/// <summary>
/// Calculate the length to write the attribute.
/// </summary>
/// <param name="syntax">The transfer syntax to calculate the length for.</param>
/// <param name="options">The write options to calculate the length for.</param>
/// <returns></returns>
internal virtual uint CalculateWriteLength(TransferSyntax syntax, DicomWriteOptions options)
{
uint length = 4; // element tag
if (syntax.ExplicitVr)
{
length += 2; // vr
if (Tag.VR.Is16BitLengthField)
length += 2;
else
length += 6;
}
else
{
length += 4; // length tag
}
length += StreamLength;
if ((length & 0x00000001) != 0)
length++;
return length;
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="message"></param>
protected DicomPixelData(DicomMessageBase message)
: this(message.DataSet)
{
_transferSyntax = message.TransferSyntax;
}
internal override uint CalculateWriteLength(TransferSyntax syntax, DicomWriteOptions options)
{
uint length = 0;
length += 4; // element tag
if (syntax.ExplicitVr)
{
length += 2; // vr
length += 6; // length
}
else
{
length += 4; // length
}
if (_values != null)
{
foreach (DicomSequenceItem item in _values)
{
length += 4 + 4; // Sequence Item Tag
length += item.CalculateWriteLength(syntax, options & ~DicomWriteOptions.CalculateGroupLengths);
if (!Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequenceItem))
length += 4 + 4; // Sequence Item Delimitation Item
}
if (!Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequence))
length += 4 + 4; // Sequence Delimitation Item
}
return length;
}
internal override ByteBuffer GetByteBuffer(TransferSyntax syntax, String specificCharacterSet)
{
throw new DicomException("Unexpected call to GetByteBuffer() for a SQ attribute");
}
internal override ByteBuffer GetByteBuffer(TransferSyntax syntax, String specificCharacterSet)
{
ByteBuffer bb = new ByteBuffer(syntax.Endian);
if (Tag.VR.SpecificCharacterSet)
bb.SpecificCharacterSet = specificCharacterSet;
//if (_value == null)
//{
// return bb; // return empty buffer if the value is not set
//}
bb.SetString(_value, (byte)' ');
return bb;
}
/// <summary>
/// Get the string representation of the value
/// when the attribute is saved using the specific character set and transfer syntax
/// and read again using one of the GetString methods
/// </summary>
/// <param name="syntax"></param>
/// <param name="specificCharacterSet"></param>
/// <returns></returns>
public virtual string GetEncodedString(TransferSyntax syntax, String specificCharacterSet)
{
var buffer = GetByteBuffer(syntax, specificCharacterSet);
if (buffer == null)
return null;
return buffer.GetString();
}
internal abstract ByteBuffer GetByteBuffer(TransferSyntax syntax, String specificCharacterSet);
/// <summary>
/// Creates a new DicomMessage instance from an existing <see cref="DicomFile"/>.
/// </summary>
/// <remarks>
/// This method creates a new command set for the DicomMessage, but shares the DataSet with <paramref name="file"/>.
/// </remarks>
/// <param name="file">The <see cref="DicomFile"/> to change into a DicomMessage.</param>
public DicomMessage(DicomFile file)
{
_transferSyntax = file.TransferSyntax;
MetaInfo = new DicomAttributeCollection(0x00000000,0x0000FFFF);
DataSet = file.DataSet;
}
/// <summary>
/// Finds the next directory record of the specified <paramref name="recordType"/>, starting at the specified <paramref name="startIndex"/>
/// </summary>
/// <param name="recordType">Type of the record.</param>
/// <param name="startIndex">The start index.</param>
/// <returns></returns>
private void CalculateOffsets(TransferSyntax syntax, DicomWriteOptions options)
{
foreach (DicomSequenceItem sq in (DicomSequenceItem[])_dicomDirFile.DataSet[DicomTags.DirectoryRecordSequence].Values)
{
DirectoryRecordSequenceItem record = sq as DirectoryRecordSequenceItem;
if (record == null)
throw new ApplicationException("Unexpected type for directory record: " + sq.GetType());
record.Offset = _fileOffset;
_fileOffset += 4 + 4; // Sequence Item Tag
_fileOffset += record.CalculateWriteLength(syntax, options & ~DicomWriteOptions.CalculateGroupLengths);
if (!Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequenceItem))
_fileOffset += 4 + 4; // Sequence Item Delimitation Item
}
if (!Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequence))
_fileOffset += 4 + 4; // Sequence Delimitation Item
}
internal override ByteBuffer GetByteBuffer(TransferSyntax syntax, string specificCharacterSet)
{
ByteBuffer bb = new ByteBuffer(syntax.Endian);
bb.SetString(ToString(), 0x00);
return bb;
}
internal override ByteBuffer GetByteBuffer(TransferSyntax syntax, string specificCharacterSet)
{
ByteBuffer bb = new ByteBuffer(syntax.Endian);
if (Tag.VR.SpecificCharacterSet)
bb.SpecificCharacterSet = specificCharacterSet;
bb.SetString(ToString(), (byte)' ');
return bb;
}
/// <summary>
/// Unregisters a private transfer syntax.
