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 {