DicomTreeCompare.py

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#
# Copyright 2021, MeVis Medical Solutions AG
#
# The user may use this file in accordance with the license agreement provided with
# the Software or, alternatively, in accordance with the terms contained in a
# written agreement between the user and MeVis Medical Solutions AG.
#
# For further information use the contact form at https://www.mevislab.de/contact
#
 
from mevis import MLAB
 
# -- class DicomTreeCompare ------------------------------------------------------------------{{{-
 
class DicomTreeCompare:
  
  def __init__(self):
    self.printDifferences = True
    self.printOnlyFirstDifference = False
    self.outputFunction = MLAB.logError
    self._hadDifferences = False
 
  def hadDifferences(self):
    return self._hadDifferences
 
  def tagName(self, tag):
    name = tag.tagName()
    if not name:
      name = tag.id()
    elif name == "PrivateCreator":
      name += " '" + tag.toString() + "' " + tag.id()
    else:
      name += " " + tag.id()
    return name
 
  def dicomPathToString(self, path):
    result = ""
    for tag, index in path:
      result += f"in {self.tagName(tag)}, position {index} "
    return result
 
  def tagValueToString(self, tag):
    if tag.isBinary():
      return f"<{tag.numberOfValues()} items>"
    else:
      return f"'{tag.toString()}'"
 
  def dicomTagError(self, path, message, tag = None):
    if self.printDifferences:
      if not self._hadDifferences or not self.printOnlyFirstDifference:
        tagString = (", tag " + self.tagName(tag)) if tag else ""
        msg = self.dicomPathToString(path) + message + tagString
        self.outputFunction(msg)
    self._hadDifferences = True
  
  def compareTags(self, tag1, tag2, path):
    if tag1.vr() != tag2.vr():
      self.dicomTagError(path, f"Different VRs ({tag1.vr()} and {tag2.vr()})", tag1)
      return False
    elif tag1.isSequence():
      n1 = tag1.numberOfSequenceItems()
      n2 = tag2.numberOfSequenceItems()
      if n1 != n2:
        self.dicomTagError(path, f"Tags have different number of sequence items ({n1} and {n2})", tag1)
        return False
      else:
        ok = True
        for i in range(tag1.numberOfSequenceItems()):
          ok = self.compareTrees(tag1.getSequenceItem(i), tag2.getSequenceItem(i), path + ((tag1, i),)) and ok
        return ok
    elif not tag1.isEqual(tag2):
      s1 = self.tagValueToString(tag1)
      s2 = self.tagValueToString(tag2)
      self.dicomTagError(path, f"Different values ({s1} != {s2})", tag1)
      return False
    else:
      return True
  
  def compareTrees(self, tree1, tree2, path = ()):
    ok = True
    if tree1 and not tree2:
      self.dicomTagError(path, "Second tree not existing")
      return False
    elif tree2 and not tree1:
      self.dicomTagError(path, "First tree not existing")
      return False
    tags1 = list(tree1.getTags())
    tags2 = list(tree2.getTags())
    tag1 = tags1.pop(0) if tags1 else None
    tag2 = tags2.pop(0) if tags2 else None
    while tag1 or tag2:
      if not tag2 or tag1.groupId() < tag2.groupId() or (tag1.groupId() == tag2.groupId() and tag1.elementId() < tag2.elementId()):
        self.dicomTagError(path, "Extra tag in first tree", tag1)
        ok = False
        tag1 = tags1.pop(0) if tags1 else None
      elif not tag1 or tag1.groupId() > tag2.groupId() or (tag1.groupId() == tag2.groupId() and tag1.elementId() > tag2.elementId()):
        self.dicomTagError(path, "Extra tag in second tree", tag2)
        ok = False
        tag2 = tags2.pop(0) if tags2 else None
      else:
        ok = self.compareTags(tag1, tag2, path) and ok
        tag1 = tags1.pop(0) if tags1 else None
        tag2 = tags2.pop(0) if tags2 else None
    return ok
# --------------------------------------------------------------------------------------------}}}-
 
# -- def compareDicomTrees -------------------------------------------------------------------{{{-
 
def compareDicomTrees(tree1, tree2, printDifferences=True, printOnlyFirstDifference=False, outputFunction=MLAB.logError):
  dc = DicomTreeCompare()
  dc.printDifferences = printDifferences
  dc.printOnlyFirstDifference = printOnlyFirstDifference
  dc.outputFunction = outputFunction
  return dc.compareTrees(tree1, tree2)
# --------------------------------------------------------------------------------------------}}}-