os-ken/ryu/lib/pack_utils.py
YAMAMOTO Takashi 72a06f6f60 Move msg_pack_into from ofproto to lib
A motivation of this change is a better modularity.
I.e. Make packet lib independent from ofproto.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
2015-02-16 13:05:32 +09:00

33 lines
1.0 KiB
Python

# Copyright (C) 2011, 2012 Nippon Telegraph and Telephone Corporation.
# Copyright (C) 2011 Isaku Yamahata <yamahata at valinux co jp>
#
# 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.
import struct
def msg_pack_into(fmt, buf, offset, *args):
if len(buf) < offset:
buf += bytearray(offset - len(buf))
if len(buf) == offset:
buf += struct.pack(fmt, *args)
return
needed_len = offset + struct.calcsize(fmt)
if len(buf) < needed_len:
buf += bytearray(needed_len - len(buf))
struct.pack_into(fmt, buf, offset, *args)