Adding tests and fixing bugs

Now it identifies qoi images successfully

ImageSharp.sln

@@ -647,6 +647,18 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Tga", "Tga", "{5DFC394F-136
 		tests\Images\Input\Tga\targa_8bit_rle.tga = tests\Images\Input\Tga\targa_8bit_rle.tga
 	EndProjectSection
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Qoi", "Qoi", "{E801B508-4935-41CD-BA85-CF11BFF55A45}"
+	ProjectSection(SolutionItems) = preProject
+		tests\Images\Input\Qoi\dice.qoi = tests\Images\Input\Qoi\dice.qoi
+		tests\Images\Input\Qoi\edgecase.qoi = tests\Images\Input\Qoi\edgecase.qoi
+		tests\Images\Input\Qoi\kodim10.qoi = tests\Images\Input\Qoi\kodim10.qoi
+		tests\Images\Input\Qoi\kodim23.qoi = tests\Images\Input\Qoi\kodim23.qoi
+		tests\Images\Input\Qoi\qoi_logo.qoi = tests\Images\Input\Qoi\qoi_logo.qoi
+		tests\Images\Input\Qoi\testcard.qoi = tests\Images\Input\Qoi\testcard.qoi
+		tests\Images\Input\Qoi\testcard_rgba.qoi = tests\Images\Input\Qoi\testcard_rgba.qoi
+		tests\Images\Input\Qoi\wikipedia_008.qoi = tests\Images\Input\Qoi\wikipedia_008.qoi
+	EndProjectSection
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -699,6 +711,7 @@ Global
 		{FC527290-2F22-432C-B77B-6E815726B02C} = {56801022-D71A-4FBE-BC5B-CBA08E2284EC}
 		{670DD46C-82E9-499A-B2D2-00A802ED0141} = {E1C42A6F-913B-4A7B-B1A8-2BB62843B254}
 		{5DFC394F-136F-4B76-9BCA-3BA786515EFC} = {9DA226A1-8656-49A8-A58A-A8B5C081AD66}
+		{E801B508-4935-41CD-BA85-CF11BFF55A45} = {9DA226A1-8656-49A8-A58A-A8B5C081AD66}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {5F8B9D1F-CD8B-4CC5-8216-D531E25BD795}

src/ImageSharp/Formats/Qoi/QoiColorSpace.cs

@@ -13,10 +13,10 @@ public enum QoiColorSpace
     /// <summary>
     /// sRGB color space with linear alpha value
     /// </summary>
-    SRGB_WITH_LINEAR_ALPHA,
+    SrgbWithLinearAlpha,
 
     /// <summary>
     /// All the values in the color space are linear
     /// </summary>
-    ALL_CHANNELS_LINEAR
+    AllChannelsLinear
 }

src/ImageSharp/Formats/Qoi/QoiConstants.cs

@@ -7,7 +7,6 @@ namespace SixLabors.ImageSharp.Formats.Qoi;
 
 internal static class QoiConstants
 {
-
     /// <summary>
     /// Gets the bytes that indicates the image is QOI
     /// </summary>
@@ -15,7 +14,7 @@ internal static class QoiConstants
 
     /// <summary>
     /// The list of mimetypes that equate to a QOI.
-    /// See <seealso cref="https://github.com/phoboslab/qoi/issues/167"/>
+    /// See https://github.com/phoboslab/qoi/issues/167
     /// </summary>
     public static readonly IEnumerable<string> MimeTypes = new[] { "image/qoi", "image/x-qoi", "image/vnd.qoi" };
 

src/ImageSharp/Formats/Qoi/QoiDecoder.cs

@@ -1,9 +1,17 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using SixLabors.ImageSharp.Formats.Png;
+
 namespace SixLabors.ImageSharp.Formats.Qoi;
 internal class QoiDecoder : ImageDecoder
 {
+    private QoiDecoder()
+    {
+    }
+
+    public static QoiDecoder Instance { get; } = new();
+
     protected override Image<TPixel> Decode<TPixel>(DecoderOptions options, Stream stream, CancellationToken cancellationToken)
     {
         Guard.NotNull(options, nameof(options));
@@ -22,6 +30,6 @@ internal class QoiDecoder : ImageDecoder
     {
         Guard.NotNull(options, nameof(options));
         Guard.NotNull(stream, nameof(stream));
-        throw new NotImplementedException();
+        return new QoiDecoderCore(options).Identify(options.Configuration, stream, cancellationToken);
     }
 }

src/ImageSharp/Formats/Qoi/QoiDecoderCore.cs

@@ -49,30 +49,31 @@ internal class QoiDecoderCore : IImageDecoderInternals
     {
         ImageMetadata metadata = new();
 
