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stgsharp/StgSharp.Common/HighPerformance/UnmanagedMemoryPool.IndexNode.cs
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2025-08-25 09:50:30 +08:00

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5.2 KiB
C#

//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="UnmanagedMemoryPool.IndexNode.cs"
// Project: StgSharp
// AuthorGroup: Nitload Space
// Copyright (c) Nitload Space. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the “Software”), to deal in the Software without restriction,
// including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software,
// and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
//
// The above copyright notice and
// this permission notice shall be included in all copies
// or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS”,
// WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH
// THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection.Emit;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;
using System.Text;
using System.Threading.Tasks;
namespace StgSharp.HighPerformance
{
public unsafe partial class UnmanagedMemoryPool
{
private const int
LevelOf4096 = 4,
LevelOf1024 = 3,
LevelOf256 = 2,
LevelOf64 = 1;
internal readonly ref struct NextIndexNode
{
private readonly Span<M64> _layout;
public readonly nuint this[int level]
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get => Position - _layout[level].Member<uint>(0);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
set => _layout[level].Member<uint>(0) = (uint)(Position - value);
}
private readonly ref nuint Position
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get => ref _layout[0].Member<nuint>(0);
}
}
internal readonly ref struct PreviousIndexNode
{
private readonly Span<M64> _layout;
public readonly nuint this[int level]
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get => Position - _layout[level].Member<uint>(1);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
set => _layout[level].Member<uint>(1) = (uint)(Position - value);
}
private readonly ref nuint Position
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get => ref _layout[0].Member<nuint>(0);
}
}
[StructLayout(LayoutKind.Explicit)]
internal readonly ref struct IndexNode
{
private static readonly uint[] _sizeArr = [16, 64, 256, 1024, 4096];
[FieldOffset(0)] private readonly NextIndexNode nxt;
[FieldOffset(0)] private readonly PreviousIndexNode pre;
[FieldOffset(0)] private readonly Span<M64> _layout;
public IndexNode(ref byte span)
{
_layout = MemoryMarshal.CreateSpan(ref Unsafe.As<byte, M64>(ref span), 8);
}
public readonly ref nuint Position => ref _layout[0].Member<nuint>(0);
public readonly ref uint Size => ref _layout[5].Member<uint>(0);
public readonly ref int Level => ref _layout[5].Member<int>(1);
public readonly ref nuint Segment => ref _layout[6].Member<nuint>(0);
public readonly uint BlockSize => LevelToSize(Level);
public static uint LevelToSize(int level)
{
return level switch
{
< 0 or > 4 => throw new ArgumentOutOfRangeException(
nameof(level), "Level must be from 1 to 4."),
_ => _sizeArr[level]
};
}
#pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
public readonly ref readonly NextIndexNode Next
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get => ref nxt;
}
public readonly ref readonly PreviousIndexNode Previous
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get => ref pre;
}
#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
}
}
}