public override ITag ReadTag()
{
if (this._position != -1)
{
this.Context.Reader.BaseStream.Seek(this._position, SeekOrigin.Begin);
}
if (this.Context.TagCountLeft == 0)
{
this._position = -1;
this.Context.NextImageFileDirectory = Helper.Read <uint>(this.Context.Reader.BaseStream);
this.FireEvent(TagState.ToNextIfd);
return(null);
}
this.Context.ValueCountLeft = (int)(this.Context.CurrentTag = Helper.Read <TiffDirEntry>(this.Context.Reader.BaseStream)).count;
this.Context.TagCountLeft--;
this._position = this.Context.Reader.BaseStream.Position;
int _itemSize = TiffDataTypeHelper.Sizeof(this.Context.CurrentTag.type);
if (_itemSize * this.Context.CurrentTag.count > 4)
{
// Массив значений
this.Context.Reader.BaseStream.Seek(this.Context.CurrentTag.offset, SeekOrigin.Begin);
}
else
{
// Массив, вписанный в поле offset
this.Context.Reader.BaseStream.Seek(Marshal.OffsetOf(typeof(TiffDirEntry), "offset").ToInt64() - Marshal.SizeOf(typeof(TiffDirEntry)), SeekOrigin.Current);
}
this.FireEvent(TagState.ToValue);
return(this.Context.CurrentTag);
}
public static Tiff.IfdEntry FromPtr(IntPtr ptr, IntPtr baseAddr)
{
TiffDirEntry _entry = (TiffDirEntry)Marshal.PtrToStructure(ptr, typeof(TiffDirEntry));
Tiff.IfdEntry _ifdEntry = new Tiff.IfdEntry {
Tag = _entry.tag,
DataType = _entry.type,
_data = Array.CreateInstance(TiffDataTypeHelper.Typeof(_entry.type), _entry.count <= int.MaxValue?_entry.count:0)
};
IntPtr _dataPtr = (IntPtr)(((_ifdEntry.DataSize = (int)(TiffDataTypeHelper.Sizeof(_entry.type) * _ifdEntry._data.Length)) > 4)?baseAddr.ToInt64() + _entry.offset:ptr.ToInt64() + 8);
_ifdEntry.DataOffset = (int)(_dataPtr.ToInt64() - baseAddr.ToInt64());
for (int i = 0, _size = TiffDataTypeHelper.Sizeof(_entry.type); i < _ifdEntry._data.Length; i++)
{
_ifdEntry._data.SetValue(Marshal.PtrToStructure((IntPtr)(_dataPtr.ToInt64() + _size * i), TiffDataTypeHelper.Typeof(_entry.type)), i);
}
return(_ifdEntry);
}