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# vi: set ft=python sw=4 ts=4 et:

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'''monotonic time for Python 2 and 3, on Linux, FreeBSD, Mac OS X, and Windows.

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Copyright 2010, 2011, 2017 Gavin Beatty <gavinbeatty@gmail.com>

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Permission is hereby granted, free of charge, to any person obtaining a copy of

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this software and associated documentation files (the "Software"), to deal in

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the Software without restriction, including without limitation the rights to

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use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies

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of the Software, and to permit persons to whom the Software is furnished to do

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so, subject to the following conditions:

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The above copyright notice and this permission notice shall be included in all

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copies or substantial portions of the Software.

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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

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SOFTWARE.

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'''

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from __future__ import print_function

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from __future__ import unicode_literals

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__author__ = 'Gavin Beatty <gavinbeatty@gmail.com>'

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__version__ = '2.1.0.dev0'

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__date__ = '2017-05-28'

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__all__ = ['monotonic']

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import contextlib

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import ctypes

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import errno

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import os

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import platform

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import sys

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import time

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_machine64 = (platform.machine(), sys.maxsize > 2**32)

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class _NS():

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    pass

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class _mach_timespec(ctypes.Structure):

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    _fields_ = [('tv_sec', ctypes.c_uint), ('tv_nsec', ctypes.c_int)]

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class _posix_timespec(ctypes.Structure):

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    _fields_ = [('tv_sec', ctypes.c_long), ('tv_nsec', ctypes.c_long)]

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def _timespec_to_seconds(ts):

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    return float(ts.tv_sec) + float(ts.tv_nsec) * 1e-9

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def _get_ctypes_libmacho_macho_functions():

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    libmacho = ctypes.CDLL('/usr/lib/system/libmacho.dylib', use_errno=True)

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    macho = _NS()

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    macho.get_host = libmacho.mach_host_self

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    macho.get_host.argtypes = []

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    macho.get_host.restype = ctypes.c_uint

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    macho.get_clock = libmacho.host_get_clock_service

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    macho.get_clock.argtypes = [ctypes.c_uint,

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                                ctypes.c_int,

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                                ctypes.POINTER(ctypes.c_uint)

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                                ]

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    macho.get_time = libmacho.clock_get_time

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    macho.get_time.argtypes = [ctypes.c_uint, ctypes.POINTER(_mach_timespec)]

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    macho.deallocate = libmacho.mach_port_deallocate

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    macho.deallocate.argtypes = [ctypes.c_uint, ctypes.c_uint]

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    return libmacho, macho

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def _get_ctypes_clock_gettime(library):

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    clock_gettime = ctypes.CDLL(library, use_errno=True).clock_gettime

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    clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(_posix_timespec)]

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    return clock_gettime

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def _call_ctypes_clock_gettime(clock_gettime, clockid):

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    timespec = _posix_timespec()

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    ret = clock_gettime(clockid, ctypes.pointer(timespec))

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    if int(ret) != 0:

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        errno_ = ctypes.get_errno()

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        raise OSError(errno_, os.strerror(errno_))

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    return timespec

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_py_monotonic = getattr(time, 'monotonic', None)

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if _py_monotonic is not None:

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    monotonic = _py_monotonic

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elif sys.platform.startswith('linux'):

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    _clock_gettime = _get_ctypes_clock_gettime('librt.so.1')

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    def monotonic():

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        clockid = ctypes.c_int(1)

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        timespec = _call_ctypes_clock_gettime(_clock_gettime, clockid)

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        return _timespec_to_seconds(timespec)

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elif sys.platform.startswith('freebsd'):

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    _clock_gettime = _get_ctypes_clock_gettime('libc.so')

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    def monotonic():

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        clockid = ctypes.c_int(4)

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        timespec = _call_ctypes_clock_gettime(_clock_gettime, clockid)

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        return _timespec_to_seconds(timespec)

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elif sys.platform.startswith('darwin') and _machine64 == ('x86_64', True):

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    _libmacho, _macho = _get_ctypes_libmacho_macho_functions()

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    @contextlib.contextmanager

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    def _deallocate(task, port):

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        try:

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            yield

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        finally:

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            if int(_macho.deallocate(task, port)) == 0:

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                return

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            errno_ = ctypes.get_errno()

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            raise OSError(errno_, os.strerror(errno_))

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    def monotonic():

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        task = ctypes.c_uint.in_dll(_libmacho, 'mach_task_self_')

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        host = _macho.get_host()

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        with _deallocate(task, host):

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            clock = ctypes.c_uint(0)

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            clockid = ctypes.c_int(0)

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            ret = _macho.get_clock(host, clockid, ctypes.pointer(clock))

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            if int(ret) != 0:

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                errno_ = ctypes.get_errno()

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                raise OSError(errno_, os.strerror(errno_))

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            with _deallocate(task, clock):

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                timespec = _mach_timespec()

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                ret = _macho.get_time(clock, ctypes.pointer(timespec))

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                if int(ret) != 0:

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                    errno_ = ctypes.get_errno()

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                    raise OSError(errno_, os.strerror(errno_))

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                return _timespec_to_seconds(timespec)

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elif sys.platform.startswith('win32'):

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    _GetTickCount = getattr(ctypes.windll.kernel32, 'GetTickCount64', None)

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    if _GetTickCount is not None:

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        _GetTickCount.restype = ctypes.c_uint64

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    else:

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        _GetTickCount = ctypes.windll.kernel32.GetTickCount

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        _GetTickCount.restype = ctypes.c_uint32

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    def monotonic():

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        return float(_GetTickCount()) * 1e-3

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else:

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    def monotonic():

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        msg = 'monotonic not supported on your platform'

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        raise OSError(errno.ENOSYS, msg)

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if __name__ == '__main__':

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    print(monotonic())