minor cache optimiziation + benchmarks

ImageSharp.46.sln

@@ -7,6 +7,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ImageSharp46", "src\ImageSh
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ImageSharp.Tests46", "tests\ImageSharp.Tests46\ImageSharp.Tests46.csproj", "{635E0A15-3893-4763-A7F6-FCCFF85BCCA4}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ConsoleBenchmark", "tests\ConsoleBenchmark\ConsoleBenchmark.csproj", "{8783E3A1-79F1-4E37-AA79-F06C48BED5E7}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -21,6 +23,10 @@ Global
 		{635E0A15-3893-4763-A7F6-FCCFF85BCCA4}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{635E0A15-3893-4763-A7F6-FCCFF85BCCA4}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{635E0A15-3893-4763-A7F6-FCCFF85BCCA4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8783E3A1-79F1-4E37-AA79-F06C48BED5E7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8783E3A1-79F1-4E37-AA79-F06C48BED5E7}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8783E3A1-79F1-4E37-AA79-F06C48BED5E7}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8783E3A1-79F1-4E37-AA79-F06C48BED5E7}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/ImageSharp46/Formats/Jpg/Components/Block.cs

@@ -3,12 +3,14 @@
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
 
+using System.Buffers;
+
 namespace ImageSharp.Formats
 {
     /// <summary>
     /// Represents an 8x8 block of coefficients to transform and encode.
     /// </summary>
-    internal class Block
+    internal struct Block
     {
         /// <summary>
         /// Gets the size of the block.
@@ -18,16 +20,23 @@ namespace ImageSharp.Formats
         /// <summary>
         /// The array of block data.
         /// </summary>
-        private readonly int[] data;
+        public int[] Data;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="Block"/> class.
         /// </summary>
-        public Block()
+        //public Block()
+        //{
+        //    this.data = new int[BlockSize];
+        //}
+
+        public void Init()
         {
-            this.data = new int[BlockSize];
+            this.Data = new int[BlockSize];
         }
 
+        public bool IsInitialized => this.Data != null;
+
         /// <summary>
         /// Gets the pixel data at the given block index.
         /// </summary>
@@ -37,8 +46,8 @@ namespace ImageSharp.Formats
         /// </returns>
         public int this[int index]
         {
-            get { return this.data[index]; }
+            get { return this.Data[index]; }
-            set { this.data[index] = value; }
+            set { this.Data[index] = value; }
         }
     }
 }

src/ImageSharp46/Formats/Jpg/Components/Component.cs

@@ -8,26 +8,26 @@ namespace ImageSharp.Formats
     /// <summary>
     /// Represents a single color component
     /// </summary>
-    internal class Component
+    internal struct Component
     {
         /// <summary>
         /// Gets or sets the horizontal sampling factor.
         /// </summary>
-        public int HorizontalFactor { get; set; }
+        public int HorizontalFactor;
 
         /// <summary>
         /// Gets or sets the vertical sampling factor.
         /// </summary>
-        public int VerticalFactor { get; set; }
+        public int VerticalFactor;
 
         /// <summary>
         /// Gets or sets the identifier
         /// </summary>
-        public byte Identifier { get; set; }
+        public byte Identifier;
 
         /// <summary>
         /// Gets or sets the quantization table destination selector.
         /// </summary>
-        public byte Selector { get; set; }
+        public byte Selector;
     }
 }

src/ImageSharp46/Formats/Jpg/Components/FDCT.cs

@@ -45,7 +45,7 @@ namespace ImageSharp.Formats
         /// Performs a forward DCT on an 8x8 block of coefficients, including a level shift.
         /// </summary>
         /// <param name="block">The block of coefficients.</param>
-        public static void Transform(Block block)
+        public static void Transform(ref Block block)
         {
             // Pass 1: process rows.
             for (int y = 0; y < 8; y++)

src/ImageSharp46/Formats/Jpg/Components/Huffman.cs

@@ -8,7 +8,7 @@ namespace ImageSharp.Formats
     /// <summary>
     /// Represents a Huffman tree
     /// </summary>
-    internal class Huffman
+    internal struct Huffman
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="Huffman"/> class.
@@ -16,20 +16,29 @@ namespace ImageSharp.Formats
         /// <param name="lutSize">The log-2 size of the Huffman decoder's look-up table.</param>
         /// <param name="maxNCodes">The maximum (inclusive) number of codes in a Huffman tree.</param>
         /// <param name="maxCodeLength">The maximum (inclusive) number of bits in a Huffman code.</param>
-        public Huffman(int lutSize, int maxNCodes, int maxCodeLength)
+        //public Huffman(int lutSize, int maxNCodes, int maxCodeLength)
+        //{
+        //    this.Lut = new ushort[1 << lutSize];
+        //    this.Values = new byte[maxNCodes];
+        //    this.MinCodes = new int[maxCodeLength];
+        //    this.MaxCodes = new int[maxCodeLength];
+        //    this.Indices = new int[maxCodeLength];
+        //    this.Length = 0;
+        //}
+
+        public void Init(int lutSize, int maxNCodes, int maxCodeLength)
         {
             this.Lut = new ushort[1 << lutSize];
             this.Values = new byte[maxNCodes];
             this.MinCodes = new int[maxCodeLength];
             this.MaxCodes = new int[maxCodeLength];
             this.Indices = new int[maxCodeLength];
-            this.Length = 0;
         }
 
         /// <summary>
         /// Gets or sets the number of codes in the tree.
         /// </summary>
-        public int Length { get; set; }
+        public int Length;
 
         /// <summary>
         /// Gets the look-up table for the next LutSize bits in the bit-stream.
@@ -37,28 +46,30 @@ namespace ImageSharp.Formats
         /// are 1 plus the code length, or 0 if the value is too large to fit in
         /// lutSize bits.
         /// </summary>
-        public ushort[] Lut { get; }
+        public ushort[] Lut;
 