-        byte[] widthBytes, heightBytes;
-        byte[] magicBytes = widthBytes = heightBytes = Array.Empty<byte>();
+        byte[] magicBytes = new byte[4], widthBytes = new byte[4], heightBytes = new byte[4];
 
         // Read magic bytes
-        int read = stream.Read(magicBytes, 0, 4);
-        if (read != 4 || !magicBytes.Equals(QoiConstants.Magic.ToArray()))
+        int read = stream.Read(magicBytes);
+        if (read != 4 || !magicBytes.SequenceEqual(QoiConstants.Magic.ToArray()))
         {
             throw new InvalidImageContentException("The image is not a QOI image");
         }
 
         // If it's a qoi image, read the rest of properties
-        read = stream.Read(widthBytes, 0, 4);
+        read = stream.Read(widthBytes);
         if (read != 4)
         {
             throw new InvalidImageContentException("The image is not a QOI image");
         }
 
-        read = stream.Read(heightBytes, 0, 4);
+        read = stream.Read(heightBytes);
         if (read != 4)
         {
             throw new InvalidImageContentException("The image is not a QOI image");
         }
 
-        Size size = new(BitConverter.ToInt32(widthBytes), BitConverter.ToInt32(heightBytes));
+        widthBytes = widthBytes.Reverse().ToArray();
+        heightBytes = heightBytes.Reverse().ToArray();
+        Size size = new((int)BitConverter.ToUInt32(widthBytes), (int)BitConverter.ToUInt32(heightBytes));
 
         int channels = stream.ReadByte();
         if (channels == -1)

tests/ImageSharp.Benchmarks/Codecs/Qoi/IdentifyQoi.cs

@@ -0,0 +1,30 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using BenchmarkDotNet.Attributes;
+using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Qoi;
+using SixLabors.ImageSharp.Tests;
+
+namespace SixLabors.ImageSharp.Benchmarks.Codecs.Qoi;
+
+[Config(typeof(Config.ShortMultiFramework))]
+public class IdentifyQoi
+{
+    private byte[] qoiBytes;
+
+    private string TestImageFullPath => Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, this.TestImage);
+
+    [Params(TestImages.Qoi.TestCardRGBA, TestImages.Qoi.TestCard, TestImages.Qoi.QoiLogo, TestImages.Qoi.EdgeCase, TestImages.Png.Bike)]
+    public string TestImage { get; set; }
+
+    [GlobalSetup]
+    public void ReadImages() => this.qoiBytes ??= File.ReadAllBytes(this.TestImageFullPath);
+
+    [Benchmark]
+    public ImageInfo Identify()
+    {
+        using MemoryStream memoryStream = new(this.qoiBytes);
+        return QoiDecoder.Instance.Identify(DecoderOptions.Default, memoryStream);
+    }
+}

tests/ImageSharp.Benchmarks/ImageSharp.Benchmarks.csproj

@@ -69,5 +69,8 @@
     <Compile Remove="PixelBlenders\**" />
     <Compile Remove="Processing\Resize.cs" />
   </ItemGroup>
+  <ItemGroup>
+    <Folder Include="Codecs\Qoi\" />
+  </ItemGroup>
 
 </Project>

tests/ImageSharp.Benchmarks/Program.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using BenchmarkDotNet.Configs;
 using BenchmarkDotNet.Running;
 
 namespace SixLabors.ImageSharp.Benchmarks;
@@ -15,5 +16,5 @@ public class Program
     /// </param>
     public static void Main(string[] args) => BenchmarkSwitcher
         .FromAssembly(typeof(Program).Assembly)
-        .Run(args);
+        .Run(args, new DebugInProcessConfig());
 }

tests/ImageSharp.Tests/TestImages.cs

@@ -1029,4 +1029,16 @@ public static class TestImages
         public const string RgbPlainNormalized = "Pbm/rgb_plain_normalized.ppm";
         public const string RgbPlainMagick = "Pbm/rgb_plain_magick.ppm";
     }
+
+    public static class Qoi
+    {
+        public const string Dice = "Qoi/dice.qoi";
+        public const string EdgeCase = "Qoi/edgecase.qoi";
+        public const string Kodim10 = "Qoi/kodim10.qoi";
+        public const string Kodim23 = "Qoi/kodim23.qoi";
+        public const string QoiLogo = "Qoi/qoi_logo.qoi";
+        public const string TestCard = "Qoi/testcard.qoi";
+        public const string TestCardRGBA = "Qoi/testcard_rgba.qoi";
+        public const string Wikipedia008 = "Qoi/wikipedia_008.qoi";
+    }
 }