uenv.py 文件源码

def export(self):
        """ Export the u-boot environment variables into bytearray.
        :return The environment variables in bytearray
        """
        env_size = self.size

        if self._redundant:
            env_size -= 5
        else:
            env_size -= 4

        data = str()
        for k in self._env:
            data += "{0:s}={1:s}".format(k, self._env[k])
            data += "\0"  # Termination of line "\0"
        data += "\0"      # End of file "\0\0"

        if len(data) > env_size:
            raise Exception("ERROR: ENV size out of range, extend required size !")

        env_blob = data + chr(self._empty_value) * (env_size - len(data))
        env_blob = env_blob.encode('utf-8')
        crc = binascii.crc32(env_blob) & 0xffffffff

        fmt = ">I" if self._bigendian else "<I"
        ret = struct.pack(fmt + "B", crc, 0x01) if self._redundant else struct.pack(fmt, crc)
        ret += env_blob

        return ret