Implement support BigTiff format decoding

src/ImageSharp/Formats/Tiff/Compression/TiffBaseDecompressor.cs

@@ -35,17 +35,17 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
         /// <param name="stripByteCount">The number of bytes to read from the input stream.</param>
         /// <param name="stripHeight">The height of the strip.</param>
         /// <param name="buffer">The output buffer for uncompressed data.</param>
-        public void Decompress(BufferedReadStream stream, uint stripOffset, uint stripByteCount, int stripHeight, Span<byte> buffer)
+        public void Decompress(BufferedReadStream stream, ulong stripOffset, ulong stripByteCount, int stripHeight, Span<byte> buffer)
         {
-            if (stripByteCount > int.MaxValue)
+            if (stripOffset > long.MaxValue || stripByteCount > long.MaxValue)
             {
-                TiffThrowHelper.ThrowImageFormatException("The StripByteCount value is too big.");
+                TiffThrowHelper.ThrowImageFormatException("The StripOffset or StripByteCount value is too big.");
             }
 
-            stream.Seek(stripOffset, SeekOrigin.Begin);
+            stream.Seek((long)stripOffset, SeekOrigin.Begin);
             this.Decompress(stream, (int)stripByteCount, stripHeight, buffer);
 
-            if (stripOffset + stripByteCount < stream.Position)
+            if ((long)stripOffset + (long)stripByteCount < stream.Position)
             {
                 TiffThrowHelper.ThrowImageFormatException("Out of range when reading a strip.");
             }

src/ImageSharp/Formats/Tiff/Constants/TiffConstants.cs

@@ -35,6 +35,16 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Constants
         /// </summary>
         public const ushort HeaderMagicNumber = 42;
 
+        /// <summary>
+        /// The big tiff header magic number
+        /// </summary>
+        public const ushort BigTiffHeaderMagicNumber = 43;
+
+        /// <summary>
+        /// The big tiff bytesize of offsets value.
+        /// </summary>
+        public const ushort BigTiffBytesize = 8;
+
         /// <summary>
         /// RowsPerStrip default value, which is effectively infinity.
         /// </summary>

src/ImageSharp/Formats/Tiff/Ifd/DirectoryReader.cs

@@ -16,11 +16,11 @@ namespace SixLabors.ImageSharp.Formats.Tiff
     {
         private readonly Stream stream;
 
-        private uint nextIfdOffset;
+        private ulong nextIfdOffset;
 
         // used for sequential read big values (actual for multiframe big files)
         // todo: different tags can link to the same data (stream offset) - investigate
-        private readonly SortedList<uint, Action> lazyLoaders = new SortedList<uint, Action>(new DuplicateKeyComparer<uint>());
+        private readonly SortedList<ulong, Action> lazyLoaders = new SortedList<ulong, Action>(new DuplicateKeyComparer<ulong>());
 
         public DirectoryReader(Stream stream) => this.stream = stream;
 
@@ -36,13 +36,17 @@ namespace SixLabors.ImageSharp.Formats.Tiff
         public IEnumerable<ExifProfile> Read()
         {
             this.ByteOrder = ReadByteOrder(this.stream);
-            this.nextIfdOffset = new HeaderReader(this.stream, this.ByteOrder).ReadFileHeader();
-            return this.ReadIfds();
+            var headerReader = new HeaderReader(this.stream, this.ByteOrder);
+            headerReader.ReadFileHeader();
+
+            this.nextIfdOffset = headerReader.FirstIfdOffset;
+
+            return this.ReadIfds(headerReader.IsBigTiff);
         }
 
         private static ByteOrder ReadByteOrder(Stream stream)
         {
-            var headerBytes = new byte[2];
+            byte[] headerBytes = new byte[2];
             stream.Read(headerBytes, 0, 2);
             if (headerBytes[0] == TiffConstants.ByteOrderLittleEndian && headerBytes[1] == TiffConstants.ByteOrderLittleEndian)
             {
@@ -56,13 +60,13 @@ namespace SixLabors.ImageSharp.Formats.Tiff
             throw TiffThrowHelper.ThrowInvalidHeader();
         }
 
