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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
#define _PyTime_check_mul_overflow(a, b) \
(assert(b > 0), \
(_PyTime_t)(a) < _PyTime_MIN / (_PyTime_t)(b) \
|| _PyTime_MAX / (_PyTime_t)(b) < (_PyTime_t)(a))
/* To millisecond (10^-3) */
#define SEC_TO_MS 1000
/* To microseconds (10^-6) */
#define MS_TO_US 1000
#define SEC_TO_US (SEC_TO_MS * MS_TO_US)
/* To nanoseconds (10^-9) */
#define US_TO_NS 1000
#define MS_TO_NS (MS_TO_US * US_TO_NS)
#define SEC_TO_NS (SEC_TO_MS * MS_TO_NS)
/* Conversion from nanoseconds */
#define NS_TO_MS (1000 * 1000)
#define NS_TO_US (1000)
static void
error_time_t_overflow(void)
{
PyErr_SetString(PyExc_OverflowError,
"timestamp out of range for platform time_t");
}
static void
_PyTime_overflow(void)
{
PyErr_SetString(PyExc_OverflowError,
"timestamp too large to convert to C _PyTime_t");
}
_PyTime_t
_PyTime_MulDiv(_PyTime_t ticks, _PyTime_t mul, _PyTime_t div)
{
_PyTime_t intpart, remaining;
/* Compute (ticks * mul / div) in two parts to prevent integer overflow:
compute integer part, and then the remaining part.
(ticks * mul) / div == (ticks / div) * mul + (ticks % div) * mul / div
The caller must ensure that "(div - 1) * mul" cannot overflow. */
intpart = ticks / div;
ticks %= div;
remaining = ticks * mul;
remaining /= div;
return intpart * mul + remaining;
}
time_t
_PyLong_AsTime_t(PyObject *obj)
{
#if SIZEOF_TIME_T == SIZEOF_LONG_LONG
long long val;
val = PyLong_AsLongLong(obj);
#else
long val;
Py_BUILD_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 SIZEOF_TIME_T == SIZEOF_LONG_LONG
return PyLong_FromLongLong((long long)t);
#else
Py_BUILD_ASSERT(sizeof(time_t) <= sizeof(long));
return PyLong_FromLong((long)t);
#endif
}
/* Round to nearest with ties going to nearest even integer
(_PyTime_ROUND_HALF_EVEN) */
static double
_PyTime_RoundHalfEven(double x)
{
double rounded = round(x);
if (fabs(x-rounded) == 0.5) {
/* halfway case: round to even */
rounded = 2.0*round(x/2.0);
}
return rounded;
}
static double
_PyTime_Round(double x, _PyTime_round_t round)
{
/* volatile avoids optimization changing how numbers are rounded */
volatile double d;
d = x;
if (round == _PyTime_ROUND_HALF_EVEN) {
d = _PyTime_RoundHalfEven(d);
}
else if (round == _PyTime_ROUND_CEILING) {
d = ceil(d);
}
else if (round == _PyTime_ROUND_FLOOR) {
d = floor(d);
}
else {
assert(round == _PyTime_ROUND_UP);
d = (d >= 0.0) ? ceil(d) : floor(d);
}
return d;
}
static int
_PyTime_DoubleToDenominator(double d, time_t *sec, long *numerator,
long idenominator, _PyTime_round_t round)
{
double denominator = (double)idenominator;
double intpart;
/* volatile avoids optimization changing how numbers are rounded */
volatile double floatpart;
floatpart = modf(d, &intpart);
floatpart *= denominator;
floatpart = _PyTime_Round(floatpart, round);
if (floatpart >= denominator) {
floatpart -= denominator;
intpart += 1.0;
}
else if (floatpart < 0) {
floatpart += denominator;
intpart -= 1.0;
}
assert(0.0 <= floatpart && floatpart < denominator);
if (!_Py_InIntegralTypeRange(time_t, intpart)) {
error_time_t_overflow();
return -1;
}
*sec = (time_t)intpart;
*numerator = (long)floatpart;
assert(0 <= *numerator && *numerator < idenominator);
return 0;
}
static int
_PyTime_ObjectToDenominator(PyObject *obj, time_t *sec, long *numerator,
