#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
#

import struct

class Packer:

  def read(self, n): abstract

  def write(self, s): abstract

  def unpack(self, fmt):
    values = struct.unpack(fmt, self.read(struct.calcsize(fmt)))
    if len(values) == 1:
      return values[0]
    else:
      return values

  def pack(self, fmt, *args):
    self.write(struct.pack(fmt, *args))
