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from shelve import Shelf
try:
import zlib
except ImportError:
# Some python installations don't have zlib.
pass
from cStringIO import StringIO
import cPickle
class DbfilenameShelf(Shelf):
"""Shelf implementation using the "anydbm" generic dbm interface.
This is initialized with the filename for the dbm database.
See the module's __doc__ string for an overview of the interface.
"""
def __init__(self, filename, flag='c'):
import dumbdbm_patched
Shelf.__init__(self, dumbdbm_patched.open(filename, flag))
def __getitem__(self, key):
compressed = self.dict[key]
try:
r = zlib.decompress(compressed)
except zlib.error:
r = compressed
except NameError:
r = compressed
return cPickle.loads(r)
def __setitem__(self, key, value):
s = cPickle.dumps(value,1)
try:
self.dict[key] = zlib.compress(s)
except NameError:
#zlib doesn't exist, leave it uncompressed.
self.dict[key] = s
def open(filename, flag='c'):
"""Open a persistent dictionary for reading and writing.
Argument is the filename for the dbm database.
See the module's __doc__ string for an overview of the interface.
"""
return DbfilenameShelf(filename, flag)
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