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Sergio0694
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stephentoub
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Add NativeMemory.ZeroMemory API (#69500)
* Add NativeMemory.ZeroMemory API * Replace Random.NextBytes with Span<byte>.Fill * Add ZeroMemory unit tests for zeroed region within buffer * Add remarks for ptr and byteCount parameters * Add test for ZeroMemory(null, 0) not throwing * Add unit tests for zeroing memory with a size of 0 * Move test cases with 0 byte count to separate method Co-authored-by: Stephen Toub <[email protected]>
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‎src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/NativeMemory.cs

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@@ -38,6 +38,19 @@ public static unsafe partial class NativeMemory
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return AllocZeroed(byteCount, elementSize: 1);
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}
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/// <summary>Clears a block of memory.</summary>
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/// <param name="ptr">A pointer to the block of memory that should be cleared.</param>
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/// <param name="byteCount">The size, in bytes, of the block to clear.</param>
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/// <remarks>
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/// <para>If this method is called with <paramref name="ptr" /> being <see langword="null"/> and <paramref name="byteCount" /> being <c>0</c>, it will be equivalent to a no-op.</para>
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/// <para>The behavior when <paramref name="ptr" /> is <see langword="null"/> and <paramref name="byteCount" /> is greater than <c>0</c> is undefined.</para>
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/// </remarks>
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[CLSCompliant(false)]
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public static unsafe void ZeroMemory(void* ptr, nuint byteCount)
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{
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SpanHelpers.ClearWithoutReferences(ref *(byte*)ptr, byteCount);
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static nuint GetByteCount(nuint elementCount, nuint elementSize)
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{

‎src/libraries/System.Runtime.InteropServices/ref/System.Runtime.InteropServices.cs

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@@ -809,6 +809,8 @@ public static void AlignedFree(void* ptr) { }
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public static void Free(void* ptr) { }
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[System.CLSCompliantAttribute(false)]
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public static void* Realloc(void* ptr, nuint byteCount) { throw null; }
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[System.CLSCompliantAttribute(false)]
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public static void ZeroMemory(void* ptr, nuint byteCount) { throw null; }
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}
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public readonly partial struct NFloat : System.IComparable, System.IComparable<System.Runtime.InteropServices.NFloat>, System.IEquatable<System.Runtime.InteropServices.NFloat>, System.IFormattable, System.IParsable<System.Runtime.InteropServices.NFloat>, System.ISpanFormattable, System.ISpanParsable<System.Runtime.InteropServices.NFloat>, System.Numerics.IAdditionOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IAdditiveIdentity<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IBinaryFloatingPointIeee754<System.Runtime.InteropServices.NFloat>, System.Numerics.IBinaryNumber<System.Runtime.InteropServices.NFloat>, System.Numerics.IBitwiseOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IComparisonOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IDecrementOperators<System.Runtime.InteropServices.NFloat>, System.Numerics.IDivisionOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IEqualityOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IExponentialFunctions<System.Runtime.InteropServices.NFloat>, System.Numerics.IFloatingPoint<System.Runtime.InteropServices.NFloat>, System.Numerics.IFloatingPointIeee754<System.Runtime.InteropServices.NFloat>, System.Numerics.IHyperbolicFunctions<System.Runtime.InteropServices.NFloat>, System.Numerics.IIncrementOperators<System.Runtime.InteropServices.NFloat>, System.Numerics.ILogarithmicFunctions<System.Runtime.InteropServices.NFloat>, System.Numerics.IMinMaxValue<System.Runtime.InteropServices.NFloat>, System.Numerics.IModulusOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IMultiplicativeIdentity<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IMultiplyOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.INumber<System.Runtime.InteropServices.NFloat>, System.Numerics.INumberBase<System.Runtime.InteropServices.NFloat>, System.Numerics.IPowerFunctions<System.Runtime.InteropServices.NFloat>, System.Numerics.IRootFunctions<System.Runtime.InteropServices.NFloat>, System.Numerics.ISignedNumber<System.Runtime.InteropServices.NFloat>, System.Numerics.ISubtractionOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.ITrigonometricFunctions<System.Runtime.InteropServices.NFloat>, System.Numerics.IUnaryNegationOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>, System.Numerics.IUnaryPlusOperators<System.Runtime.InteropServices.NFloat, System.Runtime.InteropServices.NFloat>
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{

‎src/libraries/System.Runtime.InteropServices/tests/System.Runtime.InteropServices.UnitTests/System/Runtime/InteropServices/NativeMemoryTests.cs

