Source code for pydicom.dicomdir

# Copyright 2008-2018 pydicom authors. See LICENSE file for details.
"""Module for DicomDir class"""

from pydicom.errors import InvalidDicomError
from pydicom.dataset import FileDataset


[docs]class DicomDir(FileDataset): """Hold a DICOMDIR dataset read from file. Derived from FileDataset, but additional methods are available, specific to the Directory structure """ 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_or_obj: 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.name == "Media Storage Directory Storage": 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=is_implicit_VR, is_little_endian=is_little_endian) self.parse_records()
[docs] def parse_records(self): """Build the hierarchy of given directory records, and structure into Patient, Studies, Series, Images hierarchy. This is intended for initial read of file only, it will not reorganize correctly if records are changed. :return: None """ # Define a helper function for organizing the records def get_siblings(record, map_offset_to_record): """Return a list of all siblings of the given directory record, including itself. """ sibling_list = [record] current_record = record while current_record.OffsetOfTheNextDirectoryRecord: offset_of_next = current_record.OffsetOfTheNextDirectoryRecord sibling = map_offset_to_record[offset_of_next] sibling_list.append(sibling) current_record = sibling return sibling_list # Build the mapping from file offsets to records records = self.DirectoryRecordSequence map_offset_to_record = {} for record in records: offset = record.seq_item_tell map_offset_to_record[offset] = record # logging.debug("Record offsets: " + map_offset_to_record.keys()) # Find the children of each record for record in records: child_offset = record.OffsetOfReferencedLowerLevelDirectoryEntity if child_offset: child = map_offset_to_record[child_offset] record.children = get_siblings(child, map_offset_to_record) else: record.children = [] # Find the top-level records : siblings of the first record self.patient_records = get_siblings(records[0], map_offset_to_record)