private static bool IsPrivateSequenceBad(IByteSource source, bool isExplicitVR)
{
source.Mark();
try
{
source.GetUInt16(); // group
source.GetUInt16(); // element
source.GetUInt32(); // length
source.GetUInt16(); // group
source.GetUInt16(); // element
var bytes = source.GetBytes(2);
var vr = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
DicomVR dummy;
if (DicomVR.TryParse(vr, out dummy))
{
return(!isExplicitVR);
}
// unable to parse VR
if (isExplicitVR)
{
return(true);
}
}
finally
{
source.Rewind();
}
return(false);
}
private bool ParseItemSequenceTag(IByteSource source)
{
if (this.parseStage == ParseStage.Tag)
{
source.Mark();
if (!source.Require(8))
{
this.result = DicomReaderResult.Suspended;
return(false);
}
var group = source.GetUInt16();
var element = source.GetUInt16();
this._tag = new DicomTag(@group, element);
if (this._tag != DicomTag.Item && this._tag != DicomTag.SequenceDelimitationItem)
{
// assume invalid sequence
source.Rewind();
if (!this._implicit)
{
source.PopMilestone();
}
this.observer.OnEndSequence();
if (this.badPrivateSequence)
{
this.isExplicitVR = !this.isExplicitVR;
this.badPrivateSequence = false;
}
return(false);
}
this.length = source.GetUInt32();
if (this._tag == DicomTag.SequenceDelimitationItem)
{
// #64, in case explicit length has been specified despite occurrence of Sequence Delimitation Item
if (source.HasReachedMilestone() && source.MilestonesCount > this.sequenceDepth)
{
this.ResetState();
return(true);
}
// end of sequence
this.observer.OnEndSequence();
if (this.badPrivateSequence)
{
this.isExplicitVR = !this.isExplicitVR;
this.badPrivateSequence = false;
}
this.ResetState();
return(false);
}
this.parseStage = ParseStage.Value;
}
return(true);
}
private bool IsPrivateSequenceBad(IByteSource source)
{
source.Mark();
try {
var group = source.GetUInt16();
var element = source.GetUInt16();
var tag = new DicomTag(group, element);
var length = source.GetUInt32();
group = source.GetUInt16();
element = source.GetUInt16();
tag = new DicomTag(group, element);
byte[] bytes = source.GetBytes(2);
string vr = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
DicomVR dummy;
if (DicomVR.TryParse(vr, out dummy))
{
return(!_explicit);
}
// unable to parse VR
if (_explicit)
{
return(true);
}
} finally {
source.Rewind();
}
return(false);
}
private static bool IsPrivateSequenceBad(IByteSource source, bool isExplicitVR)
{
source.Mark();
try
{
// Skip "item" tags; continue skipping until length is non-zero (#223)
while (new DicomTag(source.GetUInt16(), source.GetUInt16()) == DicomTag.Item // group, element
& source.GetUInt32() == 0) // length (using & instead of && enforces RHS to be evaluated regardless of LHS)
{
}
source.GetUInt16(); // group
source.GetUInt16(); // element
var bytes = source.GetBytes(2);
var vr = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
DicomVR dummy;
if (DicomVR.TryParse(vr, out dummy))
{
return(!isExplicitVR);
}
// unable to parse VR
if (isExplicitVR)
{
return(true);
}
}
finally
{
source.Rewind();
}
return(false);
}
private static bool IsPrivateSequenceBad(IByteSource source, uint count, bool isExplicitVR)
{
source.Mark();
try
{
// Skip "item" tags; continue skipping until length is non-zero (#223)
// Using & instead of && enforces RHS to be evaluated regardless of LHS
uint length;
while (source.GetUInt16() == DicomTag.Item.Group &
source.GetUInt16() == DicomTag.Item.Element &
(length = source.GetUInt32()) < uint.MaxValue) // Dummy condition to ensure that length is included in parsing
{
// Length non-zero, end skipping (#223)
if (length > 0)
{
break;
}
// Handle scenario where last tag is private sequence with empty items (#487)
count -= 8;
if (count <= 0)
{
return(false);
}
}
source.GetUInt16(); // group
source.GetUInt16(); // element
var bytes = source.GetBytes(2);
var vr = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
DicomVR dummy;
if (DicomVR.TryParse(vr, out dummy))
{
return(!isExplicitVR);
}
// unable to parse VR
if (isExplicitVR)
{
return(true);