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@@ -435,5 +435,128 @@ public void ReallocSmallerToLargerTest()
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NativeMemory.Free(newPtr);
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}
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[Theory]
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[InlineData(1, 0)]
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[InlineData(1, 1)]
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[InlineData(1, 2)]
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[InlineData(1, 3)]
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[InlineData(2, 0)]
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[InlineData(3, 0)]
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[InlineData(4, 0)]
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[InlineData(8, 0)]
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[InlineData(9, 0)]
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[InlineData(16, 0)]
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[InlineData(16, 1)]
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[InlineData(16, 3)]
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[InlineData(16, 7)]
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[InlineData(32, 0)]
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[InlineData(64, 0)]
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[InlineData(128, 0)]
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[InlineData(256, 0)]
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[InlineData(256, 1)]
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[InlineData(256, 2)]
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[InlineData(256, 3)]
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[InlineData(256, 5)]
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[InlineData(512, 0)]
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[InlineData(547, 0)]
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[InlineData(1 * 1024, 0)]
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public void ZeroMemoryTest(int size, int offset)
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{
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byte* ptr = (byte*)NativeMemory.AlignedAlloc((nuint)(size + offset), 8);
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Assert.True(ptr != null);
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Assert.True((nuint)ptr % 8 == 0);
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new Span<byte>(ptr, size + offset).Fill(0b10101010);
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NativeMemory.ZeroMemory(ptr + offset, (nuint)size);
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Assert.Equal(-1, new Span<byte>(ptr + offset, size).IndexOfAnyExcept((byte)0));
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NativeMemory.AlignedFree(ptr);
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}
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[Theory]
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[InlineData(1, 0)]
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[InlineData(1, 1)]
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[InlineData(1, 2)]
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[InlineData(1, 3)]
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[InlineData(1, 44)]
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[InlineData(1, 367)]
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[InlineData(2, 0)]
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[InlineData(3, 0)]
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[InlineData(4, 0)]
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[InlineData(8, 0)]
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[InlineData(9, 0)]
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[InlineData(9, 2)]
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[InlineData(9, 111)]
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[InlineData(9, 289)]
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[InlineData(16, 0)]
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[InlineData(16, 1)]
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[InlineData(16, 3)]
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[InlineData(16, 7)]
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[InlineData(32, 0)]
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[InlineData(64, 0)]
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[InlineData(128, 0)]
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[InlineData(256, 0)]
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[InlineData(256, 1)]
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[InlineData(256, 2)]
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[InlineData(256, 3)]
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[InlineData(256, 5)]
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[InlineData(256, 67)]
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[InlineData(256, 143)]
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public void ZeroMemoryWithExactRangeTest(int size, int offset)
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{
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int headLength = offset;
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int bodyLength = size;
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int tailLength = 512 - headLength - bodyLength;
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int headOffset = 0;
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int bodyOffset = headLength;
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int tailOffset = headLength + bodyLength;
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byte* ptr = (byte*)NativeMemory.AlignedAlloc(512, 8);
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Assert.True(ptr != null);
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Assert.True((nuint)ptr % 8 == 0);
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new Span<byte>(ptr, 512).Fill(0b10101010);
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NativeMemory.ZeroMemory(ptr + bodyOffset, (nuint)bodyLength);
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Assert.Equal(-1, new Span<byte>(ptr + headOffset, headLength).IndexOfAnyExcept((byte)0b10101010));
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Assert.Equal(-1, new Span<byte>(ptr + bodyOffset, bodyLength).IndexOfAnyExcept((byte)0));
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Assert.Equal(-1, new Span<byte>(ptr + tailOffset, tailLength).IndexOfAnyExcept((byte)0b10101010));
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NativeMemory.AlignedFree(ptr);
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}
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[Theory]
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[InlineData(0)]
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[InlineData(1)]
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[InlineData(167)]
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public void ZeroMemoryWithSizeEqualTo0ShouldNoOpTest(int offset)
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{
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byte* ptr = (byte*)NativeMemory.AlignedAlloc(512, 8);
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Assert.True(ptr != null);
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Assert.True((nuint)ptr % 8 == 0);
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new Span<byte>(ptr, 512).Fill(0b10101010);
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NativeMemory.ZeroMemory(ptr + offset, 0);
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Assert.Equal(-1, new Span<byte>(ptr, 512).IndexOfAnyExcept((byte)0b10101010));
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NativeMemory.AlignedFree(ptr);
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}
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[Fact]
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public void ZeroMemoryWithNullPointerAndZeroByteCountTest()
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{
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NativeMemory.ZeroMemory(null, 0);
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// This test method just needs to check that no exceptions are thrown
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}
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}
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}

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