         /// <summary>
         /// Gets the the decoded values, sorted by their encoding.
         /// </summary>
-        public byte[] Values { get; }
+        public byte[] Values;
 
         /// <summary>
         /// Gets the array of minimum codes.
         /// MinCodes[i] is the minimum code of length i, or -1 if there are no codes of that length.
         /// </summary>
-        public int[] MinCodes { get; }
+        public int[] MinCodes;
 
         /// <summary>
         /// Gets the array of maximum codes.
         /// MaxCodes[i] is the maximum code of length i, or -1 if there are no codes of that length.
         /// </summary>
-        public int[] MaxCodes { get; }
+        public int[] MaxCodes;
 
         /// <summary>
         /// Gets the array of indices. Indices[i] is the index into Values of MinCodes[i].
         /// </summary>
-        public int[] Indices { get; }
+        public int[] Indices;
     }
+
+    
 }

src/ImageSharp46/Formats/Jpg/Components/IDCT.cs

@@ -3,6 +3,8 @@
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
 
+using System.Numerics;
+
 namespace ImageSharp.Formats
 {
     /// <summary>
@@ -39,8 +41,10 @@ namespace ImageSharp.Formats
         /// ASSP, Vol. ASSP- 32, pp. 803-816, Aug. 1984.
         /// </summary>
         /// <param name="src">The source block of coefficients</param>
-        public static void Transform(Block src)
+        public static void Transform(ref Block block)
         {
+            
+            var src = block.Data;
             // Horizontal 1-D IDCT.
             for (int y = 0; y < 8; y++)
             {

src/ImageSharp46/Formats/Jpg/JpegDecoderCore.cs

@@ -44,6 +44,8 @@ namespace ImageSharp.Formats
         /// </summary>
         private const int MaxTh = 3;
 
+        private const int ThRowSize = MaxTh + 1;
+
         /// <summary>
         /// The maximum number of quantization tables
         /// </summary>
@@ -85,7 +87,9 @@ namespace ImageSharp.Formats
         /// <summary>
         /// The huffman trees
         /// </summary>
-        private readonly Huffman[,] huffmanTrees;
+        //private readonly Huffman[,] huffmanTrees;
+
+        private readonly Huffman[] huffmanTrees;
 
         /// <summary>
         /// Quantization tables, in zigzag order.
@@ -187,12 +191,16 @@ namespace ImageSharp.Formats
         /// </summary>
         private short verticalResolution;
 
+        private int blockIndex;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="JpegDecoderCore"/> class.
         /// </summary>
         public JpegDecoderCore()
         {
-            this.huffmanTrees = new Huffman[MaxTc + 1, MaxTh + 1];
+            //this.huffmanTrees = new Huffman[MaxTc + 1, MaxTh + 1];
+            this.huffmanTrees = new Huffman[(MaxTc + 1)*(MaxTh + 1)];
+
             this.quantizationTables = new Block[MaxTq + 1];
             this.temp = new byte[2 * Block.BlockSize];
             this.componentArray = new Component[MaxComponents];
@@ -201,23 +209,26 @@ namespace ImageSharp.Formats
             this.bytes = new Bytes();
 
             // TODO: This looks like it could be static.
+
             for (int i = 0; i < MaxTc + 1; i++)
             {
                 for (int j = 0; j < MaxTh + 1; j++)
                 {
-                    this.huffmanTrees[i, j] = new Huffman(LutSize, MaxNCodes, MaxCodeLength);
+                    //this.huffmanTrees[i, j].Init(LutSize, MaxNCodes, MaxCodeLength);
+                    this.huffmanTrees[i* ThRowSize + j].Init(LutSize, MaxNCodes, MaxCodeLength);
                 }
             }
 
             for (int i = 0; i < this.quantizationTables.Length; i++)
             {
-                this.quantizationTables[i] = new Block();
+                //this.quantizationTables[i] = new Block();
+                this.quantizationTables[i].Init();
             }
 
-            for (int i = 0; i < this.componentArray.Length; i++)
+            //for (int i = 0; i < this.componentArray.Length; i++)
-            {
+            //{
-                this.componentArray[i] = new Component();
+            //    this.componentArray[i] = new Component();
-            }
+            //}
         }
 
 
@@ -502,7 +513,12 @@ namespace ImageSharp.Formats
                     throw new ImageFormatException("Bad Th value");
                 }
 
-                Huffman huffman = this.huffmanTrees[tc, th];
+                ProcessDefineHuffmanTablesMarkerLoop(ref this.huffmanTrees[tc* ThRowSize + th], ref remaining);
+            }
+        }
+
+        private void ProcessDefineHuffmanTablesMarkerLoop(ref Huffman huffman, ref int remaining)
+        {
 
             // Read nCodes and huffman.Valuess (and derive h.Length).
             // nCodes[i] is the number of codes with code length i.
@@ -553,8 +569,8 @@ namespace ImageSharp.Formats
                     // whose codeLength's high bits matches code.
                     // The high 8 bits of lutValue are the encoded value.
                     // The low 8 bits are 1 plus the codeLength.
-                        byte base2 = (byte)(code << (7 - i));
+                    byte base2 = (byte) (code << (7 - i));
-                        ushort lutValue = (ushort)((huffman.Values[x] << 8) | (2 + i));
+                    ushort lutValue = (ushort) ((huffman.Values[x] << 8) | (2 + i));
 
                     for (int k = 0; k < 1 << (7 - i); k++)
                     {
@@ -589,14 +605,13 @@ namespace ImageSharp.Formats
                 c <<= 1;
             }
         }
-        }
 
