.Core.Client;
+using System;
+
+namespace MQTTnet.Core.Channel
+{
+    public class BufferedCommunicationChannel : IMqttCommunicationChannel
+    {
+        private IMqttCommunicationChannel _inner { get; }
+        private int _bufferSize = 0;
+        private int _bufferOffset = 0;
+
+        public BufferedCommunicationChannel(IMqttCommunicationChannel inner)
+        {
+            _inner = inner;
+        }
+
+        public Task ConnectAsync(MqttClientOptions options)
+        {
+            return _inner.ConnectAsync(options);
+        }
+
+        public Task DisconnectAsync()
+        {
+            return _inner.DisconnectAsync();
+        }
+
+        public int Peek()
+        {
+            return _inner.Peek();
+        }
+
+        public async Task<ArraySegment<byte>> ReadAsync(int length, byte[] buffer)
+        {
+            //read from buffer
+            if (_bufferSize > 0)
+            {
+                return ReadFomBuffer(length, buffer);
+            }
+
+            var available = _inner.Peek();
+            // if there are less or equal bytes available then requested then just read em
+            if (available <= length)
+            {
+                return await _inner.ReadAsync(length, buffer);
+            }
+
+            //if more bytes are available than requested do buffer them to reduce calls to network buffers
+            await WriteToBuffer(available, buffer).ConfigureAwait(false);
+            return ReadFomBuffer(length, buffer);
+        }
+
+        private async Task WriteToBuffer(int available, byte[] buffer)
+        {
+            await _inner.ReadAsync(available, buffer).ConfigureAwait(false);
+            _bufferSize = available;
+            _bufferOffset = 0;
+        }
+
+        private ArraySegment<byte> ReadFomBuffer(int length, byte[] buffer)
+        {
+            var result = new ArraySegment<byte>(buffer, _bufferOffset, length);
+            _bufferSize -= length;
+            _bufferOffset += length;
+
+            if (_bufferSize < 0)
+            {
+            }
+            return result;
+        }
+
+        public Task WriteAsync(byte[] buffer)
+        {
+            return _inner.WriteAsync(buffer);
+        }
+    }
+}