private DicomReadStatus InsertFragmentItem(DicomReadOptions options)
{
if (_tag == DicomTags.Item)
{
if (_len > _remain)
{
return(NeedMoreData(_len));
}
ByteBuffer data = CurrentBuffer(options);
_remain -= _len;
_read += _len;
if (!_fragment.HasOffsetTable)
{
_fragment.SetOffsetTable(data);
}
else
{
_fragment.AddFragment(data);
}
}
else if (_tag == DicomTags.SequenceDelimitationItem)
{
_fragment = null;
}
else
{
// unexpected tag
return(DicomReadStatus.UnknownError);
}
return(DicomReadStatus.Success);
}
/// <summary>
/// Read dataset from stream
/// </summary>
/// <param name="stopAtTag">End parsing at this tag</param>
/// <param name="options">DICOM read options</param>
/// <returns>Status code</returns>
public DicomReadStatus Read(DicomTag stopAtTag, DicomReadOptions options)
{
// Counters:
// _remain - bytes remaining in stream
// _bytes - estimates bytes to end of dataset
// _read - number of bytes read from stream
try {
_need = 0;
_remain = _stream.Length - _stream.Position;
while (_remain > 0)
{
DicomReadStatus status = ParseTag(stopAtTag, options);
if (status == DicomReadStatus.SuccessEndRead)
{
return(DicomReadStatus.Success);
}
if (status != DicomReadStatus.Success)
{
return(status);
}
status = ParseVR(options);
if (status != DicomReadStatus.Success)
{
return(status);
}
status = ParseLength(options);
if (status != DicomReadStatus.Success)
{
return(status);
}
if (_tag.IsPrivate)
{
if (_tag.Element != 0x0000 && _tag.Element <= 0x00ff)
{
// handle UN private creator id
if (_vr != DicomVR.LO && Flags.IsSet(options, DicomReadOptions.ForcePrivateCreatorToLO))
{
Dicom.Debug.Log.Warn("Converting Private Creator VR from '{0}' to 'LO'", _vr.VR);
_vr = DicomVR.LO;
}
}
}
if (_vr == DicomVR.UN && _syntax.IsExplicitVR && Flags.IsSet(options, DicomReadOptions.UseDictionaryForExplicitUN))
{
_vr = _tag.Entry.DefaultVR;
}
if (_fragment != null)
{
status = InsertFragmentItem(options);
if (status != DicomReadStatus.Success)
{
return(status);
}
}
else if (_sqs.Count > 0 &&
(_tag == DicomTags.Item ||
_tag == DicomTags.ItemDelimitationItem ||
_tag == DicomTags.SequenceDelimitationItem))
{
status = InsertSequenceItem(options);
if (status != DicomReadStatus.Success)
{
return(status);
}
}
else
{
if (_sqs.Count > 0)
{
DcmItemSequence sq = _sqs.Peek();
if (sq.StreamLength != UndefinedLength)
{
long end = sq.StreamPosition + 8 + sq.StreamLength;
if (_syntax.IsExplicitVR)
{
end += 2 + 2;
}
if ((_stream.Position - _offset) >= end)
{
if (_sds.Count == _sqs.Count)
{
_sds.Pop();
}
_sqs.Pop();
}
}
}
if (_len == UndefinedLength)
{
if (_vr == DicomVR.SQ)
{
DcmItemSequence sq = new DcmItemSequence(_tag, _pos, _len, _endian);
InsertDatasetItem(sq, options);
_sqs.Push(sq);
}
else
{
_fragment = new DcmFragmentSequence(_tag, _vr, _pos, _endian);
InsertDatasetItem(_fragment, options);
}
}
else
{
if (_vr == DicomVR.SQ)
{
DcmItemSequence sq = new DcmItemSequence(_tag, _pos, _len, _endian);
InsertDatasetItem(sq, options);
_sqs.Push(sq);
}
else
{
if (_len > _remain)
{
return(NeedMoreData(_len));
}
DcmElement elem = DcmElement.Create(_tag, _vr, _pos, _endian, CurrentBuffer(options));
_remain -= _len;
_read += _len;
InsertDatasetItem(elem, options);
}
}
}
_tag = null;
_vr = null;
_len = UndefinedLength;
}
return(DicomReadStatus.Success);
}
catch (EndOfStreamException) {
// should never happen
return(DicomReadStatus.UnknownError);
}
}
/// <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);
}
