gfoidl fixes

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

@@ -172,7 +172,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
 
         public static Block8x8 Load(Span<short> data)
         {
-            Block8x8 result = default;
+            Unsafe.SkipInit(out Block8x8 result);
             result.LoadFrom(data);
             return result;
         }
@@ -204,7 +204,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
         {
             ref byte selfRef = ref Unsafe.As<Block8x8, byte>(ref this);
             ref byte destRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<short, byte>(destination));
-            Unsafe.CopyBlock(ref destRef, ref selfRef, Size * sizeof(short));
+            Unsafe.CopyBlockUnaligned(ref destRef, ref selfRef, Size * sizeof(short));
         }
 
         /// <summary>
@@ -287,7 +287,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
         /// Index of the last non-zero element. Returns -1 if all elements are equal to zero.
         /// </returns>
         [MethodImpl(InliningOptions.ShortMethod)]
-        public int GetLastNonZeroIndex()
+        public nint GetLastNonZeroIndex()
         {
 #if SUPPORTS_RUNTIME_INTRINSICS
             if (Avx2.IsSupported)
@@ -298,7 +298,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
 
                 ref Vector256<short> mcuStride = ref Unsafe.As<Block8x8, Vector256<short>>(ref this);
 
-                for (int i = 3; i >= 0; i--)
+                for (nint i = 3; i >= 0; i--)
                 {
                     int areEqual = Avx2.MoveMask(Avx2.CompareEqual(Unsafe.Add(ref mcuStride, i), zero16).AsByte());
 
@@ -325,7 +325,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
             else
 #endif
             {
-                int index = Size - 1;
+                nint index = Size - 1;
                 ref short elemRef = ref Unsafe.As<Block8x8, short>(ref this);
 
                 while (index >= 0 && Unsafe.Add(ref elemRef, index) == 0)

src/ImageSharp/Formats/Jpeg/Components/Block8x8F.Intrinsic.cs

@@ -46,7 +46,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
 
             ref Vector256<short> destRef = ref dest.V01;
 
-            for (int i = 0; i < 8; i += 2)
+            for (nint i = 0; i < 8; i += 2)
             {
                 Vector256<int> row0 = Avx.ConvertToVector256Int32(Avx.Multiply(Unsafe.Add(ref aBase, i + 0), Unsafe.Add(ref bBase, i + 0)));
                 Vector256<int> row1 = Avx.ConvertToVector256Int32(Avx.Multiply(Unsafe.Add(ref aBase, i + 1), Unsafe.Add(ref bBase, i + 1)));
@@ -54,7 +54,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
                 Vector256<short> row = Avx2.PackSignedSaturate(row0, row1);
                 row = Avx2.PermuteVar8x32(row.AsInt32(), MultiplyIntoInt16ShuffleMask).AsInt16();
 
-                Unsafe.Add(ref destRef, i / 2) = row;
+                Unsafe.Add(ref destRef, (IntPtr)((uint)i / 2)) = row;
             }
         }
 
@@ -73,7 +73,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
                 Vector128<int> right = Sse2.ConvertToVector128Int32(Sse.Multiply(Unsafe.Add(ref aBase, i + 1), Unsafe.Add(ref bBase, i + 1)));
 
                 Vector128<short> row = Sse2.PackSignedSaturate(left, right);
-                Unsafe.Add(ref destBase, i / 2) = row;
+                Unsafe.Add(ref destBase, (IntPtr)((uint)i / 2)) = row;
             }
         }
 

src/ImageSharp/Formats/Jpeg/Components/Block8x8F.cs

@@ -414,12 +414,12 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
             if (Avx2.IsSupported)
             {
                 MultiplyIntoInt16_Avx2(ref block, ref qt, ref dest);
-                ZigZag.ApplyZigZagOrderingAvx(ref dest);
+                ZigZag.ApplyZigZagOrderingAvx2(ref dest);
             }
             else if (Ssse3.IsSupported)
             {
                 MultiplyIntoInt16_Sse2(ref block, ref qt, ref dest);
-                ZigZag.ApplyZigZagOrderingSse(ref dest);
+                ZigZag.ApplyZigZagOrderingSsse3(ref dest);
             }
             else
 #endif

src/ImageSharp/Formats/Jpeg/Components/Encoder/HuffmanScanEncoder.cs

@@ -115,7 +115,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Encoder
         private bool IsFlushNeeded
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => this.emitWriteIndex < this.emitBuffer.Length / 2;
+            get => this.emitWriteIndex < (uint)this.emitBuffer.Length / 2;
         }
 
         /// <summary>
@@ -408,15 +408,16 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Encoder
             // Emit the AC components.
             int[] acHuffTable = this.huffmanTables[(2 * (int)index) + 1].Values;
 
-            int lastValuableIndex = spectralBlock.GetLastNonZeroIndex();
+            nint lastValuableIndex = spectralBlock.GetLastNonZeroIndex();
 
             int runLength = 0;
-            for (int zig = 1; zig <= lastValuableIndex; zig++)
+            ref short blockRef = ref Unsafe.As<Block8x8, short>(ref spectralBlock);
+            for (nint zig = 1; zig <= lastValuableIndex; zig++)
             {
                 const int zeroRun1 = 1 << 4;
                 const int zeroRun16 = 16 << 4;
 