}
}
finally
{
source.Rewind();
}
return(false);
}
private bool ParseFragmentSequenceTag(IByteSource source)
{
if (_parseStage == ParseStage.Tag)
{
source.Mark();
if (!source.Require(8))
{
_result = DicomReaderResult.Suspended;
return(false);
}
var group = source.GetUInt16();
var element = source.GetUInt16();
var tag = new DicomTag(@group, element);
if (tag != DicomTag.Item && tag != DicomTag.SequenceDelimitationItem)
{
throw new DicomReaderException($"Unexpected tag in DICOM fragment sequence: {tag}");
}
_length = source.GetUInt32();
if (tag == DicomTag.SequenceDelimitationItem)
{
// end of fragment
_observer.OnEndFragmentSequence();
_fragmentItem = 0;
ResetState();
return(false);
}
_fragmentItem++;
_parseStage = ParseStage.Value;
}
return(true);
}
private void ParseFragmentSequence(IByteSource source, object state)
{
try {
_result = DicomReaderResult.Processing;
while (!source.IsEOF)
{
if (_state == ParseState.Tag)
{
source.Mark();
if (!source.Require(8, ParseFragmentSequence, state))
{
_result = DicomReaderResult.Suspended;
return;
}
ushort group = source.GetUInt16();
ushort element = source.GetUInt16();
DicomTag tag = new DicomTag(group, element);
if (tag != DicomTag.Item && tag != DicomTag.SequenceDelimitationItem)
{
throw new DicomReaderException("Unexpected tag in DICOM fragment sequence: {0}", tag);
}
_length = source.GetUInt32();
if (tag == DicomTag.SequenceDelimitationItem)
{
// end of fragment
_observer.OnEndFragmentSequence();
_fragmentItem = 0;
ResetState();
ParseDataset(source, PopState());
return;
}
_fragmentItem++;
_state = ParseState.Value;
}
if (_state == ParseState.Value)
{
if (!source.Require(_length, ParseFragmentSequence, state))
{
_result = DicomReaderResult.Suspended;
return;
}
IByteBuffer buffer = source.GetBuffer(_length);
if (_fragmentItem == 1)
{
buffer = EndianByteBuffer.Create(buffer, source.Endian, 4);
}
else
{
buffer = EndianByteBuffer.Create(buffer, source.Endian, _vr.UnitSize);
}
_observer.OnFragmentSequenceItem(source, buffer);
_state = ParseState.Tag;
}
}
} 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() && _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 ParseItemSequence(IByteSource source, object state)
{
try {
_result = DicomReaderResult.Processing;
while (!source.IsEOF && !source.HasReachedMilestone())
{
if (_state == ParseState.Tag)
{
source.Mark();
if (!source.Require(8, ParseItemSequence, state))
{
_result = DicomReaderResult.Suspended;
return;
}
ushort group = source.GetUInt16();
ushort element = source.GetUInt16();
_tag = new DicomTag(group, element);
if (_tag != DicomTag.Item && _tag != DicomTag.SequenceDelimitationItem)
{
// assume invalid sequence
source.Rewind();
if (!_implicit)
{
source.PopMilestone();
}
_observer.OnEndSequence();
if (_badPrivateSequence)
{
_explicit = !_explicit;
_badPrivateSequence = false;
}
return;
}
_length = source.GetUInt32();
if (_tag == DicomTag.SequenceDelimitationItem)
{
// end of sequence
_observer.OnEndSequence();
if (_badPrivateSequence)
{
_explicit = !_explicit;
_badPrivateSequence = false;
}
ResetState();
return;
}
_state = ParseState.Value;
}
if (_state == ParseState.Value)
{
if (_length != UndefinedLength)
{
if (!source.Require(_length, ParseItemSequence, state))
{
_result = DicomReaderResult.Suspended;
return;
}
source.PushMilestone(_length);
}
_observer.OnBeginSequenceItem(source, _length);
ResetState();
ParseDataset(source, state);
ResetState();
_observer.OnEndSequenceItem();
continue;
}
}
// end of explicit length sequence
if (source.HasReachedMilestone())
{
source.PopMilestone();
}
_observer.OnEndSequence();
if (_badPrivateSequence)
{
_explicit = !_explicit;
_badPrivateSequence = false;
}
} catch (Exception e) {
_exception = e;
_result = DicomReaderResult.Error;
} finally {
if (_result != DicomReaderResult.Processing && _result != DicomReaderResult.Suspended)
{
_async.Set();
}
}
}
private static bool IsPrivateSequenceBad(IByteSource source, bool isExplicitVR)
{
source.Mark();
try
{
// Skip "item" tags; continue skipping until length is non-zero (#223)
