private static List <ParserIFDEntry> ParseDirectories(EndianBinaryReader reader, uint firstIFDOffset)
{
List <ParserIFDEntry> items = new List <ParserIFDEntry>();
bool foundExif = false;
bool foundGps = false;
bool foundInterop = false;
Queue <MetadataOffset> ifdOffsets = new Queue <MetadataOffset>();
ifdOffsets.Enqueue(new MetadataOffset(MetadataSection.Image, firstIFDOffset));
while (ifdOffsets.Count > 0)
{
MetadataOffset metadataOffset = ifdOffsets.Dequeue();
MetadataSection section = metadataOffset.Section;
uint offset = metadataOffset.Offset;
if (offset >= reader.Length)
{
continue;
}
reader.Position = offset;
ushort count = reader.ReadUInt16();
if (count == 0)
{
continue;
}
items.Capacity += count;
for (int i = 0; i < count; i++)
{
ParserIFDEntry entry = new ParserIFDEntry(reader, section);
switch (entry.Tag)
{
case TiffConstants.Tags.ExifIFD:
if (!foundExif)
{
foundExif = true;
ifdOffsets.Enqueue(new MetadataOffset(MetadataSection.Exif, entry.Offset));
}
break;
case TiffConstants.Tags.GpsIFD:
if (!foundGps)
{
foundGps = true;
ifdOffsets.Enqueue(new MetadataOffset(MetadataSection.Gps, entry.Offset));
}
break;
case TiffConstants.Tags.InteropIFD:
if (!foundInterop)
{
foundInterop = true;
ifdOffsets.Enqueue(new MetadataOffset(MetadataSection.Interop, entry.Offset));
}
break;
case TiffConstants.Tags.StripOffsets:
case TiffConstants.Tags.RowsPerStrip:
case TiffConstants.Tags.StripByteCounts:
case TiffConstants.Tags.SubIFDs:
case TiffConstants.Tags.ThumbnailOffset:
case TiffConstants.Tags.ThumbnailLength:
// Skip the thumbnail and/or preview images.
// The StripOffsets and StripByteCounts tags are used to store a preview image in some formats.
// The SubIFDs tag is used to store thumbnails in TIFF and for storing other data in some camera formats.
//
// Note that some cameras will also store a thumbnail as part of their private data in the EXIF MakerNote tag.
// The EXIF MakerNote tag is treated as an opaque blob, so those thumbnails will be preserved.
break;
default:
items.Add(entry);
break;
}
System.Diagnostics.Debug.WriteLine(entry.ToString());
}
}
return(items);
}
#pragma warning restore IDE0032 // Use auto property
public ParserIFDEntry(EndianBinaryReader reader, MetadataSection section)
{
entry = new IFDEntry(reader);
offsetIsBigEndian = reader.Endianess == Endianess.Big;
Section = section;
}
private static ICollection <MetadataEntry> ConvertIFDEntriesToMetadataEntries(EndianBinaryReader reader, List <ParserIFDEntry> entries)
{
List <MetadataEntry> metadataEntries = new List <MetadataEntry>(entries.Count);
bool swapNumberByteOrder = reader.Endianess == Endianess.Big;
for (int i = 0; i < entries.Count; i++)
{
ParserIFDEntry entry = entries[i];
byte[] propertyData;
if (entry.OffsetFieldContainsValue)
{
propertyData = entry.GetValueBytesFromOffset();
if (propertyData == null)
{
continue;
}
}
else
{
long bytesToRead = entry.Count * TagDataTypeUtil.GetSizeInBytes(entry.Type);
// Skip any tags that are empty or larger than 2 GB.
if (bytesToRead == 0 || bytesToRead > int.MaxValue)
{
continue;
}
uint offset = entry.Offset;
if ((offset + bytesToRead) > reader.Length)
{
continue;
}
reader.Position = offset;
propertyData = reader.ReadBytes((int)bytesToRead);
if (swapNumberByteOrder)
{
// Paint.NET converts all multi-byte numbers to little-endian.
switch (entry.Type)
{
case TagDataType.Short:
case TagDataType.SShort:
propertyData = SwapShortArrayToLittleEndian(propertyData, entry.Count);
break;
case TagDataType.Long:
case TagDataType.SLong:
case TagDataType.Float:
propertyData = SwapLongArrayToLittleEndian(propertyData, entry.Count);
break;
case TagDataType.Rational:
case TagDataType.SRational:
propertyData = SwapRationalArrayToLittleEndian(propertyData, entry.Count);
break;
case TagDataType.Double:
propertyData = SwapDoubleArrayToLittleEndian(propertyData, entry.Count);
break;
case TagDataType.Byte:
case TagDataType.Ascii:
case TagDataType.Undefined:
case TagDataType.SByte:
default:
break;
}
}
}
metadataEntries.Add(new MetadataEntry(entry.Section, entry.Tag, entry.Type, propertyData));
}
return(metadataEntries);
}