/// </summary>
/// <param name="transferSyntax">The private transfer syntax to unreigster.</param>
public static void UnregisterTransferSyntax(TransferSyntax transferSyntax)
{
Platform.CheckForNullReference(transferSyntax, "transferSyntax");
_privateTransferSyntaxes.Remove(transferSyntax.UidString);
}
/// <summary>
/// Registers a private transfer syntax.
/// </summary>
/// <param name="transferSyntax">The private transfer syntax to reigster.</param>
public static void RegisterTransferSyntax(TransferSyntax transferSyntax)
{
Platform.CheckForNullReference(transferSyntax, "transferSyntax");
Platform.CheckTrue(!_transferSyntaxes.ContainsKey(transferSyntax.UidString), "Cannot redefine a standard transfer syntax.");
Platform.CheckTrue(!_privateTransferSyntaxes.ContainsKey(transferSyntax.UidString), "The specified private transfer syntax UID is already defined.");
_privateTransferSyntaxes.Add(transferSyntax.UidString, transferSyntax);
}
public void ChangeTransferSyntax(TransferSyntax newTransferSyntax, IDicomCodec inputCodec, DicomCodecParameters inputParameters)
{
IDicomCodec codec = inputCodec;
DicomCodecParameters parameters = inputParameters;
if (newTransferSyntax.Encapsulated && TransferSyntax.Encapsulated)
throw new DicomCodecException("Source and destination transfer syntaxes encapsulated");
if (newTransferSyntax.Encapsulated)
{
if (codec == null)
{
codec = DicomCodecRegistry.GetCodec(newTransferSyntax);
if (codec == null)
{
Platform.Log(LogLevel.Error, "Unable to get registered codec for {0}", newTransferSyntax);
throw new DicomCodecException("No registered codec for: " + newTransferSyntax.Name);
}
}
if (parameters == null)
parameters = DicomCodecRegistry.GetCodecParameters(newTransferSyntax, DataSet);
DicomAttribute pixelData;
if (DataSet.TryGetAttribute(DicomTags.PixelData, out pixelData))
{
if (pixelData.IsNull)
throw new DicomCodecException("Sop pixel data has no valid value and cannot be compressed.");
new OverlayPlaneModuleIod(DataSet).ExtractEmbeddedOverlays();
var pd = new DicomUncompressedPixelData(DataSet);
using (var pixelStream = ((DicomAttributeBinary) pixelData).AsStream())
{
//Before compression, make the pixel data more "typical", so it's harder to mess up the codecs.
//NOTE: Could combine mask and align into one method so we're not iterating twice, but I prefer having the methods separate.
if (DicomUncompressedPixelData.RightAlign(pixelStream, pd.BitsAllocated, pd.BitsStored, pd.HighBit))
{
var newHighBit = (ushort) (pd.HighBit - pd.LowBit);
Platform.Log(LogLevel.Debug, "Right aligned pixel data (High Bit: {0}->{1}).", pd.HighBit, newHighBit);
pd.HighBit = newHighBit; //correct high bit after right-aligning.
