Merge branch 'master' into js/fix-390

src/ImageSharp/Formats/Jpeg/GolangPort/OrigJpegDecoderCore.cs

@@ -688,7 +688,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort
                 }
 
                 int th = this.Temp[0] & 0x0f;
-                if (th > OrigHuffmanTree.MaxTh || (!this.IsProgressive && (th > 1)))
+                if (th > OrigHuffmanTree.MaxTh)
                 {
                     throw new ImageFormatException("Bad Th value");
                 }

src/ImageSharp/Formats/Png/Zlib/Adler32.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
+using System.Runtime.CompilerServices;
 
 namespace SixLabors.ImageSharp.Formats.Png.Zlib
 {
@@ -74,9 +75,17 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         }
 
         /// <inheritdoc/>
-        public long Value => this.checksum;
+        public long Value
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get
+            {
+                return this.checksum;
+            }
+        }
 
         /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Reset()
         {
             this.checksum = 1;
@@ -88,6 +97,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         /// <param name="value">
         /// The data value to add. The high byte of the int is ignored.
         /// </param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Update(int value)
         {
             // We could make a length 1 byte array and call update again, but I
@@ -102,6 +112,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         }
 
         /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Update(byte[] buffer)
         {
             if (buffer == null)
@@ -113,32 +124,14 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         }
 
         /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Update(byte[] buffer, int offset, int count)
         {
-            if (buffer == null)
-            {
-                throw new ArgumentNullException(nameof(buffer));
-            }
-
-            if (offset < 0)
-            {
-                throw new ArgumentOutOfRangeException(nameof(offset), "cannot be negative");
-            }
-
-            if (count < 0)
-            {
-                throw new ArgumentOutOfRangeException(nameof(count), "cannot be negative");
-            }
-
-            if (offset >= buffer.Length)
-            {
-                throw new ArgumentOutOfRangeException(nameof(offset), "not a valid index into buffer");
-            }
-
-            if (offset + count > buffer.Length)
-            {
-                throw new ArgumentOutOfRangeException(nameof(count), "exceeds buffer size");
-            }
+            DebugGuard.NotNull(buffer, nameof(buffer));
+            DebugGuard.MustBeGreaterThanOrEqualTo(offset, 0, nameof(offset));
+            DebugGuard.MustBeGreaterThanOrEqualTo(count, 0, nameof(count));
+            DebugGuard.MustBeLessThan(offset, buffer.Length, nameof(offset));
+            DebugGuard.MustBeLessThanOrEqualTo(offset + count, buffer.Length, nameof(count));
 
             // (By Per Bothner)
             uint s1 = this.checksum & 0xFFFF;
@@ -169,4 +162,4 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
             this.checksum = (s2 << 16) | s1;
         }
     }
-}
+}

src/ImageSharp/Formats/Png/Zlib/Crc32.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
+using System.Runtime.CompilerServices;
 
 namespace SixLabors.ImageSharp.Formats.Png.Zlib
 {
@@ -108,18 +109,15 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         /// <inheritdoc/>
         public long Value
         {
-            get
-            {
-                return this.crc;
-            }
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get => this.crc;
 
-            set
-            {
-                this.crc = (uint)value;
-            }
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            set => this.crc = (uint)value;
         }
 
         /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Reset()
         {
             this.crc = 0;
@@ -129,6 +127,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         /// Updates the checksum with the given value.
         /// </summary>
         /// <param name="value">The byte is taken as the lower 8 bits of value.</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Update(int value)
         {
             this.crc ^= CrcSeed;
@@ -137,6 +136,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         }
 
         /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Update(byte[] buffer)
         {
             if (buffer == null)
@@ -148,22 +148,13 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         }
 
