def __init__(self,
filename_or_obj,
dataset,
preamble=None,
file_meta=None,
is_implicit_VR=True,
is_little_endian=True):
"""Initialize a DICOMDIR dataset read from a DICOM file
Carries forward all the initialization from FileDataset class
:param filename: full path and filename to the file. Use None if is a BytesIO.
:param dataset: some form of dictionary, usually a Dataset from read_dataset()
:param preamble: the 128-byte DICOM preamble
:param file_meta: the file meta info dataset, as returned by _read_file_meta,
or an empty dataset if no file meta information is in the file
:param is_implicit_VR: True if implicit VR transfer syntax used; False if explicit VR. Default is True.
:param is_little_endian: True if little-endian transfer syntax used; False if big-endian. Default is True.
"""
# Usually this class is created through filereader.read_partial,
# and it checks class SOP, but in case of direct creation,
# check here also
if file_meta:
class_uid = file_meta.MediaStorageSOPClassUID
if not class_uid == "Media Storage Directory Storage":
print(class_uid, type(class_uid))
msg = "SOP Class is not Media Storage Directory (DICOMDIR)"
raise InvalidDicomError(msg)
FileDataset.__init__(self,
filename_or_obj,
dataset,
preamble,
file_meta,
is_implicit_VR=True,
is_little_endian=True)
self.parse_records()
def read_dicomdir(filename="DICOMDIR"):
"""Read a DICOMDIR file and return a DicomDir instance
This is just a wrapper around read_file, which gives a default file name
:param filename: full path and name to DICOMDIR file to open
:return: a DicomDir instance
:raise: InvalidDicomError is raised if file is not a DICOMDIR file.
"""
# Read the file as usual.
# read_file will return a DicomDir instance if file is one.
# Here, check that it is in fact DicomDir
ds = read_file(filename)
if not isinstance(ds, DicomDir):
msg = u"File '{0}' is not a Media Storage Directory file".format(filename)
raise InvalidDicomError(msg)
return ds
def read_preamble(fp, force):
"""Read and return the DICOM preamble and read past the 'DICM' marker.
If 'DICM' does not exist, assume no preamble, return None, and
rewind file to the beginning..
"""
logger.debug("Reading preamble...")
preamble = fp.read(0x80)
if dicom.debugging:
sample = bytes2hex(preamble[:8]) + "..." + bytes2hex(preamble[-8:])
logger.debug("{0:08x}: {1}".format(fp.tell() - 0x80, sample))
magic = fp.read(4)
if magic != b"DICM":
if force:
logger.info("File is not a standard DICOM file; 'DICM' header is "
"missing. Assuming no header and continuing")
preamble = None
fp.seek(0)
else:
raise InvalidDicomError("File is missing 'DICM' marker. "
"Use force=True to force reading")
else:
logger.debug("{0:08x}: 'DICM' marker found".format(fp.tell() - 4))
return preamble