count the number of characters that precede the sequence in a repeatmasker
  alignment line. E.g. in the following line:
         '  chr1               11 CCCTGGAGATTCTTATT--AGTGATTTGGGCT 41'
  the answer would be 24.

  :param space_pres_split: the alignment line, split into tokens around spaces,
                           but with the spaces conserved as tokens.
  :param seq: the sequence token.

def _rm_compute_leading_space_alig(space_pres_split, seq):
  """
  count the number of characters that precede the sequence in a repeatmasker
  alignment line. E.g. in the following line:
         '  chr1               11 CCCTGGAGATTCTTATT--AGTGATTTGGGCT 41'
  the answer would be 24.

  :param space_pres_split: the alignment line, split into tokens around spaces,
                           but with the spaces conserved as tokens.
  :param seq: the sequence token.
  """
  c = 0
  for i in range(0, len(space_pres_split)):
    if space_pres_split[i] == seq:
      break
    c += len(space_pres_split[i])
  return c