modernuo/Projects/Server/Buffers/SpanWriter.cs

489 lines
15 KiB
C#

/*************************************************************************
* ModernUO *
* Copyright 2019-2023 - ModernUO Development Team *
* Email: hi@modernuo.com *
* File: SpanWriter.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.Buffers.Binary;
using System.Diagnostics;
using System.IO;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using CommunityToolkit.HighPerformance;
using Server;
using Server.Buffers;
using Server.Text;
namespace System.Buffers;
public ref struct SpanWriter
{
private readonly bool _resize;
private byte[] _arrayToReturnToPool;
private Span<byte> _buffer;
private int _position;
public int BytesWritten { get; private set; }
public int Position
{
get => _position;
private set
{
_position = value;
if (value > BytesWritten)
{
BytesWritten = value;
}
}
}
public int Capacity => _buffer.Length;
public ReadOnlySpan<byte> Span => _buffer[..Position];
public Span<byte> RawBuffer => _buffer;
/**
* Converts the writer to a Span<byte> using a SpanOwner.
* If the buffer was stackalloc, it will be copied to a rented buffer.
* Otherwise the existing rented buffer is used.
*
* Note:
* Do not use the SpanWriter after calling this method.
* This method will effectively dispose of the SpanWriter and is therefore considered terminal.
*/
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public SpanOwner ToSpan()
{
var toReturn = _arrayToReturnToPool;
SpanOwner apo;
if (_position == 0)
{
apo = new SpanOwner(_position, Array.Empty<byte>());
if (toReturn != null)
{
STArrayPool<byte>.Shared.Return(toReturn);
}
}
else if (toReturn != null)
{
apo = new SpanOwner(_position, toReturn);
}
else
{
var buffer = STArrayPool<byte>.Shared.Rent(_position);
_buffer.CopyTo(buffer);
apo = new SpanOwner(_position, buffer);
}
this = default; // Don't allow two references to the same buffer
return apo;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public SpanWriter(Span<byte> initialBuffer, bool resize = false)
{
_resize = resize;
_buffer = initialBuffer;
_position = 0;
BytesWritten = 0;
_arrayToReturnToPool = null;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public SpanWriter(int initialCapacity, bool resize = false)
{
_resize = resize;
_arrayToReturnToPool = STArrayPool<byte>.Shared.Rent(initialCapacity);
_buffer = _arrayToReturnToPool;
_position = 0;
BytesWritten = 0;
}
[MethodImpl(MethodImplOptions.NoInlining)]
private void Grow(int additionalCapacity)
{
var newSize = Math.Max(BytesWritten + additionalCapacity, _buffer.Length * 2);
byte[] poolArray = STArrayPool<byte>.Shared.Rent(newSize);
_buffer[..BytesWritten].CopyTo(poolArray);
byte[] toReturn = _arrayToReturnToPool;
_buffer = _arrayToReturnToPool = poolArray;
if (toReturn != null)
{
STArrayPool<byte>.Shared.Return(toReturn);
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void GrowIfNeeded(int count)
{
if (_position + count > _buffer.Length)
{
if (!_resize)
{
throw new OutOfMemoryException();
}
Grow(count);
}
}
public ref byte GetPinnableReference() => ref MemoryMarshal.GetReference(_buffer);
public void EnsureCapacity(int capacity)
{
if (capacity > _buffer.Length)
{
if (!_resize)
{
throw new OutOfMemoryException();
}
Grow(capacity - BytesWritten);
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public unsafe void Write(bool value)
{
GrowIfNeeded(1);
_buffer[Position++] = *(byte*)&value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(byte value)
{
GrowIfNeeded(1);
_buffer[Position++] = value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(sbyte value)
{
GrowIfNeeded(1);
_buffer[Position++] = (byte)value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(short value)
{
GrowIfNeeded(2);
BinaryPrimitives.WriteInt16BigEndian(_buffer[_position..], value);
Position += 2;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteLE(short value)
{
GrowIfNeeded(2);
BinaryPrimitives.WriteInt16LittleEndian(_buffer[_position..], value);
Position += 2;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(ushort value)
{
GrowIfNeeded(2);
BinaryPrimitives.WriteUInt16BigEndian(_buffer[_position..], value);
Position += 2;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteLE(ushort value)
{
GrowIfNeeded(2);
BinaryPrimitives.WriteUInt16LittleEndian(_buffer[_position..], value);
Position += 2;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(int value)
{
GrowIfNeeded(4);
BinaryPrimitives.WriteInt32BigEndian(_buffer[_position..], value);
Position += 4;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteLE(int value)
{
GrowIfNeeded(4);
BinaryPrimitives.WriteInt32LittleEndian(_buffer[_position..], value);
Position += 4;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(uint value)
{
GrowIfNeeded(4);
BinaryPrimitives.WriteUInt32BigEndian(_buffer[_position..], value);
Position += 4;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(Serial serial) => Write(serial.Value);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteLE(uint value)
{
GrowIfNeeded(4);
BinaryPrimitives.WriteUInt32LittleEndian(_buffer[_position..], value);
Position += 4;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(long value)
{
GrowIfNeeded(8);
BinaryPrimitives.WriteInt64BigEndian(_buffer[_position..], value);
Position += 8;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(ulong value)
{
GrowIfNeeded(8);
BinaryPrimitives.WriteUInt64BigEndian(_buffer[_position..], value);
