internal override uint ParseData(SwappableBinaryReader br, ILogger logger, uint length, TransferSyntax transferSyntax)
{
//Covered by PS 3.5, Chapter 7.5 (pg. 42-45)
bool encapImage = (Tag == DICOMTags.PixelData);
bool done = false;
uint count = 0;
while (!done)
{
//If explicit length, see if we're done
if (length != 0xFFFFFFFF && count >= length)
{
done = true;
continue;
}
ushort grp = br.ReadUInt16();
ushort elem = br.ReadUInt16();
uint len = br.ReadUInt32();
count += 8;
//Sometimes there's retarded files that are msb swapped inside of sequences outside of the transfer syntax
bool needMoreSwap = (grp == 0xFEFF);
if (needMoreSwap)
{
//Swap the reader for now, then swap back after the sqitem
br.ToggleSwapped();
//still have to swap the stuff we've already read by hand tho
grp = MSBSwapper.SwapW(grp);
elem = MSBSwapper.SwapW(elem);
len = MSBSwapper.SwapDW(len);
}
if (grp == 0xFFFE && elem == 0xE000)
{
//Normal element, parse it out.
SQItem item = new SQItem(this);
count += item.ParseStream(br, logger, transferSyntax, len, encapImage);
Items.Add(item);
}
else if (grp == 0xFFFE && elem == 0xE0DD)
{
//End element
//In case there's garbage in there, read the length bytes
br.ReadBytes((int)len);
count += len;
done = true;
}
else
{
throw new NotImplementedException();
}
//toggle back in case it's just one SQItem that's hosed
if (needMoreSwap)
{
br.ToggleSwapped();
}
}
return(count);
}
//parseLen returns total bytes read
internal static DICOMElement Parse(ushort group, ushort elem, ILogger logger, TransferSyntax transferSyntax, SwappableBinaryReader br, SQItem parentSQ, bool skipOverData, out uint parseLen)
{
ushort vr;
uint len;
uint headerBytes = 0;
// Group 0 is always little-endian implicit vr, group 2 is always little-endian explicit vr
if ((transferSyntax.ExplicitVR && group != 0) || group == 2)
{
vr = br.ReadUInt16MSB();
headerBytes += 2;
if (vr == DICOMElementUT.vrshort || vr == DICOMElementUN.vrshort || vr == DICOMElementOB.vrshort ||
vr == DICOMElementOW.vrshort || vr == DICOMElementSQ.vrshort)
{
//next 2 bytes reserved
br.ReadUInt16();
headerBytes += 2;
//len is next 4
len = br.ReadUInt32();
headerBytes += 4;
}
else
{
//len is next 2
len = br.ReadUInt16();
headerBytes += 2;
}
}
else
{
//Look up VR in the dictionary
DataDictionaryElement dde = DataDictionary.LookupElement(group, elem);
if (dde != null)
{
//Found it.
vr = dde.vrshort;
}
else
{
//No idea... OB!
vr = DICOMElementOB.vrshort;
}
//Length will always be 32-bit here
len = br.ReadUInt32();
headerBytes += 4;
}
DICOMElement ret = null;
//Is it a compressed weirdo image data sequence that's actually an SQ?
if (len == 0xFFFFFFFF)
{
ret = new DICOMElementSQ(group, elem);
}
else
{
ret = CreateByVR(group, elem, vr);
}
ret.parentSQItem = parentSQ;
//Parse internal Data
parseLen = headerBytes;
try
{
// Can't skip over the length if it's not explicit
if (skipOverData && len != 0xFFFFFFFF)
{
parseLen += len;
br.BaseStream.Seek(len, SeekOrigin.Current);
}
else
{
parseLen += ret.ParseData(br, logger, len, transferSyntax);
}
}
catch (Exception e)
{
logger.Log(LogLevel.Error, "Exception in ParseData(grp=" + group + ", elem=" + elem + ", len=" + len + "): " + e.ToString());
}
return(ret);
}
