Replace MemoryMarshal generic Read/Write with BitConverter equivalents

[EgorBo]

Avoid MemoryMarshal.Read/Write because these APIs will marked as caller-unsafe. Use safer alternatives.

[Copilot]

Pull request overview

Sweep across libraries and System.Private.CoreLib replacing generic MemoryMarshal.Read/Write/TryRead/TryWrite<T> on primitive types with BitConverter span APIs (host-endian), plus adding downlevel BitConverter span polyfills for non-.NETCoreApp targets to support the migration ahead of making MemoryMarshal.*<T> caller-unsafe.

Changes:

• Replaced primitive MemoryMarshal.Read/Write usages with BitConverter.To* / BitConverter.TryWriteBytes in several libraries and CoreLib hot paths.
• Updated Boolean parsing fast-path to be endian-independent without relying on MemoryMarshal.Read<ulong>(AsBytes(chars)).
• Added/linked Common/src/Polyfills/BitConverterPolyfills.cs into multi-targeted projects to provide missing span overloads on downlevel TFMs.

Reviewed changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/PropertyRef.cs	Uses BitConverter.To* for key materialization from name bytes.
src/libraries/System.Text.Json/src/System/Text/Json/Document/JsonDocument.MetadataDb.cs	Replaces primitive reads/writes in metadata DB headers with BitConverter APIs.
src/libraries/System.Text.Json/src/System.Text.Json.csproj	Links BitConverterPolyfills.cs for non-.NETCoreApp TFMs.
src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/OpenSslCrlCache.cs	Switches URL hash extraction to BitConverter.ToUInt32.
src/libraries/System.Security.Cryptography.Pkcs/src/System.Security.Cryptography.Pkcs.csproj	Links BitConverterPolyfills.cs for non-.NETCoreApp TFMs.
src/libraries/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.cs	Uses BitConverter.ToInt32 for interop-returned primitive values.
src/libraries/System.Security.Cryptography.Cose/src/System.Security.Cryptography.Cose.csproj	Links BitConverterPolyfills.cs for non-.NETCoreApp TFMs.
src/libraries/System.Private.CoreLib/src/System/Random.Xoshiro256StarStarImpl.cs	Uses BitConverter.TryWriteBytes for NextBytes block writes.
src/libraries/System.Private.CoreLib/src/System/Random.Xoshiro128StarStarImpl.cs	Uses BitConverter.TryWriteBytes for NextBytes block writes.
src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipePayloadDecoder.cs	Simplifies byte/sbyte reads to payload[0] / cast.
src/libraries/System.Private.CoreLib/src/System/Boolean.cs	Reworks "true"/"false" case-insensitive checks to be endian-independent.
src/libraries/System.Private.CoreLib/src/Internal/Win32/RegistryKey.cs	Uses BitConverter.ToInt32/ToInt64 for registry numeric values.
src/libraries/System.Net.Primitives/src/System/Net/IPAddress.cs	Uses BitConverter for IPv4 constructor read, write, and hash computation reads.
src/libraries/System.Formats.Cbor/src/System/Formats/Cbor/CborHelpers.netstandard.cs	Uses BitConverter.To* / TryWriteBytes for big-endian float helpers on downlevel TFMs.
src/libraries/System.Formats.Cbor/src/System.Formats.Cbor.csproj	Links BitConverterPolyfills.cs for non-.NETCoreApp TFMs.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Windows.cs	Uses BitConverter.ToInt32/ToInt64 for perf counter reads.
src/libraries/System.Diagnostics.PerformanceCounter/src/System/Diagnostics/PerformanceCounterLib.cs	Uses BitConverter.ToUInt32/ToInt64 for perf counter data reads.
src/libraries/System.Diagnostics.PerformanceCounter/src/System.Diagnostics.PerformanceCounter.csproj	Links BitConverterPolyfills.cs for non-.NETCoreApp TFMs.
src/libraries/Microsoft.Win32.Registry/src/Microsoft/Win32/RegistryKey.cs	Uses BitConverter.ToInt32/ToInt64 for registry numeric values.
src/libraries/Common/src/Polyfills/HashCodePolyfills.cs	Uses BitConverter.ToInt32(ReadOnlySpan<byte>) when hashing bytes on downlevel TFMs.
src/libraries/Common/src/Polyfills/BitConverterPolyfills.cs	Adds downlevel BitConverter span overloads via extension members.

[Copilot]

Pull request overview

This PR updates multiple libraries and System.Private.CoreLib to avoid generic MemoryMarshal.Read<T>/Write<T>/TryRead<T>/TryWrite<T> on primitive types, replacing them with BitConverter (and in a few places BinaryPrimitives) equivalents as preparation for making the generic MemoryMarshal.* APIs caller-unsafe.

