public byte[] GetExifData()
{
VerifyNotDisposed();
ItemLocationEntry entry = this.parser.TryGetExifLocation(this.primaryItemId);
if (entry != null)
{
ulong length = entry.TotalItemSize;
// Ignore any EXIF blocks that are larger than 2GB.
if (length < int.MaxValue)
{
using (AvifItemData itemData = this.parser.ReadItemData(entry))
using (Stream stream = itemData.GetStream())
{
// The EXIF data block has a header that indicates the number of bytes
// that come before the start of the TIFF header.
// See ISO/IEC 23008-12:2017 section A.2.1.
long tiffStartOffset = stream.TryReadUInt32BigEndian();
if (tiffStartOffset != -1)
{
long dataLength = (long)length - tiffStartOffset - sizeof(uint);
if (dataLength > 0)
{
if (tiffStartOffset != 0)
{
stream.Position += tiffStartOffset;
}
byte[] bytes = new byte[dataLength];
stream.ProperRead(bytes, 0, bytes.Length);
return(bytes);
}
}
}
}
}
return(null);
}
private ImageGridDescriptor TryGetImageGridDescriptor(uint itemId)
{
IItemInfoEntry entry = TryGetItemInfoEntry(itemId);
if (entry != null && entry.ItemType == ItemInfoEntryTypes.ImageGrid)
{
ItemLocationEntry locationEntry = TryGetItemLocation(itemId);
if (locationEntry != null)
{
if (locationEntry.TotalItemSize < ImageGridDescriptor.SmallDescriptorLength)
{
ExceptionUtil.ThrowFormatException("Invalid image grid descriptor length.");
}
using (AvifItemData itemData = ReadItemData(locationEntry))
{
Stream stream = null;
try
{
stream = itemData.GetStream();
using (EndianBinaryReader imageGridReader = new EndianBinaryReader(stream, this.reader.Endianess, this.arrayPool))
{
stream = null;
return(new ImageGridDescriptor(imageGridReader, itemData.Length));
}
}
finally
{
stream?.Dispose();
}
}
}
}
return(null);
}