while (new DicomTag(source.GetUInt16(), source.GetUInt16()) == DicomTag.Item // group, element
& source.GetUInt32() == 0) // length (using & instead of && enforces RHS to be evaluated regardless of LHS)
{
}
source.GetUInt16(); // group
source.GetUInt16(); // element
var bytes = source.GetBytes(2);
var vr = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
DicomVR dummy;
if (DicomVR.TryParse(vr, out dummy)) return !isExplicitVR;
// unable to parse VR
if (isExplicitVR) return true;
}
finally
{
source.Rewind();
}
return false;
}
private void ParseFragmentSequence(IByteSource source, object state) {
try {
_result = DicomReaderResult.Processing;
while (!source.IsEOF) {
if (_state == ParseState.Tag) {
source.Mark();
if (!source.Require(8, ParseFragmentSequence, state)) {
_result = DicomReaderResult.Suspended;
return;
}
ushort group = source.GetUInt16();
ushort element = source.GetUInt16();
DicomTag tag = new DicomTag(group, element);
if (tag != DicomTag.Item && tag != DicomTag.SequenceDelimitationItem)
throw new DicomReaderException("Unexpected tag in DICOM fragment sequence: {0}", tag);
_length = source.GetUInt32();
if (tag == DicomTag.SequenceDelimitationItem) {
// end of fragment
_observer.OnEndFragmentSequence();
_fragmentItem = 0;
ResetState();
ParseDataset(source, PopState());
return;
}
_fragmentItem++;
_state = ParseState.Value;
}
if (_state == ParseState.Value) {
if (!source.Require(_length, ParseFragmentSequence, state)) {
_result = DicomReaderResult.Suspended;
return;
}
IByteBuffer buffer = source.GetBuffer(_length);
if (_fragmentItem == 1)
buffer = EndianByteBuffer.Create(buffer, source.Endian, 4);
else
buffer = EndianByteBuffer.Create(buffer, source.Endian, _vr.UnitSize);
_observer.OnFragmentSequenceItem(source, buffer);
_state = ParseState.Tag;
}
}
} 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() && _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);
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);
try {
_vr = DicomVR.Parse(vr);
} catch {
// unable to parse VR
_vr = DicomVR.UN;
}
} else {
DicomDictionaryEntry entry = Dictionary[_tag];
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
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);
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);
// 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 ParseItemSequence(IByteSource source, object state) {
try {
_result = DicomReaderResult.Processing;
while (!source.IsEOF && !source.HasReachedMilestone()) {
if (_state == ParseState.Tag) {
source.Mark();
if (!source.Require(8, ParseItemSequence, state)) {
_result = DicomReaderResult.Suspended;
return;
}
ushort group = source.GetUInt16();
ushort element = source.GetUInt16();
_tag = new DicomTag(group, element);
if (_tag != DicomTag.Item && _tag != DicomTag.SequenceDelimitationItem) {
// assume invalid sequence
source.Rewind();
if (!_implicit)
source.PopMilestone();
_observer.OnEndSequence();
if (_badPrivateSequence) {
_explicit = !_explicit;
_badPrivateSequence = false;
}
return;
}
_length = source.GetUInt32();
if (_tag == DicomTag.SequenceDelimitationItem) {
// end of sequence
_observer.OnEndSequence();
if (_badPrivateSequence) {
_explicit = !_explicit;
_badPrivateSequence = false;
}
ResetState();
return;
}
_state = ParseState.Value;
}
if (_state == ParseState.Value) {
if (_length != UndefinedLength) {
if (!source.Require(_length, ParseItemSequence, state)) {
_result = DicomReaderResult.Suspended;
return;
}
source.PushMilestone(_length);
}
_observer.OnBeginSequenceItem(source, _length);
ResetState();
ParseDataset(source, state);
ResetState();
_observer.OnEndSequenceItem();
continue;
}
}
// end of explicit length sequence
if (source.HasReachedMilestone())
source.PopMilestone();
_observer.OnEndSequence();
if (_badPrivateSequence) {
_explicit = !_explicit;
_badPrivateSequence = false;
}
} catch (Exception e) {
_exception = e;
_result = DicomReaderResult.Error;
} finally {