Changes:

• Replace primitive MemoryMarshal.Read/Write usage with BitConverter.To* / BitConverter.TryWriteBytes-style APIs (plus downlevel polyfills where required).
• Add BitConverter span polyfill inclusion to several non-.NETCoreApp project files.
• Simplify some endian-specific helper logic by using BinaryPrimitives big-/little-endian helpers.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/PropertyRef.cs	Switches primitive span reads from MemoryMarshal.Read<T> to BitConverter.To*.
src/libraries/System.Text.Json/src/System/Text/Json/Document/JsonDocument.MetadataDb.cs	Changes several row-field reads/writes to BinaryPrimitives.*LittleEndian.
src/libraries/System.Text.Json/src/System.Text.Json.csproj	Includes BitConverterPolyfills.cs for non-.NETCoreApp builds.
src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/OpenSslCrlCache.cs	Uses BitConverter.ToUInt32 instead of MemoryMarshal.Read<uint>.
src/libraries/System.Security.Cryptography.Pkcs/src/System.Security.Cryptography.Pkcs.csproj	Conditionally includes BitConverterPolyfills.cs for non-.NETCoreApp builds.
src/libraries/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.cs	Uses BitConverter.ToInt32 instead of MemoryMarshal.Read<int>.
src/libraries/System.Security.Cryptography.Cose/src/System.Security.Cryptography.Cose.csproj	Conditionally includes BitConverterPolyfills.cs for non-.NETCoreApp builds.
src/libraries/System.Private.CoreLib/src/System/Random.Xoshiro256StarStarImpl.cs	Changes PRNG block writes from host-endian to WriteUInt64LittleEndian.
src/libraries/System.Private.CoreLib/src/System/Random.Xoshiro128StarStarImpl.cs	Changes PRNG block writes from host-endian to WriteUInt32LittleEndian.
src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipePayloadDecoder.cs	Replaces MemoryMarshal.Read<byte/sbyte> with direct indexing.
src/libraries/System.Private.CoreLib/src/Internal/Win32/RegistryKey.cs	Uses BitConverter.ToInt32/ToInt64 instead of MemoryMarshal.Read<int/long>.
src/libraries/System.Net.Primitives/src/System/Net/IPAddress.cs	Replaces primitive reads/writes; IPv4 write uses WriteUInt32LittleEndian.
src/libraries/System.Formats.Cbor/src/System/Formats/Cbor/CborHelpers.netstandard.cs	Simplifies big-endian read/write helpers using BinaryPrimitives.
src/libraries/System.Formats.Cbor/src/System.Formats.Cbor.csproj	Includes BitConverterPolyfills.cs for non-.NETCoreApp builds.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Windows.cs	Uses BitConverter.ToInt32/ToInt64 for counter reads.
src/libraries/System.Diagnostics.PerformanceCounter/src/System/Diagnostics/PerformanceCounterLib.cs	Uses BitConverter span overloads for value reads.
src/libraries/System.Diagnostics.PerformanceCounter/src/System.Diagnostics.PerformanceCounter.csproj	Conditionally includes BitConverterPolyfills.cs for non-.NETCoreApp builds.
src/libraries/Microsoft.Win32.Registry/src/Microsoft/Win32/RegistryKey.cs	Uses BitConverter.ToInt32/ToInt64 instead of MemoryMarshal.Read<int/long>.
src/libraries/Common/src/Polyfills/HashCodePolyfills.cs	Switches to BitConverter.ToInt32(ReadOnlySpan<byte>).
src/libraries/Common/src/Polyfills/BitConverterPolyfills.cs	Adds downlevel span BitConverter.To* overloads via extension members.

[Copilot]

Pull request overview

This PR updates multiple library components to replace generic MemoryMarshal.Read/Write/TryRead/TryWrite usages on primitive types with BitConverter span-based APIs (host-endian), and adds/extends downlevel BitConverter span overload polyfills for non-.NETCoreApp targets.

Changes:

• Replace primitive MemoryMarshal.Read<T> call sites with BitConverter.To* equivalents across several libraries.
• Simplify big-endian helpers in System.Formats.Cbor to use BinaryPrimitives.Read*/Write*BigEndian.
• Extend Common BitConverter polyfills with ReadOnlySpan<byte> overloads and wire them into impacted non-.NETCoreApp projects.

