binhex.py 文件源码

def read(self, totalwtd):
        """Read at least wtd bytes (or until EOF)"""
        decdata = ''
        wtd = totalwtd
        #
        # The loop here is convoluted, since we don't really now how
        # much to decode: there may be newlines in the incoming data.
        while wtd > 0:
            if self.eof: return decdata
            wtd = ((wtd+2)//3)*4
            data = self.ifp.read(wtd)
            #
            # Next problem: there may not be a complete number of
            # bytes in what we pass to a2b. Solve by yet another
            # loop.
            #
            while 1:
                try:
                    decdatacur, self.eof = \
                            binascii.a2b_hqx(data)
                    break
                except binascii.Incomplete:
                    pass
                newdata = self.ifp.read(1)
                if not newdata:
                    raise Error, \
                          'Premature EOF on binhex file'
                data = data + newdata
            decdata = decdata + decdatacur
            wtd = totalwtd - len(decdata)
            if not decdata and not self.eof:
                raise Error, 'Premature EOF on binhex file'
        return decdata