if (_result != DicomReaderResult.Processing && _result != DicomReaderResult.Suspended) {
_async.Set();
}
}
}
private bool IsPrivateSequenceBad(IByteSource source) {
source.Mark();
try {
var group = source.GetUInt16();
var element = source.GetUInt16();
var tag = new DicomTag(group, element);
var length = source.GetUInt32();
group = source.GetUInt16();
element = source.GetUInt16();
tag = new DicomTag(group, element);
byte[] bytes = source.GetBytes(2);
string vr = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
try {
DicomVR.Parse(vr);
return !_explicit;
} catch {
// unable to parse VR
if (_explicit)
return true;
}
} finally {
source.Rewind();
}
return false;
}
private bool ParseLength(IByteSource source)
{
while (_parseStage == ParseStage.Length)
{
if (_tag == DicomTag.Item || _tag == DicomTag.ItemDelimitationItem ||
_tag == DicomTag.SequenceDelimitationItem)
{
if (!source.Require(4))
{
_result = DicomReaderResult.Suspended;
return(false);
}
_length = source.GetUInt32();
_parseStage = ParseStage.Value;
break;
}
if (_isExplicitVR || _badPrivateSequence)
{
if (_vr == DicomVR.Implicit)
{
if (!source.Require(4))
{
_result = DicomReaderResult.Suspended;
return(false);
}
_length = source.GetUInt32();
// assume that undefined length in implicit VR element is SQ
if (_length == _undefinedLength)
{
_vr = DicomVR.SQ;
}
}
else if (_vr.Is16bitLength)
{
if (!source.Require(2))
{
_result = DicomReaderResult.Suspended;
return(false);
}
_length = source.GetUInt16();
}
else
{
if (!source.Require(6))
{
_result = DicomReaderResult.Suspended;
return(false);
}
source.Skip(2);
_length = source.GetUInt32();
// CP-246 (#177) handling
// assume that Undefined Length in explicit datasets with VR UN are sequences
// According to CP-246 the sequence shall be handled as ILE, but this will be handled later...
// in the current code this needs to be restricted to privates
if (_length == _undefinedLength && _vr == DicomVR.UN && _tag.IsPrivate)
{
_vr = DicomVR.SQ;
}
}
}
else
{
if (!source.Require(4))
{
_result = DicomReaderResult.Suspended;
return(false);
}
_length = source.GetUInt32();
// assume that undefined length in implicit dataset is SQ
if (_length == _undefinedLength && _vr == DicomVR.UN)
{
_vr = DicomVR.SQ;
}
}
_parseStage = ParseStage.Value;
}
return(true);
}
private bool ParseItemSequenceTag(IByteSource source)
{
if (_parseStage == ParseStage.Tag)
{
source.Mark();
if (!source.Require(8))
{
_result = DicomReaderResult.Suspended;
return(false);
}
var group = source.GetUInt16();
var element = source.GetUInt16();
_tag = new DicomTag(@group, element);
if (_tag != DicomTag.Item && _tag != DicomTag.SequenceDelimitationItem)
{
// assume invalid sequence
source.Rewind();
if (!_implicit)
{
source.PopMilestone();
}
_observer.OnEndSequence();
// #565 Only reset the badPrivate sequence if we're in the correct depth
// This prevents prematurely resetting in case of sub-sequences contained in the bad private sequence
if (_badPrivateSequence && _sequenceDepth == _badPrivateSequenceDepth)
{
_isExplicitVR = !_isExplicitVR;
_badPrivateSequence = false;
}
return(false);
}
_length = source.GetUInt32();
if (_tag == DicomTag.SequenceDelimitationItem)
{
// #64, in case explicit length has been specified despite occurrence of Sequence Delimitation Item
if (source.HasReachedMilestone() && source.MilestonesCount > _sequenceDepth)
{
ResetState();
return(true);
}
// end of sequence
_observer.OnEndSequence();
// #565 Only reset the badPrivate sequence if we're in the correct depth
// This prevents prematurely resetting in case of sub-sequences contained in the bad private sequence
if (_badPrivateSequence && _sequenceDepth == _badPrivateSequenceDepth)
{
_isExplicitVR = !_isExplicitVR;
_badPrivateSequence = false;
}
ResetState();
return(false);
}
_parseStage = ParseStage.Value;
}
return(true);
}
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();
}
}
}
private bool ParseFragmentSequenceTag(IByteSource source)
{
if (this.parseStage == ParseStage.Tag)
{
source.Mark();
if (!source.Require(8))
{