long denominator, _PyTime_round_t round)
{
assert(denominator >= 1);
if (PyFloat_Check(obj)) {
double d = PyFloat_AsDouble(obj);
if (Py_IS_NAN(d)) {
*numerator = 0;
PyErr_SetString(PyExc_ValueError, "Invalid value NaN (not a number)");
return -1;
}
return _PyTime_DoubleToDenominator(d, sec, numerator,
denominator, round);
}
else {
*sec = _PyLong_AsTime_t(obj);
*numerator = 0;
if (*sec == (time_t)-1 && PyErr_Occurred()) {
return -1;
}
return 0;
}
}
int
_PyTime_ObjectToTime_t(PyObject *obj, time_t *sec, _PyTime_round_t round)
{
if (PyFloat_Check(obj)) {
double intpart;
/* volatile avoids optimization changing how numbers are rounded */
volatile double d;
d = PyFloat_AsDouble(obj);
if (Py_IS_NAN(d)) {
PyErr_SetString(PyExc_ValueError, "Invalid value NaN (not a number)");
return -1;
}
d = _PyTime_Round(d, round);
(void)modf(d, &intpart);
if (!_Py_InIntegralTypeRange(time_t, intpart)) {
error_time_t_overflow();
return -1;
}
*sec = (time_t)intpart;
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, SEC_TO_NS, round);
}
int
_PyTime_ObjectToTimeval(PyObject *obj, time_t *sec, long *usec,
_PyTime_round_t round)
{
return _PyTime_ObjectToDenominator(obj, sec, usec, SEC_TO_US, round);
}
_PyTime_t
_PyTime_FromSeconds(int seconds)
{
_PyTime_t t;
/* ensure that integer overflow cannot happen, int type should have 32
bits, whereas _PyTime_t type has at least 64 bits (SEC_TO_MS takes 30
bits). */
Py_BUILD_ASSERT(INT_MAX <= _PyTime_MAX / SEC_TO_NS);
Py_BUILD_ASSERT(INT_MIN >= _PyTime_MIN / SEC_TO_NS);
t = (_PyTime_t)seconds;
assert((t >= 0 && t <= _PyTime_MAX / SEC_TO_NS)
|| (t < 0 && t >= _PyTime_MIN / SEC_TO_NS));
t *= SEC_TO_NS;
return t;
}
_PyTime_t
_PyTime_FromNanoseconds(_PyTime_t ns)
{
/* _PyTime_t already uses nanosecond resolution, no conversion needed */
return ns;
}
int
_PyTime_FromNanosecondsObject(_PyTime_t *tp, PyObject *obj)
{
long long nsec;
_PyTime_t t;
if (!PyLong_Check(obj)) {
PyErr_Format(PyExc_TypeError, "expect int, got %s",
Py_TYPE(obj)->tp_name);
return -1;
}
Py_BUILD_ASSERT(sizeof(long long) == sizeof(_PyTime_t));
nsec = PyLong_AsLongLong(obj);
if (nsec == -1 && PyErr_Occurred()) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
_PyTime_overflow();
}
return -1;
}
/* _PyTime_t already uses nanosecond resolution, no conversion needed */
t = (_PyTime_t)nsec;
*tp = t;
return 0;
}
#ifdef HAVE_CLOCK_GETTIME
static int
pytime_fromtimespec(_PyTime_t *tp, struct timespec *ts, int raise)
{
_PyTime_t t, nsec;
int res = 0;
Py_BUILD_ASSERT(sizeof(ts->tv_sec) <= sizeof(_PyTime_t));
t = (_PyTime_t)ts->tv_sec;
if (_PyTime_check_mul_overflow(t, SEC_TO_NS)) {
if (raise) {
_PyTime_overflow();
}
res = -1;
t = (t > 0) ? _PyTime_MAX : _PyTime_MIN;
}
else {
t = t * SEC_TO_NS;
}
nsec = ts->tv_nsec;
/* The following test is written for positive only nsec */
assert(nsec >= 0);
if (t > _PyTime_MAX - nsec) {
if (raise) {
_PyTime_overflow();
}
res = -1;
t = _PyTime_MAX;
}
else {
t += nsec;
}
*tp = t;
return res;
}
int
_PyTime_FromTimespec(_PyTime_t *tp, struct timespec *ts)
{
return pytime_fromtimespec(tp, ts, 1);
}
#endif
#if !defined(MS_WINDOWS)
static int
pytime_fromtimeval(_PyTime_t *tp, struct timeval *tv, int raise)
{
_PyTime_t t, usec;
int res = 0;
Py_BUILD_ASSERT(sizeof(tv->tv_sec) <= sizeof(_PyTime_t));
t = (_PyTime_t)tv->tv_sec;
if (_PyTime_check_mul_overflow(t, SEC_TO_NS)) {
if (raise) {
_PyTime_overflow();
