message_list.py

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# Software License Agreement (BSD License)
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# Copyright (c) 2013, Open Source Robotics Foundation Inc.
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class MessageList(object):

    def __init__(self):
        super(MessageList, self).__init__()
        self._messages = []

    def __getitem__(self, key):
        return self._messages[len(self._messages) - key - 1]

    def __delitem__(self, key):
        if isinstance(key, slice):
            assert key.step is None or key.step == 1, \
                'MessageList.__delitem__ not implemented for slices with step argument ' \
                'different than 1'
            del self._messages[len(self._messages) - key.stop:len(self._messages) - key.start]
        else:
            del self._messages[len(self._messages) - key - 1]

    def __iter__(self):
        return reversed(self._messages)

    def __reversed__(self):
        return iter(self._messages)

    def __contains__(self, item):
        return item in self._messages

    def __len__(self):
        return len(self._messages)

    def extend(self, item):
        self._messages.extend(item)