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/PropertyRef.cs	Switch key extraction reads from MemoryMarshal.Read<*> to BitConverter.To* on spans.
src/libraries/System.Text.Json/src/System/Text/Json/Document/JsonDocument.MetadataDb.cs	Adjust MemoryMarshal.Write argument passing (ref → in) in metadata DB updates.
src/libraries/System.Text.Json/src/System.Text.Json.csproj	Include BitConverterPolyfills.cs for non-.NETCoreApp builds.
src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/OpenSslCrlCache.cs	Use BitConverter.ToUInt32 to interpret 4-byte hash span.
src/libraries/System.Security.Cryptography.Pkcs/src/System.Security.Cryptography.Pkcs.csproj	Include BitConverterPolyfills.cs for non-.NETCoreApp Windows builds.
src/libraries/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.cs	Replace primitive reads with BitConverter.ToInt32 on spans.
src/libraries/System.Security.Cryptography.Cose/src/System.Security.Cryptography.Cose.csproj	Include BitConverterPolyfills.cs for non-.NETCoreApp builds.
src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipePayloadDecoder.cs	Replace byte/sbyte MemoryMarshal.Read<T> with direct span indexing.
src/libraries/System.Private.CoreLib/src/Internal/Win32/RegistryKey.cs	Use BitConverter.ToInt32/ToInt64 to decode registry integer values.
src/libraries/System.Net.Primitives/src/System/Net/IPAddress.cs	Replace primitive span reads in ctor/hash code with BitConverter.ToUInt32.
src/libraries/System.Formats.Cbor/src/System/Formats/Cbor/CborHelpers.netstandard.cs	Use BinaryPrimitives big-endian APIs for half/single/double helpers.
src/libraries/System.Formats.Cbor/src/System.Formats.Cbor.csproj	Include BitConverterPolyfills.cs for non-.NETCoreApp builds.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Windows.cs	Replace perf-counter numeric reads with BitConverter.ToInt32/ToInt64.
src/libraries/System.Diagnostics.PerformanceCounter/src/System/Diagnostics/PerformanceCounterLib.cs	Replace span numeric reads with BitConverter.ToUInt32/ToInt64.
src/libraries/System.Diagnostics.PerformanceCounter/src/System.Diagnostics.PerformanceCounter.csproj	Include BitConverterPolyfills.cs for non-.NETCoreApp Windows builds.
src/libraries/Microsoft.Win32.Registry/src/Microsoft/Win32/RegistryKey.cs	Replace primitive registry value reads with BitConverter.ToInt32/ToInt64.
src/libraries/Common/src/Polyfills/HashCodePolyfills.cs	Switch HashCode.AddBytes chunk reads to BitConverter.ToInt32.
src/libraries/Common/src/Polyfills/BitConverterPolyfills.cs	Add span-based BitConverter.To* polyfills implemented via MemoryMarshal.Read<T>.

[EgorBo]

Note

This benchmark request was generated by GitHub Copilot.

@EgorBot -linux_amd -windows_amd -osx_arm64

using System;
using System.Buffers.Binary;
using System.IO.Hashing;
using System.Numerics;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

BenchmarkSwitcher.FromAssembly(typeof(SafeSpanRewriteBenchmarks).Assembly).Run(args);

[MemoryDiagnoser]
public class SafeSpanRewriteBenchmarks
{
    private byte[] _bytes = null!;
    private byte[] _randomBuffer = null!;
    private int[] _ints = null!;
    private int[] _reversedInts = null!;
    private long[] _longs = null!;
    private long[] _reversedLongs = null!;
    private BigInteger _bigInteger;
    private Random _random = null!;

    [Params(64, 1024, 4096)]
    public int Length { get; set; }

    [GlobalSetup]
    public void Setup()
    {
        _bytes = new byte[Length];
        _randomBuffer = new byte[Length];
        var seed = new Random(12345);
        seed.NextBytes(_bytes);
        _bytes[^1] |= 1;

        _ints = new int[Math.Max(1, Length / sizeof(int))];
        _reversedInts = new int[_ints.Length];
        for (int i = 0; i < _ints.Length; i++)
        {
            _ints[i] = i * 0x01020304 + 0x10203040;
        }

        _longs = new long[Math.Max(1, Length / sizeof(long))];
        _reversedLongs = new long[_longs.Length];
        for (int i = 0; i < _longs.Length; i++)
        {
            _longs[i] = ((long)i << 32) | (uint)(i * 0x01020304 + 0x10203040);
        }

        _bigInteger = new BigInteger(_bytes, isUnsigned: true);
        _random = new Random();
    }

    [Benchmark]
    public int HashCodeAddBytes()
    {
        HashCode hashCode = default;
        hashCode.AddBytes(_bytes);
        return hashCode.ToHashCode();
    }

