/// <summary>Tries to read the DICOM file header from a stream</summary>
public static bool TryReadHeader(BufferedStreamReader input, out DicomFileMetaInformation fileMetaInformation)
{
fileMetaInformation = null;
Span <byte> header = stackalloc byte[128 + BeforeFileMetaInformationLength.Length + 4 + AfterFileMetaInformationLength.Length];
if (!TryReadAll(input, header))
{
return(false);
}
var before = header.Slice(128, BeforeFileMetaInformationLength.Length);
var after = header.Slice(128 + BeforeFileMetaInformationLength.Length + 4, AfterFileMetaInformationLength.Length);
if (!before.SequenceEqual(BeforeFileMetaInformationLength) || !after.SequenceEqual(AfterFileMetaInformationLength))
{
return(false);
}
var metaInformationLength = BitConverter.ToUInt32(header.Slice(128 + BeforeFileMetaInformationLength.Length, 4));
DicomFileMetaInformation tmp = null;
input.Read((int)metaInformationLength - AfterFileMetaInformationLength.Length, () =>
{
var metaInformationReader = DicomStreamReader.Create(input, DicomUID.TransferSyntax.ExplicitVRLittleEndian);
tmp = FileMetaInformationSerializer.Deserialize(metaInformationReader);
});
fileMetaInformation = tmp;
return(true);
}
/// <summary>Writes a DICOM file header to a stream</summary>
public static void WriteHeader(BufferedStreamWriter output, DicomFileMetaInformation fileMetaInformation)
{
output.WriteZeros(128);
output.WriteBytes(BeforeFileMetaInformationLength);
var fileMetaInformationLengthPosition = output.Position;
output.WriteZeros(4);
output.WriteBytes(AfterFileMetaInformationLength);
var metaInformationWriter = DicomStreamWriter.Create(output, DicomUID.TransferSyntax.ExplicitVRLittleEndian);
FileMetaInformationSerializer.Serialize(metaInformationWriter, fileMetaInformation);
var endOfFileMetaInformationPosition = output.Position;
output.Flush(FlushMode.Shallow);
var fileMetaInformationLength = endOfFileMetaInformationPosition - (fileMetaInformationLengthPosition + 4);
output.Stream.Seek(fileMetaInformationLengthPosition, SeekOrigin.Begin);
output.Stream.Write(BitConverter.GetBytes((uint)fileMetaInformationLength));
output.Stream.Seek(endOfFileMetaInformationPosition, SeekOrigin.Begin);
}
