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cpython/Python/pytime.c

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#include "Python.h"
#ifdef MS_WINDOWS
#include <windows.h>
#endif
#if defined(__APPLE__)
#include <mach/mach_time.h> /* mach_absolute_time(), mach_timebase_info() */
#endif
#ifdef MS_WINDOWS
static OSVERSIONINFOEX winver;
#endif
static int
pygettimeofday(_PyTime_timeval *tp, _Py_clock_info_t *info, int raise)
{
#ifdef MS_WINDOWS
FILETIME system_time;
ULARGE_INTEGER large;
ULONGLONG microseconds;
assert(info == NULL || raise);
GetSystemTimeAsFileTime(&system_time);
large.u.LowPart = system_time.dwLowDateTime;
large.u.HighPart = system_time.dwHighDateTime;
/* 11,644,473,600,000,000: number of microseconds between
the 1st january 1601 and the 1st january 1970 (369 years + 89 leap
days). */
microseconds = large.QuadPart / 10 - 11644473600000000;
tp->tv_sec = microseconds / 1000000;
tp->tv_usec = microseconds % 1000000;
if (info) {
DWORD timeAdjustment, timeIncrement;
BOOL isTimeAdjustmentDisabled, ok;
info->implementation = "GetSystemTimeAsFileTime()";
info->monotonic = 0;
ok = GetSystemTimeAdjustment(&timeAdjustment, &timeIncrement,
&isTimeAdjustmentDisabled);
if (!ok) {
PyErr_SetFromWindowsErr(0);
return -1;
}
info->resolution = timeIncrement * 1e-7;
info->adjustable = 1;
}
#else /* MS_WINDOWS */
int err;
#ifdef HAVE_CLOCK_GETTIME
struct timespec ts;
#endif
assert(info == NULL || raise);
#ifdef HAVE_CLOCK_GETTIME
err = clock_gettime(CLOCK_REALTIME, &ts);
if (err) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
tp->tv_sec = ts.tv_sec;
tp->tv_usec = ts.tv_nsec / 1000;
if (info) {
struct timespec res;
info->implementation = "clock_gettime(CLOCK_REALTIME)";
info->monotonic = 0;
info->adjustable = 1;
if (clock_getres(CLOCK_REALTIME, &res) == 0)
info->resolution = res.tv_sec + res.tv_nsec * 1e-9;
else
info->resolution = 1e-9;
}
#else /* HAVE_CLOCK_GETTIME */
/* test gettimeofday() */
#ifdef GETTIMEOFDAY_NO_TZ
err = gettimeofday(tp);
#else
err = gettimeofday(tp, (struct timezone *)NULL);
#endif
if (err) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (info) {
info->implementation = "gettimeofday()";
info->resolution = 1e-6;
info->monotonic = 0;
info->adjustable = 1;
}
#endif /* !HAVE_CLOCK_GETTIME */
#endif /* !MS_WINDOWS */
assert(0 <= tp->tv_usec && tp->tv_usec < 1000 * 1000);
return 0;
}
void
_PyTime_gettimeofday(_PyTime_timeval *tp)
{
if (pygettimeofday(tp, NULL, 0) < 0) {
/* cannot happen, _PyTime_Init() checks that pygettimeofday() works */
assert(0);
tp->tv_sec = 0;
tp->tv_usec = 0;
}
}
int
_PyTime_gettimeofday_info(_PyTime_timeval *tp, _Py_clock_info_t *info)
{
return pygettimeofday(tp, info, 1);
}
static int
pymonotonic(_PyTime_timeval *tp, _Py_clock_info_t *info, int raise)
{
#ifdef Py_DEBUG
static _PyTime_timeval last = {0, -1};
#endif
#if defined(MS_WINDOWS)
static ULONGLONG (*GetTickCount64) (void) = NULL;
static ULONGLONG (CALLBACK *Py_GetTickCount64)(void);
static int has_gettickcount64 = -1;
ULONGLONG result;
assert(info == NULL || raise);
