Example #1
0
    def __init__(self, name=None, buffer=1):
        if name == None:
            # Create unique name
            name = str(random.random()) + str(time.time())

        self.name = name
        self.__inChan = Channel(name=name + 'inChan')
        self.__outChan = Channel(name=name + 'outChan')
        self.__bufferProcess = self.Buffer(self.__inChan.reader(),
                                           self.__outChan.writer(),
                                           N=buffer)

        # Retrieve channel ends
        self.reader = self.__outChan.reader
        self.writer = self.__inChan.writer

        # Set buffer process as deamon to allow kill if mother process
        # exists.
        self.__bufferProcess.daemon = True

        # Start buffer process
        Spawn(self.__bufferProcess)
Example #2
0
    def __init__(self, name=None, buffer=1):
        if name == None:
            # Create unique name
            name = str(random.random())+str(time.time())

        self.name = name
        self.__inChan = Channel(name=name+'inChan')
        self.__outChan = Channel(name=name+'outChan')
        self.__bufferProcess = self.Buffer(self.__inChan.reader(),
                                       self.__outChan.writer(),
                                       N=buffer)

        # Retrieve channel ends
        self.reader = self.__outChan.reader
        self.writer = self.__inChan.writer

        # Set buffer process as deamon to allow kill if mother process
        # exists.
        self.__bufferProcess.daemon = True

        # Start buffer process        
        Spawn(self.__bufferProcess)
Example #3
0
class BufferedChannel(object):
    """ Channel class.
    Blocking or buffered communication.
    
    >>> from pycsp import *

    >>> @process
    ... def P1(cout):
    ...     while True:
    ...         cout('Hello World')

    >>> C = Channel()
    >>> Spawn(P1(C.writer()))
    
    >>> cin = C.reader()
    >>> cin()
    'Hello World'

    >>> retire(cin)

    Buffered channels are semantically equivalent with a chain
    of forwarding processes.
    >>> B = Channel(buffer=5)
    >>> cout = B.writer()
    >>> for i in range(5):
    ...     cout(i)

    Poison and retire are attached to final element of the buffer.
    >>> poison(cout)

    >>> @process
    ... def sink(cin, L):
    ...     while True:
    ...         L.append(cin())

    >>> L = []
    >>> Parallel(sink(B.reader(), L))
    >>> L
    [0, 1, 2, 3, 4]
    """
    def __init__(self, name=None, buffer=1):
        if name == None:
            # Create unique name
            name = str(random.random()) + str(time.time())

        self.name = name
        self.__inChan = Channel(name=name + 'inChan')
        self.__outChan = Channel(name=name + 'outChan')
        self.__bufferProcess = self.Buffer(self.__inChan.reader(),
                                           self.__outChan.writer(),
                                           N=buffer)

        # Retrieve channel ends
        self.reader = self.__outChan.reader
        self.writer = self.__inChan.writer

        # Set buffer process as deamon to allow kill if mother process
        # exists.
        self.__bufferProcess.daemon = True

        # Start buffer process
        Spawn(self.__bufferProcess)

    def __pos__(self):
        return self.reader()

    def __neg__(self):
        return self.writer()

    def poison(self):
        self.__inChan.poison()
        self.__outChan.poison()

    @process
    def Buffer(self, cin, cout, N):
        queue = deque()
        poisoned = False
        retired = False
        while True:
            try:
                import pycsp.current
                if pycsp.current.trace:
                    TraceMsg(len(queue))

                # Handling poison / retire
                if (poisoned or retired):
                    if len(queue):
                        try:
                            cout(queue.popleft())
                        except:
                            if poisoned:
                                poison(cin, cout)
                            if retired:
                                retire(cin, cout)
                    else:
                        if poisoned:
                            poison(cin, cout)
                        if retired:
                            retire(cin, cout)
                        return  # quit
                # Queue empty
                elif len(queue) == 0:
                    queue.append(cin())
                # Queue not full and not empty
                elif len(queue) < N:
                    g, msg = Alternation([(cout, queue[0], None),
                                          (cin, None)]).select()
                    if g == cin:
                        queue.append(msg)
                    else:
                        queue.popleft()
                # Queue full
                else:
                    cout(queue.popleft())
            except ChannelPoisonException as e:
                poisoned = True
            except ChannelRetireException as e:
                retired = True
Example #4
0
class BufferedChannel:
    """ Channel class.
    Blocking or buffered communication.
    
    >>> from pycsp import *

    >>> @process
    ... def P1(cout):
    ...     while True:
    ...         cout('Hello World')

    >>> C = Channel()
    >>> Spawn(P1(C.writer()))
    
    >>> cin = C.reader()
    >>> cin()
    'Hello World'

    >>> retire(cin)

    Buffered channels are semantically equivalent with a chain
    of forwarding processes.
    >>> B = Channel(buffer=5)
    >>> cout = B.writer()
    >>> for i in range(5):
    ...     cout(i)

    Poison and retire are attached to final element of the buffer.
    >>> poison(cout)

    >>> @process
    ... def sink(cin, L):
    ...     while True:
    ...         L.append(cin())

    >>> L = []
    >>> Parallel(sink(B.reader(), L))
    >>> L
    [0, 1, 2, 3, 4]
    """
    def __init__(self, name=None, buffer=1):
        if name == None:
            # Create unique name
            name = str(random.random())+str(time.time())

        self.name = name
        self.__inChan = Channel(name=name+'inChan')
        self.__outChan = Channel(name=name+'outChan')
        self.__bufferProcess = self.Buffer(self.__inChan.reader(),
                                       self.__outChan.writer(),
                                       N=buffer)

        # Retrieve channel ends
        self.reader = self.__outChan.reader
        self.writer = self.__inChan.writer

        # Set buffer process as deamon to allow kill if mother process
        # exists.
        self.__bufferProcess.daemon = True

        # Start buffer process        
        Spawn(self.__bufferProcess)

    def __pos__(self):
        return self.reader()

    def __neg__(self):
        return self.writer()

    def poison(self):
        self.__inChan.poison()
        self.__outChan.poison()

    @process
    def Buffer(self, cin, cout, N):
        queue = deque()
        poisoned = False
        retired = False
        while True:
            try:
                import pycsp.current
                if pycsp.current.trace:
                    TraceMsg(len(queue))

                # Handling poison / retire
                if (poisoned or retired):
                    if len(queue):
                        try:
                            cout(queue.popleft())
                        except:
                            if poisoned:
                                poison(cin, cout)
                            if retired:
                                retire(cin, cout)
                    else:
                        if poisoned:
                            poison(cin, cout)
                        if retired:
                            retire(cin, cout)
                        return # quit
                # Queue empty
                elif len(queue) == 0:
                    queue.append(cin())
                # Queue not full and not empty
                elif len(queue) < N:
                    g, msg = Alternation([
                            (cout, queue[0], None),
                            (cin, None)
                            ]).select()
                    if g == cin:
                        queue.append(msg)
                    else:
                        queue.popleft()
                # Queue full
                else:
                    cout(queue.popleft())
            except ChannelPoisonException, e:
                poisoned = True
            except ChannelRetireException, e:
                retired = True