DataSet[DicomTags.HighBit].SetUInt16(0, newHighBit);
}
if (DicomUncompressedPixelData.ZeroUnusedBits(pixelStream, pd.BitsAllocated, pd.BitsStored, pd.HighBit))
{
Platform.Log(LogLevel.Debug, "Zeroed some unused bits before compression.");
}
}
// Set transfer syntax before compression, the codecs need it.
var fragments = new DicomCompressedPixelData(pd) { TransferSyntax = newTransferSyntax };
codec.Encode(pd, fragments, parameters);
fragments.UpdateMessage(this);
//TODO: should we validate the number of frames in the compressed data?
if (!DataSet.TryGetAttribute(DicomTags.PixelData, out pixelData) || pixelData.IsNull)
throw new DicomCodecException("Sop has no pixel data after compression.");
}
else
{
//A bit cheap, but check for basic image attributes - if any exist
// and are non-empty, there should probably be pixel data too.
DicomAttribute attribute;
if (DataSet.TryGetAttribute(DicomTags.Rows, out attribute) && !attribute.IsNull)
throw new DicomCodecException("Suspect Sop appears to be an image (Rows is non-empty), but has no pixel data.");
if (DataSet.TryGetAttribute(DicomTags.Columns, out attribute) && !attribute.IsNull)
throw new DicomCodecException("Suspect Sop appears to be an image (Columns is non-empty), but has no pixel data.");
TransferSyntax = newTransferSyntax;
}
}
else
{
if (codec == null)
{
codec = DicomCodecRegistry.GetCodec(TransferSyntax);
if (codec == null)
{
Platform.Log(LogLevel.Error, "Unable to get registered codec for {0}", TransferSyntax);
throw new DicomCodecException("No registered codec for: " + TransferSyntax.Name);
}
if (parameters == null)
parameters = DicomCodecRegistry.GetCodecParameters(TransferSyntax, DataSet);
}
DicomAttribute pixelData;
if (DataSet.TryGetAttribute(DicomTags.PixelData, out pixelData))
{
if (pixelData.IsNull)
throw new DicomCodecException("Sop pixel data has no valid value and cannot be decompressed.");
var fragments = new DicomCompressedPixelData(DataSet);
var pd = new DicomUncompressedPixelData(fragments);
codec.Decode(fragments, pd, parameters);
pd.TransferSyntax = TransferSyntax.ExplicitVrLittleEndian;
TransferSyntax = TransferSyntax.ExplicitVrLittleEndian;
pd.UpdateMessage(this);
//TODO: should we validate the number of frames in the decompressed data?
if (!DataSet.TryGetAttribute(DicomTags.PixelData, out pixelData) || pixelData.IsNull)
throw new DicomCodecException("Sop has no pixel data after decompression.");
}
else
{
//NOTE: doing this for consistency, really.
DicomAttribute attribute;
if (DataSet.TryGetAttribute(DicomTags.Rows, out attribute) && !attribute.IsNull)
throw new DicomCodecException("Suspect Sop appears to be an image (Rows is non-empty), but has no pixel data.");
if (DataSet.TryGetAttribute(DicomTags.Columns, out attribute) && !attribute.IsNull)
throw new DicomCodecException("Suspect Sop appears to be an image (Columns is non-empty), but has no pixel data.");
TransferSyntax = TransferSyntax.ExplicitVrLittleEndian;
}
}
}
public void ChangeTransferSyntax(TransferSyntax newTransferSyntax)
{
ChangeTransferSyntax(newTransferSyntax, null, null);
}
public DicomWriteStatus Write(TransferSyntax syntax, DicomAttributeCollection dataset, DicomWriteOptions options)
{
TransferSyntax = syntax;
foreach (DicomAttribute item in dataset)
{
if (item.Tag.Element == 0x0000)
continue;
if (item.IsEmpty)
