text: import logging
  import operator
  
  from .constants import DEBUG
  from .undefined import Undefined, undefined
  
  l = logging.getLogger(name=__name__)
  
  
  class DataSet:
      """
      This class represents a set of data.
  
      Addition and subtraction are performed on the cartesian product of the operands. Duplicate results are removed.
      Data must always include a set.
  
      :ivar set data:    The set of data to represent.
      :ivar int bits:    The size of an element of the set, in number of bits its representation takes.
      """
      maximum_size = 5
  
      def __init__(self, data, bits):
          self.data = data if type(data) is set else {data}
          self._bits = bits
          self._mask = (1 << bits) - 1
          self._limit()
  
      @property
      def bits(self):
          return self._bits
  
      @property
      def mask(self):
          return self._mask
  
      def _limit(self):
          if DEBUG is True:
              # Deterministic limit
              if (len(self.data)) > DataSet.maximum_size:
                  data = list(self.data)
                  data.sort(key=repr)
                  self.data = set(data[:DataSet.maximum_size])
                  l.warning('Reached maximum size of DataSet, discarded %s.', str(data[DataSet.maximum_size:]))
          else:
              # Hash dependent implementation
              while len(self.data) > DataSet.maximum_size:
                  l.warning('Reached maximum size of DataSet, discarded %s.', str(self.data.pop()))
  
      def update(self, data):
          if type(data) is DataSet:
              if self.bits != data.bits:
                  l.warning('Update with different sizes.')
              self.data.update(data.data)
          else:
              self.data.add(data)
          self._limit()
  
      def get_first_element(self):
          assert len(self.data) >= 1
          return next(iter(self.data))
  
      def __len__(self):
          return len(self.data)
  
      def _un_op(self, op):
          res = set()
  
          for s in self:
              if type(s) is Undefined:
                  res.add(undefined)
              else:
                  try:
                      tmp = op(s)
                      if isinstance(tmp, int):
                          tmp &= self._mask
                      res.add(tmp)
                  except TypeError as ex:  # pylint:disable=try-except-raise,unused-variable
                      # l.warning(ex)
                      raise
  
          return DataSet(res, self._bits)
  
      def _bin_op(self, other, op):
          if not type(other) is DataSet:
              raise TypeError("_bin_op() only works on another DataSet instance.")
  
          res = set()
  
          if self._bits != other.bits:
              l.warning('Binary operation with different sizes.')
  
          for o in other:
              for s in self:
                  if type(o) is Undefined or type(s) is Undefined:
                      res.add(undefined)
                  else:
                      try:
                          tmp = op(s, o)
                          if isinstance(tmp, int):
                              tmp &= self._mask
                          res.add(tmp)
                      except TypeError as ex:  # pylint;disable=try-except-raise,unused-variable
                          # l.warning(ex)
                          raise
  
          return DataSet(res, self._bits)
  
      def __add__(self, other):
          return self._bin_op(other, operator.add)
  
      def __sub__(self, other):
          return self._bin_op(other, operator.sub)
  
      def __mul__(self, other):
          return self._bin_op(other, operator.mul)
  
      def __div__(self, other):
          return self._bin_op(other, operator.floordiv)
  
      def __lshift__(self, other):
          return self._bin_op(other, operator.lshift)
  
      def __rshift__(self, other):
          return self._bin_op(other, operator.rshift)
  
      def __and__(self, other):
          return self._bin_op(other, operator.and_)
  
      def __xor__(self, other):
          return self._bin_op(other, operator.xor)
  
      def __or__(self, other):
          return self._bin_op(other, operator.or_)
  
      def __neg__(self):
          return self._un_op(operator.neg)
  
      def __invert__(self):
          return self._un_op(operator.invert)
  
      def __eq__(self, other):
          if type(other) == DataSet:
              return self.data == other.data and self._bits == other.bits and self._mask == other.mask
          else:
              return False
  
      def __hash__(self):
          return hash((self._bits, self._mask))
  
      def __iter__(self):
          return iter(self.data)
  
      def __str__(self):
          return 'DataSet<%d>: %s' % (self._bits, str(self.data))
  