/// <summary>
/// Handler for traversing a DICOM element.
/// </summary>
/// <param name="element">Element to traverse.</param>
/// <returns>true if traversing completed without issues, false otherwise.</returns>
/// <remarks>On false return value, the method will invoke the callback method passed in <see cref="IDicomDatasetWalker.OnBeginWalk"/> before returning.</remarks>
public bool OnElement(DicomElement element)
{
WriteTagHeader(element.Tag, element.ValueRepresentation, element.Length);
IByteBuffer buffer = element.Buffer;
if (buffer is EndianByteBuffer)
{
EndianByteBuffer ebb = buffer as EndianByteBuffer;
if (ebb.Endian != Endian.LocalMachine && ebb.Endian == _target.Endian) buffer = ebb.Internal;
}
else if (_target.Endian != Endian.LocalMachine)
{
if (element.ValueRepresentation.UnitSize > 1) buffer = new SwapByteBuffer(buffer, element.ValueRepresentation.UnitSize);
}
_target.Write(buffer.Data, 0, buffer.Size);
return true;
}
public override IByteBuffer GetFrame(int frame)
{
if (frame < 0 || frame >= NumberOfFrames) throw new IndexOutOfRangeException("Requested frame out of range!");
IByteBuffer buffer = null;
if (NumberOfFrames == 1)
{
if (Element.Fragments.Count == 1) buffer = Element.Fragments[0];
else buffer = new CompositeByteBuffer(Element.Fragments.ToArray());
}
else if (Element.Fragments.Count == NumberOfFrames) buffer = Element.Fragments[frame];
else if (Element.OffsetTable.Count == NumberOfFrames)
{
uint start = Element.OffsetTable[frame];
uint stop = (Element.OffsetTable.Count == (frame + 1))
? uint.MaxValue
: Element.OffsetTable[frame + 1];
var composite = new CompositeByteBuffer();
uint pos = 0;
int frag = 0;
while (pos < start && frag < Element.Fragments.Count)
{
pos += 8;
pos += Element.Fragments[frag].Size;
frag++;
}
if (pos != start) throw new DicomImagingException("Fragment start position does not match offset table.");
while (pos < stop && frag < Element.Fragments.Count)
{
composite.Buffers.Add(Element.Fragments[frag]);
pos += 8;
pos += Element.Fragments[frag].Size;
frag++;
}
if (pos < stop && stop != uint.MaxValue)
throw new DicomImagingException(
"Image frame truncated while reading fragments from offset table.");
buffer = composite;
}
else
throw new DicomImagingException(
"Support for multi-frame images with varying fragment sizes and no offset table has not been implemented.");
// mainly for GE Private Implicit VR Little Endian
if (!Syntax.IsEncapsulated && BitsAllocated == 16 && Syntax.SwapPixelData) buffer = new SwapByteBuffer(buffer, 2);
return EndianByteBuffer.Create(buffer, Syntax.Endian, BytesAllocated);
}
public override void AddFrame(IByteBuffer data)
{
if (!(Element.Buffer is CompositeByteBuffer)) throw new DicomImagingException("Expected pixel data element to have a CompositeByteBuffer.");
CompositeByteBuffer buffer = Element.Buffer as CompositeByteBuffer;
if (Syntax.SwapPixelData) data = new SwapByteBuffer(data, 2);
buffer.Buffers.Add(data);
NumberOfFrames++;
}
public override IByteBuffer GetFrame(int frame)
{
if (frame < 0 || frame >= NumberOfFrames) throw new IndexOutOfRangeException("Requested frame out of range!");
int offset = UncompressedFrameSize * frame;
IByteBuffer buffer = new RangeByteBuffer(Element.Buffer, (uint)offset, (uint)UncompressedFrameSize);
// mainly for GE Private Implicit VR Big Endian
if (Syntax.SwapPixelData) buffer = new SwapByteBuffer(buffer, 2);
return buffer;
}
public override IByteBuffer GetFrame(int frame)
{
int offset = UncompressedFrameSize * frame;
IByteBuffer buffer = new RangeByteBuffer(Element.Buffer, (uint)offset, (uint)UncompressedFrameSize);
//TODO: trace down the need for this additional byte swap
if (Syntax.Endian == Endian.Big && !Syntax.SwapPixelData)
buffer = new SwapByteBuffer(buffer, 2);
// mainly for GE Private Implicit VR Little Endian
if (Syntax.SwapPixelData)
buffer = new SwapByteBuffer(buffer, 2);
return buffer;
}
/// <summary>
/// Asynchronous handler for traversing a DICOM element.
/// </summary>
/// <param name="element">Element to traverse.</param>
/// <returns>true if traversing completed without issues, false otherwise.</returns>
public async Task<bool> OnElementAsync(DicomElement element)
{
WriteTagHeader(element.Tag, element.ValueRepresentation, element.Length);
IByteBuffer buffer = element.Buffer;
if (buffer is EndianByteBuffer)
{
EndianByteBuffer ebb = buffer as EndianByteBuffer;
if (ebb.Endian != Endian.LocalMachine && ebb.Endian == _target.Endian) buffer = ebb.Internal;
}
else if (_target.Endian != Endian.LocalMachine)
{
if (element.ValueRepresentation.UnitSize > 1) buffer = new SwapByteBuffer(buffer, element.ValueRepresentation.UnitSize);
}
if (element.Length < this._options.LargeObjectSize)
{
_target.Write(buffer.Data, 0, buffer.Size);
}
else
{
await _target.WriteAsync(buffer.Data, 0, buffer.Size).ConfigureAwait(false);
}
return true;
}
public override IByteBuffer GetFrame(int frame)
{
if (frame < 0 || frame >= NumberOfFrames)
throw new IndexOutOfRangeException("Requested frame out of range!");
int offset = UncompressedFrameSize * frame;
IByteBuffer buffer = new RangeByteBuffer(Element.Buffer, (uint)offset, (uint)UncompressedFrameSize);
//TODO: trace down the need for this additional byte swap
if (Syntax.Endian == Endian.Big && !Syntax.SwapPixelData)
buffer = new SwapByteBuffer(buffer, 2);
// mainly for GE Private Implicit VR Little Endian
if (Syntax.SwapPixelData)
buffer = new SwapByteBuffer(buffer, 2);
return buffer;
}