continue;
if (Flags.IsSet(options, DicomWriteOptions.CalculateGroupLengths)
&& item.Tag.Group != _group && item.Tag.Group <= 0x7fe0)
{
_group = item.Tag.Group;
_writer.Write((ushort)_group);
_writer.Write((ushort)0x0000);
if (_syntax.ExplicitVr)
{
_writer.Write((byte)'U');
_writer.Write((byte)'L');
_writer.Write((ushort)4);
}
else
{
_writer.Write((uint)4);
}
_writer.Write((uint)dataset.CalculateGroupWriteLength(_group, _syntax, options));
}
_writer.Write((ushort)item.Tag.Group);
_writer.Write((ushort)item.Tag.Element);
if (_syntax.ExplicitVr)
{
_writer.Write((byte)item.Tag.VR.Name[0]);
_writer.Write((byte)item.Tag.VR.Name[1]);
}
if (item is DicomAttributeSQ)
{
DicomAttributeSQ sq = item as DicomAttributeSQ;
if (_syntax.ExplicitVr)
_writer.Write((ushort)0x0000);
if (Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequence))
{
int hl = _syntax.ExplicitVr ? 12 : 8;
_writer.Write((uint)sq.CalculateWriteLength(_syntax, options & ~DicomWriteOptions.CalculateGroupLengths) - (uint)hl);
}
else
{
_writer.Write((uint)UndefinedLength);
}
foreach (DicomSequenceItem ids in item.Values as DicomSequenceItem[])
{
_writer.Write((ushort)DicomTag.Item.Group);
_writer.Write((ushort)DicomTag.Item.Element);
if (Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequenceItem))
{
_writer.Write((uint)ids.CalculateWriteLength(_syntax, options & ~DicomWriteOptions.CalculateGroupLengths));
}
else
{
_writer.Write((uint)UndefinedLength);
}
Write(this.TransferSyntax, ids, options & ~DicomWriteOptions.CalculateGroupLengths);
if (!Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequenceItem))
{
_writer.Write((ushort)DicomTag.ItemDelimitationItem.Group);
_writer.Write((ushort)DicomTag.ItemDelimitationItem.Element);
_writer.Write((uint)0x00000000);
}
}
if (!Flags.IsSet(options, DicomWriteOptions.ExplicitLengthSequence))
{
_writer.Write((ushort)DicomTag.SequenceDelimitationItem.Group);
_writer.Write((ushort)DicomTag.SequenceDelimitationItem.Element);
_writer.Write((uint)0x00000000);
}
}
else if (item is DicomFragmentSequence)
{
DicomFragmentSequence fs = item as DicomFragmentSequence;
if (_syntax.ExplicitVr)
_writer.Write((ushort)0x0000);
_writer.Write((uint)UndefinedLength);
_writer.Write((ushort)DicomTag.Item.Group);
_writer.Write((ushort)DicomTag.Item.Element);
if (Flags.IsSet(options, DicomWriteOptions.WriteFragmentOffsetTable) && fs.HasOffsetTable)
{
_writer.Write((uint)fs.OffsetTableBuffer.Length);
fs.OffsetTableBuffer.CopyTo(_writer);
}
else
{
_writer.Write((uint)0x00000000);
}
foreach (DicomFragment bb in fs.Fragments)
{
_writer.Write((ushort)DicomTag.Item.Group);
_writer.Write((ushort)DicomTag.Item.Element);
_writer.Write((uint)bb.Length);
bb.GetByteBuffer(_syntax).CopyTo(_writer);
}
_writer.Write((ushort)DicomTag.SequenceDelimitationItem.Group);
_writer.Write((ushort)DicomTag.SequenceDelimitationItem.Element);
_writer.Write((uint)0x00000000);
}
else
{
DicomAttribute de = item;
ByteBuffer theData = de.GetByteBuffer(_syntax, dataset.SpecificCharacterSet);
if (_syntax.ExplicitVr)
{
if (de.Tag.VR.Is16BitLengthField)
{
_writer.Write((ushort)theData.Length);
}
else
{
_writer.Write((ushort)0x0000);
_writer.Write((uint)theData.Length);
}
}
else
{
_writer.Write((uint)theData.Length);
}
if (theData.Length > 0)
theData.CopyTo(_writer);
}
}
return DicomWriteStatus.Success;
}