         /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Update(byte[] buffer, int offset, int count)
         {
-            if (buffer == null)
-            {
-                throw new ArgumentNullException(nameof(buffer));
-            }
-
-            if (count < 0)
-            {
-                throw new ArgumentOutOfRangeException(nameof(count), "Count cannot be less than zero");
-            }
-
-            if (offset < 0 || offset + count > buffer.Length)
-            {
-                throw new ArgumentOutOfRangeException(nameof(offset));
-            }
+            DebugGuard.NotNull(buffer, nameof(buffer));
+            DebugGuard.MustBeGreaterThanOrEqualTo(count, 0, nameof(count));
+            DebugGuard.MustBeGreaterThanOrEqualTo(offset, 0, nameof(offset));
+            DebugGuard.MustBeLessThanOrEqualTo(offset + count, buffer.Length, nameof(count));
 
             this.crc ^= CrcSeed;
 

src/ImageSharp/Memory/Buffer2DExtensions.cs

@@ -70,7 +70,7 @@ namespace SixLabors.ImageSharp.Memory
         /// </summary>
         /// <typeparam name="T">The element type</typeparam>
         /// <param name="buffer">The <see cref="IBuffer2D{T}"/></param>
-        /// <param name="rectangle">The rectangel subarea</param>
+        /// <param name="rectangle">The rectangle subarea</param>
         /// <returns>The <see cref="BufferArea{T}"/></returns>
         public static BufferArea<T> GetArea<T>(this IBuffer2D<T> buffer, Rectangle rectangle)
             where T : struct => new BufferArea<T>(buffer, rectangle);

src/ImageSharp/Processing/Processors/Transforms/ResamplingWeightedProcessor.Weights.cs

@@ -14,7 +14,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
     internal abstract partial class ResamplingWeightedProcessor<TPixel>
     {
         /// <summary>
-        /// Points to a collection of of weights allocated in <see cref="WeightsBuffer"/>.
+        /// Points to a collection of weights allocated in <see cref="WeightsBuffer"/>.
         /// </summary>
         internal struct WeightsWindow
         {
@@ -153,7 +153,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
         }
 
         /// <summary>
-        /// Holds the <see cref="WeightsWindow"/> values in an optimized contigous memory region.
+        /// Holds the <see cref="WeightsWindow"/> values in an optimized contiguous memory region.
         /// </summary>
         internal class WeightsBuffer : IDisposable
         {
@@ -196,4 +196,4 @@ namespace SixLabors.ImageSharp.Processing.Processors
             }
         }
     }
-}
+}

src/ImageSharp/Processing/Processors/Transforms/ResizeProcessor.cs

@@ -58,9 +58,9 @@ namespace SixLabors.ImageSharp.Processing.Processors
             // We will always be creating the clone even for mutate because thats the way this base processor works
             // ------------
             // For resize we know we are going to populate every pixel with fresh data and we want a different target size so
-            // let's manually clone an empty set of images at the correct target and then have the base class processs them in turn.
+            // let's manually clone an empty set of images at the correct target and then have the base class process them in turn.
             IEnumerable<ImageFrame<TPixel>> frames = source.Frames.Select(x => new ImageFrame<TPixel>(this.Width, this.Height, x.MetaData.Clone())); // this will create places holders
-            var image = new Image<TPixel>(config, source.MetaData.Clone(), frames); // base the place holder images in to prevet a extra frame being added
+            var image = new Image<TPixel>(config, source.MetaData.Clone(), frames); // base the place holder images in to prevent a extra frame being added
 
             return image;
         }

src/ImageSharp/Quantizers/Box.cs

@@ -5,9 +5,8 @@ namespace SixLabors.ImageSharp.Quantizers
 {
     /// <summary>
     /// Represents a box color cube.
-    /// TODO: This should be a struct for performance
     /// </summary>
-    internal sealed class Box
+    internal struct Box
     {
         /// <summary>
         /// Gets or sets the min red value, exclusive.
@@ -54,4 +53,4 @@ namespace SixLabors.ImageSharp.Quantizers
         /// </summary>
         public int Volume { get; set; }
     }
-}
+}

src/ImageSharp/Quantizers/WuQuantizer{TPixel}.cs

@@ -168,20 +168,19 @@ namespace SixLabors.ImageSharp.Quantizers
                 this.palette = new TPixel[this.colors];
                 for (int k = 0; k < this.colors; k++)
                 {
-                    this.Mark(this.colorCube[k], (byte)k);
+                    this.Mark(ref this.colorCube[k], (byte)k);
 
