Added generic benchmark

tests/ImageSharp.Benchmarks/Codecs/Jpeg/DecodeJpeg.cs

@@ -0,0 +1,81 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.IO;
+using BenchmarkDotNet.Attributes;
+using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Tests;
+
+namespace SixLabors.ImageSharp.Benchmarks.Codecs.Jpeg
+{
+    public class DecodeJpeg
+    {
+        private JpegDecoder decoder;
+
+        private MemoryStream preloadedImageStream;
+
+        private void GenericSetup(string imageSubpath)
+        {
+            this.decoder = new JpegDecoder();
+            byte[] bytes = File.ReadAllBytes(Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, imageSubpath));
+            this.preloadedImageStream = new MemoryStream(bytes);
+        }
+
+        private void GenericBechmark()
+        {
+            this.preloadedImageStream.Position = 0;
+            using Image img = this.decoder.Decode(Configuration.Default, this.preloadedImageStream);
+        }
+
+        [GlobalSetup(Target = nameof(JpegBaselineInterleaved444))]
+        public void SetupBaselineInterleaved444() =>
+            this.GenericSetup(TestImages.Jpeg.Baseline.Winter444_Interleaved);
+
+        [GlobalSetup(Target = nameof(JpegBaselineInterleaved420))]
+        public void SetupBaselineInterleaved420() =>
+            this.GenericSetup(TestImages.Jpeg.Baseline.Hiyamugi);
+
+        [GlobalSetup(Target = nameof(JpegBaseline400))]
+        public void SetupBaselineSingleComponent() =>
+            this.GenericSetup(TestImages.Jpeg.Baseline.Jpeg400);
+
+        [GlobalSetup(Target = nameof(JpegProgressiveNonInterleaved420))]
+        public void SetupProgressiveNoninterleaved420() =>
+            this.GenericSetup(TestImages.Jpeg.Progressive.Winter420_NonInterleaved);
+
+        [GlobalCleanup]
+        public void Cleanup()
+        {
+            this.preloadedImageStream.Dispose();
+            this.preloadedImageStream = null;
+        }
+
+        [Benchmark(Description = "Baseline 4:4:4 Interleaved")]
+        public void JpegBaselineInterleaved444() => this.GenericBechmark();
+
+        [Benchmark(Description = "Baseline 4:2:0 Interleaved")]
+        public void JpegBaselineInterleaved420() => this.GenericBechmark();
+
+        [Benchmark(Description = "Baseline 4:0:0 (grayscale)")]
+        public void JpegBaseline400() => this.GenericBechmark();
+
+        [Benchmark(Description = "Progressive 4:2:0 Non-Interleaved")]
+        public void JpegProgressiveNonInterleaved420() => this.GenericBechmark();
+    }
+}
+
+
+/*
+BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19042.1288 (20H2/October2020Update)
+Intel Core i7-6700K CPU 4.00GHz (Skylake), 1 CPU, 8 logical and 4 physical cores
+.NET SDK=6.0.100-preview.3.21202.5
+  [Host]     : .NET Core 3.1.18 (CoreCLR 4.700.21.35901, CoreFX 4.700.21.36305), X64 RyuJIT
+  DefaultJob : .NET Core 3.1.18 (CoreCLR 4.700.21.35901, CoreFX 4.700.21.36305), X64 RyuJIT
+MASTER
+|                              Method |      Mean |     Error |    StdDev |
+|------------------------------------ |----------:|----------:|----------:|
+|        'Baseline 4:4:4 Interleaved' | 12.710 ms | 0.1120 ms | 0.0990 ms |
+|        'Baseline 4:2:0 Interleaved' |  8.855 ms | 0.1447 ms | 0.1353 ms |
+|        'Baseline 4:0:0 (grayscale)' |  1.660 ms | 0.0106 ms | 0.0088 ms |
+| 'Progressive 4:2:0 Non-Interleaved' | 14.138 ms | 0.2797 ms | 0.3330 ms |
+*/

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

@@ -56,7 +56,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
             { TestImages.Jpeg.Progressive.Fb, 75 },
             { TestImages.Jpeg.Issues.IncorrectQuality845, 98 },
             { TestImages.Jpeg.Baseline.ForestBridgeDifferentComponentsQuality, 89 },
-            { TestImages.Jpeg.Progressive.Winter, 80 }
+            { TestImages.Jpeg.Progressive.Winter420_NonInterleaved, 80 }
         };
 
         [Theory]

tests/ImageSharp.Tests/TestImages.cs

@@ -163,7 +163,7 @@ namespace SixLabors.ImageSharp.Tests
                 public const string Fb = "Jpg/progressive/fb.jpg";
                 public const string Progress = "Jpg/progressive/progress.jpg";
                 public const string Festzug = "Jpg/progressive/Festzug.jpg";
-                public const string Winter = "Jpg/progressive/winter.jpg";
+                public const string Winter420_NonInterleaved = "Jpg/progressive/winter420_noninterleaved.jpg";
 
                 public static class Bad
                 {
@@ -213,6 +213,7 @@ namespace SixLabors.ImageSharp.Tests
                 public const string ArithmeticCoding = "Jpg/baseline/arithmetic_coding.jpg";
                 public const string ArithmeticCodingProgressive = "Jpg/progressive/arithmetic_progressive.jpg";
                 public const string Lossless = "Jpg/baseline/lossless.jpg";
+                public const string Winter444_Interleaved = "Jpg/baseline/winter444_interleaved.jpg";
 
                 public static readonly string[] All =
                 {

tests/Images/Input/Jpg/baseline/winter444_interleaved.jpg

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:73b1deb4e2fb8027f6bb4fb293e5b2615c80b3ac0a7f99fd90118fd340a9fd12
+size 283330