}
res = -1;
t = (t > 0) ? _PyTime_MAX : _PyTime_MIN;
}
else {
t = t * SEC_TO_NS;
}
usec = (_PyTime_t)tv->tv_usec * US_TO_NS;
/* The following test is written for positive only usec */
assert(usec >= 0);
if (t > _PyTime_MAX - usec) {
if (raise) {
_PyTime_overflow();
}
res = -1;
t = _PyTime_MAX;
}
else {
t += usec;
}
*tp = t;
return res;
}
int
_PyTime_FromTimeval(_PyTime_t *tp, struct timeval *tv)
{
return pytime_fromtimeval(tp, tv, 1);
}
#endif
static int
_PyTime_FromDouble(_PyTime_t *t, double value, _PyTime_round_t round,
long unit_to_ns)
{
/* volatile avoids optimization changing how numbers are rounded */
volatile double d;
/* convert to a number of nanoseconds */
d = value;
d *= (double)unit_to_ns;
d = _PyTime_Round(d, round);
if (!_Py_InIntegralTypeRange(_PyTime_t, d)) {
_PyTime_overflow();
return -1;
}
*t = (_PyTime_t)d;
return 0;
}
static int
_PyTime_FromObject(_PyTime_t *t, PyObject *obj, _PyTime_round_t round,
long unit_to_ns)
{
if (PyFloat_Check(obj)) {
double d;
d = PyFloat_AsDouble(obj);
if (Py_IS_NAN(d)) {
PyErr_SetString(PyExc_ValueError, "Invalid value NaN (not a number)");
return -1;
}
return _PyTime_FromDouble(t, d, round, unit_to_ns);
}
else {
long long sec;
Py_BUILD_ASSERT(sizeof(long long) <= sizeof(_PyTime_t));
sec = PyLong_AsLongLong(obj);
if (sec == -1 && PyErr_Occurred()) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
_PyTime_overflow();
}
return -1;
}
if (_PyTime_check_mul_overflow(sec, unit_to_ns)) {
_PyTime_overflow();
return -1;
}
*t = sec * unit_to_ns;
return 0;
}
}
int
_PyTime_FromSecondsObject(_PyTime_t *t, PyObject *obj, _PyTime_round_t round)
{
return _PyTime_FromObject(t, obj, round, SEC_TO_NS);
}
int
_PyTime_FromMillisecondsObject(_PyTime_t *t, PyObject *obj, _PyTime_round_t round)
{
return _PyTime_FromObject(t, obj, round, MS_TO_NS);
}
double
_PyTime_AsSecondsDouble(_PyTime_t t)
{
/* volatile avoids optimization changing how numbers are rounded */
volatile double d;
if (t % SEC_TO_NS == 0) {
_PyTime_t secs;
/* Divide using integers to avoid rounding issues on the integer part.
1e-9 cannot be stored exactly in IEEE 64-bit. */
secs = t / SEC_TO_NS;
d = (double)secs;
}
else {
d = (double)t;
d /= 1e9;
}
return d;
}
PyObject *
_PyTime_AsNanosecondsObject(_PyTime_t t)
{
Py_BUILD_ASSERT(sizeof(long long) >= sizeof(_PyTime_t));
return PyLong_FromLongLong((long long)t);
}
static _PyTime_t
_PyTime_Divide(const _PyTime_t t, const _PyTime_t k,
const _PyTime_round_t round)
{
assert(k > 1);
if (round == _PyTime_ROUND_HALF_EVEN) {
_PyTime_t x, r, abs_r;
x = t / k;
r = t % k;
abs_r = Py_ABS(r);
if (abs_r > k / 2 || (abs_r == k / 2 && (Py_ABS(x) & 1))) {
if (t >= 0) {
x++;
}
else {
x--;
}
}
return x;
}
else if (round == _PyTime_ROUND_CEILING) {
if (t >= 0) {
return (t + k - 1) / k;
}
else {
return t / k;
}
}
else if (round == _PyTime_ROUND_FLOOR){
if (t >= 0) {
return t / k;
}
else {
return (t - (k - 1)) / k;
}
}
else {
assert(round == _PyTime_ROUND_UP);
if (t >= 0) {
return (t + k - 1) / k;
}
else {
return (t - (k - 1)) / k;
}
}
}
_PyTime_t
_PyTime_AsMilliseconds(_PyTime_t t, _PyTime_round_t round)
{
return _PyTime_Divide(t, NS_TO_MS, round);
}
_PyTime_t
_PyTime_AsMicroseconds(_PyTime_t t, _PyTime_round_t round)
{
return _PyTime_Divide(t, NS_TO_US, round);
}
static int
_PyTime_AsTimeval_impl(_PyTime_t t, _PyTime_t *p_secs, int *p_us,
_PyTime_round_t round)
{
