public static IfdEntry ParseFromByte(byte[] imageData, int startIndex, ByteOrder byteOrder)
{
var typeValue =
BitConverterExtension.ToUInt16(imageData, startIndex + 2, byteOrder, BitConverterExtension.SystemByteOrder);
if (!typeof(FieldType).IsEnumDefined(typeValue))
{
throw new ArgumentOutOfRangeException("Invalid field type value");
}
var tag = BitConverterExtension.ToUInt16(imageData, startIndex, byteOrder, BitConverterExtension.SystemByteOrder);
var count = BitConverterExtension.ToUInt32(imageData, startIndex + 4, byteOrder,
BitConverterExtension.SystemByteOrder);
var value = BitConverterExtension.CopyArrayEndianness(imageData, startIndex + 8, byteOrder,
BitConverterExtension.SystemByteOrder,
IfdEntryValueByteLength);
var valueLength = FieldTypeHelper.GetFieldTypeByteLength((FieldType)typeValue) * (int)count;
if (valueLength > IfdEntryValueByteLength)
{
var valueOffset = BitConverterExtension.ToUInt32(value, 0, byteOrder, BitConverterExtension.SystemByteOrder);
value = BitConverterExtension.CopyArrayEndianness(imageData, (int)valueOffset, byteOrder,
BitConverterExtension.SystemByteOrder,
valueLength);
}
return(new IfdEntry(tag, typeValue, count, value));
}
public static ImageFileDirectory ParseFromImageData(byte[] imageData, int startIndex, ByteOrder byteOrder)
{
var ifd = new ImageFileDirectory
{
NumberOfIfdEntries =
BitConverterExtension.ToUInt16(imageData, startIndex, byteOrder, BitConverterExtension.SystemByteOrder)
};
ifd.IfdEntries = new List <IfdEntry>(ifd.NumberOfIfdEntries);
for (var i = 0; i < ifd.NumberOfIfdEntries; i++)
{
var ifdEntry = IfdEntry.ParseFromByte(imageData, startIndex + NumberOfFieldsByteLength + IfdEntryByteLength * i,
byteOrder);
ifd.IfdEntries.Add(ifdEntry);
}
ifd.NextIfdOffset = BitConverterExtension.ToUInt32(imageData,
startIndex + NumberOfFieldsByteLength + IfdEntryByteLength * ifd.NumberOfIfdEntries, byteOrder,
BitConverterExtension.SystemByteOrder);
return(ifd);
}
