Add IHash256Generator interfaces

- FsSystem.IHash256Generator
- FsSystem.IHash256GeneratorFactory
- FsSystem.IHash256GeneratorFactorySelector

src/LibHac/FsSystem/IHash256Generator.cs

@@ -0,0 +1,79 @@
+// ReSharper disable InconsistentNaming
+using System;
+using LibHac.Common;
+using LibHac.Diag;
+
+namespace LibHac.FsSystem;
+
+/// <summary>
+/// Generates a hash for a stream of data. The data can be given to the <see cref="IHash256Generator"/>
+/// as multiple, smaller sequential blocks of data.
+/// </summary>
+/// <remarks>Based on FS 13.1.0 (nnSdk 13.4.0)</remarks>
+public abstract class IHash256Generator : IDisposable
+{
+    public static readonly long HashSize = 256 / 8;
+
+    public virtual void Dispose() { }
+
+    public void Initialize()
+    {
+        DoInitialize();
+    }
+
+    public void Update(ReadOnlySpan<byte> data)
+    {
+        DoUpdate(data);
+    }
+
+    public void GetHash(Span<byte> hashBuffer)
+    {
+        Assert.SdkRequiresEqual(HashSize, hashBuffer.Length);
+
+        DoGetHash(hashBuffer);
+    }
+
+    protected abstract void DoInitialize();
+    protected abstract void DoUpdate(ReadOnlySpan<byte> data);
+    protected abstract void DoGetHash(Span<byte> hashBuffer);
+}
+
+/// <summary>
+/// Creates <see cref="IHash256Generator"/> objects and can generate a hash for a single, in-memory block of data.
+/// </summary>
+/// <remarks>Based on FS 13.1.0 (nnSdk 13.4.0)</remarks>
+public abstract class IHash256GeneratorFactory : IDisposable
+{
+    public virtual void Dispose() { }
+
+    public UniqueRef<IHash256Generator> Create()
+    {
+        return DoCreate();
+    }
+
+    public void GenerateHash(Span<byte> hashBuffer, ReadOnlySpan<byte> data)
+    {
+        Assert.SdkRequiresEqual(IHash256Generator.HashSize, hashBuffer.Length);
+
+        DoGenerateHash(hashBuffer, data);
+    }
+
+    protected abstract UniqueRef<IHash256Generator> DoCreate();
+    protected abstract void DoGenerateHash(Span<byte> hashBuffer, ReadOnlySpan<byte> data);
+}
+
+/// <summary>
+/// Creates <see cref="IHash256GeneratorFactory"/> objects.
+/// </summary>
+/// <remarks>Based on FS 13.1.0 (nnSdk 13.4.0)</remarks>
+public abstract class IHash256GeneratorFactorySelector : IDisposable
+{
+    public virtual void Dispose() { }
+
+    public IHash256GeneratorFactory GetFactory()
+    {
+        return DoGetFactory();
+    }
+
+    protected abstract IHash256GeneratorFactory DoGetFactory();
+}