this.result = DicomReaderResult.Suspended;
return false;
}
var group = source.GetUInt16();
var element = source.GetUInt16();
DicomTag tag = new DicomTag(@group, element);
if (tag != DicomTag.Item && tag != DicomTag.SequenceDelimitationItem)
{
throw new DicomReaderException("Unexpected tag in DICOM fragment sequence: {0}", tag);
}
this.length = source.GetUInt32();
if (tag == DicomTag.SequenceDelimitationItem)
{
// end of fragment
this.observer.OnEndFragmentSequence();
this.fragmentItem = 0;
this.ResetState();
return false;
}
this.fragmentItem++;
this.parseStage = ParseStage.Value;
}
return true;
}
private bool ParseItemSequenceTag(IByteSource source)
{
if (this.parseStage == ParseStage.Tag)
{
source.Mark();
if (!source.Require(8))
{
this.result = DicomReaderResult.Suspended;
return false;
}
var group = source.GetUInt16();
var element = source.GetUInt16();
this._tag = new DicomTag(@group, element);
if (this._tag != DicomTag.Item && this._tag != DicomTag.SequenceDelimitationItem)
{
// assume invalid sequence
source.Rewind();
if (!this._implicit)
{
source.PopMilestone();
}
this.observer.OnEndSequence();
if (this.badPrivateSequence)
{
this.isExplicitVR = !this.isExplicitVR;
this.badPrivateSequence = false;
}
return false;
}
this.length = source.GetUInt32();
if (this._tag == DicomTag.SequenceDelimitationItem)
{
// #64, in case explicit length has been specified despite occurrence of Sequence Delimitation Item
if (source.HasReachedMilestone() && source.MilestonesCount > this.sequenceDepth)
{
this.ResetState();
return true;
}
// end of sequence
this.observer.OnEndSequence();
if (this.badPrivateSequence)
{
this.isExplicitVR = !this.isExplicitVR;
this.badPrivateSequence = false;
}
this.ResetState();
return false;
}
this.parseStage = ParseStage.Value;
}
return true;
}
private bool ParseLength(IByteSource source)
{
while (this.parseStage == ParseStage.Length)
{
if (this._tag == DicomTag.Item || this._tag == DicomTag.ItemDelimitationItem
|| this._tag == DicomTag.SequenceDelimitationItem)
{
if (!source.Require(4))
{
this.result = DicomReaderResult.Suspended;
return false;
}
this.length = source.GetUInt32();
this.parseStage = ParseStage.Value;
break;
}
if (this.isExplicitVR)
{
if (this._vr == DicomVR.Implicit)
{
if (!source.Require(4))
{
this.result = DicomReaderResult.Suspended;
return false;
}
this.length = source.GetUInt32();
// assume that undefined length in implicit VR element is SQ
if (this.length == UndefinedLength)
{
this._vr = DicomVR.SQ;
}
}
else if (this._vr.Is16bitLength)
{
if (!source.Require(2))
{
this.result = DicomReaderResult.Suspended;
return false;
}
this.length = source.GetUInt16();
}
else
{
if (!source.Require(6))
{
this.result = DicomReaderResult.Suspended;
return false;
}
source.Skip(2);
this.length = source.GetUInt32();
// CP-246 (#177) handling
// assume that Undefined Length in explicit datasets with VR UN are sequences
// According to CP-246 the sequence shall be handled as ILE, but this will be handled later...
// in the current code this needs to be restricted to privates
if (this.length == UndefinedLength && this._vr == DicomVR.UN && this._tag.IsPrivate)
{
this._vr = DicomVR.SQ;
}
}
}
else
{
if (!source.Require(4))
{
this.result = DicomReaderResult.Suspended;
return false;
}
this.length = source.GetUInt32();
// assume that undefined length in implicit dataset is SQ
if (this.length == UndefinedLength && this._vr == DicomVR.UN)
{
this._vr = DicomVR.SQ;
}
}
this.parseStage = ParseStage.Value;
}
return true;
}
private static bool IsPrivateSequenceBad(IByteSource source, bool isExplicitVR)
{
source.Mark();
try
{
source.GetUInt16(); // group
source.GetUInt16(); // element
source.GetUInt32(); // length
source.GetUInt16(); // group
source.GetUInt16(); // element
var bytes = source.GetBytes(2);
var vr = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
DicomVR dummy;
if (DicomVR.TryParse(vr, out dummy)) return !isExplicitVR;
// unable to parse VR
if (isExplicitVR) return true;
}
finally
{
source.Rewind();
}
return false;
}