Add HashData/TryHashData/HashDataAsync polyfills for MD5, SHA1, SHA256, SHA384, SHA512

[Copilot]

Polyfills the static HashData, TryHashData, and HashDataAsync methods introduced in .NET 5–7 for MD5, SHA1, SHA256, SHA384, and SHA512, enabling one-shot hashing without manually instantiating a HashAlgorithm.

Net50 — PolyShim/Net50/<Algorithm>.cs

Guard: (NETCOREAPP && !NET5_0_OR_GREATER) || NETFRAMEWORK || NETSTANDARD

• HashData(byte[]) → byte[] (primary; creates the hasher and calls ComputeHash)
• HashData(ReadOnlySpan<byte>) → byte[] (delegates via ToArray())
• HashData(ReadOnlySpan<byte>, Span<byte>) → int
• TryHashData(ReadOnlySpan<byte>, Span<byte>, out int) → bool

Net50 — PolyShim/Net50/HashAlgorithm.cs

Guard: (NETCOREAPP && !NET5_0_OR_GREATER) || NETFRAMEWORK || NETSTANDARD

• ComputeHashAsync(Stream, CancellationToken) → Task<byte[]> (polyfilled via Task.Run)

Net70 — PolyShim/Net70/<Algorithm>.cs

Guard: (NETCOREAPP && !NET7_0_OR_GREATER) || NETFRAMEWORK || NETSTANDARD

• HashData(Stream) → byte[]
• HashDataAsync(Stream, CancellationToken) → ValueTask<byte[]> (delegates to HashAlgorithm.ComputeHashAsync)
• HashDataAsync(Stream, Memory<byte>, CancellationToken) → ValueTask<int>

Async methods are gated on #if FEATURE_TASK. All crypto-using code is gated on #if !NETSTANDARD || NETSTANDARD1_3_OR_GREATER since these types aren't available before netstandard1.3.

HashDataAsync(Stream, CT) creates a hash instance and delegates to ComputeHashAsync(Stream, CT), which is itself polyfilled via Task.Run(() => ComputeHash(stream), cancellationToken) for pre-.NET 5 targets.

// Before — required manual instantiation
byte[] hash;
using (var sha = SHA256.Create())
    hash = sha.ComputeHash(data);

// After — works on all target frameworks
var hash = SHA256.HashData(data);
var hash = await SHA256.HashDataAsync(stream, cancellationToken);

[Tyrrrz]

@copilot delegate methods to each other as much as possible to reduce LOC and improve self-testing

[Copilot]

@copilot delegate methods to each other as much as possible to reduce LOC and improve self-testing

Done in e00a241. For all 5 Net50 algorithms the delegation chain is now:

• HashData(byte[]) → HashData(ReadOnlySpan<byte>) (the core that creates the SHA instance)
• HashData(ReadOnlySpan<byte>, Span<byte>) → HashData(ReadOnlySpan<byte>) then copies
• TryHashData → HashData(ReadOnlySpan<byte>, Span<byte>) via try/catch

Net70 was already well-chained (HashDataAsync(Stream, Memory) → HashDataAsync(Stream) → HashData(Stream)).

[codecov]

Codecov Report

❌ Patch coverage is 94.34673% with 45 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.93%. Comparing base (deb0a71) to head (c855f2d).
⚠️ Report is 1 commits behind head on prime.

Files with missing lines	Patch %	Lines
PolyShim/Net50/MD5.cs	61.53%	4 Missing and 1 partial ⚠️
PolyShim/Net50/SHA1.cs	61.53%	4 Missing and 1 partial ⚠️
PolyShim/Net50/SHA256.cs	61.53%	4 Missing and 1 partial ⚠️
PolyShim/Net50/SHA384.cs	61.53%	4 Missing and 1 partial ⚠️
PolyShim/Net50/SHA512.cs	61.53%	4 Missing and 1 partial ⚠️
PolyShim/Net70/MD5.cs	69.23%	3 Missing and 1 partial ⚠️
PolyShim/Net70/SHA1.cs	69.23%	3 Missing and 1 partial ⚠️
PolyShim/Net70/SHA256.cs	69.23%	3 Missing and 1 partial ⚠️
PolyShim/Net70/SHA384.cs	69.23%	3 Missing and 1 partial ⚠️
PolyShim/Net70/SHA512.cs	69.23%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##            prime     #126      +/-   ##
==========================================
+ Coverage   90.43%   90.93%   +0.49%     
==========================================
  Files         289      310      +21     
  Lines        5070     5866     +796     
  Branches      419      429      +10     
==========================================
+ Hits         4585     5334     +749     
- Misses        389      426      +37     
- Partials       96      106      +10     