-                int ac = spectralBlock[zig];
+                int ac = Unsafe.Add(ref blockRef, zig);
                 if (ac == 0)
                 {
                     runLength += zeroRun1;

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

@@ -68,7 +68,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
         /// Values are also scaled by 8 so DCT code won't do unnecessary division.
         /// </para>
         /// </remarks>
-        public static ReadOnlySpan<float> DctReciprocalAdjustmentCoefficients => new float[]
+        public static readonly float[] DctReciprocalAdjustmentCoefficients = new float[]
         {
             0.125f, 0.09011998f, 0.09567086f, 0.10630376f, 0.125f, 0.15909483f, 0.23096988f, 0.45306373f,
             0.09011998f, 0.064972885f, 0.068974845f, 0.07664074f, 0.09011998f, 0.11470097f, 0.16652f, 0.32664075f,
@@ -104,7 +104,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
         public static void TransformFDCT(ref Block8x8F block)
         {
 #if SUPPORTS_RUNTIME_INTRINSICS
-            if (Avx.IsSupported || Sse.IsSupported)
+            if (Sse.IsSupported)
             {
                 ForwardTransformSimd(ref block);
             }

src/ImageSharp/Formats/Jpeg/Components/ZigZag.Intrinsic.cs

@@ -18,7 +18,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
 #pragma warning restore SA1309
 
         /// <summary>
-        /// Gets shuffle vectors for <see cref="ApplyZigZagOrderingSse"/>
+        /// Gets shuffle vectors for <see cref="ApplyZigZagOrderingSsse3"/>
         /// zig zag implementation.
         /// </summary>
         private static ReadOnlySpan<byte> SseShuffleMasks => new byte[]
@@ -63,7 +63,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
         };
 
         /// <summary>
-        /// Gets shuffle vectors for <see cref="ApplyZigZagOrderingAvx"/>
+        /// Gets shuffle vectors for <see cref="ApplyZigZagOrderingAvx2"/>
         /// zig zag implementation.
         /// </summary>
         private static ReadOnlySpan<byte> AvxShuffleMasks => new byte[]
@@ -126,11 +126,8 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
         /// <summary>
         /// Applies zig zag ordering for given 8x8 matrix using SSE cpu intrinsics.
         /// </summary>
-        /// <remarks>
-        /// Requires Ssse3 support.
-        /// </remarks>
         /// <param name="block">Input matrix.</param>
-        public static unsafe void ApplyZigZagOrderingSse(ref Block8x8 block)
+        public static unsafe void ApplyZigZagOrderingSsse3(ref Block8x8 block)
         {
             DebugGuard.IsTrue(Ssse3.IsSupported, "Ssse3 support is required to run this operation!");
 
@@ -227,11 +224,8 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
         /// <summary>
         /// Applies zig zag ordering for given 8x8 matrix using AVX cpu intrinsics.
         /// </summary>
-        /// <remarks>
-        /// Requires Avx2 support.
-        /// </remarks>
         /// <param name="block">Input matrix.</param>
-        public static unsafe void ApplyZigZagOrderingAvx(ref Block8x8 block)
+        public static unsafe void ApplyZigZagOrderingAvx2(ref Block8x8 block)
         {
             DebugGuard.IsTrue(Avx2.IsSupported, "Avx2 support is required to run this operation!");
 

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

@@ -130,9 +130,9 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
             {
                 Block8x8 data = default;
 
-                int expected = -1;
+                nint expected = -1;
 
-                int actual = data.GetLastNonZeroIndex();
+                nint actual = data.GetLastNonZeroIndex();
 
                 Assert.Equal(expected, actual);
             }
@@ -153,9 +153,9 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
                     data[i] = 10;
                 }
 
-                int expected = Block8x8.Size - 1;
+                nint expected = Block8x8.Size - 1;
 
-                int actual = data.GetLastNonZeroIndex();
+                nint actual = data.GetLastNonZeroIndex();
 
                 Assert.Equal(expected, actual);
             }
@@ -182,9 +182,9 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
                     int setIndex = rng.Next(1, Block8x8.Size);
                     data[setIndex] = (short)rng.Next(-2000, 2000);
 
-                    int expected = setIndex;
+                    nint expected = setIndex;
 
-                    int actual = data.GetLastNonZeroIndex();
+                    nint actual = data.GetLastNonZeroIndex();
 
                     Assert.Equal(expected, actual);
                 }
@@ -219,7 +219,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
 
                     int expected = lastIndex;
 
-                    int actual = data.GetLastNonZeroIndex();
+                    nint actual = data.GetLastNonZeroIndex();
 
                     Assert.Equal(expected, actual);
                 }
@@ -265,7 +265,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
 
                     int expected = secondChunkEnd;
 
-                    int actual = data.GetLastNonZeroIndex();
+                    nint actual = data.GetLastNonZeroIndex();
 
                     Assert.True(expected == actual, $"Expected: {expected}\nActual: {actual}\nInput matrix: {data}");
                 }