Merge pull request #399 from SixLabors/js/fix-390

Fix 390

src/ImageSharp/Formats/Gif/GifDecoderCore.cs

@@ -7,6 +7,7 @@ using System.IO;
 using System.Runtime.CompilerServices;
 using System.Text;
 using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.MetaData;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.Primitives;
@@ -38,7 +39,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <summary>
         /// The global color table.
         /// </summary>
-        private byte[] globalColorTable;
+        private Buffer<byte> globalColorTable;
 
         /// <summary>
         /// The global color table length
@@ -123,10 +124,10 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 if (this.logicalScreenDescriptor.GlobalColorTableFlag)
                 {
                     this.globalColorTableLength = this.logicalScreenDescriptor.GlobalColorTableSize * 3;
-                    this.globalColorTable = ArrayPool<byte>.Shared.Rent(this.globalColorTableLength);
+                    this.globalColorTable = Buffer<byte>.CreateClean(this.globalColorTableLength);
 
                     // Read the global color table from the stream
-                    stream.Read(this.globalColorTable, 0, this.globalColorTableLength);
+                    stream.Read(this.globalColorTable.Array, 0, this.globalColorTableLength);
                 }
 
                 // Loop though the respective gif parts and read the data.
@@ -175,10 +176,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
             }
             finally
             {
-                if (this.globalColorTable != null)
-                {
-                    ArrayPool<byte>.Shared.Return(this.globalColorTable);
-                }
+                this.globalColorTable?.Dispose();
             }
 
             return this.image;
@@ -309,19 +307,19 @@ namespace SixLabors.ImageSharp.Formats.Gif
         {
             GifImageDescriptor imageDescriptor = this.ReadImageDescriptor();
 
-            byte[] localColorTable = null;
-            byte[] indices = null;
+            Buffer<byte> localColorTable = null;
+            Buffer<byte> indices = null;
             try
             {
                 // Determine the color table for this frame. If there is a local one, use it otherwise use the global color table.
                 if (imageDescriptor.LocalColorTableFlag)
                 {
                     int length = imageDescriptor.LocalColorTableSize * 3;
-                    localColorTable = ArrayPool<byte>.Shared.Rent(length);
-                    this.currentStream.Read(localColorTable, 0, length);
+                    localColorTable = Buffer<byte>.CreateClean(length);
+                    this.currentStream.Read(localColorTable.Array, 0, length);
                 }
 
-                indices = ArrayPool<byte>.Shared.Rent(imageDescriptor.Width * imageDescriptor.Height);
+                indices = Buffer<byte>.CreateClean(imageDescriptor.Width * imageDescriptor.Height);
 
                 this.ReadFrameIndices(imageDescriptor, indices);
                 this.ReadFrameColors(indices, localColorTable ?? this.globalColorTable, imageDescriptor);
@@ -331,12 +329,8 @@ namespace SixLabors.ImageSharp.Formats.Gif
             }
             finally
             {
-                if (localColorTable != null)
-                {
-                    ArrayPool<byte>.Shared.Return(localColorTable);
-                }
-
-                ArrayPool<byte>.Shared.Return(indices);
+                localColorTable?.Dispose();
+                indices?.Dispose();
             }
         }
 
@@ -346,7 +340,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <param name="imageDescriptor">The <see cref="GifImageDescriptor"/>.</param>
         /// <param name="indices">The pixel array to write to.</param>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private void ReadFrameIndices(GifImageDescriptor imageDescriptor, byte[] indices)
+        private void ReadFrameIndices(GifImageDescriptor imageDescriptor, Span<byte> indices)
         {
             int dataSize = this.currentStream.ReadByte();
             using (var lzwDecoder = new LzwDecoder(this.currentStream))
@@ -361,7 +355,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <param name="indices">The indexed pixels.</param>
         /// <param name="colorTable">The color table containing the available colors.</param>
         /// <param name="descriptor">The <see cref="GifImageDescriptor"/></param>
-        private void ReadFrameColors(byte[] indices, byte[] colorTable, GifImageDescriptor descriptor)
+        private void ReadFrameColors(Span<byte> indices, Span<byte> colorTable, GifImageDescriptor descriptor)
         {
             int imageWidth = this.logicalScreenDescriptor.Width;
             int imageHeight = this.logicalScreenDescriptor.Height;

src/ImageSharp/Formats/Gif/LzwDecoder.cs

@@ -83,7 +83,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <param name="height">The height of the pixel index array.</param>
         /// <param name="dataSize">Size of the data.</param>
         /// <param name="pixels">The pixel array to decode to.</param>
-        public void DecodePixels(int width, int height, int dataSize, byte[] pixels)
+        public void DecodePixels(int width, int height, int dataSize, Span<byte> pixels)
         {
             Guard.MustBeLessThan(dataSize, int.MaxValue, nameof(dataSize));
 

src/ImageSharp/Image/PixelArea{TPixel}.cs

@@ -30,7 +30,7 @@ namespace SixLabors.ImageSharp
         /// <summary>
         /// The underlying buffer containing the raw pixel data.
         /// </summary>
-        private Buffer<byte> byteBuffer;
+        private readonly Buffer<byte> byteBuffer;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="PixelArea{TPixel}"/> class.
@@ -116,7 +116,7 @@ namespace SixLabors.ImageSharp
             this.RowStride = (width * GetComponentCount(componentOrder)) + padding;
             this.Length = this.RowStride * height;
 
