internal bool ParseStream(Stream stream, TransferSyntax transferSyntax, bool allowSyntaxChanges, bool loadImageData, ILogger logger)
{
SwappableBinaryReader sr = new SwappableBinaryReader(stream);
long readPosition = stream.Position;
bool inGroup2 = false;
if (transferSyntax.MSBSwap) //this should be applicable...
{
sr.ToggleSwapped();
}
TransferSyntax parsedSyntax = null;
while (readPosition + 8 < stream.Length)
{
//Read in group/element info
ushort group = sr.ReadUInt16();
ushort elem = sr.ReadUInt16();
//Leaving the header?
if (inGroup2 != (group == 2))
{
if (transferSyntax.MSBSwap)
{
sr.ToggleSwapped();
}
inGroup2 = (group == 2);
}
//Stop loading if we're at image data and not supposed to read it
var skipData = !loadImageData && group == 0x7FE0 && elem == 0x0010;
//Make element
uint outLen;
DICOMElement nelem;
try
{
nelem = DICOMElement.Parse(group, elem, logger, transferSyntax, sr, null, skipData, out outLen);
}
catch (Exception e)
{
logger.Log(LogLevel.Error, "Exception in DICOMElement.Parse: " + e.ToString());
return(false);
}
//Debugging:
//Console.WriteLine(nelem.Dump());
//Store reading position in case it's useful later
nelem.ReadPosition = readPosition;
//Store element in lookup array
Elements[nelem.Tag] = nelem;
//Store transfer syntax change for after the header
if (nelem.Tag == DICOMTags.TransferSyntaxUID)
{
parsedSyntax = TransferSyntaxes.Lookup((string)nelem.Data);
if (allowSyntaxChanges)
{
transferSyntax = parsedSyntax;
}
}
//update read position pointer
readPosition = stream.Position;
}
//Store whatever TS we ended up with
TransferSyntax = (parsedSyntax != null) ? parsedSyntax : transferSyntax;
return(true);
}
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);
}