-                    float weight = Volume(this.colorCube[k], this.vwt);
+                    float weight = Volume(ref this.colorCube[k], this.vwt);
 
                     if (MathF.Abs(weight) > Constants.Epsilon)
                     {
-                        float r = Volume(this.colorCube[k], this.vmr) / weight;
-                        float g = Volume(this.colorCube[k], this.vmg) / weight;
-                        float b = Volume(this.colorCube[k], this.vmb) / weight;
-                        float a = Volume(this.colorCube[k], this.vma) / weight;
-
-                        var color = default(TPixel);
-                        color.PackFromVector4(new Vector4(r, g, b, a) / 255F);
-                        this.palette[k] = color;
+                        float r = Volume(ref this.colorCube[k], this.vmr);
+                        float g = Volume(ref this.colorCube[k], this.vmg);
+                        float b = Volume(ref this.colorCube[k], this.vmb);
+                        float a = Volume(ref this.colorCube[k], this.vma);
+
+                        ref TPixel color = ref this.palette[k];
+                        color.PackFromVector4(new Vector4(r, g, b, a) / weight / 255F);
                     }
                 }
             }
@@ -197,19 +196,21 @@ namespace SixLabors.ImageSharp.Quantizers
             var rgba = default(Rgba32);
             pixel.ToRgba32(ref rgba);
 
-            int r = rgba.R >> 2; // 8 - IndexBits
-            int g = rgba.G >> 2;
-            int b = rgba.B >> 2;
-            int a = rgba.A >> 5; // 8 - IndexAlphaBits
+            int r = rgba.R >> (8 - IndexBits);
+            int g = rgba.G >> (8 - IndexBits);
+            int b = rgba.B >> (8 - IndexBits);
+            int a = rgba.A >> (8 - IndexAlphaBits);
+
+            int index = GetPaletteIndex(r + 1, g + 1, b + 1, a + 1);
 
-            int ind = GetPaletteIndex(r + 1, g + 1, b + 1, a + 1);
+            this.vwt[index]++;
+            this.vmr[index] += rgba.R;
+            this.vmg[index] += rgba.G;
+            this.vmb[index] += rgba.B;
+            this.vma[index] += rgba.A;
 
-            this.vwt[ind]++;
-            this.vmr[ind] += r;
-            this.vmg[ind] += g;
-            this.vmb[ind] += b;
-            this.vma[ind] += a;
-            this.m2[ind] += (r * r) + (g * g) + (b * b) + (a * a);
+            var vector = new Vector4(rgba.R, rgba.G, rgba.B, rgba.A);
+            this.m2[index] += Vector4.Dot(vector, vector);
         }
 
         /// <inheritdoc/>
@@ -301,7 +302,7 @@ namespace SixLabors.ImageSharp.Quantizers
         /// <param name="cube">The cube.</param>
         /// <param name="moment">The moment.</param>
         /// <returns>The result.</returns>
-        private static float Volume(Box cube, long[] moment)
+        private static float Volume(ref Box cube, long[] moment)
         {
             return moment[GetPaletteIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
                    - moment[GetPaletteIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
@@ -328,12 +329,12 @@ namespace SixLabors.ImageSharp.Quantizers
         /// <param name="direction">The direction.</param>
         /// <param name="moment">The moment.</param>
         /// <returns>The result.</returns>
-        private static long Bottom(Box cube, int direction, long[] moment)
+        private static long Bottom(ref Box cube, int direction, long[] moment)
         {
             switch (direction)
             {
                 // Red
-                case 0:
+                case 3:
                     return -moment[GetPaletteIndex(cube.R0, cube.G1, cube.B1, cube.A1)]
                            + moment[GetPaletteIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
                            + moment[GetPaletteIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
@@ -344,7 +345,7 @@ namespace SixLabors.ImageSharp.Quantizers
                            + moment[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
 
                 // Green
-                case 1:
+                case 2:
                     return -moment[GetPaletteIndex(cube.R1, cube.G0, cube.B1, cube.A1)]
                            + moment[GetPaletteIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
                            + moment[GetPaletteIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
@@ -355,7 +356,7 @@ namespace SixLabors.ImageSharp.Quantizers
                            + moment[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
 
                 // Blue
-                case 2:
+                case 1:
                     return -moment[GetPaletteIndex(cube.R1, cube.G1, cube.B0, cube.A1)]
                            + moment[GetPaletteIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
                            + moment[GetPaletteIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
@@ -366,7 +367,7 @@ namespace SixLabors.ImageSharp.Quantizers
                            + moment[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
 