    [Benchmark]
    public int RandomNextBytes()
    {
        _random.NextBytes(_randomBuffer);
        return _randomBuffer[0];
    }

    [Benchmark]
    public uint Adler32HashToUInt32() => Adler32.HashToUInt32(_bytes);

    [Benchmark]
    public uint Crc32HashToUInt32() => Crc32.HashToUInt32(_bytes);

    [Benchmark]
    public ulong Crc64HashToUInt64() => Crc64.HashToUInt64(_bytes);

    [Benchmark]
    public int ReverseEndiannessInt32()
    {
        BinaryPrimitives.ReverseEndianness(_ints, _reversedInts);
        return _reversedInts[0];
    }

    [Benchmark]
    public long ReverseEndiannessInt64()
    {
        BinaryPrimitives.ReverseEndianness(_longs, _reversedLongs);
        return _reversedLongs[0];
    }

    [Benchmark]
    public BigInteger BigIntegerLeftShift() => _bigInteger << 13;

    [Benchmark]
    public BigInteger BigIntegerRightShift() => _bigInteger >> 13;

    [Benchmark]
    public BigInteger BigIntegerOnesComplement() => ~_bigInteger;
}

[EgorBo]

@MihuBot

[Copilot]

Pull request overview

Sweep across src/libraries (and CoreLib) to replace generic MemoryMarshal.Read<T>/Write<T> on primitive types with host-endian BitConverter.* equivalents, and to add downlevel span-based BitConverter polyfills where needed.

Changes:

• Replace MemoryMarshal.Read<T> usages on primitive types with BitConverter.To* / direct byte access for 1-byte primitives.
• Add BitConverter span overload polyfill to downlevel-targeting projects that now call BitConverter.To*(ReadOnlySpan<byte>).
• Simplify big-endian CBOR helpers to use BinaryPrimitives.{Read,Write}*BigEndian directly.

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/PropertyRef.cs	Switch primitive span reads to BitConverter.ToUInt16/32/64 for key generation.
src/libraries/System.Text.Json/src/System.Text.Json.csproj	Include BitConverterPolyfills.cs for non-.NETCoreApp TFMs.
src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/OpenSslCrlCache.cs	Replace MemoryMarshal.Read<uint> with BitConverter.ToUInt32 for URL hash derivation.
src/libraries/System.Security.Cryptography.Pkcs/src/System.Security.Cryptography.Pkcs.csproj	Conditionally include BitConverterPolyfills.cs for downlevel Windows builds.
src/libraries/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/Pal/Windows/HelpersWindows.cs	Replace primitive reads with BitConverter.ToInt32.
src/libraries/System.Security.Cryptography.Cose/src/System.Security.Cryptography.Cose.csproj	Include BitConverterPolyfills.cs for non-.NETCoreApp TFMs.
src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipePayloadDecoder.cs	Replace 1-byte primitive reads with direct indexing/cast.
src/libraries/System.Private.CoreLib/src/Internal/Win32/RegistryKey.cs	Replace primitive registry value reads with BitConverter.ToInt32/ToInt64.
src/libraries/System.Net.Primitives/src/System/Net/IPAddress.cs	Replace primitive reads with BitConverter.ToUInt32 / BitConverter.ToUInt32 in IPv6 hash computation.
src/libraries/System.Formats.Cbor/src/System/Formats/Cbor/CborHelpers.netstandard.cs	Replace manual endianness handling with BinaryPrimitives.*BigEndian APIs.
src/libraries/System.Formats.Cbor/src/System.Formats.Cbor.csproj	Include BitConverterPolyfills.cs for non-.NETCoreApp TFMs.
src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Windows.cs	Replace primitive reads with BitConverter.ToInt32/ToInt64.
src/libraries/System.Diagnostics.PerformanceCounter/src/System/Diagnostics/PerformanceCounterLib.cs	Replace primitive reads with BitConverter.ToUInt32/ToInt64.
src/libraries/System.Diagnostics.PerformanceCounter/src/System.Diagnostics.PerformanceCounter.csproj	Conditionally include BitConverterPolyfills.cs for downlevel Windows builds.
src/libraries/Microsoft.Win32.Registry/src/Microsoft/Win32/RegistryKey.cs	Replace primitive registry value reads with BitConverter.ToInt32/ToInt64.
src/libraries/Common/src/Polyfills/HashCodePolyfills.cs	Use BitConverter.ToInt32(ReadOnlySpan<byte>) when folding bytes into HashCode.
src/libraries/Common/src/Polyfills/BitConverterPolyfills.cs	Add downlevel span-based BitConverter.To* overloads via extension(BitConverter) members.