         /// <summary>
         /// Returns the next Huffman-coded value from the bit-stream, decoded according to the given value.
         /// </summary>
         /// <param name="huffman">The huffman value</param>
         /// <returns>The <see cref="byte"/></returns>
-        private byte DecodeHuffman(Huffman huffman)
+        private byte DecodeHuffman(ref Huffman huffman)
         {
             if (huffman.Length == 0)
             {
@@ -1480,7 +1495,8 @@ namespace ImageSharp.Formats
             this.ReadFull(this.temp, 0, remaining);
             byte scanComponentCount = this.temp[0];
 
-            if (remaining != 4 + (2 * scanComponentCount))
+            int scanComponentCountBy2 = 2 * scanComponentCount;
+            if (remaining != 4 + scanComponentCountBy2)
             {
                 throw new ImageFormatException("SOS length inconsistent with number of components");
             }
@@ -1490,51 +1506,7 @@ namespace ImageSharp.Formats
 
             for (int i = 0; i < scanComponentCount; i++)
             {
-                // Component selector.
+                ProcessScanImpl(i, ref scan[i], scan, ref totalHv);
-                int cs = this.temp[1 + (2 * i)];
-                int compIndex = -1;
-                for (int j = 0; j < this.componentCount; j++)
-                {
-                    Component compv = this.componentArray[j];
-                    if (cs == compv.Identifier)
-                    {
-                        compIndex = j;
-                    }
-                }
-
-                if (compIndex < 0)
-                {
-                    throw new ImageFormatException("Unknown component selector");
-                }
-
-                scan[i].Index = (byte)compIndex;
-
-                // Section B.2.3 states that "the value of Cs_j shall be different from
-                // the values of Cs_1 through Cs_(j-1)". Since we have previously
-                // verified that a frame's component identifiers (C_i values in section
-                // B.2.2) are unique, it suffices to check that the implicit indexes
-                // into comp are unique.
-                for (int j = 0; j < i; j++)
-                {
-                    if (scan[i].Index == scan[j].Index)
-                    {
-                        throw new ImageFormatException("Repeated component selector");
-                    }
-                }
-
-                totalHv += this.componentArray[compIndex].HorizontalFactor * this.componentArray[compIndex].VerticalFactor;
-
-                scan[i].DcTableSelector = (byte)(this.temp[2 + (2 * i)] >> 4);
-                if (scan[i].DcTableSelector > MaxTh)
-                {
-                    throw new ImageFormatException("Bad DC table selector value");
-                }
-
-                scan[i].AcTableSelector = (byte)(this.temp[2 + (2 * i)] & 0x0f);
-                if (scan[i].AcTableSelector > MaxTh)
-                {
-                    throw new ImageFormatException("Bad AC table selector  value");
-                }
             }
 
             // Section B.2.3 states that if there is more than one component then the
@@ -1565,10 +1537,10 @@ namespace ImageSharp.Formats
 
             if (this.isProgressive)
             {
-                zigStart = this.temp[1 + (2 * scanComponentCount)];
+                zigStart = this.temp[1 + scanComponentCountBy2];
-                zigEnd = this.temp[2 + (2 * scanComponentCount)];
+                zigEnd = this.temp[2 + scanComponentCountBy2];
-                ah = this.temp[3 + (2 * scanComponentCount)] >> 4;
+                ah = this.temp[3 + scanComponentCountBy2] >> 4;
-                al = this.temp[3 + (2 * scanComponentCount)] & 0x0f;
+                al = this.temp[3 + scanComponentCountBy2] & 0x0f;
 
                 if ((zigStart == 0 && zigEnd != 0) || zigStart > zigEnd || Block.BlockSize <= zigEnd)
                 {
@@ -1608,7 +1580,7 @@ namespace ImageSharp.Formats
 
                         for (int j = 0; j < this.progCoeffs[compIndex].Length; j++)
                         {
-                            this.progCoeffs[compIndex][j] = new Block();
+                            this.progCoeffs[compIndex][j].Init();
                         }
                     }
                 }
@@ -1620,7 +1592,7 @@ namespace ImageSharp.Formats
             byte expectedRst = JpegConstants.Markers.RST0;
 
             // b is the decoded coefficients block, in natural (not zig-zag) order.
-            Block b;
+            //Block b;
             int[] dc = new int[MaxComponents];
 
             // bx and by are the location of the current block, in units of 8x8
@@ -1636,7 +1608,7 @@ namespace ImageSharp.Formats
                         int compIndex = scan[i].Index;
                         int hi = this.componentArray[compIndex].HorizontalFactor;
                         int vi = this.componentArray[compIndex].VerticalFactor;
-                        Block qt = this.quantizationTables[this.componentArray[compIndex].Selector];
+                        
 
                         for (int j = 0; j < hi * vi; j++)
                         {
@@ -1679,12 +1651,76 @@ namespace ImageSharp.Formats
                                 }
                             }
 
+                            var qtIndex = this.componentArray[compIndex].Selector;
+                            
                             // Load the previous partially decoded coefficients, if applicable.
-                            b = this.isProgressive ? this.progCoeffs[compIndex][((@by * mxx) * hi) + bx] : new Block();
                             