if (has_gettickcount64 == -1) {
/* GetTickCount64() was added to Windows Vista */
has_gettickcount64 = (winver.dwMajorVersion >= 6);
if (has_gettickcount64) {
HINSTANCE hKernel32;
hKernel32 = GetModuleHandleW(L"KERNEL32");
*(FARPROC*)&Py_GetTickCount64 = GetProcAddress(hKernel32,
"GetTickCount64");
assert(Py_GetTickCount64 != NULL);
}
}
if (has_gettickcount64) {
result = Py_GetTickCount64();
}
else {
static DWORD last_ticks = 0;
static DWORD n_overflow = 0;
DWORD ticks;
ticks = GetTickCount();
if (ticks < last_ticks)
n_overflow++;
last_ticks = ticks;
result = (ULONGLONG)n_overflow << 32;
result += ticks;
}
tp->tv_sec = result / 1000;
tp->tv_usec = (result % 1000) * 1000;
if (info) {
DWORD timeAdjustment, timeIncrement;
BOOL isTimeAdjustmentDisabled, ok;
if (has_gettickcount64)
info->implementation = "GetTickCount64()";
else
info->implementation = "GetTickCount()";
info->monotonic = 1;
ok = GetSystemTimeAdjustment(&timeAdjustment, &timeIncrement,
&isTimeAdjustmentDisabled);
if (!ok) {
PyErr_SetFromWindowsErr(0);
return -1;
}
info->resolution = timeIncrement * 1e-7;
info->adjustable = 0;
}
#elif defined(__APPLE__)
static mach_timebase_info_data_t timebase;
uint64_t time;
if (timebase.denom == 0) {
/* According to the Technical Q&A QA1398, mach_timebase_info() cannot
fail: https://developer.apple.com/library/mac/#qa/qa1398/ */
(void)mach_timebase_info(&timebase);
}
time = mach_absolute_time();
/* nanoseconds => microseconds */
time /= 1000;
/* apply timebase factor */
time *= timebase.numer;
time /= timebase.denom;
tp->tv_sec = time / (1000 * 1000);
tp->tv_usec = time % (1000 * 1000);
if (info) {
info->implementation = "mach_absolute_time()";
info->resolution = (double)timebase.numer / timebase.denom * 1e-9;
info->monotonic = 1;
info->adjustable = 0;
}
#else
struct timespec ts;
#ifdef CLOCK_HIGHRES
const clockid_t clk_id = CLOCK_HIGHRES;
const char *implementation = "clock_gettime(CLOCK_HIGHRES)";
#else
const clockid_t clk_id = CLOCK_MONOTONIC;
const char *implementation = "clock_gettime(CLOCK_MONOTONIC)";
#endif
assert(info == NULL || raise);
if (clock_gettime(clk_id, &ts) != 0) {
if (raise) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
tp->tv_sec = 0;
tp->tv_usec = 0;
return -1;
}
if (info) {
struct timespec res;
info->monotonic = 1;
info->implementation = implementation;
info->adjustable = 0;
if (clock_getres(clk_id, &res) != 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
info->resolution = res.tv_sec + res.tv_nsec * 1e-9;
}
tp->tv_sec = ts.tv_sec;
tp->tv_usec = ts.tv_nsec / 1000;
#endif
assert(0 <= tp->tv_usec && tp->tv_usec < 1000 * 1000);
#ifdef Py_DEBUG
/* monotonic clock cannot go backward */
assert(last.tv_usec == -1
|| tp->tv_sec > last.tv_sec
|| (tp->tv_sec == last.tv_sec && tp->tv_usec >= last.tv_usec));
last = *tp;
#endif
return 0;
}
void
_PyTime_monotonic(_PyTime_timeval *tp)
{
if (pymonotonic(tp, NULL, 0) < 0) {
/* cannot happen, _PyTime_Init() checks that pymonotonic() works */
assert(0);
tp->tv_sec = 0;
tp->tv_usec = 0;
}
}
int
_PyTime_monotonic_info(_PyTime_timeval *tp, _Py_clock_info_t *info)
