finish decoder

Author: Poker-sang

src/ImageSharp/Formats/Ani/AniChunk.cs

@@ -5,7 +5,66 @@ namespace SixLabors.ImageSharp.Formats.Ani;
 
 internal enum AniChunkType : uint
 {
-    Seq = 0x73_65_71_20,
-    Rate = 0x72_61_74_65,
-    List = 0x4C_49_53_54
+    /// <summary>
+    /// "anih"
+    /// </summary>
+    AniH = 0x68_69_6E_61,
+
+    /// <summary>
+    /// "seq "
+    /// </summary>
+    Seq = 0x20_71_65_73,
+
+    /// <summary>
+    /// "rate"
+    /// </summary>
+    Rate = 0x65_74_61_72,
+
+    /// <summary>
+    /// "LIST"
+    /// </summary>
+    List = 0x54_53_49_4C
+}
+
+/// <summary>
+/// ListType
+/// </summary>
+internal enum AniListType : uint
+{
+    /// <summary>
+    /// "INFO" (ListType)
+    /// </summary>
+    Info = 0x4F_46_4E_49,
+
+    /// <summary>
+    /// "fram"
+    /// </summary>
+    Fram = 0x6D_61_72_66
+}
+
+/// <summary>
+/// in "INFO"
+/// </summary>
+internal enum AniListInfoType : uint
+{
+    /// <summary>
+    /// "INAM"
+    /// </summary>
+    INam = 0x4D_41_4E_49,
+
+    /// <summary>
+    /// "IART"
+    /// </summary>
+    IArt = 0x54_52_41_49
+}
+
+/// <summary>
+/// in "Fram"
+/// </summary>
+internal enum AniListFrameType : uint
+{
+    /// <summary>
+    /// "icon"
+    /// </summary>
+    Icon = 0x6E_6F_63_69
 }

src/ImageSharp/Formats/Ani/AniChunkType.cs

@@ -0,0 +1,18 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Ani;
+
+/// <summary>
+/// Registers the image encoders, decoders and mime type detectors for the Ico format.
+/// </summary>
+public sealed class AniConfigurationModule : IImageFormatConfigurationModule
+{
+    /// <inheritdoc/>
+    public void Configure(Configuration configuration)
+    {
+        // configuration.ImageFormatsManager.SetEncoder(AniFormat.Instance, new AniEncoder());
+        configuration.ImageFormatsManager.SetDecoder(AniFormat.Instance, AniDecoder.Instance);
+        configuration.ImageFormatsManager.AddImageFormatDetector(new AniImageFormatDetector());
+    }
+}

src/ImageSharp/Formats/Ani/AniConfigurationModule.cs

@@ -8,14 +8,31 @@ internal static class AniConstants
     /// <summary>
     /// The list of mime types that equate to an ani.
     /// </summary>
-    /// <remarks>
-    /// See <see href="https://en.wikipedia.org/wiki/ICO_(file_format)#MIME_type"/>
-    /// </remarks>
-    public static readonly IEnumerable<string> MimeTypes = [];
+    public static readonly IEnumerable<string> MimeTypes = ["application/x-navi-animation"];
 
     /// <summary>
     /// The list of file extensions that equate to an ani.
     /// </summary>
     public static readonly IEnumerable<string> FileExtensions = ["ani"];
 
+    /// <summary>
+    /// Gets the header bytes identifying an ani.
+    /// </summary>
+    public static ReadOnlySpan<byte> AniFormTypeFourCc => "ACON"u8;
+
+    /// <summary>
+    /// Gets the header bytes identifying an ani.
+    /// </summary>
+    public const uint AniFourCc = 0x41_43_4F_4E;
+
+    public static class ChunkFourCcs
+    {
+        public static ReadOnlySpan<byte> AniHeader => "anih"u8;
+
+        public static ReadOnlySpan<byte> Seq => "seq "u8;
+
+        public static ReadOnlySpan<byte> Rate => "rate"u8;
+
+        public static ReadOnlySpan<byte> Icon => "icon"u8;
+    }
 }