+                            //b = this.isProgressive ? this.progCoeffs[compIndex][blockIndex] : new Block();
+
+                            if (this.isProgressive)
+                            {
+                                blockIndex = ((@by * mxx) * hi) + bx;
+                                ProcessBlockImpl(ah, 
+                                    ref this.progCoeffs[compIndex][blockIndex], 
+                                    scan, i, zigStart, zigEnd, al, dc, compIndex, @by, mxx, hi, bx,
+                                    ref this.quantizationTables[qtIndex]
+                                    );
+                            }
+                            else
+                            {
+                                var b = new Block();
+                                b.Init();
+                                ProcessBlockImpl(ah, ref b, scan, i, zigStart, zigEnd, al, dc, compIndex, @by, mxx, hi,
+                                    bx, ref this.quantizationTables[qtIndex]
+                                    );
+                            }
+                        }
+
+                        // for j
+                    }
+
+                    // for i
+                    mcu++;
+
+                    if (this.restartInterval > 0 && mcu % this.restartInterval == 0 && mcu < mxx * myy)
+                    {
+                        // A more sophisticated decoder could use RST[0-7] markers to resynchronize from corrupt input,
+                        // but this one assumes well-formed input, and hence the restart marker follows immediately.
+                        this.ReadFull(this.temp, 0, 2);
+                        if (this.temp[0] != 0xff || this.temp[1] != expectedRst)
+                        {
+                            throw new ImageFormatException("Bad RST marker");
+                        }
+
+                        expectedRst++;
+                        if (expectedRst == JpegConstants.Markers.RST7 + 1)
+                        {
+                            expectedRst = JpegConstants.Markers.RST0;
+                        }
+
+                        // Reset the Huffman decoder.
+                        this.bits = new Bits();
+
+                        // Reset the DC components, as per section F.2.1.3.1.
+                        dc = new int[MaxComponents];
+
+                        // Reset the progressive decoder state, as per section G.1.2.2.
+                        this.eobRun = 0;
+                    }
+                }
+
+                // for mx
+            }
+
+            // for my
+        }
+
+        private void ProcessBlockImpl(int ah, ref Block b, Scan[] scan, int i, int zigStart, int zigEnd, int al,
+            int[] dc, int compIndex, int @by, int mxx, int hi, int bx, ref Block qt)
+        {
             if (ah != 0)
             {
-                                this.Refine(b, this.huffmanTrees[AcTable, scan[i].AcTableSelector], zigStart, zigEnd, 1 << al);
+                this.Refine(ref b, ref this.huffmanTrees[AcTable * ThRowSize + scan[i].AcTableSelector], zigStart, zigEnd, 1 << al);
             }
             else
             {
@@ -1694,7 +1730,7 @@ namespace ImageSharp.Formats
                     zig++;
 
                     // Decode the DC coefficient, as specified in section F.2.2.1.
-                                    byte value = this.DecodeHuffman(this.huffmanTrees[DcTable, scan[i].DcTableSelector]);
+                    byte value = this.DecodeHuffman(ref this.huffmanTrees[DcTable * ThRowSize + scan[i].DcTableSelector]);
                     if (value > 16)
                     {
                         throw new ImageFormatException("Excessive DC component");
@@ -1712,12 +1748,12 @@ namespace ImageSharp.Formats
                 else
                 {
                     // Decode the AC coefficients, as specified in section F.2.2.2.
-                                    Huffman huffv = this.huffmanTrees[AcTable, scan[i].AcTableSelector];
+                    //Huffman huffv = ;
                     for (; zig <= zigEnd; zig++)
                     {
-                                        byte value = this.DecodeHuffman(huffv);
+                        byte value = this.DecodeHuffman(ref this.huffmanTrees[AcTable * ThRowSize + scan[i].AcTableSelector]);
-                                        byte val0 = (byte)(value >> 4);
+                        byte val0 = (byte) (value >> 4);
-                                        byte val1 = (byte)(value & 0x0f);
+                        byte val1 = (byte) (value & 0x0f);
                         if (val1 != 0)
                         {
                             zig += val0;
@@ -1733,10 +1769,10 @@ namespace ImageSharp.Formats
                         {
                             if (val0 != 0x0f)
                             {
-                                                this.eobRun = (ushort)(1 << val0);
+                                this.eobRun = (ushort) (1 << val0);
                                 if (val0 != 0)
                                 {
-                                                    this.eobRun |= (ushort)this.DecodeBits(val0);
+                                    this.eobRun |= (ushort) this.DecodeBits(val0);
                                 }
 
                                 this.eobRun--;
@@ -1754,14 +1790,14 @@ namespace ImageSharp.Formats
                 if (zigEnd != Block.BlockSize - 1 || al != 0)
                 {
                     // We haven't completely decoded this 8x8 block. Save the coefficients.
-                                    this.progCoeffs[compIndex][((by * mxx) * hi) + bx] = b;
+                    this.progCoeffs[compIndex][((@by*mxx)*hi) + bx] = b;
 
                     // At this point, we could execute the rest of the loop body to dequantize and
                     // perform the inverse DCT, to save early stages of a progressive image to the
                     // *image.YCbCr buffers (the whole point of progressive encoding), but in Go,
                     // the jpeg.Decode function does not return until the entire image is decoded,
                     // so we "continue" here to avoid wasted computation.
-                                    continue;
+                    return;
                 }
             }
 
@@ -1771,7 +1807,7 @@ namespace ImageSharp.Formats
                 b[Unzig[zig]] *= qt[zig];
             }
 
-                            IDCT.Transform(b);
+            IDCT.Transform(ref b);
 
             byte[] dst;
             int offset;
@@ -1781,7 +1817,7 @@ namespace ImageSharp.Formats
             {
                 dst = this.grayImage.Pixels;
                 stride = this.grayImage.Stride;
-                                offset = this.grayImage.Offset + (8 * ((by * this.grayImage.Stride) + bx));
+                offset = this.grayImage.Offset + (8*((@by*this.grayImage.Stride) + bx));
             }
             else
             {
@@ -1790,26 +1826,26 @@ namespace ImageSharp.Formats
                     case 0:
                         dst = this.ycbcrImage.YChannel;
                         stride = this.ycbcrImage.YStride;
-                                        offset = this.ycbcrImage.YOffset + (8 * ((by * this.ycbcrImage.YStride) + bx));
+                        offset = this.ycbcrImage.YOffset + (8*((@by*this.ycbcrImage.YStride) + bx));
                         break;
 
                     case 1:
                         dst = this.ycbcrImage.CbChannel;
                         stride = this.ycbcrImage.CStride;
-                                        offset = this.ycbcrImage.COffset + (8 * ((by * this.ycbcrImage.CStride) + bx));
+                        offset = this.ycbcrImage.COffset + (8*((@by*this.ycbcrImage.CStride) + bx));
                         break;
 
                     case 2:
                         dst = this.ycbcrImage.CrChannel;
                         stride = this.ycbcrImage.CStride;
-                                        offset = this.ycbcrImage.COffset + (8 * ((by * this.ycbcrImage.CStride) + bx));
+                        offset = this.ycbcrImage.COffset + (8*((@by*this.ycbcrImage.CStride) + bx));
                         break;
 
                     case 3:
 
