class PDF::Reader::CMap

def str_to_int(str)
  return nil if str.nil? || str.size == 0
  unpacked_string = if str.size == 1 # UTF-8
    str.unpack("C*")
  else # UTF-16
     str.unpack("n*")
  end
  if unpacked_string.size == 1
    unpacked_string
  elsif unpacked_string.size == 2 && unpacked_string[0] > 0xD800 && unpacked_string[0] < 0xDBFF
    # this is a Unicode UTF-16 "Surrogate Pair" see Unicode Spec. Chapter 3.7
    # lets convert to a UTF-32. (the high bit is between 0xD800-0xDBFF, the
    # low bit is between 0xDC00-0xDFFF) for example: U+1D44E (U+D835 U+DC4E)
    [(unpacked_string[0] - 0xD800) * 0x400 + (unpacked_string[1] - 0xDC00) + 0x10000]
  else
    # it is a bad idea to just return the first 16 bits, as this doesn't allow
    # for ligatures for example fi (U+0066 U+0069)
    unpacked_string
  end
end