private bool ParseValue(IByteSource source)
{
if (_parseStage == ParseStage.Value)
{
// check dictionary for VR after reading length to handle 16-bit lengths
// check before reading value to handle SQ elements
var parsedVR = _vr;
// check dictionary for VR after reading length to handle 16-bit lengths
// check before reading value to handle SQ elements
if (_vr == DicomVR.Implicit || (_vr == DicomVR.UN && _isExplicitVR))
{
var entry = _dictionary[_tag];
if (entry != null)
{
_vr = entry.ValueRepresentations.FirstOrDefault();
}
if (_vr == null)
{
_vr = DicomVR.UN;
}
}
if (_tag == DicomTag.ItemDelimitationItem || _tag == DicomTag.SequenceDelimitationItem)
{
// end of sequence item
return(false);
}
while (_vr == DicomVR.SQ && _tag.IsPrivate && _length > 0)
{
if (!IsPrivateSequence(source))
{
_vr = DicomVR.UN;
break;
}
if (IsPrivateSequenceBad(source, _length, _isExplicitVR))
{
_badPrivateSequence = true;
// store the depth of the bad sequence, we only want to switch back once we've processed
// the entire sequence, regardless of any sub-sequences.
_badPrivateSequenceDepth = _sequenceDepth;
_isExplicitVR = !_isExplicitVR;
}
break;
}
var curIndex = source.Position;
// Fix to handle sequence items not associated with any sequence (#364)
if (_tag.Equals(DicomTag.Item))
{
source.Rewind();
_vr = DicomVR.SQ;
}
if (_vr == DicomVR.SQ)
{
// start of sequence
_observer.OnBeginSequence(source, _tag, _length);
_parseStage = ParseStage.Tag;
if (_length == 0)
{
_implicit = false;
source.PushMilestone((uint)(source.Position - curIndex));
}
else if (_length != _undefinedLength)
{
_implicit = false;
source.PushMilestone(_length);
}
else
{
_implicit = true;
}
var last = source.Position;
// Conformance with CP-246 (#177)
var needtoChangeEndian = false;
if (parsedVR == DicomVR.UN && !_tag.IsPrivate)
{
_implicit = true;
needtoChangeEndian = source.Endian == Endian.Big;
}
if (needtoChangeEndian)
{
source.Endian = Endian.Little;
}
ParseItemSequence(source);
if (needtoChangeEndian)
{
source.Endian = Endian.Big;
}
// Aeric Sylvan - https://github.com/rcd/fo-dicom/issues/62#issuecomment-46248073
// Fix reading of SQ with parsed VR of UN
if (source.Position > last || _length == 0)
{
return(true);
}
_parseStage = ParseStage.Value;
_vr = parsedVR;
}
if (_length == _undefinedLength)
{
_observer.OnBeginFragmentSequence(source, _tag, _vr);
_parseStage = ParseStage.Tag;
ParseFragmentSequence(source);
return(true);
}
if (!source.Require(_length))
{
_result = DicomReaderResult.Suspended;
return(false);
}
var buffer = source.GetBuffer(_length);
if (buffer != null)
{
if (!_vr.IsString)
{
buffer = EndianByteBuffer.Create(buffer, source.Endian, _vr.UnitSize);
}
_observer.OnElement(source, _tag, _vr, buffer);
}
// parse private creator value and add to lookup table
// according to
// http://dicom.nema.org/medical/dicom/current/output/chtml/part05/sect_7.8.html
// Private Creator Data Elements numbered (gggg,0010-00FF) (gggg is odd)
// The VR of the private identification code shall be LO (Long String) and the VM shall be equal to 1.
if (_tag.IsPrivate && _tag.Element >= 0x0010 && _tag.Element <= 0x00ff)
{
var creator =
DicomEncoding.Default.GetString(buffer.Data, 0, buffer.Data.Length)
.TrimEnd((char)DicomVR.LO.PaddingValue);
var card = (uint)(_tag.Group << 16) + _tag.Element;
lock (_locker)
{
_private[card] = creator;
}
}
ResetState();
}
return(true);
}
private void ParseDataset(IByteSource source, object state)
{
try {
_result = DicomReaderResult.Processing;
while (!source.IsEOF && !source.HasReachedMilestone() && _result == DicomReaderResult.Processing)
{
if (_state == ParseState.Tag)
{
source.Mark();
if (!source.Require(4, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
ushort group = source.GetUInt16();
ushort element = source.GetUInt16();
DicomPrivateCreator creator = null;
if (group.IsOdd() && element > 0x00ff)
{
string pvt = null;
uint card = (uint)(group << 16) + (uint)(element >> 8);
if (_private.TryGetValue(card, out pvt))
{
creator = Dictionary.GetPrivateCreator(pvt);
}
}
_tag = new DicomTag(group, element, creator);
_entry = Dictionary[_tag];
if (!_tag.IsPrivate && _entry != null && _entry.MaskTag == null)
{
_tag = _entry.Tag; // Use dictionary tag
}
if (_stop != null && _tag.CompareTo(_stop) >= 0)
{
_result = DicomReaderResult.Stopped;
return;
}
_state = ParseState.VR;
}
while (_state == ParseState.VR)
{
if (_tag == DicomTag.Item || _tag == DicomTag.ItemDelimitationItem || _tag == DicomTag.SequenceDelimitationItem)
{
_vr = DicomVR.NONE;
_state = ParseState.Length;
break;
}
if (IsExplicitVR)
{
if (!source.Require(2, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
byte[] bytes = source.GetBytes(2);
string vr = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
if (!DicomVR.TryParse(vr, out _vr))
{
// unable to parse VR
_vr = DicomVR.UN;
}
}
else
{
if (_entry != null)
{
if (_entry == DicomDictionary.UnknownTag)
{
_vr = DicomVR.UN;
}
else if (_entry.ValueRepresentations.Contains(DicomVR.OB) && _entry.ValueRepresentations.Contains(DicomVR.OW))
{
_vr = DicomVR.OW; // ???
