Dicom.Data.DcmDataset.CalculateGroupWriteLength C# (CSharp) Method

        public uint CalculateGroupWriteLength(ushort group, DicomTransferSyntax syntax, DicomWriteOptions options)
        {
            uint length = 0;
            foreach (DcmItem item in _items.Values) {
                if (item.Tag.Group < group || item.Tag.Element == 0x0000)
                    continue;
                if (item.Tag.Group > group)
                    return length;
                length += item.CalculateWriteLength(syntax, options);
            }
            return length;
        }

		/// <summary>
		/// Write dataset to stream
		/// </summary>
		/// <param name="dataset">Dataset</param>
		/// <param name="options">DICOM write options</param>
		/// <returns>Status code</returns>
		public DicomWriteStatus Write(DcmDataset dataset, DicomWriteOptions options) {
			TransferSyntax = dataset.InternalTransferSyntax;
			dataset.SelectByteOrder(_syntax.Endian);

			foreach (DcmItem item in dataset.Elements) {
				if (item.Tag.Element == 0x0000)
					continue;

				if (Flags.IsSet(options, DicomWriteOptions.CalculateGroupLengths) 
					&& item.Tag.Group != _group && item.Tag.Group <= 0x7fe0)
				{
					_group = item.Tag.Group;
					_writer.Write((ushort)_group);
					_writer.Write((ushort)0x0000);
					if (_syntax.IsExplicitVR) {
						_writer.Write((byte)'U');
						_writer.Write((byte)'L');
						_writer.Write((ushort)4);
					} else {
						_writer.Write((uint)4);
					}
					_writer.Write((uint)dataset.CalculateGroupWriteLength(_group, _syntax, options));
				}

				_writer.Write((ushort)item.Tag.Group);
				_writer.Write((ushort)item.Tag.Element);

				if (_syntax.IsExplicitVR) {
					_writer.Write((byte)item.VR.VR[0]);
					_writer.Write((byte)item.VR.VR[1]);
				}

				if (item is DcmItemSequence) {
					DcmItemSequence sq = item as DcmItemSequence;

					if (_syntax.IsExplicitVR)
						_writer.Write((ushort)0x0000);

					if (Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequence) || (item.Tag.IsPrivate && !_syntax.IsExplicitVR)) {
						int hl = _syntax.IsExplicitVR ? 12 : 8;
						_writer.Write((uint)sq.CalculateWriteLength(_syntax, options & ~DicomWriteOptions.CalculateGroupLengths) - (uint)hl);
					} else {
						_writer.Write((uint)UndefinedLength);
					}

					foreach (DcmItemSequenceItem ids in sq.SequenceItems) {
						ids.Dataset.ChangeTransferSyntax(dataset.InternalTransferSyntax, null);

						_writer.Write((ushort)DicomTags.Item.Group);
						_writer.Write((ushort)DicomTags.Item.Element);

						if (Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequenceItem)) {
							_writer.Write((uint)ids.CalculateWriteLength(_syntax, options & ~DicomWriteOptions.CalculateGroupLengths) - (uint)8);
						} else {
							_writer.Write((uint)UndefinedLength);
						}

						Write(ids.Dataset, options & ~DicomWriteOptions.CalculateGroupLengths);

						if (!Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequenceItem)) {
							_writer.Write((ushort)DicomTags.ItemDelimitationItem.Group);
							_writer.Write((ushort)DicomTags.ItemDelimitationItem.Element);
							_writer.Write((uint)0x00000000);
						}
					}

					if (!Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequence) && !(item.Tag.IsPrivate && !_syntax.IsExplicitVR)) {
						_writer.Write((ushort)DicomTags.SequenceDelimitationItem.Group);
						_writer.Write((ushort)DicomTags.SequenceDelimitationItem.Element);
						_writer.Write((uint)0x00000000);
					}
				}
				
				else if (item is DcmFragmentSequence) {
					DcmFragmentSequence fs = item as DcmFragmentSequence;

					if (_syntax.IsExplicitVR)
						_writer.Write((ushort)0x0000);
					_writer.Write((uint)UndefinedLength);

					_writer.Write((ushort)DicomTags.Item.Group);
					_writer.Write((ushort)DicomTags.Item.Element);

					if (Flags.IsSet(options, DicomWriteOptions.WriteFragmentOffsetTable) && fs.HasOffsetTable) {
						_writer.Write((uint)fs.OffsetTableBuffer.Length);
						fs.OffsetTableBuffer.CopyTo(_writer.BaseStream);
					} else {
						_writer.Write((uint)0x00000000);
					}

					foreach (ByteBuffer bb in fs.Fragments) {
						_writer.Write((ushort)DicomTags.Item.Group);
						_writer.Write((ushort)DicomTags.Item.Element);
						_writer.Write((uint)bb.Length);
						bb.CopyTo(_writer.BaseStream);
					}

					_writer.Write((ushort)DicomTags.SequenceDelimitationItem.Group);
					_writer.Write((ushort)DicomTags.SequenceDelimitationItem.Element);
					_writer.Write((uint)0x00000000);
				}
				
				else {
					DcmElement de = item as DcmElement;

					if (_syntax.IsExplicitVR) {
						if (de.VR.Is16BitLengthField) {
							_writer.Write((ushort)de.Length);
						} else {
							_writer.Write((ushort)0x0000);
							_writer.Write((uint)de.Length);
						}
					} else {
						_writer.Write((uint)de.Length);
					}

					de.ByteBuffer.CopyTo(_writer.BaseStream);
				}
			}

			return DicomWriteStatus.Success;
		}