"""
    NEPI, a framework to manage network experiments
    Copyright (C) 2013 INRIA

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""

# FIXME: This class is not thread-safe. 
# Should it be made thread-safe?
class GuidGenerator(object):
    def __init__(self):
        self._guids = list()

    def next(self, guid = None):
        if guid != None:
            return guid
        else:
            last_guid = 0 if len(self._guids) == 0 else self._guids[-1]
            guid = last_guid + 1 
        self._guids.append(guid)
        self._guids.sort()
        return guid