}
else
{
_vr = _entry.ValueRepresentations.FirstOrDefault();
}
}
}
if (_vr == null)
{
_vr = DicomVR.UN;
}
_state = ParseState.Length;
if (_vr == DicomVR.UN)
{
if (_tag.Element == 0x0000)
{
// Group Length to UL
_vr = DicomVR.UL;
break;
}
else if (IsExplicitVR)
{
break;
}
}
if (_tag.IsPrivate)
{
if (_tag.Element != 0x0000 && _tag.Element <= 0x00ff && _vr == DicomVR.UN)
{
_vr = DicomVR.LO; // force private creator to LO
}
}
}
while (_state == ParseState.Length)
{
if (_tag == DicomTag.Item || _tag == DicomTag.ItemDelimitationItem || _tag == DicomTag.SequenceDelimitationItem)
{
if (!source.Require(4, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
_length = source.GetUInt32();
_state = ParseState.Value;
break;
}
if (IsExplicitVR)
{
if (_vr.Is16bitLength)
{
if (!source.Require(2, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
_length = source.GetUInt16();
}
else
{
if (!source.Require(6, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
source.Skip(2);
_length = source.GetUInt32();
}
}
else
{
if (!source.Require(4, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
_length = source.GetUInt32();
// assume that undefined length in implicit dataset is SQ
if (_length == UndefinedLength && _vr == DicomVR.UN)
{
_vr = DicomVR.SQ;
}
}
_state = ParseState.Value;
}
if (_state == ParseState.Value)
{
// check dictionary for VR after reading length to handle 16-bit lengths
// check before reading value to handle SQ elements
var parsedVR = _vr;
// check dictionary for VR after reading length to handle 16-bit lengths
// check before reading value to handle SQ elements
if (_vr == DicomVR.UN && IsExplicitVR)
{
var entry = Dictionary[_tag];
if (entry != null)
{
_vr = entry.ValueRepresentations.FirstOrDefault();
}
if (_vr == null)
{
_vr = DicomVR.UN;
}
}
if (_tag == DicomTag.ItemDelimitationItem)
{
// end of sequence item
return;
}
while (_vr == DicomVR.SQ && _tag.IsPrivate)
{
if (!IsPrivateSequence(source))
{
_vr = DicomVR.UN;
break;
}
if (IsPrivateSequenceBad(source))
{
_badPrivateSequence = true;
_explicit = !_explicit;
}
break;
}
if (_vr == DicomVR.SQ)
{
// start of sequence
_observer.OnBeginSequence(source, _tag, _length);
_state = ParseState.Tag;
if (_length != UndefinedLength)
{
_implicit = false;
source.PushMilestone(_length);
}
else
{
_implicit = true;
}
PushState(state);
var last = source.Position;
ParseItemSequence(source, null);
// Aeric Sylvan - https://github.com/rcd/fo-dicom/issues/62#issuecomment-46248073
// Fix reading of SQ with parsed VR of UN
if (source.Position > last || _length == 0)
{
continue;
}
else
{
_state = ParseState.Value;
_vr = parsedVR;
}
}
if (_length == UndefinedLength)
{
_observer.OnBeginFragmentSequence(source, _tag, _vr);
_state = ParseState.Tag;
PushState(state);
ParseFragmentSequence(source, null);
continue;
}
if (!source.Require(_length, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
IByteBuffer buffer = source.GetBuffer(_length);
if (!_vr.IsString)
{
buffer = EndianByteBuffer.Create(buffer, source.Endian, _vr.UnitSize);
}
_observer.OnElement(source, _tag, _vr, buffer);
// parse private creator value and add to lookup table
if (_tag.IsPrivate && _tag.Element != 0x0000 && _tag.Element <= 0x00ff)
{
var creator = DicomEncoding.Default.GetString(buffer.Data, 0, buffer.Data.Length).TrimEnd((char)DicomVR.LO.PaddingValue);
var card = (uint)(_tag.Group << 16) + (uint)(_tag.Element);
_private[card] = creator;
}
ResetState();
}
}
if (source.HasReachedMilestone())
{
// end of explicit length sequence item
source.PopMilestone();
return;
}
if (_result != DicomReaderResult.Processing)
{
return;
}
// end of processing
_result = DicomReaderResult.Success;
} catch (Exception e) {
_exception = e;
_result = DicomReaderResult.Error;
} finally {
if (_result != DicomReaderResult.Processing && _result != DicomReaderResult.Suspended)
{
_async.Set();
}
}
}
private void ParseDataset(IByteSource source, object state)
{
try {
