Source code for soma.uuid

# -*- coding: utf-8 -*-

#  This software and supporting documentation are distributed by
#      Institut Federatif de Recherche 49
#      CEA/NeuroSpin, Batiment 145,
#      91191 Gif-sur-Yvette cedex
#      France
#
# This software is governed by the CeCILL-B license under
# French law and abiding by the rules of distribution of free software.
# You can  use, modify and/or redistribute the software under the
# terms of the CeCILL-B license as circulated by CEA, CNRS
# and INRIA at the following URL "http://www.cecill.info".
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'''
Universal unique identifier.

- author: Yann Cointepas
- organization: NeuroSpin
- license: `CeCILL B <http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.html>`_
'''
from __future__ import absolute_import
import six
__docformat__ = "epytext en"

import struct
import random
import binascii
import sys

#-------------------------------------------------------------------------


[docs]class Uuid(object): ''' An Uuid instance is a universal unique identifier. It is a 128 bits random value. ''' def __new__(cls, value=None): if isinstance(value, Uuid): return value return object.__new__(cls) def __init__(self, uuid=None): ''' Uuid constructor. If *uuid* is ommited or *None*, a new random Uuid is created; if it is a string if must be 36 characters long and follow the pattern:: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX where ``X`` is an hexadecimal digit (example: ``'ad2d8fb0-7831-50bc-2fb6-5df048304001'``). If *uuid* is an Uuid instance, no new instance is created, in this case, *Uuid(uuid)* returns *uuid*. ''' if isinstance(uuid, Uuid): return if uuid is None: # Generate a new 128 bits uuid self.__uuid = struct.pack('QQ', random.randrange(2 ** 64 - 1), random.randrange(2 ** 64 - 1)) else: try: uuid = six.ensure_binary(uuid, encoding='ascii') self.__uuid = binascii.unhexlify(uuid[0:8] + uuid[9:13] + uuid[14:18] + uuid[19:23] + uuid[24:36]) except Exception: raise ValueError("Invalid uuid string %s" % (repr(uuid), )) def __getnewargs__(self): return (str(self), ) def __str__(self): if not isinstance(self.__uuid, bytes): # this should not happen, but has been seen in some places import warnings warnings.warn('soma.uuid.Uuid: self.__uuid is not of type bytes, ' 'but {0}. This is not supposed to happen.' .format(type(self.__uuid))) self.__uuid = bytes(self.__uuid, encoding='utf-8') return six.ensure_str( binascii.hexlify(self.__uuid[0:4]) + b'-' + binascii.hexlify(self.__uuid[4:6]) + b'-' + binascii.hexlify(self.__uuid[6:8]) + b'-' + binascii.hexlify(self.__uuid[8:10]) + b'-' + binascii.hexlify(self.__uuid[10:16]) ) def __repr__(self): return repr(str(self)) def __hash__(self): return hash(self.__uuid) def __eq__(self, other): if isinstance(other, Uuid): return self.__uuid == other.__uuid elif isinstance(other, six.string_types): # assume string-like object (str or unicode) try: uuid_other = Uuid(other) except ValueError: return False return self.__uuid == uuid_other.__uuid else: return False def __ne__(self, other): if isinstance(other, Uuid): return self.__uuid != other.__uuid elif isinstance(other, six.string_types): # assume string-like object (str or unicode) try: uuid_other = Uuid(other) except ValueError: return True return self.__uuid != uuid_other.__uuid else: return True