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[Copilot]

Pull request overview

This PR adds PolyShim polyfills for the one-shot hashing APIs introduced in newer .NET versions—HashData, TryHashData, and HashDataAsync—for MD5 and the SHA* family, so consumers can hash buffers/streams without manually creating HashAlgorithm instances.

Changes:

• Added .NET 5-era HashData/TryHashData polyfills for MD5/SHA1/SHA256/SHA384/SHA512.
• Added .NET 7-era stream-based HashData(Stream) and HashDataAsync(...) polyfills for the same algorithms.
• Added/updated tests and refreshed Signatures.md to reflect the new surface area.

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
Signatures.md	Updates the generated public API signature listing to include new hash APIs.
PolyShim/Net70/MD5.cs	Adds .NET 7-style stream hashing APIs for MD5.
PolyShim/Net70/SHA1.cs	Adds .NET 7-style stream hashing APIs for SHA1.
PolyShim/Net70/SHA256.cs	Adds .NET 7-style stream hashing APIs for SHA256.
PolyShim/Net70/SHA384.cs	Adds .NET 7-style stream hashing APIs for SHA384.
PolyShim/Net70/SHA512.cs	Adds .NET 7-style stream hashing APIs for SHA512.
PolyShim/Net50/MD5.cs	Adds .NET 5-style HashData/TryHashData polyfills for MD5.
PolyShim/Net50/SHA1.cs	Adds .NET 5-style HashData/TryHashData polyfills for SHA1.
PolyShim/Net50/SHA256.cs	Adds .NET 5-style HashData/TryHashData polyfills for SHA256.
PolyShim/Net50/SHA384.cs	Adds .NET 5-style HashData/TryHashData polyfills for SHA384.
PolyShim/Net50/SHA512.cs	Adds .NET 5-style HashData/TryHashData polyfills for SHA512.
PolyShim/Net50/HashAlgorithm.cs	Adds a HashAlgorithm.ComputeHashAsync(Stream, CancellationToken) polyfill used by the stream hashing APIs.
PolyShim.Tests/Net70/MD5Tests.cs	Tests the stream-based async hashing destination overload for MD5.
PolyShim.Tests/Net70/SHA1Tests.cs	Tests the stream-based async hashing destination overload for SHA1.
PolyShim.Tests/Net70/SHA256Tests.cs	Tests the stream-based async hashing destination overload for SHA256.
PolyShim.Tests/Net70/SHA384Tests.cs	Tests the stream-based async hashing destination overload for SHA384.
PolyShim.Tests/Net70/SHA512Tests.cs	Tests the stream-based async hashing destination overload for SHA512.
PolyShim.Tests/Net50/MD5Tests.cs	Tests HashData and TryHashData behavior for MD5.
PolyShim.Tests/Net50/SHA1Tests.cs	Tests HashData and TryHashData behavior for SHA1.
PolyShim.Tests/Net50/SHA256Tests.cs	Tests HashData and TryHashData behavior for SHA256.
PolyShim.Tests/Net50/SHA384Tests.cs	Tests HashData and TryHashData behavior for SHA384.
PolyShim.Tests/Net50/SHA512Tests.cs	Tests HashData and TryHashData behavior for SHA512.

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[Tyrrrz]

@copilot please fix formatting errors

[Copilot]

@copilot please fix formatting errors

Done in c855f2d — ran dotnet format to fix all formatting errors flagged by CI (long lines split in SHA256/384/512, byte array literals expanded one-per-line in tests).