ModernUO/Projects/Server/Buffers/CircularBufferReader.cs
Kamron Batman 351611a23a
Updates movement packets & Fastwalk (#324)
- [X] Updates Movement packets
- [X] Adds OSI fastwalk packets. These aren't used on OSi anymore.
- [X] Adds new movement handling, but looks like the client doesn't use it. (Also leaving the 0x4000 Character List Flag off)
- [X] Adds time sync request handler, but also looks like the client doesn't use it.
- [X] Adds time sync response for time sync, just in case, but it isn't used, so not sure about the arguments.
- [X] Reimplements RunUO's fastwalk to use a circular array on the netstate instead of every mobile
- [X] Removes ClearFastwalkStack from RunUO implementation. This shouldn't be needed anymore

Changed fastwalk settings:
```cs
        public static int WalkFootDelay { get; set; } = 440;
        public static int RunFootDelay { get; set; } = 220;
        public static int WalkMountDelay { get; set; } = 220;
        public static int RunMountDelay { get; set; } = 110;

        public static bool EnableFastwalkPrevention { get; set; } = true;
        public static AccessLevel FastwalkExemptionLevel { get; set; } = AccessLevel.Counselor;

        // If this is changed during runtime, then the steps array needs resizing.
        public static int MaxSteps { get; private set; } = 4;
```

modernuo.json
```json
{
  "settings": {
    "movement.delay.runFoot": "220",
    "movement.delay.runMount": "110",
    "movement.delay.walkFoot": "440",
    "movement.delay.walkMount": "220",
    "movement.enableFastWalkPrevention": "True",
    "movement.fastwalkExemptionLevel": "Counselor",
    "movement.maxSteps": "4"
  }
}
```

Notes about OSI fastwalk:
While it does work, I can't find a benefit in using it because of the variable speeds. If players moved at a single speed then we could refill the stack every X milliseconds with 6 keys and use a naive token bucket implementation.
Unfortunately variable speeds mount/run/walk/etc means we would have to use a leaky bucket algorithm.
If we are using a leaky bucket algorithm with a variable leak, then we don't need to send tokens because we are already tracking it on the server side.

ModernUO vs OSI Fastwalk:
When the fastwalk was implemented on OSI, it used up to 6 tokens. These tokens were probably distributed every 600-750 milliseconds. To get the same effect, the new fastwalk settings might need to be adjusted. I would tweak them and feel free to let me know what worked for you!

