def skipOverComment(stream):
    tok = stream.read(1)
    stream.seek(-1, 1)
    if tok == b_('%'):
        while tok not in (b_('\n'), b_('\r')):
            tok = stream.read(1)

class SafeStream(object):
    def __init__(self, stream):
        self.stream = stream
        self.seek = stream.seek
        self.tell = stream.tell
        self._empty_reads = 0

    def read(self, *args):
        res = self.stream.read(*args)
        if res == "":
             self._empty_reads += 1
             if self._empty_reads > 1000:
                 raise Exception("too many empty reads")
        else:
             self._empty_reads = 0
        return res