                         dst = this.blackPixels;
                         stride = this.blackStride;
-                                        offset = 8 * ((by * this.blackStride) + bx);
+                        offset = 8*((@by*this.blackStride) + bx);
                         break;
 
                     default:
@@ -1820,8 +1856,8 @@ namespace ImageSharp.Formats
             // Level shift by +128, clip to [0, 255], and write to dst.
             for (int y = 0; y < 8; y++)
             {
-                                int y8 = y * 8;
+                int y8 = y*8;
-                                int yStride = y * stride;
+                int yStride = y*stride;
 
                 for (int x = 0; x < 8; x++)
                 {
@@ -1839,48 +1875,64 @@ namespace ImageSharp.Formats
                         c += 128;
                     }
 
-                                    dst[yStride + x + offset] = (byte)c;
+                    dst[yStride + x + offset] = (byte) c;
-                                }
                 }
             }
-
-                        // for j
         }
 
-                    // for i
+        private void ProcessScanImpl(int i, ref Scan currentScan, Scan[] scan, ref int totalHv)
-                    mcu++;
-
-                    if (this.restartInterval > 0 && mcu % this.restartInterval == 0 && mcu < mxx * myy)
         {
-                        // A more sophisticated decoder could use RST[0-7] markers to resynchronize from corrupt input,
+            // Component selector.
-                        // but this one assumes well-formed input, and hence the restart marker follows immediately.
+            int cs = this.temp[1 + (2 * i)];
-                        this.ReadFull(this.temp, 0, 2);
+            int compIndex = -1;
-                        if (this.temp[0] != 0xff || this.temp[1] != expectedRst)
+            for (int j = 0; j < this.componentCount; j++)
             {
-                            throw new ImageFormatException("Bad RST marker");
+                //Component compv = ;
+                if (cs == this.componentArray[j].Identifier)
+                {
+                    compIndex = j;
+                }
             }
 
-                        expectedRst++;
+            if (compIndex < 0)
-                        if (expectedRst == JpegConstants.Markers.RST7 + 1)
             {
-                            expectedRst = JpegConstants.Markers.RST0;
+                throw new ImageFormatException("Unknown component selector");
             }
 
-                        // Reset the Huffman decoder.
+            currentScan.Index = (byte)compIndex;
-                        this.bits = new Bits();
 
-                        // Reset the DC components, as per section F.2.1.3.1.
+            ProcessComponentImpl(i, ref currentScan, scan, ref totalHv, ref this.componentArray[compIndex]);
-                        dc = new int[MaxComponents];
+        }
 
-                        // Reset the progressive decoder state, as per section G.1.2.2.
+        private void ProcessComponentImpl(int i, ref Scan currentScan, Scan[] scan, ref int totalHv, ref Component currentComponent)
-                        this.eobRun = 0;
+        {
+            // Section B.2.3 states that "the value of Cs_j shall be different from
+            // the values of Cs_1 through Cs_(j-1)". Since we have previously
+            // verified that a frame's component identifiers (C_i values in section
+            // B.2.2) are unique, it suffices to check that the implicit indexes
+            // into comp are unique.
+            for (int j = 0; j < i; j++)
+            {
+                if (currentScan.Index == scan[j].Index)
+                {
+                    throw new ImageFormatException("Repeated component selector");
                 }
             }
 
-                // for mx
+
+            totalHv += currentComponent.HorizontalFactor*currentComponent.VerticalFactor;
+
+            currentScan.DcTableSelector = (byte) (this.temp[2 + (2*i)] >> 4);
+            if (currentScan.DcTableSelector > MaxTh)
+            {
+                throw new ImageFormatException("Bad DC table selector value");
             }
 
-            // for my
+            currentScan.AcTableSelector = (byte) (this.temp[2 + (2*i)] & 0x0f);
+            if (currentScan.AcTableSelector > MaxTh)
+            {
+                throw new ImageFormatException("Bad AC table selector  value");
+            }
         }
 
         /// <summary>
@@ -1891,7 +1943,7 @@ namespace ImageSharp.Formats
         /// <param name="zigStart">The zig-zag start index</param>
         /// <param name="zigEnd">The zig-zag end index</param>
         /// <param name="delta">The low transform offset</param>
-        private void Refine(Block b, Huffman h, int zigStart, int zigEnd, int delta)
+        private void Refine(ref Block b, ref Huffman h, int zigStart, int zigEnd, int delta)
         {
             // Refining a DC component is trivial.
             if (zigStart == 0)
@@ -1918,7 +1970,7 @@ namespace ImageSharp.Formats
                 {
                     bool done = false;
                     int z = 0;
-                    byte val = this.DecodeHuffman(h);
+                    byte val = this.DecodeHuffman(ref h);
                     int val0 = val >> 4;
                     int val1 = val & 0x0f;
 

src/ImageSharp46/Formats/Jpg/JpegEncoderCore.cs

@@ -488,9 +488,9 @@ namespace ImageSharp.Formats
         /// <param name="index">The quantization table index.</param>
         /// <param name="prevDC">The previous DC value.</param>
         /// <returns>The <see cref="int"/></returns>
-        private int WriteBlock(Block block, QuantIndex index, int prevDC)
+        private int WriteBlock(ref Block block, QuantIndex index, int prevDC)
         {
-            FDCT.Transform(block);
+            FDCT.Transform(ref block);
 
