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Add BinaryPrimitives.ReverseEndianness for spans of elements (#76339)
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‎src/libraries/System.Memory/ref/System.Memory.cs

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@@ -442,6 +442,27 @@ public static partial class BinaryPrimitives
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public static uint ReverseEndianness(uint value) { throw null; }
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[System.CLSCompliantAttribute(false)]
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public static ulong ReverseEndianness(ulong value) { throw null; }
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public static nint ReverseEndianness(nint value) { throw null; }
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[System.CLSCompliantAttribute(false)]
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public static nuint ReverseEndianness(nuint value) { throw null; }
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public static System.Int128 ReverseEndianness(System.Int128 value) { throw null; }
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[System.CLSCompliantAttribute(false)]
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public static System.UInt128 ReverseEndianness(System.UInt128 value) { throw null; }
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public static void ReverseEndianness(System.ReadOnlySpan<int> source, System.Span<int> destination) { }
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public static void ReverseEndianness(System.ReadOnlySpan<Int128> source, System.Span<Int128> destination) { }
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public static void ReverseEndianness(System.ReadOnlySpan<long> source, System.Span<long> destination) { }
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public static void ReverseEndianness(System.ReadOnlySpan<nint> source, System.Span<nint> destination) { }
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public static void ReverseEndianness(System.ReadOnlySpan<short> source, System.Span<short> destination) { }
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[System.CLSCompliant(false)]
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public static void ReverseEndianness(System.ReadOnlySpan<nuint> source, System.Span<nuint> destination) { }
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[System.CLSCompliant(false)]
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public static void ReverseEndianness(System.ReadOnlySpan<uint> source, System.Span<uint> destination) { }
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[System.CLSCompliant(false)]
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public static void ReverseEndianness(System.ReadOnlySpan<UInt128> source, System.Span<UInt128> destination) { }
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[System.CLSCompliant(false)]
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public static void ReverseEndianness(System.ReadOnlySpan<ulong> source, System.Span<ulong> destination) { }
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[System.CLSCompliant(false)]
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public static void ReverseEndianness(System.ReadOnlySpan<ushort> source, System.Span<ushort> destination) { }
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public static bool TryReadDoubleBigEndian(System.ReadOnlySpan<byte> source, out double value) { throw null; }
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public static bool TryReadDoubleLittleEndian(System.ReadOnlySpan<byte> source, out double value) { throw null; }
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public static bool TryReadHalfBigEndian(System.ReadOnlySpan<byte> source, out System.Half value) { throw null; }

