will be used for BGP-4. --- ryu/lib/packet/stream_parser.py | 77 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 ryu/lib/packet/stream_parser.py
diff --git a/ryu/lib/packet/stream_parser.py b/ryu/lib/packet/stream_parser.py new file mode 100644 index 0000000..87e1aed --- /dev/null +++ b/ryu/lib/packet/stream_parser.py @@ -0,0 +1,77 @@ +# Copyright (C) 2013 Nippon Telegraph and Telephone Corporation. +# Copyright (C) 2013 YAMAMOTO Takashi <yamamoto 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. + + +from abc import ABCMeta, abstractmethod + + +class StreamParser(object): + """Streaming parser base class. + + An instance of a subclass of this class is used to extract messages + from a raw byte stream. + + It's designed to be used for data read from a transport which doesn't + preserve message boundaries. A typical example of such a transport + is TCP. + + """ + + __metaclass__ = ABCMeta + + class TooSmallException(Exception): + pass + + def __init__(self): + self._q = bytearray() + + def parse(self, data): + """Tries to extract messages from a raw byte stream. + + The data argument would be python bytes newly read from the input + stream. + + Returns an ordered list of extracted messages. + It can be an empty list. + + The rest of data which doesn't produce a complete message is + kept internally and will be used when more data is come. + I.e. next time this method is called again. + """ + self._q.append(data) + msgs = [] + while True: + try: + msg, self._q = self.try_parse(self._q) + except self.TooSmallException: + break + msgs.append(msg) + return msgs + + @abstractmethod + def try_parse(self, q): + """Try to extract a message from the given bytes. + + This is an override point for subclasses. + + This method tries to extract a message from bytes given by the + argument. + + Raises TooSmallException if the given data is not enough to + extract a complete message but there's still a chance to extract + a message if more data is come later. + """ + pass -- 1.8.3.1 ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk _______________________________________________ Ryu-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ryu-devel