{
return pymonotonic(tp, info, 1);
}
static void
error_time_t_overflow(void)
{
PyErr_SetString(PyExc_OverflowError,
"timestamp out of range for platform time_t");
}
time_t
_PyLong_AsTime_t(PyObject *obj)
{
#if defined(HAVE_LONG_LONG) && SIZEOF_TIME_T == SIZEOF_LONG_LONG
PY_LONG_LONG val;
val = PyLong_AsLongLong(obj);
#else
long val;
assert(sizeof(time_t) <= sizeof(long));
val = PyLong_AsLong(obj);
#endif
if (val == -1 && PyErr_Occurred()) {
if (PyErr_ExceptionMatches(PyExc_OverflowError))
error_time_t_overflow();
return -1;
}
return (time_t)val;
}
PyObject *
_PyLong_FromTime_t(time_t t)
{
#if defined(HAVE_LONG_LONG) && SIZEOF_TIME_T == SIZEOF_LONG_LONG
return PyLong_FromLongLong((PY_LONG_LONG)t);
#else
assert(sizeof(time_t) <= sizeof(long));
return PyLong_FromLong((long)t);
#endif
}
static int
_PyTime_ObjectToDenominator(PyObject *obj, time_t *sec, long *numerator,
double denominator, _PyTime_round_t round)
{
assert(denominator <= LONG_MAX);
if (PyFloat_Check(obj)) {
double d, intpart, err;
/* volatile avoids unsafe optimization on float enabled by gcc -O3 */
volatile double floatpart;
d = PyFloat_AsDouble(obj);
floatpart = modf(d, &intpart);
if (floatpart < 0) {
floatpart = 1.0 + floatpart;
intpart -= 1.0;
}
floatpart *= denominator;
if (round == _PyTime_ROUND_UP) {
if (intpart >= 0) {
floatpart = ceil(floatpart);
if (floatpart >= denominator) {
floatpart = 0.0;
intpart += 1.0;
}
}
else {
floatpart = floor(floatpart);
}
}
*sec = (time_t)intpart;
err = intpart - (double)*sec;
if (err <= -1.0 || err >= 1.0) {
error_time_t_overflow();
return -1;
}
*numerator = (long)floatpart;
return 0;
}
else {
*sec = _PyLong_AsTime_t(obj);
if (*sec == (time_t)-1 && PyErr_Occurred())
return -1;
*numerator = 0;
return 0;
}
}
int
_PyTime_ObjectToTime_t(PyObject *obj, time_t *sec, _PyTime_round_t round)
{
if (PyFloat_Check(obj)) {
double d, intpart, err;
d = PyFloat_AsDouble(obj);
if (round == _PyTime_ROUND_UP) {
if (d >= 0)
d = ceil(d);
else
d = floor(d);
}
(void)modf(d, &intpart);
*sec = (time_t)intpart;
err = intpart - (double)*sec;
if (err <= -1.0 || err >= 1.0) {
error_time_t_overflow();
return -1;
}
return 0;
}
else {
*sec = _PyLong_AsTime_t(obj);
if (*sec == (time_t)-1 && PyErr_Occurred())
return -1;
return 0;
}
}
int
_PyTime_ObjectToTimespec(PyObject *obj, time_t *sec, long *nsec,
_PyTime_round_t round)
{
return _PyTime_ObjectToDenominator(obj, sec, nsec, 1e9, round);
}
int
_PyTime_ObjectToTimeval(PyObject *obj, time_t *sec, long *usec,
_PyTime_round_t round)
{
return _PyTime_ObjectToDenominator(obj, sec, usec, 1e6, round);
}
int
_PyTime_Init(void)
{
_PyTime_timeval tv;
#ifdef MS_WINDOWS
winver.dwOSVersionInfoSize = sizeof(winver);
if (!GetVersionEx((OSVERSIONINFO*)&winver)) {
PyErr_SetFromWindowsErr(0);
return -1;
}
#endif
/* ensure that the system clock works */
if (_PyTime_gettimeofday_info(&tv, NULL) < 0)
return -1;
/* ensure that the operating system provides a monotonic clock */
if (_PyTime_monotonic_info(&tv, NULL) < 0)
return -1;
return 0;
}
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