‎src/libraries/System.Memory/tests/Binary/ReverseEndiannessUnitTests.cs

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@@ -1,6 +1,10 @@
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// 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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using System.Collections.Generic;
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using System.Linq;
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using System.Numerics;
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using System.Runtime.InteropServices;
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using Xunit;
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namespace System.Buffers.Binary.Tests
@@ -41,6 +45,13 @@ public void ReverseEndianness_Int32AndUInt32(uint a, uint b)
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Assert.Equal((int)a, BinaryPrimitives.ReverseEndianness((int)b));
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Assert.Equal(b, BinaryPrimitives.ReverseEndianness(a));
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Assert.Equal(a, BinaryPrimitives.ReverseEndianness(b));
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if (IntPtr.Size == 4)
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{
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Assert.Equal((nint)b, BinaryPrimitives.ReverseEndianness((nint)a));
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Assert.Equal((nint)a, BinaryPrimitives.ReverseEndianness((nint)b));
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Assert.Equal((nuint)b, BinaryPrimitives.ReverseEndianness((nuint)a));
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Assert.Equal((nuint)a, BinaryPrimitives.ReverseEndianness((nuint)b));
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}
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}
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[Theory]
@@ -52,6 +63,129 @@ public void ReverseEndianness_Int64AndUInt64(ulong a, ulong b)
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Assert.Equal((long)a, BinaryPrimitives.ReverseEndianness((long)b));
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Assert.Equal(b, BinaryPrimitives.ReverseEndianness(a));
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Assert.Equal(a, BinaryPrimitives.ReverseEndianness(b));
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if (IntPtr.Size == 8)
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{
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Assert.Equal((nint)b, BinaryPrimitives.ReverseEndianness((nint)a));
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Assert.Equal((nint)a, BinaryPrimitives.ReverseEndianness((nint)b));
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Assert.Equal((nuint)b, BinaryPrimitives.ReverseEndianness((nuint)a));
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Assert.Equal((nuint)a, BinaryPrimitives.ReverseEndianness((nuint)b));
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}
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}
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[Theory]
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[InlineData(0x0123456789ABCDEF, 0xABCDEF0123456789)]
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public void ReverseEndianness_Int128AndUInt128(ulong aLower, ulong aUpper)
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{
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Int128 original = new Int128(aLower, aUpper);
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Int128 reversed = new Int128(BinaryPrimitives.ReverseEndianness(aUpper), BinaryPrimitives.ReverseEndianness(aLower));
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Assert.Equal(reversed, BinaryPrimitives.ReverseEndianness(original));
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Assert.Equal((UInt128)reversed, BinaryPrimitives.ReverseEndianness((UInt128)original));
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}
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public static IEnumerable<object[]> ReverseEndianness_Span_MemberData()
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{
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var r = new Random(42);
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foreach (int length in Enumerable.Range(0, 36))
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{
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yield return new object[] { Enumerable.Range(0, length).Select(_ => (ushort)r.Next(int.MinValue, int.MaxValue)).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => (short)r.Next(int.MinValue, int.MaxValue)).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => (uint)r.Next(int.MinValue, int.MaxValue)).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => r.Next(int.MinValue, int.MaxValue)).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => (ulong)r.NextInt64(long.MinValue, long.MaxValue)).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => r.NextInt64(long.MinValue, long.MaxValue)).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => (nuint)r.NextInt64(long.MinValue, long.MaxValue)).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => (nint)r.NextInt64(long.MinValue, long.MaxValue)).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => new UInt128((ulong)r.NextInt64(long.MinValue, long.MaxValue), (ulong)r.NextInt64(long.MinValue, long.MaxValue))).ToArray() };
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yield return new object[] { Enumerable.Range(0, length).Select(_ => new Int128((ulong)r.NextInt64(long.MinValue, long.MaxValue), (ulong)r.NextInt64(long.MinValue, long.MaxValue))).ToArray() };
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}
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}
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[Theory]
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[MemberData(nameof(ReverseEndianness_Span_MemberData))]
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public void ReverseEndianness_Span_AllElementsReversed<T>(T[] original) where T : struct, INumber<T>
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{
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T[] expected = original.Select(ReverseEndianness).ToArray();
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T[] originalCopy = (T[])original.Clone();
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T[] actual1 = (T[])original.Clone();
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T[] actual2 = new T[original.Length];
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T[] actual3 = new T[original.Length + 1];
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// In-place
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ReverseEndianness<T>(actual1, actual1);
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Assert.Equal(expected, actual1);
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// Different destination
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ReverseEndianness<T>(original, actual2);
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Assert.Equal(originalCopy, original);
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Assert.Equal(expected, actual2);
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// Different larger destination
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ReverseEndianness<T>(original, actual3);
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Assert.Equal(originalCopy, original);
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Assert.Equal(expected, actual3[0..^1]);
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Assert.Equal(default, actual3[^1]);
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foreach (int offset in new[] { 1, 2, 3 })
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{
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if (original.Length > offset)