                 // Alpha
-                case 3:
+                case 0:
                     return -moment[GetPaletteIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
                            + moment[GetPaletteIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
                            + moment[GetPaletteIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
@@ -389,12 +390,12 @@ namespace SixLabors.ImageSharp.Quantizers
         /// <param name="position">The position.</param>
         /// <param name="moment">The moment.</param>
         /// <returns>The result.</returns>
-        private static long Top(Box cube, int direction, int position, long[] moment)
+        private static long Top(ref Box cube, int direction, int position, long[] moment)
         {
             switch (direction)
             {
                 // Red
-                case 0:
+                case 3:
                     return moment[GetPaletteIndex(position, cube.G1, cube.B1, cube.A1)]
                            - moment[GetPaletteIndex(position, cube.G1, cube.B1, cube.A0)]
                            - moment[GetPaletteIndex(position, cube.G1, cube.B0, cube.A1)]
@@ -405,7 +406,7 @@ namespace SixLabors.ImageSharp.Quantizers
                            - moment[GetPaletteIndex(position, cube.G0, cube.B0, cube.A0)];
 
                 // Green
-                case 1:
+                case 2:
                     return moment[GetPaletteIndex(cube.R1, position, cube.B1, cube.A1)]
                            - moment[GetPaletteIndex(cube.R1, position, cube.B1, cube.A0)]
                            - moment[GetPaletteIndex(cube.R1, position, cube.B0, cube.A1)]
@@ -416,7 +417,7 @@ namespace SixLabors.ImageSharp.Quantizers
                            - moment[GetPaletteIndex(cube.R0, position, cube.B0, cube.A0)];
 
                 // Blue
-                case 2:
+                case 1:
                     return moment[GetPaletteIndex(cube.R1, cube.G1, position, cube.A1)]
                            - moment[GetPaletteIndex(cube.R1, cube.G1, position, cube.A0)]
                            - moment[GetPaletteIndex(cube.R1, cube.G0, position, cube.A1)]
@@ -427,7 +428,7 @@ namespace SixLabors.ImageSharp.Quantizers
                            - moment[GetPaletteIndex(cube.R0, cube.G0, position, cube.A0)];
 
                 // Alpha
-                case 3:
+                case 0:
                     return moment[GetPaletteIndex(cube.R1, cube.G1, cube.B1, position)]
                            - moment[GetPaletteIndex(cube.R1, cube.G1, cube.B0, position)]
                            - moment[GetPaletteIndex(cube.R1, cube.G0, cube.B1, position)]
@@ -553,12 +554,12 @@ namespace SixLabors.ImageSharp.Quantizers
         /// </summary>
         /// <param name="cube">The cube.</param>
         /// <returns>The <see cref="float"/>.</returns>
-        private float Variance(Box cube)
+        private float Variance(ref Box cube)
         {
-            float dr = Volume(cube, this.vmr);
-            float dg = Volume(cube, this.vmg);
-            float db = Volume(cube, this.vmb);
-            float da = Volume(cube, this.vma);
+            float dr = Volume(ref cube, this.vmr);
+            float dg = Volume(ref cube, this.vmg);
+            float db = Volume(ref cube, this.vmb);
+            float da = Volume(ref cube, this.vma);
 
             float xx =
                 this.m2[GetPaletteIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
@@ -578,7 +579,8 @@ namespace SixLabors.ImageSharp.Quantizers
                 - this.m2[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
                 + this.m2[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
 
-            return xx - (((dr * dr) + (dg * dg) + (db * db) + (da * da)) / Volume(cube, this.vwt));
+            var vector = new Vector4(dr, dg, db, da);
+            return xx - (Vector4.Dot(vector, vector) / Volume(ref cube, this.vwt));
         }
 
         /// <summary>
@@ -599,38 +601,33 @@ namespace SixLabors.ImageSharp.Quantizers
         /// <param name="wholeA">The whole alpha.</param>
         /// <param name="wholeW">The whole weight.</param>
         /// <returns>The <see cref="float"/>.</returns>
-        private float Maximize(Box cube, int direction, int first, int last, out int cut, float wholeR, float wholeG, float wholeB, float wholeA, float wholeW)
+        private float Maximize(ref Box cube, int direction, int first, int last, out int cut, float wholeR, float wholeG, float wholeB, float wholeA, float wholeW)
         {
-            long baseR = Bottom(cube, direction, this.vmr);
-            long baseG = Bottom(cube, direction, this.vmg);
-            long baseB = Bottom(cube, direction, this.vmb);
-            long baseA = Bottom(cube, direction, this.vma);
-            long baseW = Bottom(cube, direction, this.vwt);
+            long baseR = Bottom(ref cube, direction, this.vmr);
+            long baseG = Bottom(ref cube, direction, this.vmg);
+            long baseB = Bottom(ref cube, direction, this.vmb);
+            long baseA = Bottom(ref cube, direction, this.vma);
+            long baseW = Bottom(ref cube, direction, this.vwt);
 