             // Emit the DC delta.
             int dc = Round(block[0], 8 * this.quant[(int)index][0]);
@@ -541,7 +541,8 @@ namespace ImageSharp.Formats
         /// <param name="cbBlock">The red chroma block.</param>
         /// <param name="crBlock">The blue chroma block.</param>
         // ReSharper disable StyleCop.SA1305
-        private void ToYCbCr<TColor, TPacked>(PixelAccessor<TColor, TPacked> pixels, int x, int y, Block yBlock, Block cbBlock, Block crBlock)
+        private void ToYCbCr<TColor, TPacked>(PixelAccessor<TColor, TPacked> pixels, int x, int y, 
+            ref Block yBlock, ref Block cbBlock, ref Block crBlock)
             // ReSharper restore StyleCop.SA1305
             where TColor : struct, IPackedPixel<TPacked>
             where TPacked : struct
@@ -858,10 +859,10 @@ namespace ImageSharp.Formats
             {
                 for (int x = 0; x < pixels.Width; x += 8)
                 {
-                    this.ToYCbCr(pixels, x, y, b, cb, cr);
+                    this.ToYCbCr(pixels, x, y, ref b, ref cb, ref cr);
-                    prevDCY = this.WriteBlock(b, QuantIndex.Luminance, prevDCY);
+                    prevDCY = this.WriteBlock(ref b, QuantIndex.Luminance, prevDCY);
-                    prevDCCb = this.WriteBlock(cb, QuantIndex.Chrominance, prevDCCb);
+                    prevDCCb = this.WriteBlock(ref cb, QuantIndex.Chrominance, prevDCCb);
-                    prevDCCr = this.WriteBlock(cr, QuantIndex.Chrominance, prevDCCr);
+                    prevDCCr = this.WriteBlock(ref cr, QuantIndex.Chrominance, prevDCCr);
                 }
             }
         }
@@ -902,14 +903,14 @@ namespace ImageSharp.Formats
                         int xOff = (i & 1) * 8;
                         int yOff = (i & 2) * 4;
 
-                        this.ToYCbCr(pixels, x + xOff, y + yOff, b, cb[i], cr[i]);
+                        this.ToYCbCr(pixels, x + xOff, y + yOff, ref b, ref cb[i], ref cr[i]);
-                        prevDCY = this.WriteBlock(b, QuantIndex.Luminance, prevDCY);
+                        prevDCY = this.WriteBlock(ref b, QuantIndex.Luminance, prevDCY);
                     }
 
                     this.Scale16X16To8X8(b, cb);
-                    prevDCCb = this.WriteBlock(b, QuantIndex.Chrominance, prevDCCb);
+                    prevDCCb = this.WriteBlock(ref b, QuantIndex.Chrominance, prevDCCb);
                     this.Scale16X16To8X8(b, cr);
-                    prevDCCr = this.WriteBlock(b, QuantIndex.Chrominance, prevDCCr);
+                    prevDCCr = this.WriteBlock(ref b, QuantIndex.Chrominance, prevDCCr);
                 }
             }
         }

src/ImageSharp46/ImageSharp46.csproj

@@ -86,7 +86,10 @@
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Numerics" />
-    <Reference Include="System.Numerics.Vectors" />
+    <Reference Include="System.Numerics.Vectors, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\System.Numerics.Vectors.4.1.1\lib\net46\System.Numerics.Vectors.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="System.Runtime.CompilerServices.Unsafe, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
       <HintPath>..\..\packages\System.Runtime.CompilerServices.Unsafe.4.0.0\lib\netstandard1.0\System.Runtime.CompilerServices.Unsafe.dll</HintPath>
       <Private>True</Private>

src/ImageSharp46/packages.config

@@ -23,6 +23,7 @@
   <package id="System.Net.Http" version="4.1.0" targetFramework="net461" />
   <package id="System.Net.Primitives" version="4.0.11" targetFramework="net461" />
   <package id="System.Net.Sockets" version="4.1.0" targetFramework="net461" />
+  <package id="System.Numerics.Vectors" version="4.1.1" targetFramework="net461" />
   <package id="System.ObjectModel" version="4.0.12" targetFramework="net461" />
   <package id="System.Reflection" version="4.1.0" targetFramework="net461" />
   <package id="System.Reflection.Extensions" version="4.0.1" targetFramework="net461" />

tests/ConsoleBenchmark/App.config

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
+    </startup>
+  <runtime>
+    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
+      <dependentAssembly>
+        <assemblyIdentity name="System.Security.Cryptography.X509Certificates" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.1.0.0" newVersion="4.1.0.0" />
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="Microsoft.Win32.Primitives" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.1.0" newVersion="4.0.1.0" />
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="System.IO.Compression" publicKeyToken="b77a5c561934e089" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.1.0.0" newVersion="4.1.0.0" />
+      </dependentAssembly>
+    </assemblyBinding>
+  </runtime>
+</configuration>