-            this.byteBuffer = new Buffer<byte>(this.Length);
+            this.byteBuffer = Buffer<byte>.CreateClean(this.Length);
         }
 
         /// <summary>

tests/ImageSharp.Tests/Formats/Gif/GifDecoderTests.cs

@@ -10,12 +10,15 @@ using Xunit;
 // ReSharper disable InconsistentNaming
 namespace SixLabors.ImageSharp.Tests
 {
+    using SixLabors.ImageSharp.Advanced;
+
     public class GifDecoderTests
     {
         private const PixelTypes PixelTypes = Tests.PixelTypes.Rgba32 | Tests.PixelTypes.RgbaVector | Tests.PixelTypes.Argb32;
 
         public static readonly string[] TestFiles = { TestImages.Gif.Giphy, TestImages.Gif.Rings, TestImages.Gif.Trans };
 
+
         [Theory]
         [WithFileCollection(nameof(TestFiles), PixelTypes)]
         public void DecodeAndReSave<TPixel>(TestImageProvider<TPixel> imageProvider)
@@ -113,5 +116,21 @@ namespace SixLabors.ImageSharp.Tests
                 Assert.True(image.Frames.Count > 1);
             }
         }
+
+        [Fact]
+        public void CanDecodeIntermingledImages()
+        {
+            using (var kumin1 = Image.Load(TestFile.Create(TestImages.Gif.Kumin).Bytes))
+            using (var icon = Image.Load(TestFile.Create(TestImages.Png.Icon).Bytes))
+            using (var kumin2 = Image.Load(TestFile.Create(TestImages.Gif.Kumin).Bytes))
+            {
+                for (int i = 0; i < kumin1.Frames.Count; i++)
+                {
+                    ImageFrame<Rgba32> first = kumin1.Frames[i];
+                    ImageFrame<Rgba32> second = kumin2.Frames[i];
+                    first.ComparePixelBufferTo(second.GetPixelSpan());
+                }
+            }
+        }
     }
 }

tests/ImageSharp.Tests/TestImages.cs

@@ -31,6 +31,7 @@ namespace SixLabors.ImageSharp.Tests
             public const string BikeGrayscale = "Png/BikeGrayscale.png";
             public const string Rgb48BppInterlaced = "Png/rgb-48bpp-interlaced.png";
             public const string SnakeGame = "Png/SnakeGame.png";
+            public const string Icon = "Png/icon.png";
 
             // Filtered test images from http://www.schaik.com/pngsuite/pngsuite_fil_png.html
             public const string Filter0 = "Png/filter0.png";
@@ -154,8 +155,9 @@ namespace SixLabors.ImageSharp.Tests
             public const string Giphy = "Gif/giphy.gif";
             public const string Cheers = "Gif/cheers.gif";
             public const string Trans = "Gif/trans.gif";
+            public const string Kumin = "Gif/kumin.gif";
 
-            public static readonly string[] All = { Rings, Giphy, Cheers, Trans };
+            public static readonly string[] All = { Rings, Giphy, Cheers, Trans, Kumin };
         }
     }
 }

tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs

@@ -29,7 +29,6 @@ namespace SixLabors.ImageSharp.Tests
         /// <param name="provider">The image provider</param>
         /// <param name="testOutputDetails">Details to be concatenated to the test output file, describing the parameters of the test.</param>
         /// <param name="extension">The extension</param>
-        /// <param name="grayscale">A boolean indicating whether we should save a smaller in size.</param>
         /// <param name="appendPixelTypeToFileName">A boolean indicating whether to append the pixel type to the  output file name.</param>
         public static Image<TPixel> DebugSave<TPixel>(
             this Image<TPixel> image,

tests/Images/Input/Gif/kumin.gif

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:345556b9a0e064412acc3b2ee87a9226113eb65c0a1791c2f855ac3fa1e6b7ad
+size 868269

tests/Images/Input/Png/icon.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:18f1eb7c5019153f4a0b2de90e7e0f0521193f003fabd6ac31c2f58c2562ae42
+size 4040