_PyTime_t secs, ns;
int usec;
int res = 0;
secs = t / SEC_TO_NS;
ns = t % SEC_TO_NS;
usec = (int)_PyTime_Divide(ns, US_TO_NS, round);
if (usec < 0) {
usec += SEC_TO_US;
if (secs != _PyTime_MIN) {
secs -= 1;
}
else {
res = -1;
}
}
else if (usec >= SEC_TO_US) {
usec -= SEC_TO_US;
if (secs != _PyTime_MAX) {
secs += 1;
}
else {
res = -1;
}
}
assert(0 <= usec && usec < SEC_TO_US);
*p_secs = secs;
*p_us = usec;
return res;
}
static int
_PyTime_AsTimevalStruct_impl(_PyTime_t t, struct timeval *tv,
_PyTime_round_t round, int raise)
{
_PyTime_t secs, secs2;
int us;
int res;
res = _PyTime_AsTimeval_impl(t, &secs, &us, round);
#ifdef MS_WINDOWS
tv->tv_sec = (long)secs;
#else
tv->tv_sec = secs;
#endif
tv->tv_usec = us;
secs2 = (_PyTime_t)tv->tv_sec;
if (res < 0 || secs2 != secs) {
if (raise) {
error_time_t_overflow();
}
return -1;
}
return 0;
}
int
_PyTime_AsTimeval(_PyTime_t t, struct timeval *tv, _PyTime_round_t round)
{
return _PyTime_AsTimevalStruct_impl(t, tv, round, 1);
}
int
_PyTime_AsTimeval_noraise(_PyTime_t t, struct timeval *tv, _PyTime_round_t round)
{
return _PyTime_AsTimevalStruct_impl(t, tv, round, 0);
}
int
_PyTime_AsTimevalTime_t(_PyTime_t t, time_t *p_secs, int *us,
_PyTime_round_t round)
{
_PyTime_t secs;
int res;
res = _PyTime_AsTimeval_impl(t, &secs, us, round);
*p_secs = secs;
if (res < 0 || (_PyTime_t)*p_secs != secs) {
error_time_t_overflow();
return -1;
}
return 0;
}
#if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_KQUEUE)
int
_PyTime_AsTimespec(_PyTime_t t, struct timespec *ts)
{
_PyTime_t secs, nsec;
secs = t / SEC_TO_NS;
nsec = t % SEC_TO_NS;
if (nsec < 0) {
nsec += SEC_TO_NS;
secs -= 1;
}
ts->tv_sec = (time_t)secs;
assert(0 <= nsec && nsec < SEC_TO_NS);
ts->tv_nsec = nsec;
if ((_PyTime_t)ts->tv_sec != secs) {
error_time_t_overflow();
return -1;
}
return 0;
}
#endif
static int
pygettimeofday(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
{
#ifdef MS_WINDOWS
FILETIME system_time;
ULARGE_INTEGER large;
assert(info == NULL || raise);
GetSystemTimeAsFileTime(&system_time);
large.u.LowPart = system_time.dwLowDateTime;
large.u.HighPart = system_time.dwHighDateTime;
/* 11,644,473,600,000,000,000: number of nanoseconds between
the 1st january 1601 and the 1st january 1970 (369 years + 89 leap
days). */
*tp = large.QuadPart * 100 - 11644473600000000000;
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;
#else
struct timeval tv;
#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;
}
if (pytime_fromtimespec(tp, &ts, raise) < 0) {
return -1;
}
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() */
err = gettimeofday(&tv, (struct timezone *)NULL);
if (err) {
if (raise) {
PyErr_SetFromErrno(PyExc_OSError);
}
return -1;
}
if (pytime_fromtimeval(tp, &tv, raise) < 0) {
return -1;
}
if (info) {
info->implementation = "gettimeofday()";
info->resolution = 1e-6;
info->monotonic = 0;
info->adjustable = 1;
}
#endif /* !HAVE_CLOCK_GETTIME */
#endif /* !MS_WINDOWS */
return 0;
}
_PyTime_t
_PyTime_GetSystemClock(void)
{
_PyTime_t t;
if (pygettimeofday(&t, NULL, 0) < 0) {
/* should not happen, _PyTime_Init() checked the clock at startup */
Py_UNREACHABLE();
}
return t;
}
int
_PyTime_GetSystemClockWithInfo(_PyTime_t *t, _Py_clock_info_t *info)
{
return pygettimeofday(t, info, 1);
}
static int
pymonotonic(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
{