tests/ConsoleBenchmark/ConsoleBenchmark.csproj

@@ -0,0 +1,89 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{8783E3A1-79F1-4E37-AA79-F06C48BED5E7}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>ConsoleBenchmark</RootNamespace>
+    <AssemblyName>ConsoleBenchmark</AssemblyName>
+    <TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <TargetFrameworkProfile />
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Numerics" />
+    <Reference Include="System.Numerics.Vectors, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\System.Numerics.Vectors.4.1.1\lib\net46\System.Numerics.Vectors.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Xml" />
+    <Reference Include="xunit.abstractions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=8d05b1bb7a6fdb6c, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\xunit.abstractions.2.0.0\lib\net35\xunit.abstractions.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
+    <Reference Include="xunit.core, Version=2.1.0.3179, Culture=neutral, PublicKeyToken=8d05b1bb7a6fdb6c, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\xunit.extensibility.core.2.1.0\lib\dotnet\xunit.core.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
+    <Reference Include="xunit.execution.desktop, Version=2.1.0.3179, Culture=neutral, PublicKeyToken=8d05b1bb7a6fdb6c, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\xunit.extensibility.execution.2.1.0\lib\net45\xunit.execution.desktop.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="App.config" />
+    <None Include="packages.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\ImageSharp46\ImageSharp46.csproj">
+      <Project>{fba0b5f6-09c2-4317-8ef6-6adb9b20e6b1}</Project>
+      <Name>ImageSharp46</Name>
+    </ProjectReference>
+    <ProjectReference Include="..\ImageSharp.Tests46\ImageSharp.Tests46.csproj">
+      <Project>{635e0a15-3893-4763-a7f6-fccff85bcca4}</Project>
+      <Name>ImageSharp.Tests46</Name>
+    </ProjectReference>
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+       Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+</Project>

tests/ConsoleBenchmark/Program.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using ImageSharp.Tests;
+using ImageSharp.Tests46.Benchmark;
+using Xunit.Abstractions;
+
+namespace ConsoleBenchmark
+{
+    class Program
+    {
+        private class Output : ITestOutputHelper
+        {
+            public void WriteLine(string message)
+            {
+                Console.WriteLine(message);
+            }
+
+            public void WriteLine(string format, params object[] args)
+            {
+                Console.WriteLine(format, args);
+            }
+        }
+
+        static void Main(string[] args)
+        {
+            DecodeJpegBenchmark benchmark = new DecodeJpegBenchmark(new Output());
+            benchmark.JpegCore(100);
+            //JpegSandbox test = new JpegSandbox(null);
+
+            //test.OpenJpeg_SaveBmp(TestImages.Jpeg.Calliphora);
+        }
+    }
+}

tests/ConsoleBenchmark/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following 
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("ConsoleBenchmark")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("Sapa")]
+[assembly: AssemblyProduct("ConsoleBenchmark")]
+[assembly: AssemblyCopyright("Copyright © Sapa 2016")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible 
+// to COM components.  If you need to access a type in this assembly from 
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("8783e3a1-79f1-4e37-aa79-f06c48bed5e7")]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version 
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers 
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

tests/ConsoleBenchmark/packages.config

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="System.Numerics.Vectors" version="4.1.1" targetFramework="net461" />
+  <package id="xunit.abstractions" version="2.0.0" targetFramework="net461" />
+  <package id="xunit.core" version="2.1.0" targetFramework="net461" />
+  <package id="xunit.extensibility.core" version="2.1.0" targetFramework="net461" />
+  <package id="xunit.extensibility.execution" version="2.1.0" targetFramework="net461" />
+</packages>

tests/ImageSharp.Benchmarks/Image/DecodeJpeg.cs

@@ -26,17 +26,17 @@ namespace ImageSharp.Benchmarks.Image
             }
         }
 
-        [Benchmark(Baseline = true, Description = "System.Drawing Jpeg")]
+        //[Benchmark(Baseline = true, Description = "System.Drawing Jpeg")]
-        public Size JpegSystemDrawing()
+        //public Size JpegSystemDrawing()
-        {
+        //{
-            using (MemoryStream memoryStream = new MemoryStream(this.jpegBytes))
+        //    using (MemoryStream memoryStream = new MemoryStream(this.jpegBytes))
-            {
+        //    {
-                using (Image image = Image.FromStream(memoryStream))
+        //        using (Image image = Image.FromStream(memoryStream))
-                {
+        //        {
-                    return image.Size;
+        //            return image.Size;
-                }
+        //        }
-            }
+        //    }
-        }
+        //}
 
         [Benchmark(Description = "ImageSharp Jpeg")]
         public CoreSize JpegCore()

tests/ImageSharp.Tests46/Benchmark/DecodeJpeg.cs → tests/ImageSharp.Tests46/Benchmark/DecodeJpegBenchmark.cs

@@ -14,20 +14,20 @@ namespace ImageSharp.Tests46.Benchmark
     using CoreImage = ImageSharp.Image;
     using CoreSize = ImageSharp.Size;
 
-    public class DecodeJpeg
+    public class DecodeJpegBenchmark
     {
         private static byte[] jpegBytes = File.ReadAllBytes(TestImages.Jpeg.Calliphora);
 
         private ITestOutputHelper _output;
 
-        public DecodeJpeg(ITestOutputHelper output)
+        public DecodeJpegBenchmark(ITestOutputHelper output)
         {
             _output = output;
         }
 
         private void DoBenchmark(int times, Action<Stream> action, [CallerMemberName]string method = null)
         {
-            _output.WriteLine($"Starting {method}.. ");
+            _output.WriteLine($"{method} x {times} ... ");
             Stopwatch sw = Stopwatch.StartNew();
             for (int i = 0; i < times; i++)
             {

