diff --git a/src/ImageSharp/Formats/Gif/GifDecoderCore.cs b/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
index b8a270b3f..bfa91416a 100644
--- a/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
+++ b/src/ImageSharp/Formats/Gif/GifDecoderCore.cs
@@ -142,8 +142,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
this.ReadApplicationExtension();
break;
case GifConstants.PlainTextLabel:
- int plainLength = stream.ReadByte();
- this.Skip(plainLength); // Not supported by any known decoder.
+ this.SkipBlock(); // Not supported by any known decoder.
break;
}
}
@@ -190,9 +189,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
switch (stream.ReadByte())
{
case GifConstants.GraphicControlLabel:
-
- // Skip graphic control extension block
- this.Skip(0);
+ this.SkipBlock(); // Skip graphic control extension block
break;
case GifConstants.CommentLabel:
this.ReadComments();
@@ -201,8 +198,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
this.ReadApplicationExtension();
break;
case GifConstants.PlainTextLabel:
- int plainLength = stream.ReadByte();
- this.Skip(plainLength); // Not supported by any known decoder.
+ this.SkipBlock(); // Not supported by any known decoder.
break;
}
}
@@ -288,24 +284,27 @@ namespace SixLabors.ImageSharp.Formats.Gif
// Could be XMP or something else not supported yet.
// Back up and skip.
this.stream.Position -= appLength + 1;
- this.Skip(appLength);
+ this.SkipBlock(appLength);
return;
}
- this.Skip(appLength); // Not supported by any known decoder.
+ this.SkipBlock(appLength); // Not supported by any known decoder.
}
///
- /// Skips the designated number of bytes in the stream.
+ /// Skips over a block or reads its terminator.
+ /// The length of the block to skip.
///
- /// The number of bytes to skip.
- private void Skip(int length)
+ private void SkipBlock(int blockSize = 0)
{
- this.stream.Skip(length);
+ if (blockSize > 0)
+ {
+ this.stream.Skip(blockSize);
+ }
int flag;
- while ((flag = this.stream.ReadByte()) != 0)
+ while ((flag = this.stream.ReadByte()) > 0)
{
this.stream.Skip(flag);
}
@@ -370,7 +369,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
this.ReadFrameColors(ref image, ref previousFrame, indices.GetSpan(), colorTable, this.imageDescriptor);
// Skip any remaining blocks
- this.Skip(0);
+ this.SkipBlock();
}
finally
{
diff --git a/tests/ImageSharp.Sandbox46/ImageSharp.Sandbox46.csproj b/tests/ImageSharp.Sandbox46/ImageSharp.Sandbox46.csproj
index bb559b70d..4d7b7de75 100644
--- a/tests/ImageSharp.Sandbox46/ImageSharp.Sandbox46.csproj
+++ b/tests/ImageSharp.Sandbox46/ImageSharp.Sandbox46.csproj
@@ -11,7 +11,7 @@
James Jackson-South and contributors
James Jackson-South
SixLabors.ImageSharp.Sandbox46
- 7.2
+ 7.3
diff --git a/tests/ImageSharp.Tests/Formats/Gif/GifDecoderTests.cs b/tests/ImageSharp.Tests/Formats/Gif/GifDecoderTests.cs
index 6d2a74c03..5bfbb058b 100644
--- a/tests/ImageSharp.Tests/Formats/Gif/GifDecoderTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Gif/GifDecoderTests.cs
@@ -1,20 +1,20 @@
// Copyright (c) Six Labors and contributors.
// Licensed under the Apache License, Version 2.0.
+using System;
+using System.Collections.Generic;
+using System.IO;
using System.Text;
+using SixLabors.ImageSharp.Advanced;
using SixLabors.ImageSharp.Formats.Gif;
+using SixLabors.ImageSharp.MetaData;
using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
using Xunit;
-using System.IO;
-using SixLabors.ImageSharp.Advanced;
// ReSharper disable InconsistentNaming
namespace SixLabors.ImageSharp.Tests.Formats.Gif
{
- using System.Collections.Generic;
- using SixLabors.ImageSharp.MetaData;
- using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
-
public class GifDecoderTests
{
private const PixelTypes TestPixelTypes = PixelTypes.Rgba32 | PixelTypes.RgbaVector | PixelTypes.Argb32;
@@ -70,6 +70,27 @@ namespace SixLabors.ImageSharp.Tests.Formats.Gif
}
}
+ [Fact]
+ public unsafe void Decode_NonTerminatedFinalFrame()
+ {
+ var testFile = TestFile.Create(TestImages.Gif.Rings);
+
+ int length = testFile.Bytes.Length - 2;
+
+ fixed (byte* data = testFile.Bytes.AsSpan(0, length))
+ {
+ using (var stream = new UnmanagedMemoryStream(data, length))
+ {
+ var decoder = new GifDecoder();
+
+ using (Image image = decoder.Decode(Configuration.Default, stream))
+ {
+ Assert.Equal((200, 200), (image.Width, image.Height));
+ }
+ }
+ }
+ }
+
[Theory]
[MemberData(nameof(RatioFiles))]
public void Decode_VerifyRatio(string imagePath, int xResolution, int yResolution, PixelResolutionUnit resolutionUnit)