93 lines
2.2 KiB
C#
93 lines
2.2 KiB
C#
using System.Net.Sockets;
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namespace InnovEnergy.Lib.Protocols.DBus.Transport;
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// one could use new BufferedStream(new NetworkStream(socket)) instead.
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// I did not know this when I wrote this code...
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// then again, the Streams API kinda sucks...
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public class BufferedSocketReader
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{
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private readonly Socket _Socket;
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private Byte[] _Buffer ;
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private Int32 _DataEnd = 0;
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private Int32 Free => _Buffer.Length - _DataEnd;
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private Int32 Available => _DataEnd - BytesRead;
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public Int32 BytesRead { get; private set; } = 0; // TODO: un-expose this?
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public BufferedSocketReader(Socket socket, Byte[]? buffer = null)
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{
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_Socket = socket;
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_Buffer = buffer ?? new Byte[1024];
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}
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private void FetchData()
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{
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var free = GetFreeSpace();
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var span = new Span<Byte>(_Buffer, _DataEnd, free);
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_DataEnd += Read(span);
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}
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private Int32 Read(Span<Byte> targetArea)
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{
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var nReceived = _Socket.Receive(targetArea, SocketFlags.None, out var err);
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if (err != SocketError.Success) throw new Exception($"Failed to read from socket: {err}");
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if (nReceived <= 0) throw new Exception("Socket closed");
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return nReceived;
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}
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private Int32 GetFreeSpace()
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{
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if (Free != 0)
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return Free;
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Array.Resize(ref _Buffer, _Buffer.Length * 2);
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return Free;
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}
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public Byte PeekByte(Int32 pos = 0)
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{
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if (Available < 1 + pos)
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FetchData();
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return _Buffer[BytesRead + pos];
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}
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public Byte ReadByte()
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{
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if (Available < 1)
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FetchData();
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return _Buffer[BytesRead++];
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}
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public ArraySegment<Byte> ReadSegment(Int32 size)
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{
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var segment = PeekSegment(size);
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BytesRead += size;
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return segment;
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}
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public ArraySegment<Byte> PeekSegment(Int32 size)
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{
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while (Available < size)
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FetchData();
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return new ArraySegment<Byte>(_Buffer, BytesRead, size);
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}
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public void Reset()
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{
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if (BytesRead > 0 && Available > 0)
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Array.Copy(_Buffer, BytesRead, _Buffer, 0, Available);
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_DataEnd = Available;
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BytesRead = 0;
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}
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} |