Bumps release version
2020-11-26 23:53:47 -08:00

377 lines
13 KiB
C#

/*************************************************************************
* ModernUO *
* Copyright 2019-2020 - ModernUO Development Team *
* Email: hi@modernuo.com *
* File: PacketReader.cs *
* *
* This program is free software: you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation, either version 3 of the License, or *
* (at your option) any later version. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
*************************************************************************/
using System;
using System.Buffers;
using System.Buffers.Binary;
using System.IO;
using System.Runtime.CompilerServices;
using System.Text;
namespace Server.Network
{
public ref struct CircularBufferReader
{
private readonly ReadOnlySpan<byte> _first;
private readonly ReadOnlySpan<byte> _second;
public int Length { get; }
public int Position { get; private set; }
public int Remaining => Length - Position;
public CircularBufferReader(ref CircularBuffer<byte> buffer) : this(buffer.GetSpan(0), buffer.GetSpan(1))
{
}
public CircularBufferReader(ArraySegment<byte>[] buffer) : this(buffer[0], buffer[1])
{
}
public CircularBufferReader(ReadOnlySpan<byte> first, ReadOnlySpan<byte> second)
{
_first = first;
_second = second;
Position = 0;
Length = first.Length + second.Length;
}
public void Trace(NetState state)
{
// We don't have data, so nothing to trace
if (_first.Length == 0)
{
return;
}
try
{
using var sw = new StreamWriter("Packets.log", true);
sw.WriteLine("Client: {0}: Unhandled packet 0x{1:X2}", state, _first[0]);
Utility.FormatBuffer(sw, _first.ToArray(), new Memory<byte>(_second.ToArray()));
sw.WriteLine();
sw.WriteLine();
}
catch
{
// ignored
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public byte ReadByte()
{
if (Position < _first.Length)
{
return _first[Position++];
}
if (Position < Length)
{
return _second[Position++ - _first.Length];
}
throw new OutOfMemoryException();
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool ReadBoolean() => ReadByte() > 0;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public sbyte ReadSByte() => (sbyte)ReadByte();
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public short ReadInt16()
{
short value;
if (Position < _first.Length)
{
if (!BinaryPrimitives.TryReadInt16BigEndian(_first.Slice(Position), out value))
{
// Not enough space. Split the spans
return (short)((ReadByte() >> 8) | ReadByte());
}
}
else if (!BinaryPrimitives.TryReadInt16BigEndian(_second.Slice(Position - _first.Length), out value))
{
throw new OutOfMemoryException();
}
Position += 2;
return value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public ushort ReadUInt16()
{
ushort value;
if (Position < _first.Length)
{
if (!BinaryPrimitives.TryReadUInt16BigEndian(_first.Slice(Position), out value))
{
// Not enough space. Split the spans
return (ushort)((ReadByte() >> 8) | ReadByte());
}
}
else if (!BinaryPrimitives.TryReadUInt16BigEndian(_second.Slice(Position - _first.Length), out value))
{
throw new OutOfMemoryException();
}
Position += 2;
return value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int ReadInt32()
{
int value;
if (Position < _first.Length)
{
if (!BinaryPrimitives.TryReadInt32BigEndian(_first.Slice(Position), out value))
{
// Not enough space. Split the spans
return (ReadByte() >> 24) | (ReadByte() >> 16) | (ReadByte() >> 8) | ReadByte();
}
}
else if (!BinaryPrimitives.TryReadInt32BigEndian(_second.Slice(Position - _first.Length), out value))
{
throw new OutOfMemoryException();
}
Position += 4;
return value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint ReadUInt32()
{
uint value;
if (Position < _first.Length)
{
if (!BinaryPrimitives.TryReadUInt32BigEndian(_first.Slice(Position), out value))
{
// Not enough space. Split the spans
return (uint)((ReadByte() >> 24) | (ReadByte() >> 16) | (ReadByte() >> 8) | ReadByte());
}
}
else if (!BinaryPrimitives.TryReadUInt32BigEndian(_second.Slice(Position - _first.Length), out value))
{
throw new OutOfMemoryException();
}
Position += 4;
return value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public long ReadInt64()
{
long value;
if (Position < _first.Length)
{
if (!BinaryPrimitives.TryReadInt64BigEndian(_first.Slice(Position), out value))
{
// Not enough space. Split the spans
return ((long)ReadByte() >> 56) |
((long)ReadByte() >> 48) |
((long)ReadByte() >> 40) |
((long)ReadByte() >> 32) |
((long)ReadByte() >> 24) |
((long)ReadByte() >> 16) |
((long)ReadByte() >> 8) |
ReadByte();
}
}
else if (!BinaryPrimitives.TryReadInt64BigEndian(_second.Slice(Position - _first.Length), out value))
{
throw new OutOfMemoryException();
}
Position += 8;
return value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public ulong ReadUInt64()
{
ulong value;
if (Position < _first.Length)
{
if (!BinaryPrimitives.TryReadUInt64BigEndian(_first.Slice(Position), out value))
{
// Not enough space. Split the spans
return ((ulong)ReadByte() >> 56) |
((ulong)ReadByte() >> 48) |
((ulong)ReadByte() >> 40) |
((ulong)ReadByte() >> 32) |
((ulong)ReadByte() >> 24) |
((ulong)ReadByte() >> 16) |
((ulong)ReadByte() >> 8) |
ReadByte();
}
}
else if (!BinaryPrimitives.TryReadUInt64BigEndian(_second.Slice(Position - _first.Length), out value))
{
throw new OutOfMemoryException();
}
Position += 8;
return value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadString(Encoding encoding, bool safeString = false, int fixedLength = -1)
{
int sizeT = Utility.GetByteLengthForEncoding(encoding);
bool isFixedLength = fixedLength > -1;
var remaining = Remaining;
int size;
if (isFixedLength)
{
size = fixedLength * sizeT;
if (size > Remaining)
{
throw new OutOfMemoryException();
}
}
else
{
size = remaining - (remaining & (sizeT - 1));
}
ReadOnlySpan<byte> span;
int index;
if (Position < _first.Length)
{
var firstLength = Math.Min(_first.Length - Position, size);
// Find terminator
index = Utility.IndexOfTerminator(_first.Slice(Position, firstLength), sizeT);
if (index < 0)
{
remaining = size - firstLength;
// We don't have a terminator, but a fixed size to the end of the first span, so stop there
if (remaining <= 0)
{
index = firstLength;
}
else
{
index = Utility.IndexOfTerminator(_second.Slice(0, remaining), sizeT);
int secondLength = index < 0 ? remaining : index;
int length = firstLength + secondLength;
// Assume no strings should be too long for the stack
Span<byte> bytes = stackalloc byte[length];
_first.Slice(Position).CopyTo(bytes);
_second.Slice(0, secondLength).CopyTo(bytes.Slice(firstLength));
Position += length + (index >= 0 ? sizeT : 0);
return Utility.GetString(bytes, encoding, safeString);
}
}
span = _first.Slice(Position, index);
}
else
{
size = Math.Min(remaining, size);
span = _second.Slice( Position - _first.Length, size);
index = Utility.IndexOfTerminator(span, sizeT);
if (index >= 0)
{
span = span.Slice(0, index);
}
else
{
index = size;
}
}
Position += isFixedLength ? size : index + sizeT;
return Utility.GetString(span, encoding, safeString);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadLittleUniSafe(int fixedLength) => ReadString(Utility.UnicodeLE, true, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadLittleUniSafe() => ReadString(Utility.UnicodeLE, true);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadLittleUni(int fixedLength) => ReadString(Utility.UnicodeLE, false, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadLittleUni() => ReadString(Utility.UnicodeLE);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadBigUniSafe(int fixedLength) => ReadString(Utility.Unicode, true, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadBigUniSafe() => ReadString(Utility.Unicode, true);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadBigUni(int fixedLength) => ReadString(Utility.Unicode, false, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadBigUni() => ReadString(Utility.Unicode);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadUTF8Safe(int fixedLength) => ReadString(Utility.UTF8, true, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadUTF8Safe() => ReadString(Utility.UTF8, true);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadUTF8() => ReadString(Utility.UTF8);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadAsciiSafe(int fixedLength) => ReadString(Encoding.ASCII, true, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadAsciiSafe() => ReadString(Encoding.ASCII, true);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadAscii(int fixedLength) => ReadString(Encoding.ASCII, false, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public string ReadAscii() => ReadString(Encoding.ASCII);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int Seek(int offset, SeekOrigin origin) =>
Position = origin switch
{
SeekOrigin.Begin => offset,
SeekOrigin.End => Length - offset,
_ => Position + offset // Current
};
}
}