Add Unit Test

src/ImageSharp/Formats/Ani/AniDecoderCore.cs

@@ -16,6 +16,21 @@ internal class AniDecoderCore : ImageDecoderCore
     protected override Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken cancellationToken)
     {
         this.ReadHeader(stream);
+        Span<byte> buffer = stackalloc byte[4];
+        _ = stream.Read(buffer);
+        uint type = BitConverter.ToUInt32(buffer);
+        switch (type)
+        {
+            case 0x73_65_71_20: // seq
+                break;
+            case 0x72_61_74_65: // rate
+                break;
+            case 0x4C_49_53_54: // list
+                break;
+            default:
+                break;
+        }
+
         throw new NotImplementedException();
     }
 
@@ -28,7 +43,7 @@ internal class AniDecoderCore : ImageDecoderCore
     {
         // Skip the identifier
         stream.Skip(12);
-        Span<byte> buffer = stackalloc byte[AniHeader.Size];
+        Span<byte> buffer = stackalloc byte[36];
         _ = stream.Read(buffer);
         AniHeader header = AniHeader.Parse(buffer);
     }

src/ImageSharp/Formats/Ani/AniHeader.cs

@@ -5,26 +5,26 @@ using System.Runtime.InteropServices;
 
 namespace SixLabors.ImageSharp.Formats.Ani;
 
-[StructLayout(LayoutKind.Sequential, Pack = 1, Size = Size)]
+[StructLayout(LayoutKind.Sequential, Pack = 1, Size = 36)]
 internal readonly struct AniHeader
 {
-    public const int Size = 36;
+    public uint Size { get; }
 
-    public ushort Frames { get; }
+    public uint Frames { get; }
 
-    public ushort Steps { get; }
+    public uint Steps { get; }
 
-    public ushort Width { get; }
+    public uint Width { get; }
 
-    public ushort Height { get; }
+    public uint Height { get; }
 
-    public ushort BitCount { get; }
+    public uint BitCount { get; }
 
-    public ushort Planes { get; }
+    public uint Planes { get; }
 
-    public ushort DisplayRate { get; }
+    public uint DisplayRate { get; }
 
-    public ushort Flags { get; }
+    public AniHeaderFlags Flags { get; }
 
     public static AniHeader Parse(in ReadOnlySpan<byte> data)
     => MemoryMarshal.Cast<byte, AniHeader>(data)[0];
@@ -32,3 +32,10 @@ internal readonly struct AniHeader
     public readonly unsafe void WriteTo(in Stream stream)
     => stream.Write(MemoryMarshal.Cast<AniHeader, byte>([this]));
 }
+
+[Flags]
+public enum AniHeaderFlags : uint
+{
+    IsIcon = 1,
+    ContainsSeq = 2
+}

tests/ImageSharp.Tests/Formats/Ani/AniDecoderTests.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats.Ani;
+using SixLabors.ImageSharp.Formats.Bmp;
+using SixLabors.ImageSharp.Formats.Cur;
+using SixLabors.ImageSharp.Formats.Icon;
+using SixLabors.ImageSharp.PixelFormats;
+using static SixLabors.ImageSharp.Tests.TestImages.Ani;
+
+namespace SixLabors.ImageSharp.Tests.Formats.Ani;
+
+[Trait("format", "Ani")]
+[ValidateDisposedMemoryAllocations]
+public class AniDecoderTests
+{
+    [Theory]
+    [WithFile(Work, PixelTypes.Rgba32)]
+    public void CurDecoder_Decode(TestImageProvider<Rgba32> provider)
+    {
+        using Image<Rgba32> image = provider.GetImage(AniDecoder.Instance);
+    }
+}

tests/ImageSharp.Tests/TestImages.cs

@@ -1254,4 +1254,10 @@ public static class TestImages
         public const string CurReal = "Icon/cur_real.cur";
         public const string CurFake = "Icon/cur_fake.ico";
     }
+
+    public static class Ani
+    {
+        public const string Work = "Ani/Work.ani";
+    }
+
 }

tests/Images/Input/Ani/Work.ani

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:740353739d3763addddd383614d125918781b8879f7c1ad3c770162a3e143a33
+size 1150338