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{
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// In-place shifted +offset
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expected = original.AsSpan(0, original.Length - offset).ToArray().Select(ReverseEndianness).ToArray();
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actual1 = (T[])original.Clone();
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ReverseEndianness(actual1.AsSpan(0, actual1.Length - offset), actual1.AsSpan(offset));
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Assert.Equal(expected, actual1.AsSpan(offset).ToArray());
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for (int i = 0; i < offset; i++)
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{
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Assert.Equal(original[i], actual1[i]);
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}
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// In-place shifted -offset
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expected = original.AsSpan(offset).ToArray().Select(ReverseEndianness).ToArray();
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actual2 = (T[])original.Clone();
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ReverseEndianness(actual2.AsSpan(offset), actual2.AsSpan(0, actual2.Length - offset));
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Assert.Equal(expected, actual2.AsSpan(0, actual2.Length - offset).ToArray());
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Assert.Equal(original[^offset], actual2[^offset]);
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}
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}
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// Throws if the destination is too short
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if (original.Length > 0)
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{
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T[] destination = new T[original.Length - 1];
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AssertExtensions.Throws<ArgumentException>("destination", () => ReverseEndianness<T>(original, destination));
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}
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}
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private static T ReverseEndianness<T>(T value)
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{
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if (typeof(T) == typeof(ushort)) return (T)(object)BinaryPrimitives.ReverseEndianness((ushort)(object)value);
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if (typeof(T) == typeof(short)) return (T)(object)BinaryPrimitives.ReverseEndianness((short)(object)value);
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if (typeof(T) == typeof(uint)) return (T)(object)BinaryPrimitives.ReverseEndianness((uint)(object)value);
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if (typeof(T) == typeof(int)) return (T)(object)BinaryPrimitives.ReverseEndianness((int)(object)value);
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if (typeof(T) == typeof(ulong)) return (T)(object)BinaryPrimitives.ReverseEndianness((ulong)(object)value);
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if (typeof(T) == typeof(long)) return (T)(object)BinaryPrimitives.ReverseEndianness((long)(object)value);
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if (typeof(T) == typeof(nuint)) return (T)(object)BinaryPrimitives.ReverseEndianness((nuint)(object)value);
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if (typeof(T) == typeof(nint)) return (T)(object)BinaryPrimitives.ReverseEndianness((nint)(object)value);
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if (typeof(T) == typeof(UInt128)) return (T)(object)BinaryPrimitives.ReverseEndianness((UInt128)(object)value);
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if (typeof(T) == typeof(Int128)) return (T)(object)BinaryPrimitives.ReverseEndianness((Int128)(object)value);
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throw new Exception($"Unexpected type {typeof(T)}");
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}
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private static void ReverseEndianness<T>(ReadOnlySpan<T> source, Span<T> destination) where T : struct
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{
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if (typeof(T) == typeof(ushort)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, ushort>(source), MemoryMarshal.Cast<T, ushort>(destination)); return; }
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if (typeof(T) == typeof(short)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, short>(source), MemoryMarshal.Cast<T, short>(destination)); return; }
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if (typeof(T) == typeof(uint)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, uint>(source), MemoryMarshal.Cast<T, uint>(destination)); return; }
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if (typeof(T) == typeof(int)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, int>(source), MemoryMarshal.Cast<T, int>(destination)); return; }
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if (typeof(T) == typeof(ulong)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, ulong>(source), MemoryMarshal.Cast<T, ulong>(destination)); return; }
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if (typeof(T) == typeof(long)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, long>(source), MemoryMarshal.Cast<T, long>(destination)); return; }
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if (typeof(T) == typeof(nuint)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, nuint>(source), MemoryMarshal.Cast<T, nuint>(destination)); return; }
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if (typeof(T) == typeof(nint)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, nint>(source), MemoryMarshal.Cast<T, nint>(destination)); return; }
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if (typeof(T) == typeof(UInt128)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, UInt128>(source), MemoryMarshal.Cast<T, UInt128>(destination)); return; }
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if (typeof(T) == typeof(Int128)) { BinaryPrimitives.ReverseEndianness(MemoryMarshal.Cast<T, Int128>(source), MemoryMarshal.Cast<T, Int128>(destination)); return; }
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throw new Exception($"Unexpected type {typeof(T)}");
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}
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}
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}

‎src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

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@@ -103,6 +103,7 @@
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<Compile Include="$(MSBuildThisFileDirectory)System\Buffer.cs" />
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<Compile Include="$(MSBuildThisFileDirectory)System\Buffers\ArrayPool.cs" />
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<Compile Include="$(MSBuildThisFileDirectory)System\Buffers\ArrayPoolEventSource.cs" />
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<Compile Include="$(MSBuildThisFileDirectory)System\Buffers\Binary\BinaryPrimitives.ReverseEndianness.cs" />
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<Compile Include="$(MSBuildThisFileDirectory)System\Buffers\Binary\Reader.cs" />
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<Compile Include="$(MSBuildThisFileDirectory)System\Buffers\Binary\ReaderBigEndian.cs" />
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<Compile Include="$(MSBuildThisFileDirectory)System\Buffers\Binary\ReaderLittleEndian.cs" />

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