def test_base_n(self):
"""Test to/from_base_n conversions."""
alphabet = (string.digits + string.ascii_lowercase +
string.ascii_uppercase)
for base in [2, 10, 16, 36, 62]:
for num in [0, 10, 2313, 23134223879243284]:
n_num = utils.to_base_n(num, base=base, alphabet=alphabet)
_num = utils.from_base_n(n_num, base=base, alphabet=alphabet)
self.assertTrue(num == _num)
self.assertEquals(utils.to_base_n(15, base=16), 'f')
self.assertEquals(utils.to_base_n(10, base=2), '1010')
self.assertEquals(
utils.from_base_n('101', base=2),
int('101', base=2),
)
self.assertEquals(utils.from_base_n('deadbeef', base=16),
int('deadbeef', base=16))
def gen_uniqueid(event_file):
"""Generate a uniqueid for a given event file
Uniqueid needs to be length constrained (exactly 13 char) and character set
constrained ([a-z0-9]) to avoid issues with the naming limitations of the
different resources of the container (root dir, logical volume, virtual
ethernet device, ...)
The current smallest length limiter is:
virtual ethernet device(13): IFNAMESZ 16 char
- 1 (zero terminated)
- 2 ('.0'/'.1' suffix)
This function will output an unique identifier of a maximum of 13 chars
by encoding the event's instance_id, inode number and ctime in base 62.
:param event_file:
Full path to an event file
:type event_file:
``str``
:returns:
(``str``) -- 13 chars identifier
"""
event_stat = os.stat(event_file)
# Event time is the creation time in millisec
event_time = int(event_stat.st_ctime * 10**6)
# Event data is the event inode (64bit) combined with the instance id
# (33bit)
# Why: InstanceID is 10 digits:
# int(10 * math.log(10) / math.log(2)) -> 33
event_data = int(event_stat.st_ino)
_name, _sep, instance = os.path.basename(event_file).rpartition('#')
event_data ^= (int(instance) << 31)
event_data &= (2**64) - 1
seed = (event_time << 64) + int(event_data)
# Trim the top bits so that we only consider 77bits.
# Note we trim from the ctime high bits.
# Why: int(13 * math.log(62) / math.log(2)) -> 77
seed &= (2**77) - 1
numerals = string.digits + string.ascii_lowercase + string.ascii_uppercase
ret = utils.to_base_n(seed, base=len(numerals), alphabet=numerals)
return '{identifier:>013s}'.format(identifier=ret)