#if defined(MS_WINDOWS)
ULONGLONG ticks;
_PyTime_t t;
assert(info == NULL || raise);
ticks = GetTickCount64();
Py_BUILD_ASSERT(sizeof(ticks) <= sizeof(_PyTime_t));
t = (_PyTime_t)ticks;
if (_PyTime_check_mul_overflow(t, MS_TO_NS)) {
if (raise) {
_PyTime_overflow();
return -1;
}
/* Hello, time traveler! */
Py_UNREACHABLE();
}
*tp = t * MS_TO_NS;
if (info) {
DWORD timeAdjustment, timeIncrement;
BOOL isTimeAdjustmentDisabled, ok;
info->implementation = "GetTickCount64()";
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;
static uint64_t t0 = 0;
uint64_t ticks;
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);
/* Sanity check: should never occur in practice */
if (timebase.numer < 1 || timebase.denom < 1) {
PyErr_SetString(PyExc_RuntimeError,
"invalid mach_timebase_info");
return -1;
}
/* Check that timebase.numer and timebase.denom can be casted to
_PyTime_t. In practice, timebase uses uint32_t, so casting cannot
overflow. At the end, only make sure that the type is uint32_t
(_PyTime_t is 64-bit long). */
assert(sizeof(timebase.numer) < sizeof(_PyTime_t));
assert(sizeof(timebase.denom) < sizeof(_PyTime_t));
/* Make sure that (ticks * timebase.numer) cannot overflow in
_PyTime_MulDiv(), with ticks < timebase.denom.
Known time bases:
* always (1, 1) on Intel
* (1000000000, 33333335) or (1000000000, 25000000) on PowerPC
None of these time bases can overflow with 64-bit _PyTime_t, but
check for overflow, just in case. */
if ((_PyTime_t)timebase.numer > _PyTime_MAX / (_PyTime_t)timebase.denom) {
PyErr_SetString(PyExc_OverflowError,
"mach_timebase_info is too large");
return -1;
}
t0 = mach_absolute_time();
}
if (info) {
info->implementation = "mach_absolute_time()";
info->resolution = (double)timebase.numer / (double)timebase.denom * 1e-9;
info->monotonic = 1;
info->adjustable = 0;
}
ticks = mach_absolute_time();
/* Use a "time zero" to reduce precision loss when converting time
to floatting point number, as in time.monotonic(). */
ticks -= t0;
*tp = _PyTime_MulDiv(ticks,
(_PyTime_t)timebase.numer,
(_PyTime_t)timebase.denom);
#elif defined(__hpux)
hrtime_t time;
time = gethrtime();
if (time == -1) {
if (raise) {
PyErr_SetFromErrno(PyExc_OSError);
}
return -1;
}
*tp = time;
if (info) {
info->implementation = "gethrtime()";
info->resolution = 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;
}
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;
}
if (pytime_fromtimespec(tp, &ts, raise) < 0) {
return -1;
}
#endif
return 0;
}
_PyTime_t
_PyTime_GetMonotonicClock(void)
{
_PyTime_t t;
if (pymonotonic(&t, NULL, 0) < 0) {
/* should not happen, _PyTime_Init() checked that monotonic clock at
startup */
Py_UNREACHABLE();
}
return t;
}
int
_PyTime_GetMonotonicClockWithInfo(_PyTime_t *tp, _Py_clock_info_t *info)
{
return pymonotonic(tp, info, 1);
}
#ifdef MS_WINDOWS
static int
win_perf_counter(_PyTime_t *tp, _Py_clock_info_t *info)
{
static LONGLONG frequency = 0;
static LONGLONG t0 = 0;
LARGE_INTEGER now;
LONGLONG ticksll;
_PyTime_t ticks;
if (frequency == 0) {
LARGE_INTEGER freq;
if (!QueryPerformanceFrequency(&freq)) {
PyErr_SetFromWindowsErr(0);
return -1;
}
frequency = freq.QuadPart;
/* Sanity check: should never occur in practice */
if (frequency < 1) {
PyErr_SetString(PyExc_RuntimeError,
"invalid QueryPerformanceFrequency");
return -1;
}
/* Check that frequency can be casted to _PyTime_t.
