51 lines
1.8 KiB
C#
51 lines
1.8 KiB
C#
// Copyright (c) Six Labors.
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// Licensed under the Six Labors Split License.
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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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using System.Runtime.InteropServices;
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namespace SixLabors.PolygonClipper {
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/// <summary>
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/// A custom <see cref="MemoryManager{T}"/> that can wrap <see cref="Memory{T}"/> of <see cref="byte"/> instances
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/// and cast them to be <see cref="Memory{T}"/> for any arbitrary unmanaged <typeparamref name="T"/> value type.
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/// </summary>
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/// <typeparam name="T">The value type to use when casting the wrapped <see cref="Memory{T}"/> instance.</typeparam>
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internal sealed class ByteMemoryManager<T> : MemoryManager<T>
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where T : unmanaged
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{
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/// <summary>
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/// The wrapped <see cref="Memory{T}"/> of <see cref="byte"/> instance.
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/// </summary>
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private readonly Memory<byte> memory;
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/// <summary>
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/// Initializes a new instance of the <see cref="ByteMemoryManager{T}"/> class.
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/// </summary>
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/// <param name="memory">The <see cref="Memory{T}"/> of <see cref="byte"/> instance to wrap.</param>
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public ByteMemoryManager(Memory<byte> memory) => this.memory = memory;
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/// <inheritdoc/>
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protected override void Dispose(bool disposing)
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{
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}
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/// <inheritdoc/>
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public override Span<T> GetSpan() => MemoryMarshal.Cast<byte, T>(this.memory.Span);
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/// <inheritdoc/>
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public override MemoryHandle Pin(int elementIndex = 0)
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// We need to adjust the offset into the wrapped byte segment,
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// as the input index refers to the target-cast memory of T.
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// We just have to shift this index by the byte size of T.
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=> this.memory[(elementIndex * Unsafe.SizeOf<T>())..].Pin();
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/// <inheritdoc/>
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public override void Unpin()
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{
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}
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}
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}
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