-        private IEnumerable<ExifProfile> ReadIfds()
+        private IEnumerable<ExifProfile> ReadIfds(bool isBigTiff)
         {
             var readers = new List<EntryReader>();
-            while (this.nextIfdOffset != 0 && this.nextIfdOffset < this.stream.Length)
+            while (this.nextIfdOffset != 0 && this.nextIfdOffset < (ulong)this.stream.Length)
             {
-                var reader = new EntryReader(this.stream, this.ByteOrder, this.nextIfdOffset, this.lazyLoaders);
-                reader.ReadTags();
+                var reader = new EntryReader(this.stream, this.ByteOrder, this.lazyLoaders);
+                reader.ReadTags(isBigTiff, this.nextIfdOffset);
 
                 this.nextIfdOffset = reader.NextIfdOffset;
 
@@ -75,7 +79,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
                 loader();
             }
 
-            var list = new List<ExifProfile>();
+            var list = new List<ExifProfile>(readers.Count);
             foreach (EntryReader reader in readers)
             {
                 var profile = new ExifProfile(reader.Values, reader.InvalidTags);

src/ImageSharp/Formats/Tiff/Ifd/EntryReader.cs

@@ -12,31 +12,38 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 {
     internal class EntryReader : BaseExifReader
     {
-        private readonly uint startOffset;
+        private readonly SortedList<ulong, Action> lazyLoaders;
 
-        private readonly SortedList<uint, Action> lazyLoaders;
-
-        public EntryReader(Stream stream, ByteOrder byteOrder, uint ifdOffset, SortedList<uint, Action> lazyLoaders)
+        public EntryReader(Stream stream, ByteOrder byteOrder, SortedList<ulong, Action> lazyLoaders)
             : base(stream)
         {
             this.IsBigEndian = byteOrder == ByteOrder.BigEndian;
-            this.startOffset = ifdOffset;
             this.lazyLoaders = lazyLoaders;
         }
 
         public List<IExifValue> Values { get; } = new List<IExifValue>();
 
-        public uint NextIfdOffset { get; private set; }
+        public ulong NextIfdOffset { get; private set; }
 
-        public void ReadTags()
+        public void ReadTags(bool isBigTiff, ulong ifdOffset)
         {
-            this.ReadValues(this.Values, this.startOffset);
-            this.NextIfdOffset = this.ReadUInt32();
+            if (!isBigTiff)
+            {
+                this.ReadValues(this.Values, (uint)ifdOffset);
+                this.NextIfdOffset = this.ReadUInt32();
+
+                this.ReadSubIfd(this.Values);
+            }
+            else
+            {
+                this.ReadValues64(this.Values, ifdOffset);
+                this.NextIfdOffset = this.ReadUInt64();
 
-            this.ReadSubIfd(this.Values);
+                this.ReadSubIfd64(this.Values);
+            }
         }
 
-        protected override void RegisterExtLoader(uint offset, Action reader) =>
+        protected override void RegisterExtLoader(ulong offset, Action reader) =>
             this.lazyLoaders.Add(offset, reader);
     }
 
@@ -46,20 +53,35 @@ namespace SixLabors.ImageSharp.Formats.Tiff
             : base(stream) =>
             this.IsBigEndian = byteOrder == ByteOrder.BigEndian;
 
-        public uint FirstIfdOffset { get; private set; }
+        public bool IsBigTiff { get; private set; }
+
+        public ulong FirstIfdOffset { get; private set; }
 
