Add all found chunk types to the metadata

Note: this does not seem to work in all cases at the moment

src/ImageSharp/Formats/WebP/Vp8LBitReader.cs

@@ -18,10 +18,7 @@ namespace SixLabors.ImageSharp.Formats.WebP
         /// <param name="inputStream">The input stream to read from.</param>
         public Vp8LBitReader(Stream inputStream)
         {
-            this.stream = new MemoryStream();
+            this.stream = inputStream;
-            long inputStreamPos = inputStream.Position;
-            inputStream.CopyTo(this.stream);
-            inputStream.Position = inputStreamPos;
             this.Offset = 0;
             this.Bit = 0;
         }

src/ImageSharp/Formats/WebP/WebPChunkType.cs

@@ -6,7 +6,7 @@ namespace SixLabors.ImageSharp.Formats.WebP
     /// <summary>
     /// Contains a list of different webp chunk types.
     /// </summary>
-    internal enum WebPChunkType : uint
+    public enum WebPChunkType : uint
     {
         /// <summary>
         /// Header signaling the use of VP8 video format.

src/ImageSharp/Formats/WebP/WebPDecoderCore.cs

@@ -67,8 +67,6 @@ namespace SixLabors.ImageSharp.Formats.WebP
         public Image<TPixel> Decode<TPixel>(Stream stream)
             where TPixel : struct, IPixel<TPixel>
         {
-            var metadata = new ImageMetadata();
-            WebPMetadata webpMetadata = metadata.GetFormatMetadata(WebPFormat.Instance);
             this.currentStream = stream;
 
             uint fileSize = this.ReadImageHeader();
@@ -298,11 +296,8 @@ namespace SixLabors.ImageSharp.Formats.WebP
 
             // The next 3 bytes are the version. The version_number is a 3 bit code that must be set to 0.
             // Any other value should be treated as an error.
+            // TODO: should we throw here when version number is != 0?
             uint version = bitReader.Read(3);
-            if (version != 0)
-            {
-                WebPThrowHelper.ThrowImageFormatException($"Unexpected webp version number: {version}");
-            }
 
             // Next bit indicates, if a transformation is present.
             bool transformPresent = bitReader.ReadBit();
@@ -365,15 +360,15 @@ namespace SixLabors.ImageSharp.Formats.WebP
         private void ReadSimpleLossy<TPixel>(Buffer2D<TPixel> pixels, int width, int height, int imageDataSize)
             where TPixel : struct, IPixel<TPixel>
         {
-            // TODO: implement decoding, for simulating the decoding, skipping the chunk size bytes.
+            // TODO: implement decoding. For simulating the decoding: skipping the chunk size bytes.
-            this.currentStream.Skip(imageDataSize - 10);  // 10 bytes because of VP8X header.
+            this.currentStream.Skip(imageDataSize); // TODO: this does not seem to work in all cases
         }
 
         private void ReadSimpleLossless<TPixel>(Buffer2D<TPixel> pixels, int width, int height, int imageDataSize)
             where TPixel : struct, IPixel<TPixel>
         {
-            // TODO: implement decoding, for simulating the decoding, skipping the chunk size bytes.
+            // TODO: implement decoding. For simulating the decoding: skipping the chunk size bytes.
-            this.currentStream.Skip(imageDataSize - 10); // 10 bytes because of VP8X header.
+            this.currentStream.Skip(imageDataSize); // TODO: this does not seem to work in all cases
         }
 
         private void ReadExtended<TPixel>(Buffer2D<TPixel> pixels, int width, int height)
@@ -403,9 +398,14 @@ namespace SixLabors.ImageSharp.Formats.WebP
         /// </exception>
         private WebPChunkType ReadChunkType()
         {
-            return this.currentStream.Read(this.buffer, 0, 4) == 4
+            if (this.currentStream.Read(this.buffer, 0, 4) == 4)
-                       ? (WebPChunkType)BinaryPrimitives.ReadUInt32BigEndian(this.buffer)
+            {
-                       : throw new ImageFormatException("Invalid WebP data.");
+                var chunkType = (WebPChunkType)BinaryPrimitives.ReadUInt32BigEndian(this.buffer);
+                this.webpMetadata.ChunkTypes.Enqueue(chunkType);
+                return chunkType;
+            }
+
+            throw new ImageFormatException("Invalid WebP data.");
         }
 
         /// <summary>

src/ImageSharp/Formats/WebP/WebPMetadata.cs

@@ -1,6 +1,9 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
+using System.Collections;
+using System.Collections.Generic;
+
 namespace SixLabors.ImageSharp.Formats.WebP
 {
     /// <summary>
@@ -33,6 +36,11 @@ namespace SixLabors.ImageSharp.Formats.WebP
         /// </summary>
         public WebPFormatType Format { get; set; }
 
+        /// <summary>
+        /// All found chunk types ordered by appearance.
+        /// </summary>
+        public Queue<WebPChunkType> ChunkTypes { get; set; } = new Queue<WebPChunkType>();
+
         /// <summary>
         /// Indicates, if the webp file contains a animation.
         /// </summary>

tests/ImageSharp.Tests/Formats/WebP/WebPDecoderTests.cs

@@ -17,7 +17,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.WebP
         [InlineData(Lossless.Lossless2, 1000, 307, 24)]
         [InlineData(Lossy.Alpha.LossyAlpha1, 1000, 307, 24)]
         [InlineData(Lossy.Alpha.LossyAlpha2, 1000, 307, 24)]
-        //[InlineData(Animated.Animated1, 400, 400, 24)]
+        [InlineData(Animated.Animated1, 400, 400, 24)]
         public void Identify_DetectsCorrectDimensions(string imagePath, int expectedWidth, int expectedHeight, int expectedBitsPerPixel)
         {
             var testFile = TestFile.Create(imagePath);