_result = DicomReaderResult.Processing;
while (!source.IsEOF && !source.HasReachedMilestone())
{
if (_state == ParseState.Tag)
{
source.Mark();
if (!source.Require(4, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
ushort group = source.GetUInt16();
ushort element = source.GetUInt16();
DicomPrivateCreator creator = null;
if (group.IsOdd() && element > 0x00ff)
{
string pvt = null;
uint card = (uint)(group << 16) + (uint)(element >> 8);
if (_private.TryGetValue(card, out pvt))
{
creator = Dictionary.GetPrivateCreator(pvt);
}
}
_tag = new DicomTag(group, element, creator);
if (_stop != null && _tag.CompareTo(_stop) >= 0)
{
_result = DicomReaderResult.Stopped;
return;
}
_state = ParseState.VR;
}
while (_state == ParseState.VR)
{
if (_tag == DicomTag.Item || _tag == DicomTag.ItemDelimitationItem || _tag == DicomTag.SequenceDelimitationItem)
{
_vr = DicomVR.NONE;
_state = ParseState.Length;
break;
}
if (IsExplicitVR)
{
if (!source.Require(2, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
byte[] bytes = source.GetBytes(2);
string vr = Encoding.ASCII.GetString(bytes);
_vr = DicomVR.Parse(vr);
}
else
{
DicomDictionaryEntry entry = Dictionary[_tag];
if (entry != null)
{
if (entry.ValueRepresentations.Contains(DicomVR.OB) && entry.ValueRepresentations.Contains(DicomVR.OW))
{
_vr = DicomVR.OW; // ???
}
else
{
_vr = entry.ValueRepresentations.FirstOrDefault();
}
}
}
if (_vr == null)
{
_vr = DicomVR.UN;
}
_state = ParseState.Length;
if (_vr == DicomVR.UN)
{
if (_tag.Element == 0x0000)
{
// Group Length to UL
_vr = DicomVR.UL;
break;
}
if (_tag.Group.IsOdd())
{
if (_tag.Element <= 0x00ff)
{
// Private Creator to LO
_vr = DicomVR.LO;
break;
}
else if (IsExplicitVR)
{
DicomDictionaryEntry entry = Dictionary[_tag];
if (entry != null)
{
_vr = entry.ValueRepresentations.FirstOrDefault();
}
if (_vr == null)
{
_vr = DicomVR.UN;
}
break;
}
}
}
}
while (_state == ParseState.Length)
{
if (_tag == DicomTag.Item || _tag == DicomTag.ItemDelimitationItem || _tag == DicomTag.SequenceDelimitationItem)
{
if (!source.Require(4, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
_length = source.GetUInt32();
_state = ParseState.Value;
break;
}
if (IsExplicitVR)
{
if (_vr.Is16bitLength)
{
if (!source.Require(2, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
_length = source.GetUInt16();
}
else
{
if (!source.Require(6, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
source.Skip(2);
_length = source.GetUInt32();
}
}
else
{
if (!source.Require(4, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
_length = source.GetUInt32();
}
_state = ParseState.Value;
}
if (_state == ParseState.Value)
{
if (_tag == DicomTag.ItemDelimitationItem)
{
// end of sequence item
ParseItemSequence(source, state);
return;
}
if (_vr == DicomVR.SQ)
{
// start of sequence
_observer.OnBeginSequence(source, _tag, _length);
_state = ParseState.Tag;
if (_length != UndefinedLength)
{
source.PushMilestone(_length);
}
PushState(state);
ParseItemSequence(source, null);
continue;
}
if (_length == UndefinedLength)
{
_observer.OnBeginFragmentSequence(source, _tag, _vr);
_state = ParseState.Tag;
PushState(state);
ParseFragmentSequence(source, null);
continue;
}
if (!source.Require(_length, ParseDataset, state))
{
_result = DicomReaderResult.Suspended;
return;
}
IByteBuffer buffer = source.GetBuffer(_length);
if (!_vr.IsString)
{
buffer = EndianByteBuffer.Create(buffer, source.Endian, _vr.UnitSize);
}
_observer.OnElement(source, _tag, _vr, buffer);
ResetState();
}
}
if (source.HasReachedMilestone())
{
// end of explicit length sequence item
_observer.OnEndSequenceItem();
source.PopMilestone();
ParseItemSequence(source, state);
return;
}
// end of processing
_result = DicomReaderResult.Success;
} catch (Exception e) {
_exception = e;
_result = DicomReaderResult.Error;
} finally {
if (_result != DicomReaderResult.Processing && _result != DicomReaderResult.Suspended)
{
_async.Set();
}
}
}