             float max = 0F;
             cut = -1;
 
             for (int i = first; i < last; i++)
             {
-                float halfR = baseR + Top(cube, direction, i, this.vmr);
-                float halfG = baseG + Top(cube, direction, i, this.vmg);
-                float halfB = baseB + Top(cube, direction, i, this.vmb);
-                float halfA = baseA + Top(cube, direction, i, this.vma);
-                float halfW = baseW + Top(cube, direction, i, this.vwt);
-
-                float temp;
+                float halfR = baseR + Top(ref cube, direction, i, this.vmr);
+                float halfG = baseG + Top(ref cube, direction, i, this.vmg);
+                float halfB = baseB + Top(ref cube, direction, i, this.vmb);
+                float halfA = baseA + Top(ref cube, direction, i, this.vma);
+                float halfW = baseW + Top(ref cube, direction, i, this.vwt);
 
                 if (MathF.Abs(halfW) < Constants.Epsilon)
                 {
                     continue;
                 }
 
-                temp = ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW;
+                var vector = new Vector4(halfR, halfG, halfB, halfA);
+                float temp = Vector4.Dot(vector, vector) / halfW;
 
-                halfR = wholeR - halfR;
-                halfG = wholeG - halfG;
-                halfB = wholeB - halfB;
-                halfA = wholeA - halfA;
                 halfW = wholeW - halfW;
 
                 if (MathF.Abs(halfW) < Constants.Epsilon)
@@ -638,7 +635,14 @@ namespace SixLabors.ImageSharp.Quantizers
                     continue;
                 }
 
-                temp += ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW;
+                halfR = wholeR - halfR;
+                halfG = wholeG - halfG;
+                halfB = wholeB - halfB;
+                halfA = wholeA - halfA;
+
+                vector = new Vector4(halfR, halfG, halfB, halfA);
+
+                temp += Vector4.Dot(vector, vector) / halfW;
 
                 if (temp > max)
                 {
@@ -656,24 +660,24 @@ namespace SixLabors.ImageSharp.Quantizers
         /// <param name="set1">The first set.</param>
         /// <param name="set2">The second set.</param>
         /// <returns>Returns a value indicating whether the box has been split.</returns>
-        private bool Cut(Box set1, Box set2)
+        private bool Cut(ref Box set1, ref Box set2)
         {
-            float wholeR = Volume(set1, this.vmr);
-            float wholeG = Volume(set1, this.vmg);
-            float wholeB = Volume(set1, this.vmb);
-            float wholeA = Volume(set1, this.vma);
-            float wholeW = Volume(set1, this.vwt);
+            float wholeR = Volume(ref set1, this.vmr);
+            float wholeG = Volume(ref set1, this.vmg);
+            float wholeB = Volume(ref set1, this.vmb);
+            float wholeA = Volume(ref set1, this.vma);
+            float wholeW = Volume(ref set1, this.vwt);
 
-            float maxr = this.Maximize(set1, 0, set1.R0 + 1, set1.R1, out int cutr, wholeR, wholeG, wholeB, wholeA, wholeW);
-            float maxg = this.Maximize(set1, 1, set1.G0 + 1, set1.G1, out int cutg, wholeR, wholeG, wholeB, wholeA, wholeW);
-            float maxb = this.Maximize(set1, 2, set1.B0 + 1, set1.B1, out int cutb, wholeR, wholeG, wholeB, wholeA, wholeW);
-            float maxa = this.Maximize(set1, 3, set1.A0 + 1, set1.A1, out int cuta, wholeR, wholeG, wholeB, wholeA, wholeW);
+            float maxr = this.Maximize(ref set1, 3, set1.R0 + 1, set1.R1, out int cutr, wholeR, wholeG, wholeB, wholeA, wholeW);
+            float maxg = this.Maximize(ref set1, 2, set1.G0 + 1, set1.G1, out int cutg, wholeR, wholeG, wholeB, wholeA, wholeW);
+            float maxb = this.Maximize(ref set1, 1, set1.B0 + 1, set1.B1, out int cutb, wholeR, wholeG, wholeB, wholeA, wholeW);
+            float maxa = this.Maximize(ref set1, 0, set1.A0 + 1, set1.A1, out int cuta, wholeR, wholeG, wholeB, wholeA, wholeW);
 
