mirror of
https://github.com/modernuo/ModernUO
synced 2026-08-11 22:23:06 -04:00
114 lines
3.6 KiB
C#
114 lines
3.6 KiB
C#
/*************************************************************************
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* ModernUO *
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* Copyright 2019-2023 - ModernUO Development Team *
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* Email: hi@modernuo.com *
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* File: PacketContainerBuilder.cs *
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* *
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* This program is free software: you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation, either version 3 of the License, or *
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* (at your option) any later version. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program. If not, see <http://www.gnu.org/licenses/>. *
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*************************************************************************/
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using System;
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using System.Buffers.Binary;
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using System.Runtime.CompilerServices;
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using Server.Buffers;
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namespace Server.Network;
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public ref struct PacketContainerBuilder
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{
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public const int MinPacketLength = 5;
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private bool _finished;
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private int _count;
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private byte[] _arrayToReturnToPool;
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private Span<byte> _bytes;
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public PacketContainerBuilder(Span<byte> initialBuffer)
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{
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_arrayToReturnToPool = null;
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_finished = false;
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_count = 0;
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_bytes = initialBuffer;
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_bytes[0] = 0xF7; // Packet ID
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Length = MinPacketLength; // Length + Count
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}
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public int Length { get; set; }
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public int Capacity => _bytes.Length;
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[MethodImpl(MethodImplOptions.NoInlining)]
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public ReadOnlySpan<byte> Finalize()
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{
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if (!_finished)
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{
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BinaryPrimitives.WriteUInt16BigEndian(_bytes[1..3], (ushort)Length);
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BinaryPrimitives.WriteUInt16BigEndian(_bytes[3..5], (ushort)_count);
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}
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return _bytes[..Length];
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}
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[MethodImpl(MethodImplOptions.NoInlining)]
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public Span<byte> GetSpan(int bytesNeeded)
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{
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if (_finished)
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{
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throw new InvalidOperationException("Attempted to use PacketContainerBuilder after finalize");
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}
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if (Length > _bytes.Length - bytesNeeded)
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{
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Grow(bytesNeeded);
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}
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return _bytes[Length..];
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}
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[MethodImpl(MethodImplOptions.NoInlining)]
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public void Advance(int bytesWritten)
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{
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if (_finished)
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{
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throw new InvalidOperationException("Attempted to use PacketContainerBuilder after finalize");
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}
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_count++;
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Length += bytesWritten;
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}
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[MethodImpl(MethodImplOptions.NoInlining)]
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private void Grow(int additionalCapacityBeyondPos)
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{
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var newLength = Math.Max(Length + additionalCapacityBeyondPos, _bytes.Length * 2);
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byte[] poolArray = STArrayPool<byte>.Shared.Rent(newLength);
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_bytes[..Length].CopyTo(poolArray);
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byte[] toReturn = _arrayToReturnToPool;
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_bytes = _arrayToReturnToPool = poolArray;
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if (toReturn != null)
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{
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STArrayPool<byte>.Shared.Return(toReturn);
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}
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public void Dispose()
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{
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byte[] toReturn = _arrayToReturnToPool;
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this = default; // for safety, to avoid using pooled array if this instance is erroneously appended to again
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if (toReturn != null)
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{
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STArrayPool<byte>.Shared.Return(toReturn);
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}
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}
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}
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