Make also sure that (ticks * SEC_TO_NS) cannot overflow in
_PyTime_MulDiv(), with ticks < frequency.
Known QueryPerformanceFrequency() values:
* 10,000,000 (10 MHz): 100 ns resolution
* 3,579,545 Hz (3.6 MHz): 279 ns resolution
None of these frequencies can overflow with 64-bit _PyTime_t, but
check for overflow, just in case. */
if (frequency > _PyTime_MAX
|| frequency > (LONGLONG)_PyTime_MAX / (LONGLONG)SEC_TO_NS) {
PyErr_SetString(PyExc_OverflowError,
"QueryPerformanceFrequency is too large");
return -1;
}
QueryPerformanceCounter(&now);
t0 = now.QuadPart;
}
if (info) {
info->implementation = "QueryPerformanceCounter()";
info->resolution = 1.0 / (double)frequency;
info->monotonic = 1;
info->adjustable = 0;
}
QueryPerformanceCounter(&now);
ticksll = now.QuadPart;
/* Use a "time zero" to reduce precision loss when converting time
to floatting point number, as in time.perf_counter(). */
ticksll -= t0;
/* Make sure that casting LONGLONG to _PyTime_t cannot overflow,
both types are signed */
Py_BUILD_ASSERT(sizeof(ticksll) <= sizeof(ticks));
ticks = (_PyTime_t)ticksll;
*tp = _PyTime_MulDiv(ticks, SEC_TO_NS, (_PyTime_t)frequency);
return 0;
}
#endif
int
_PyTime_GetPerfCounterWithInfo(_PyTime_t *t, _Py_clock_info_t *info)
{
#ifdef MS_WINDOWS
return win_perf_counter(t, info);
#else
return _PyTime_GetMonotonicClockWithInfo(t, info);
#endif
}
_PyTime_t
_PyTime_GetPerfCounter(void)
{
_PyTime_t t;
if (_PyTime_GetPerfCounterWithInfo(&t, NULL)) {
Py_UNREACHABLE();
}
return t;
}
int
_PyTime_Init(void)
{
/* check that time.time(), time.monotonic() and time.perf_counter() clocks
are working properly to not have to check for exceptions at runtime. If
a clock works once, it cannot fail in next calls. */
_PyTime_t t;
if (_PyTime_GetSystemClockWithInfo(&t, NULL) < 0) {
return -1;
}
if (_PyTime_GetMonotonicClockWithInfo(&t, NULL) < 0) {
return -1;
}
if (_PyTime_GetPerfCounterWithInfo(&t, NULL) < 0) {
return -1;
}
return 0;
}
int
_PyTime_localtime(time_t t, struct tm *tm)
{
#ifdef MS_WINDOWS
int error;
error = localtime_s(tm, &t);
if (error != 0) {
errno = error;
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return 0;
#else /* !MS_WINDOWS */
#if defined(_AIX) && (SIZEOF_TIME_T < 8)
/* bpo-34373: AIX does not return NULL if t is too small or too large */
if (t < -2145916800 /* 1902-01-01 */
|| t > 2145916800 /* 2038-01-01 */) {
errno = EINVAL;
PyErr_SetString(PyExc_OverflowError,
"localtime argument out of range");
return -1;
}
#endif
errno = 0;
if (localtime_r(&t, tm) == NULL) {
if (errno == 0) {
errno = EINVAL;
}
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return 0;
#endif /* MS_WINDOWS */
}
int
_PyTime_gmtime(time_t t, struct tm *tm)
{
#ifdef MS_WINDOWS
int error;
error = gmtime_s(tm, &t);
if (error != 0) {
errno = error;
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return 0;
#else /* !MS_WINDOWS */
if (gmtime_r(&t, tm) == NULL) {
#ifdef EINVAL
if (errno == 0) {
errno = EINVAL;
}
#endif
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return 0;
#endif /* MS_WINDOWS */
}
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