Position += 8;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Write(ReadOnlySpan<byte> buffer)
{
var count = buffer.Length;
GrowIfNeeded(count);
buffer.CopyTo(_buffer[_position..]);
Position += count;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteAscii(char chr) => Write((byte)chr);
public void WriteAscii(
ref RawInterpolatedStringHandler handler)
{
Write(handler.Text, Encoding.ASCII);
handler.Clear();
}
public void WriteAscii(
IFormatProvider? formatProvider,
[InterpolatedStringHandlerArgument("formatProvider")]
ref RawInterpolatedStringHandler handler)
{
Write(handler.Text, Encoding.ASCII);
handler.Clear();
}
public void Write(
Encoding encoding,
ref RawInterpolatedStringHandler handler)
{
Write(handler.Text, encoding);
handler.Clear();
}
public void Write(
Encoding encoding,
IFormatProvider? formatProvider,
[InterpolatedStringHandlerArgument("formatProvider")]
ref RawInterpolatedStringHandler handler)
{
Write(handler.Text, encoding);
handler.Clear();
}
public void Write(ReadOnlySpan<char> value, Encoding encoding, int fixedLength = -1)
{
var charLength = Math.Min(fixedLength > -1 ? fixedLength : value.Length, value.Length);
var src = value[..charLength];
var byteLength = encoding.GetByteLengthForEncoding();
var byteCount = encoding.GetByteCount(src);
if (fixedLength > src.Length)
{
byteCount += (fixedLength - src.Length) * byteLength;
}
if (byteCount == 0)
{
return;
}
GrowIfNeeded(byteCount);
var bytesWritten = encoding.GetBytes(src, _buffer[_position..]);
Position += bytesWritten;
if (fixedLength > -1)
{
var extra = fixedLength * byteLength - bytesWritten;
if (extra > 0)
{
Clear(extra);
}
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteLittleUni(string value) => Write(value, TextEncoding.UnicodeLE);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteLittleUniNull(string value)
{
Write(value, TextEncoding.UnicodeLE);
Write((ushort)0);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteLittleUni(string value, int fixedLength) => Write(value, TextEncoding.UnicodeLE, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteBigUni(string value) => Write(value, TextEncoding.Unicode);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteBigUniNull(string value)
{
Write(value, TextEncoding.Unicode);
Write((ushort)0); // '\0'
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteBigUni(string value, int fixedLength) => Write(value, TextEncoding.Unicode, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteUTF8(string value) => Write(value, TextEncoding.UTF8);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteUTF8Null(string value)
{
Write(value, TextEncoding.UTF8);
Write((byte)0); // '\0'
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteAscii(string value) => Write(value, Encoding.ASCII);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteAsciiNull(string value)
{
Write(value, Encoding.ASCII);
Write((byte)0); // '\0'
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void WriteAscii(string value, int fixedLength) => Write(value, Encoding.ASCII, fixedLength);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Clear(int count)
{
GrowIfNeeded(count);
_buffer.Slice(_position, count).Clear();
Position += count;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int Seek(int offset, SeekOrigin origin)
{
Debug.Assert(
origin != SeekOrigin.End || _resize || offset <= 0,
"Attempting to seek to a position beyond capacity using SeekOrigin.End without resize"
);
Debug.Assert(
origin != SeekOrigin.End || offset >= -_buffer.Length,
"Attempting to seek to a negative position using SeekOrigin.End"
);
Debug.Assert(
origin != SeekOrigin.Begin || offset >= 0,
"Attempting to seek to a negative position using SeekOrigin.Begin"
);
Debug.Assert(
origin != SeekOrigin.Begin || _resize || offset <= _buffer.Length,
"Attempting to seek to a position beyond the capacity using SeekOrigin.Begin without resize"
);
Debug.Assert(
origin != SeekOrigin.Current || _position + offset >= 0,
"Attempting to seek to a negative position using SeekOrigin.Current"
);
Debug.Assert(
origin != SeekOrigin.Current || _resize || _position + offset <= _buffer.Length,
"Attempting to seek to a position beyond the capacity using SeekOrigin.Current without resize"
);
var newPosition = Math.Max(0, origin switch
{
SeekOrigin.Current => _position + offset,
SeekOrigin.End => BytesWritten + offset,
_ => offset // Begin
});
if (newPosition > _buffer.Length)
{
Grow(newPosition - _buffer.Length + 1);
}
return Position = newPosition;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Dispose()
{
byte[] toReturn = _arrayToReturnToPool;
this = default; // for safety, to avoid using pooled array if this instance is erroneously appended to again
if (toReturn != null)
{
STArrayPool<byte>.Shared.Return(toReturn);
}
}
public struct SpanOwner : IDisposable
{
private readonly int _length;
private readonly byte[] _arrayToReturnToPool;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal SpanOwner(int length, byte[] buffer)
{
_length = length;
_arrayToReturnToPool = buffer;
}
public Span<byte> Span
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get => MemoryMarshal.CreateSpan(ref _arrayToReturnToPool.DangerousGetReference(), _length);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Dispose()
{
byte[] toReturn = _arrayToReturnToPool;
this = default;
if (_length > 0)
{
STArrayPool<byte>.Shared.Return(toReturn);
}
}
}
}