tests/ImageSharp.Tests46/ImageSharp.Tests46.csproj

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="..\..\packages\xunit.runner.visualstudio.2.1.0\build\net20\xunit.runner.visualstudio.props" Condition="Exists('..\..\packages\xunit.runner.visualstudio.2.1.0\build\net20\xunit.runner.visualstudio.props')" />
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -12,6 +13,8 @@
     <TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
     <TargetFrameworkProfile />
+    <NuGetPackageImportStamp>
+    </NuGetPackageImportStamp>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -37,7 +40,10 @@
     <Reference Include="System.Core" />
     <Reference Include="System.Drawing" />
     <Reference Include="System.Numerics" />
-    <Reference Include="System.Numerics.Vectors" />
+    <Reference Include="System.Numerics.Vectors, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\System.Numerics.Vectors.4.1.1\lib\net46\System.Numerics.Vectors.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />
@@ -62,7 +68,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="Benchmark\DecodeJpeg.cs" />
+    <Compile Include="Benchmark\DecodeJpegBenchmark.cs" />
     <Compile Include="Colors\ColorConversionTests.cs" />
     <Compile Include="Colors\ColorTests.cs" />
     <Compile Include="FileTestBase.cs" />
@@ -148,8 +154,16 @@
     <Content Include="TestImages\Formats\Png\pl.png" />
     <Content Include="TestImages\Formats\Png\splash.png" />
   </ItemGroup>
-  <ItemGroup />
+  <ItemGroup>
+    <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
+    <PropertyGroup>
+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
+    </PropertyGroup>
+    <Error Condition="!Exists('..\..\packages\xunit.runner.visualstudio.2.1.0\build\net20\xunit.runner.visualstudio.props')" Text="$([System.String]::Format('$(ErrorText)', '..\..\packages\xunit.runner.visualstudio.2.1.0\build\net20\xunit.runner.visualstudio.props'))" />
+  </Target>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">

tests/ImageSharp.Tests46/JpegSandbox.cs

@@ -1,14 +1,26 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
+using System.Linq;
+using System.Numerics;
 using ImageSharp.Formats;
 using Xunit;
+using Xunit.Abstractions;
 
 namespace ImageSharp.Tests
 {
     public class JpegSandbox
     {
+        
         public const string SandboxOutputDirectory = "_SandboxOutput";
 
+        private ITestOutputHelper Output { get; }
+
+        public JpegSandbox(ITestOutputHelper output)
+        {
+            Output = output;
+        }
+
         protected string CreateTestOutputFile(string fileName)
         {
             if (!Directory.Exists(SandboxOutputDirectory))
@@ -27,18 +39,36 @@ namespace ImageSharp.Tests
         protected Stream CreateOutputStream(string fileName)
         {
             fileName = CreateTestOutputFile(fileName);
+            Output?.WriteLine("Opened for write: "+fileName);
             return File.OpenWrite(fileName);
         }
 
-        [Fact]
+        //public static string[][] AllJpegFiles = new[]
-        public void OpenJpeg_SaveBmp()
+        //{
+        //    TestImages.Jpeg.All
+        //};
+
+        public static IEnumerable<object[]> AllJpegFiles => TestImages.Jpeg.All.Select(fn => new object[] {fn});
+
+        [Theory]
+        [MemberData(nameof(AllJpegFiles))]
+        public void OpenJpeg_SaveBmp(string jpegFileName)
         {
-            var image = new TestFile(TestImages.Jpeg.Calliphora).CreateImage();
+            var image = new TestFile(jpegFileName).CreateImage();
+            string bmpFileName = Path.GetFileNameWithoutExtension(jpegFileName) + ".bmp";
 
-            using (var stream = CreateOutputStream(nameof(OpenJpeg_SaveBmp)+".bmp"))
+            using (var stream = CreateOutputStream(bmpFileName))
             {
                 image.Save(stream, new BmpFormat());
             }
         }
+
+        [Fact]
+        public void Boo()
+        {
+            Vector<int> hej = new Vector<int>();
+            
+        }
+        
     }
 }

tests/ImageSharp.Tests46/TestImages.cs

@@ -23,15 +23,20 @@ namespace ImageSharp.Tests
 
         public static class Jpeg
         {
-            private static readonly string folder = "../../TestImages/Formats/Jpg/";
+            private const string Folder = "../../TestImages/Formats/Jpg/";
-            public static string Cmyk => folder + "cmyk.jpg";
+            public const string Cmyk = Folder + "cmyk.jpg";
-            public static string Exif => folder + "exif.jpeg";
+            public const string Exif = Folder + "exif.jpg";
-            public static string Floorplan => folder + "Floorplan.jpeg";
+            public const string Floorplan = Folder + "Floorplan.jpeg";
-            public static string Calliphora => folder + "Calliphora.jpg";
+            public const string Calliphora = Folder + "Calliphora.jpg";
-            public static string Turtle => folder + "turtle.jpg";
+            public const string Turtle = Folder + "turtle.jpg";
-            public static string Fb => folder + "fb.jpg";
+            public const string Fb = Folder + "fb.jpg";
-            public static string Progress => folder + "progress.jpg";
+            public const string Progress = Folder + "progress.jpg";
-            public static string GammaDalaiLamaGray => folder + "gamma_dalai_lama_gray.jpg";
+            public const string GammaDalaiLamaGray = Folder + "gamma_dalai_lama_gray.jpg";
+
+            public static readonly string[] All = new[]
+            {
+                Cmyk, Exif, Floorplan, Calliphora, Turtle, Fb, Progress, GammaDalaiLamaGray
+            };
         }
 
         public static class Bmp

tests/ImageSharp.Tests46/packages.config

@@ -1,9 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
+  <package id="System.Numerics.Vectors" version="4.1.1" targetFramework="net461" />
   <package id="xunit" version="2.1.0" targetFramework="net461" />
   <package id="xunit.abstractions" version="2.0.0" targetFramework="net461" />
   <package id="xunit.assert" version="2.1.0" targetFramework="net461" />
   <package id="xunit.core" version="2.1.0" targetFramework="net461" />
   <package id="xunit.extensibility.core" version="2.1.0" targetFramework="net461" />
   <package id="xunit.extensibility.execution" version="2.1.0" targetFramework="net461" />
+  <package id="xunit.runner.visualstudio" version="2.1.0" targetFramework="net461" />
 </packages>