old_contents: # Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
  #
  # Licensed 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.
  
  
  class PacketBase(object):
      """A base class for a protocol (ethernet, ipv4, ...) header."""
      _TYPES = {}
  
      @classmethod
      def get_packet_type(cls, type_):
          """Per-protocol dict-like get method.
  
          Provided for convenience of protocol implementers.
          Internal use only."""
          return cls._TYPES.get(type_)
  
      @classmethod
      def register_packet_type(cls, cls_, type_):
          """Per-protocol dict-like set method.
  
          Provided for convenience of protocol implementers.
          Internal use only."""
          cls._TYPES[type_] = cls_
  
      def __init__(self):
          super(PacketBase, self).__init__()
          self.length = 0
          self.protocol_name = self.__class__.__name__
  
      @classmethod
      def parser(cls, buf):
          """Decode a protocol header.
  
          This method is used only when decoding a packet.
  
          Decode a protocol header at offset 0 in bytearray *buf*.
          Returns the following two objects.
  
          * An object to describe the decoded header.
            It should have the following attributes at least.
  
            =========== ============
            Attribute   Description
            =========== ============
            length      The number of the corresponding on-wire octets.
            =========== ============
  
          * A packet_base.PacketBase subclass appropriate for the rest of
            the packet.  None when the rest of the packet should be considered
            as raw payload.
  
          """
          pass
  
      def serialize(self, payload, prev):
          """Encode a protocol header.
  
          This method is used only when encoding a packet.
  
          Encode a protocol header.
          Returns a bytearray which contains the header.
  
          *payload* is the rest of the packet which will immediately follow
          this header.
  
          *prev* is a packet_base.PacketBase subclass for the outer protocol
          header.  *prev* is None if the current header is the outer-most.
          For example, *prev* is ipv4 or ipv6 for tcp.serialize.
          """
          pass
  
new_contents: # Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
  #
  # Licensed 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.
  
  
  class PacketBase(object):
      """A base class for a protocol (ethernet, ipv4, ...) header."""
      _TYPES = {}
  
      @classmethod
      def get_packet_type(cls, type_):
          """Per-protocol dict-like get method.
  
          Provided for convenience of protocol implementers.
          Internal use only."""
          return cls._TYPES.get(type_)
  
      @classmethod
      def register_packet_type(cls, cls_, type_):
          """Per-protocol dict-like set method.
  
          Provided for convenience of protocol implementers.
          Internal use only."""
          cls._TYPES[type_] = cls_
  
      def __init__(self):
          super(PacketBase, self).__init__()
          self.length = 0
  
      @property
      def protocol_name(self):
          return self.__class__.__name__
  
      @classmethod
      def parser(cls, buf):
          """Decode a protocol header.
  
          This method is used only when decoding a packet.
  
          Decode a protocol header at offset 0 in bytearray *buf*.
          Returns the following two objects.
  
          * An object to describe the decoded header.
            It should have the following attributes at least.
  
            =========== ============
            Attribute   Description
            =========== ============
            length      The number of the corresponding on-wire octets.
            =========== ============
  
          * A packet_base.PacketBase subclass appropriate for the rest of
            the packet.  None when the rest of the packet should be considered
            as raw payload.
  
          """
          pass
  
      def serialize(self, payload, prev):
          """Encode a protocol header.
  
          This method is used only when encoding a packet.
  
          Encode a protocol header.
          Returns a bytearray which contains the header.
  
          *payload* is the rest of the packet which will immediately follow
          this header.
  
          *prev* is a packet_base.PacketBase subclass for the outer protocol
          header.  *prev* is None if the current header is the outer-most.
          For example, *prev* is ipv4 or ipv6 for tcp.serialize.
          """
          pass
  
subject: make protocol_name property instead of attributes