From 48374293f9347b276354ca2c6e1eae16eddc23b1 Mon Sep 17 00:00:00 2001
From: Brian Popow <popow@gmx.de>
Date: Wed, 11 Aug 2021 15:34:46 +0200
Subject: [PATCH] Read complete jpeg stream, if JPEGTables is not present

---
 .../Decompressors/JpegTiffCompression.cs      | 25 +++++++++++++------
 .../Formats/Tiff/TiffDecoderTests.cs          |  1 +
 tests/ImageSharp.Tests/TestImages.cs          |  1 +
 .../Tiff/rgb_jpegcompressed_nojpegtable.tiff  |  3 +++
 4 files changed, 22 insertions(+), 8 deletions(-)
 create mode 100644 tests/Images/Input/Tiff/rgb_jpegcompressed_nojpegtable.tiff

diff --git a/src/ImageSharp/Formats/Tiff/Compression/Decompressors/JpegTiffCompression.cs b/src/ImageSharp/Formats/Tiff/Compression/Decompressors/JpegTiffCompression.cs
index 5a26df95ac..2722c7db48 100644
--- a/src/ImageSharp/Formats/Tiff/Compression/Decompressors/JpegTiffCompression.cs
+++ b/src/ImageSharp/Formats/Tiff/Compression/Decompressors/JpegTiffCompression.cs
@@ -42,16 +42,25 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression.Decompressors
         /// <inheritdoc/>
         protected override void Decompress(BufferedReadStream stream, int byteCount, Span<byte> buffer)
         {
-            var jpegDecoder = new JpegDecoderCore(this.configuration, new JpegDecoder());
+            Image<Rgb24> image;
+            if (this.jpegTables != null)
+            {
+                var jpegDecoder = new JpegDecoderCore(this.configuration, new JpegDecoder());
+
+                // Should we pass through the CancellationToken from the tiff decoder?
+                using var spectralConverter = new SpectralConverter<Rgb24>(this.configuration, CancellationToken.None);
+                var scanDecoder = new HuffmanScanDecoder(stream, spectralConverter, CancellationToken.None);
+                jpegDecoder.LoadTables(this.jpegTables, scanDecoder);
+                scanDecoder.ResetInterval = 0;
+                jpegDecoder.ParseStream(stream, scanDecoder, CancellationToken.None);
 
-            // Should we pass through the CancellationToken from the tiff decoder?
-            using var spectralConverter = new SpectralConverter<Rgb24>(this.configuration, CancellationToken.None);
-            var scanDecoder = new HuffmanScanDecoder(stream, spectralConverter, CancellationToken.None);
-            jpegDecoder.LoadTables(this.jpegTables, scanDecoder);
-            scanDecoder.ResetInterval = 0;
-            jpegDecoder.ParseStream(stream, scanDecoder, CancellationToken.None);
+                image = new Image<Rgb24>(this.configuration, spectralConverter.PixelBuffer, new ImageMetadata());
+            }
+            else
+            {
+                image = Image.Load<Rgb24>(stream);
+            }
 
-            var image = new Image<Rgb24>(this.configuration, spectralConverter.PixelBuffer, new ImageMetadata());
             int offset = 0;
             for (int y = 0; y < image.Height; y++)
             {
diff --git a/tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs b/tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs
index 157a48d6d8..a1d3865a29 100644
--- a/tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs
@@ -372,6 +372,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tiff
         [WithFile(RgbJpegCompressed, PixelTypes.Rgba32)]
         [WithFile(RgbWithStripsJpegCompressed, PixelTypes.Rgba32)]
         [WithFile(YCbCrJpegCompressed, PixelTypes.Rgba32)]
+        [WithFile(RgbJpegCompressedNoJpegTable, PixelTypes.Rgba32)]
         public void TiffDecoder_CanDecode_JpegCompressed<TPixel>(TestImageProvider<TPixel> provider)
             where TPixel : unmanaged, IPixel<TPixel> => TestTiffDecoder(provider);
 
diff --git a/tests/ImageSharp.Tests/TestImages.cs b/tests/ImageSharp.Tests/TestImages.cs
index 6cdf498949..b0b962624b 100644
--- a/tests/ImageSharp.Tests/TestImages.cs
+++ b/tests/ImageSharp.Tests/TestImages.cs
@@ -554,6 +554,7 @@ namespace SixLabors.ImageSharp.Tests
             public const string RgbDeflateMultistrip = "Tiff/rgb_deflate_multistrip.tiff";
             public const string RgbJpegCompressed = "Tiff/rgb_jpegcompression.tiff";
             public const string RgbWithStripsJpegCompressed = "Tiff/rgb_jpegcompressed_stripped.tiff";
+            public const string RgbJpegCompressedNoJpegTable = "Tiff/rgb_jpegcompressed_nojpegtable.tiff";
             public const string RgbLzwPredictor = "Tiff/rgb_lzw_predictor.tiff";
             public const string RgbLzwNoPredictor = "Tiff/rgb_lzw_no_predictor.tiff";
             public const string RgbLzwNoPredictorMultistrip = "Tiff/rgb_lzw_noPredictor_multistrip.tiff";
diff --git a/tests/Images/Input/Tiff/rgb_jpegcompressed_nojpegtable.tiff b/tests/Images/Input/Tiff/rgb_jpegcompressed_nojpegtable.tiff
new file mode 100644
index 0000000000..b97ab8830d
--- /dev/null
+++ b/tests/Images/Input/Tiff/rgb_jpegcompressed_nojpegtable.tiff
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:6b81013d7b0a29ed1ac9c33e175e0c0e69494b93b2b65b692f16d9ea042b9d5d
+size 7759