/usr/lib/python2.6/site-packages
Edit: /usr/lib/python2.6/site-packages/monotonic.py (5345B)
# -*- coding: utf-8 -*-
"""
monotonic
~~~~~~~~~
This module provides a ``monotonic()`` function which returns the
value (in fractional seconds) of a clock which never goes backwards.
On Python 3.3 or newer, ``monotonic`` will be an alias of
``time.monotonic`` from the standard library. On older versions,
it will fall back to an equivalent implementation:
+-------------+--------------------+
| Linux, BSD | clock_gettime(3) |
+-------------+--------------------+
| Windows | GetTickCount64 |
+-------------+--------------------+
| OS X | mach_absolute_time |
+-------------+--------------------+
If no suitable implementation exists for the current platform,
attempting to import this module (or to import from it) will
cause a RuntimeError exception to be raised.
Copyright 2014 Ori Livneh
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""
import ctypes
import ctypes.util
import os
import platform
import re
import sys
import time
__all__ = ('monotonic',)
def get_os_release():
"""Get the leading numeric component of the OS release."""
return re.match('[\d.]+', platform.release()).group(0)
def compare_versions(v1, v2):
"""Compare two version strings."""
def normalize(v):
return map(int, re.sub(r'(\.0+)*$', '', v).split('.'))
return cmp(normalize(v1), normalize(v2))
try:
monotonic = time.monotonic
except AttributeError:
try:
if sys.platform == 'darwin': # OS X, iOS
# See Technical Q&A QA1398 of the Mac Developer Library:
#
libc = ctypes.CDLL('/usr/lib/libc.dylib', use_errno=True)
class mach_timebase_info_data_t(ctypes.Structure):
"""System timebase info. Defined in ."""
_fields_ = (('numer', ctypes.c_uint32),
('denom', ctypes.c_uint32))
mach_absolute_time = libc.mach_absolute_time
mach_absolute_time.restype = ctypes.c_uint64
timebase = mach_timebase_info_data_t()
libc.mach_timebase_info(ctypes.byref(timebase))
ticks_per_second = timebase.numer / timebase.denom * 1.0e9
def monotonic():
"""Monotonic clock, cannot go backward."""
return mach_absolute_time() / ticks_per_second
elif sys.platform.startswith('win32'):
# Windows Vista / Windows Server 2008 or newer.
GetTickCount64 = ctypes.windll.kernel32.GetTickCount64
GetTickCount64.restype = ctypes.c_ulonglong
def monotonic():
"""Monotonic clock, cannot go backward."""
return GetTickCount64() / 1000.0
elif sys.platform.startswith('cygwin'):
# Cygwin
kernel32 = ctypes.cdll.LoadLibrary('kernel32.dll')
GetTickCount64 = kernel32.GetTickCount64
GetTickCount64.restype = ctypes.c_ulonglong
def monotonic():
"""Monotonic clock, cannot go backward."""
return GetTickCount64() / 1000.0
else:
try:
clock_gettime = ctypes.CDLL(ctypes.util.find_library('c'),
use_errno=True).clock_gettime
except AttributeError:
clock_gettime = ctypes.CDLL(ctypes.util.find_library('rt'),
use_errno=True).clock_gettime
class timespec(ctypes.Structure):
"""Time specification, as described in clock_gettime(3)."""
_fields_ = (('tv_sec', ctypes.c_long),
('tv_nsec', ctypes.c_long))
ts = timespec()
if sys.platform.startswith('linux'):
if compare_versions(get_os_release(), '2.6.28') > 0:
CLOCK_MONOTONIC = 4 # CLOCK_MONOTONIC_RAW
else:
CLOCK_MONOTONIC = 1
elif sys.platform.startswith('freebsd'):
CLOCK_MONOTONIC = 4
elif sys.platform.startswith('sunos5'):
CLOCK_MONOTONIC = 4
elif 'bsd' in sys.platform:
CLOCK_MONOTONIC = 3
def monotonic():
"""Monotonic clock, cannot go backward."""
if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(ts)):
errno = ctypes.get_errno()
raise OSError(errno, os.strerror(errno))
return ts.tv_sec + ts.tv_nsec / 1.0e9
# Perform a sanity-check.
if monotonic() - monotonic() > 0:
raise ValueError('monotonic() is not monotonic!')
except Exception:
raise RuntimeError('no suitable implementation for this system')