             int dir;
 
             if ((maxr >= maxg) && (maxr >= maxb) && (maxr >= maxa))
             {
-                dir = 0;
+                dir = 3;
 
                 if (cutr < 0)
                 {
@@ -682,15 +686,15 @@ namespace SixLabors.ImageSharp.Quantizers
             }
             else if ((maxg >= maxr) && (maxg >= maxb) && (maxg >= maxa))
             {
-                dir = 1;
+                dir = 2;
             }
             else if ((maxb >= maxr) && (maxb >= maxg) && (maxb >= maxa))
             {
-                dir = 2;
+                dir = 1;
             }
             else
             {
-                dir = 3;
+                dir = 0;
             }
 
             set2.R1 = set1.R1;
@@ -701,7 +705,7 @@ namespace SixLabors.ImageSharp.Quantizers
             switch (dir)
             {
                 // Red
-                case 0:
+                case 3:
                     set2.R0 = set1.R1 = cutr;
                     set2.G0 = set1.G0;
                     set2.B0 = set1.B0;
@@ -709,7 +713,7 @@ namespace SixLabors.ImageSharp.Quantizers
                     break;
 
                 // Green
-                case 1:
+                case 2:
                     set2.G0 = set1.G1 = cutg;
                     set2.R0 = set1.R0;
                     set2.B0 = set1.B0;
@@ -717,7 +721,7 @@ namespace SixLabors.ImageSharp.Quantizers
                     break;
 
                 // Blue
-                case 2:
+                case 1:
                     set2.B0 = set1.B1 = cutb;
                     set2.R0 = set1.R0;
                     set2.G0 = set1.G0;
@@ -725,7 +729,7 @@ namespace SixLabors.ImageSharp.Quantizers
                     break;
 
                 // Alpha
-                case 3:
+                case 0:
                     set2.A0 = set1.A1 = cuta;
                     set2.R0 = set1.R0;
                     set2.G0 = set1.G0;
@@ -744,7 +748,7 @@ namespace SixLabors.ImageSharp.Quantizers
         /// </summary>
         /// <param name="cube">The cube.</param>
         /// <param name="label">A label.</param>
-        private void Mark(Box cube, byte label)
+        private void Mark(ref Box cube, byte label)
         {
             for (int r = cube.R0 + 1; r <= cube.R1; r++)
             {
@@ -769,23 +773,21 @@ namespace SixLabors.ImageSharp.Quantizers
             this.colorCube = new Box[this.colors];
             float[] vv = new float[this.colors];
 
-            for (int i = 0; i < this.colors; i++)
-            {
-                this.colorCube[i] = new Box();
-            }
-
-            this.colorCube[0].R0 = this.colorCube[0].G0 = this.colorCube[0].B0 = this.colorCube[0].A0 = 0;
-            this.colorCube[0].R1 = this.colorCube[0].G1 = this.colorCube[0].B1 = IndexCount - 1;
-            this.colorCube[0].A1 = IndexAlphaCount - 1;
+            ref var cube = ref this.colorCube[0];
+            cube.R0 = cube.G0 = cube.B0 = cube.A0 = 0;
+            cube.R1 = cube.G1 = cube.B1 = IndexCount - 1;
+            cube.A1 = IndexAlphaCount - 1;
 
             int next = 0;
 
             for (int i = 1; i < this.colors; i++)
             {
-                if (this.Cut(this.colorCube[next], this.colorCube[i]))
+                ref var nextCube = ref this.colorCube[next];
+                ref var currentCube = ref this.colorCube[i];
+                if (this.Cut(ref nextCube, ref currentCube))
                 {
-                    vv[next] = this.colorCube[next].Volume > 1 ? this.Variance(this.colorCube[next]) : 0F;
-                    vv[i] = this.colorCube[i].Volume > 1 ? this.Variance(this.colorCube[i]) : 0F;
+                    vv[next] = nextCube.Volume > 1 ? this.Variance(ref nextCube) : 0F;
+                    vv[i] = currentCube.Volume > 1 ? this.Variance(ref currentCube) : 0F;
                 }
                 else
                 {
@@ -805,7 +807,7 @@ namespace SixLabors.ImageSharp.Quantizers
                     }
                 }
 
