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# Copyright (C) 2009 Canonical Ltd
#
# 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 2 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
"""The pure-python implementation of the StaticTuple type.
Note that it is generally just implemented as using tuples of tuples of
strings.
"""
class StaticTuple(object):
"""A static type, similar to a tuple of strings."""
__slots__ = ('_tuple',)
def __new__(cls, *args):
if not args and _empty_tuple is not None:
return _empty_tuple
return object.__new__(cls)
def __init__(self, *args):
"""Create a new 'StaticTuple'"""
for bit in args:
if not isinstance(bit, str) and not isinstance(bit, StaticTuple):
raise TypeError('key bits must be strings or StaticTuple')
num_keys = len(args)
if num_keys < 0 or num_keys > 255:
raise ValueError('must have 1 => 256 key bits')
self._tuple = args
def __repr__(self):
return repr(self._tuple)
def __hash__(self):
return hash(self._tuple)
def __eq__(self, other):
if isinstance(other, StaticTuple):
return self._tuple == other._tuple
if isinstance(other, tuple):
return other == self._tuple
return NotImplemented
def __len__(self):
return len(self._tuple)
def __cmp__(self, other):
return cmp(self._tuple, other)
def __getitem__(self, idx):
return self._tuple[idx]
def as_tuple(self):
return self._tuple
def intern(self):
return _interned_tuples.setdefault(self, self)
_empty_tuple = None
_empty_tuple = StaticTuple()
_interned_tuples = {}
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