72 lines
2.5 KiB
C#
72 lines
2.5 KiB
C#
// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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// See the LICENSE file in the project root for more information.
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using System;
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using System.Buffers;
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using System.Runtime.CompilerServices;
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namespace CommunityToolkit.HighPerformance.Streams;
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/// <summary>
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/// An <see cref="ISpanOwner"/> implementation wrapping a <see cref="MemoryManager{T}"/> of <see cref="byte"/> instance.
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/// </summary>
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internal readonly struct MemoryManagerOwner : ISpanOwner
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{
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/// <summary>
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/// The wrapped <see cref="MemoryManager{T}"/> instance.
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/// </summary>
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private readonly MemoryManager<byte> memoryManager;
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/// <summary>
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/// The starting offset within <see cref="memoryManager"/>.
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/// </summary>
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private readonly int offset;
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/// <summary>
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/// The usable length within <see cref="memoryManager"/>.
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/// </summary>
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private readonly int length;
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/// <summary>
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/// Initializes a new instance of the <see cref="MemoryManagerOwner"/> struct.
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/// </summary>
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/// <param name="memoryManager">The wrapped <see cref="MemoryManager{T}"/> instance.</param>
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/// <param name="offset">The starting offset within <paramref name="memoryManager"/>.</param>
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/// <param name="length">The usable length within <paramref name="memoryManager"/>.</param>
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public MemoryManagerOwner(MemoryManager<byte> memoryManager, int offset, int length)
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{
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this.memoryManager = memoryManager;
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this.offset = offset;
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this.length = length;
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}
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/// <inheritdoc/>
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public int Length
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{
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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get => this.length;
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}
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/// <inheritdoc/>
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public Span<byte> Span
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{
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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get
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{
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// We can't use the same trick we use for arrays to optimize the creation of
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// the offset span, as otherwise a bugged MemoryManager<T> instance returning
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// a span of an incorrect size could cause an access violation. Instead, we just
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// get the span and then slice it, which will validate both offset and length.
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return this.memoryManager.GetSpan().Slice(this.offset, this.length);
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}
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}
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/// <inheritdoc/>
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public Memory<byte> Memory
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{
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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get => this.memoryManager.Memory.Slice(this.offset, this.length);
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}
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}
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