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#
# 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
from qpid.framer import Frame, FIRST_SEG, LAST_SEG, FIRST_FRM, LAST_FRM
from qpid.assembler import Segment
class FrameDecoder:
def __init__(self):
self.input = ""
self.output = []
self.parse = self.__frame_header
def write(self, bytes):
self.input += bytes
while True:
next = self.parse()
if next is None:
break
else:
self.parse = next
def __consume(self, n):
result = self.input[:n]
self.input = self.input[n:]
return result
def __frame_header(self):
if len(self.input) >= Frame.HEADER_SIZE:
st = self.__consume(Frame.HEADER_SIZE)
self.flags, self.type, self.size, self.track, self.channel = \
struct.unpack(Frame.HEADER, st)
return self.__frame_body
def __frame_body(self):
size = self.size - Frame.HEADER_SIZE
if len(self.input) >= size:
payload = self.__consume(size)
frame = Frame(self.flags, self.type, self.track, self.channel, payload)
self.output.append(frame)
return self.__frame_header
def read(self):
result = self.output
self.output = []
return result
class FrameEncoder:
def __init__(self):
self.output = ""
def write(self, *frames):
for frame in frames:
size = len(frame.payload) + Frame.HEADER_SIZE
track = frame.track & 0x0F
self.output += struct.pack(Frame.HEADER, frame.flags, frame.type, size,
track, frame.channel)
self.output += frame.payload
def read(self):
result = self.output
self.output = ""
return result
class SegmentDecoder:
def __init__(self):
self.fragments = {}
self.segments = []
def write(self, *frames):
for frm in frames:
key = (frm.channel, frm.track)
seg = self.fragments.get(key)
if seg == None:
seg = Segment(frm.isFirstSegment(), frm.isLastSegment(),
frm.type, frm.track, frm.channel, "")
self.fragments[key] = seg
seg.payload += frm.payload
if frm.isLastFrame():
self.fragments.pop(key)
self.segments.append(seg)
def read(self):
result = self.segments
self.segments = []
return result
class SegmentEncoder:
def __init__(self, max_payload=Frame.MAX_PAYLOAD):
self.max_payload = max_payload
self.frames = []
def write(self, *segments):
for seg in segments:
remaining = seg.payload
first = True
while first or remaining:
payload = remaining[:self.max_payload]
remaining = remaining[self.max_payload:]
flags = 0
if first:
flags |= FIRST_FRM
first = False
if not remaining:
flags |= LAST_FRM
if seg.first:
flags |= FIRST_SEG
if seg.last:
flags |= LAST_SEG
frm = Frame(flags, seg.type, seg.track, seg.channel, payload)
self.frames.append(frm)
def read(self):
result = self.frames
self.frames = []
return result
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