-                if (temp <= 0.0)
+                if (temp <= 0F)
                 {
                     this.colors = i + 1;
                     break;

tests/ImageSharp.Benchmarks/Image/DecodePng.cs

@@ -10,29 +10,39 @@ namespace SixLabors.ImageSharp.Benchmarks.Image
 
     using BenchmarkDotNet.Attributes;
 
+    using SixLabors.ImageSharp.Tests;
+
     using CoreImage = ImageSharp.Image;
 
     using CoreSize = SixLabors.Primitives.Size;
 
+    [Config(typeof(Config.ShortClr))]
     public class DecodePng : BenchmarkBase
     {
         private byte[] pngBytes;
 
+        private string TestImageFullPath => Path.Combine(
+            TestEnvironment.InputImagesDirectoryFullPath,
+            this.TestImage);
+
+        [Params(TestImages.Png.Splash)]
+        public string TestImage { get; set; }
+
         [GlobalSetup]
         public void ReadImages()
         {
             if (this.pngBytes == null)
             {
-                this.pngBytes = File.ReadAllBytes("../ImageSharp.Tests/TestImages/Formats/Png/splash.png");
+                this.pngBytes = File.ReadAllBytes(this.TestImageFullPath);
             }
         }
 
         [Benchmark(Baseline = true, Description = "System.Drawing Png")]
         public Size PngSystemDrawing()
         {
-            using (MemoryStream memoryStream = new MemoryStream(this.pngBytes))
+            using (var memoryStream = new MemoryStream(this.pngBytes))
             {
-                using (Image image = Image.FromStream(memoryStream))
+                using (var image = Image.FromStream(memoryStream))
                 {
                     return image.Size;
                 }
@@ -42,9 +52,9 @@ namespace SixLabors.ImageSharp.Benchmarks.Image
         [Benchmark(Description = "ImageSharp Png")]
         public CoreSize PngCore()
         {
-            using (MemoryStream memoryStream = new MemoryStream(this.pngBytes))
+            using (var memoryStream = new MemoryStream(this.pngBytes))
             {
-                using (Image<Rgba32> image = CoreImage.Load<Rgba32>(memoryStream))
+                using (var image = CoreImage.Load<Rgba32>(memoryStream))
                 {
                     return new CoreSize(image.Width, image.Height);
                 }

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

@@ -42,6 +42,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
                 TestImages.Jpeg.Baseline.Jpeg444,
                 TestImages.Jpeg.Baseline.Bad.BadEOF,
                 TestImages.Jpeg.Baseline.Bad.ExifUndefType,
+                TestImages.Jpeg.Issues.MultiHuffmanBaseline394,
             };
 
         public static string[] ProgressiveTestJpegs =

tests/ImageSharp.Tests/TestImages.cs

@@ -124,6 +124,7 @@ namespace SixLabors.ImageSharp.Tests
                 public const string MissingFF00ProgressiveGirl159 = "Jpg/issues/Issue159-MissingFF00-Progressive-Girl.jpg";
                 public const string BadCoeffsProgressive178 = "Jpg/issues/Issue178-BadCoeffsProgressive-Lemon.jpg";
                 public const string BadZigZagProgressive385 = "Jpg/issues/Issue385-BadZigZag-Progressive.jpg";
+                public const string MultiHuffmanBaseline394 = "Jpg/issues/Issue394-MultiHuffmanBaseline-Speakers.jpg";
             }
 
             public static readonly string[] All = Baseline.All.Concat(Progressive.All).ToArray();

tests/Images/External

@@ -1 +1 @@
-Subproject commit ab7c90362a4881c790c6f264f400dcf4b4dea0ce
+Subproject commit dc5479d00b2312f691e6249b9f7765e2316d4a30

tests/Images/Input/Jpg/issues/Issue394-MultiHuffmanBaseline-Speakers.jpg

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:8e90cf157d8e2599598c1bea1b8e2bf262651b004cc6261d87bbb49bd6131034
+size 257401