-        public uint ReadFileHeader()
+        public void ReadFileHeader()
         {
             ushort magic = this.ReadUInt16();
-            if (magic != TiffConstants.HeaderMagicNumber)
+            if (magic == TiffConstants.HeaderMagicNumber)
             {
-                TiffThrowHelper.ThrowInvalidHeader();
+                this.IsBigTiff = false;
+                this.FirstIfdOffset = this.ReadUInt32();
+                return;
+            }
+            else if (magic == TiffConstants.BigTiffHeaderMagicNumber)
+            {
+                this.IsBigTiff = true;
+
+                ushort bytesize = this.ReadUInt16();
+                ushort reserve = this.ReadUInt16();
+                if (bytesize == TiffConstants.BigTiffBytesize && reserve == 0)
+                {
+                    this.FirstIfdOffset = this.ReadUInt64();
+                    return;
+                }
             }
 
-            this.FirstIfdOffset = this.ReadUInt32();
-            return this.FirstIfdOffset;
+            TiffThrowHelper.ThrowInvalidHeader();
         }
 
-        protected override void RegisterExtLoader(uint offset, Action reader) => throw new NotSupportedException();
+        protected override void RegisterExtLoader(ulong offset, Action reader) => throw new NotSupportedException();
     }
 }

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -432,6 +432,11 @@ namespace SixLabors.ImageSharp.Formats.Tiff
                 TiffThrowHelper.ThrowImageFormatException("The TIFF image frame is missing the ImageWidth");
             }
 
+            if (((ulong)width.Value) > int.MaxValue)
+            {
+                TiffThrowHelper.ThrowImageFormatException("Too big ImageWidth value");
+            }
+
             return (int)width.Value;
         }
 

src/ImageSharp/Formats/Tiff/TiffDecoderOptionsParser.cs

@@ -24,12 +24,12 @@ namespace SixLabors.ImageSharp.Formats.Tiff
         /// <param name="frameMetadata">The IFD entries container to read the image format information for current frame.</param>
         public static void VerifyAndParse(this TiffDecoderCore options, ExifProfile exifProfile, TiffFrameMetadata frameMetadata)
         {
-            if (exifProfile.GetValue(ExifTag.TileOffsets)?.Value != null)
+            if (exifProfile.GetValueInternal(ExifTag.TileOffsets) is not null || exifProfile.GetValueInternal(ExifTag.TileByteCounts) is not null)
             {
                 TiffThrowHelper.ThrowNotSupported("Tiled images are not supported.");
             }
 
-            if (exifProfile.GetValue(ExifTag.ExtraSamples)?.Value != null)
+            if (exifProfile.GetValueInternal(ExifTag.ExtraSamples) is not null)
             {
                 TiffThrowHelper.ThrowNotSupported("ExtraSamples is not supported.");
             }
@@ -95,12 +95,12 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 
         private static void VerifyRequiredFieldsArePresent(ExifProfile exifProfile, TiffFrameMetadata frameMetadata)
         {
-            if (exifProfile.GetValue(ExifTag.StripOffsets) == null)
+            if (exifProfile.GetValueInternal(ExifTag.StripOffsets) is null)
             {
                 TiffThrowHelper.ThrowImageFormatException("StripOffsets are missing and are required for decoding the TIFF image!");
             }
 
-            if (exifProfile.GetValue(ExifTag.StripByteCounts) == null)
+            if (exifProfile.GetValueInternal(ExifTag.StripByteCounts) is null)
             {
                 TiffThrowHelper.ThrowImageFormatException("StripByteCounts are missing and are required for decoding the TIFF image!");
             }
@@ -384,7 +384,8 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 
         private static void ParseCompression(this TiffDecoderCore options, TiffCompression? compression, ExifProfile exifProfile)
         {
-            switch (compression)
+            // Default 1 (No compression) https://www.awaresystems.be/imaging/tiff/tifftags/compression.html
+            switch (compression ?? TiffCompression.None)
             {
                 case TiffCompression.None:
                 {
@@ -441,7 +442,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 
                 default:
                 {
-                    TiffThrowHelper.ThrowNotSupported($"The specified TIFF compression format {compression} is not supported");
+                    TiffThrowHelper.ThrowNotSupported($"The specified TIFF compression format '{compression}' is not supported");
                     break;
                 }
             }