Block8x8 Load and CopyTo simplified

Similar to a534328

Author: gfoidl

src/ImageSharp/Formats/Jpeg/Components/Block8x8.cs

@@ -63,9 +63,10 @@ public short this[int idx]
 
     public static Block8x8 Load(Span<short> data)
     {
-        Unsafe.SkipInit(out Block8x8 result);
-        result.LoadFrom(data);
-        return result;
+        DebugGuard.MustBeGreaterThanOrEqualTo(data.Length, Size, "data is too small");
+
+        ref byte src = ref Unsafe.As<short, byte>(ref MemoryMarshal.GetReference(data));
+        return Unsafe.ReadUnaligned<Block8x8>(ref src);
     }
 
     /// <summary>
@@ -93,9 +94,10 @@ public short[] ToArray()
     /// </summary>
     public void CopyTo(Span<short> destination)
     {
-        ref byte selfRef = ref Unsafe.As<Block8x8, byte>(ref this);
-        ref byte destRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<short, byte>(destination));
-        Unsafe.CopyBlockUnaligned(ref destRef, ref selfRef, Size * sizeof(short));
+        DebugGuard.MustBeGreaterThanOrEqualTo(destination.Length, Size, "destination is too small");
+
+        ref byte destRef = ref Unsafe.As<short, byte>(ref MemoryMarshal.GetReference(destination));
+        Unsafe.WriteUnaligned(ref destRef, this);
     }
 
     /// <summary>
@@ -124,19 +126,6 @@ public void LoadFrom(ReadOnlySpan<byte> source)
         }
     }
 
-    /// <summary>
-    /// Load raw 16bit integers from source.
-    /// </summary>
-    /// <param name="source">Source</param>
-    [MethodImpl(InliningOptions.ShortMethod)]
-    public void LoadFrom(Span<short> source)
-    {
-        ref byte sourceRef = ref Unsafe.As<short, byte>(ref MemoryMarshal.GetReference(source));
-        ref byte destRef = ref Unsafe.As<Block8x8, byte>(ref this);
-
-        Unsafe.CopyBlockUnaligned(ref destRef, ref sourceRef, Size * sizeof(short));
-    }
-
     /// <summary>
     /// Cast and copy <see cref="Size"/> <see cref="int"/>-s from the beginning of 'source' span.
     /// </summary>

tests/ImageSharp.Tests/Formats/Jpg/Block8x8Tests.cs

@@ -269,8 +269,7 @@ static void RunTest()
             short[] expected = Create8x8ShortData();
             ReferenceImplementations.Transpose8x8(expected);
 
-            var block8x8 = default(Block8x8);
-            block8x8.LoadFrom(Create8x8ShortData());
+            Block8x8 block8x8 = Block8x8.Load(Create8x8ShortData());
 
             block8x8.TransposeInplace();