cpython/Python/pytime.c at 51b93984449ec79908036cc7a1a5922458f87690 · python/cpython · GitHub

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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");

}

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

}

/* 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

d = floor(d);

return d;

}

static int

_PyTime_DoubleToDenominator(double d, time_t *sec, long *numerator,

double denominator, _PyTime_round_t round)

{

double intpart, err;

/* 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);

*sec = (time_t)intpart;

*numerator = (long)floatpart;

err = intpart - (double)*sec;

if (err <= -1.0 || err >= 1.0) {

error_time_t_overflow();

return -1;

}

return 0;

}

static int

_PyTime_ObjectToDenominator(PyObject *obj, time_t *sec, long *numerator,

double denominator, _PyTime_round_t round)

{

assert(denominator <= (double)LONG_MAX);

if (PyFloat_Check(obj)) {

double d = PyFloat_AsDouble(obj);

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, err;

/* volatile avoids optimization changing how numbers are rounded */

volatile double d;

d = PyFloat_AsDouble(obj);

d = _PyTime_Round(d, round);

(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)

{

int res;

res = _PyTime_ObjectToDenominator(obj, sec, nsec, 1e9, round);

assert(0 <= *nsec && *nsec < SEC_TO_NS);

return res;

}

int

_PyTime_ObjectToTimeval(PyObject *obj, time_t *sec, long *usec,

_PyTime_round_t round)

{

int res;

res = _PyTime_ObjectToDenominator(obj, sec, usec, 1e6, round);

assert(0 <= *usec && *usec < SEC_TO_US);

return res;

}

static void

_PyTime_overflow(void)

{

PyErr_SetString(PyExc_OverflowError,

"timestamp too large to convert to C _PyTime_t");

}

_PyTime_t

_PyTime_FromSeconds(int seconds)

{

_PyTime_t t;

t = (_PyTime_t)seconds;

/* 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). */

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(PY_LONG_LONG ns)

{

_PyTime_t t;

assert(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t));

t = Py_SAFE_DOWNCAST(ns, PY_LONG_LONG, _PyTime_t);

return t;

}

#ifdef HAVE_CLOCK_GETTIME

static int

_PyTime_FromTimespec(_PyTime_t *tp, struct timespec *ts, int raise)

{

_PyTime_t t;

int res = 0;

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 * SEC_TO_NS;

t += ts->tv_nsec;

*tp = t;

return res;

}

#elif !defined(MS_WINDOWS)

static int

_PyTime_FromTimeval(_PyTime_t *tp, struct timeval *tv, int raise)

{

_PyTime_t t;

int res = 0;

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 * SEC_TO_NS;

t += (_PyTime_t)tv->tv_usec * US_TO_NS;

*tp = t;

return res;

}

#endif

static int

_PyTime_FromFloatObject(_PyTime_t *t, double value, _PyTime_round_t round,

long unit_to_ns)

{

double err;

/* 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);

*t = (_PyTime_t)d;

err = d - (double)*t;

if (fabs(err) >= 1.0) {

_PyTime_overflow();

return -1;

}

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);

return _PyTime_FromFloatObject(t, d, round, unit_to_ns);

}

else {

#ifdef HAVE_LONG_LONG

PY_LONG_LONG sec;

assert(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t));

sec = PyLong_AsLongLong(obj);

#else

long sec;

assert(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t));

sec = PyLong_AsLong(obj);

#endif

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)

{

#ifdef HAVE_LONG_LONG

assert(sizeof(PY_LONG_LONG) >= sizeof(_PyTime_t));

return PyLong_FromLongLong((PY_LONG_LONG)t);

#else

assert(sizeof(long) >= sizeof(_PyTime_t));

return PyLong_FromLong((long)t);

#endif

}

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 (t >= 0)

return t / 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, struct timeval *tv, _PyTime_round_t round,

int raise)

{

_PyTime_t secs, ns;

int res = 0;

int usec;

secs = t / SEC_TO_NS;

ns = t % SEC_TO_NS;

#ifdef MS_WINDOWS

tv->tv_sec = (long)secs;

#else

tv->tv_sec = secs;

#endif

if ((_PyTime_t)tv->tv_sec != secs)

res = -1;

usec = (int)_PyTime_Divide(ns, US_TO_NS, round);

if (usec < 0) {

usec += SEC_TO_US;

tv->tv_sec -= 1;

}

else if (usec >= SEC_TO_US) {

usec -= SEC_TO_US;

tv->tv_sec += 1;

}

assert(0 <= usec && usec < SEC_TO_US);

tv->tv_usec = usec;

if (res && raise)

error_time_t_overflow();

return res;

}

int

_PyTime_AsTimeval(_PyTime_t t, struct timeval *tv, _PyTime_round_t round)

{

return _PyTime_AsTimeval_impl(t, tv, round, 1);

}

int

_PyTime_AsTimeval_noraise(_PyTime_t t, struct timeval *tv, _PyTime_round_t round)

{

return _PyTime_AsTimeval_impl(t, tv, round, 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_new(_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() */

#ifdef GETTIMEOFDAY_NO_TZ

err = gettimeofday(&tv);

#else

err = gettimeofday(&tv, (struct timezone *)NULL);

#endif

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_new(&t, NULL, 0) < 0) {

/* should not happen, _PyTime_Init() checked the clock at startup */

assert(0);

/* use a fixed value instead of a random value from the stack */

t = 0;

}

return t;

}

int

_PyTime_GetSystemClockWithInfo(_PyTime_t *t, _Py_clock_info_t *info)

{

return pygettimeofday_new(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();

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! */

assert(0);

}

*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;

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();

/* apply timebase factor */

time *= timebase.numer;

time /= timebase.denom;

*tp = time;

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;

}

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 */

assert(0);

/* use a fixed value instead of a random value from the stack */

t = 0;

}

return t;

}

int

_PyTime_GetMonotonicClockWithInfo(_PyTime_t *tp, _Py_clock_info_t *info)

{

return pymonotonic(tp, info, 1);

}

int

_PyTime_Init(void)

{

_PyTime_t t;

/* ensure that the system clock works */

if (_PyTime_GetSystemClockWithInfo(&t, NULL) < 0)

return -1;

/* ensure that the operating system provides a monotonic clock */

if (_PyTime_GetMonotonicClockWithInfo(&t, NULL) < 0)

return -1;

/* check that _PyTime_FromSeconds() cannot overflow */

assert(INT_MAX <= _PyTime_MAX / SEC_TO_NS);

assert(INT_MIN >= _PyTime_MIN / SEC_TO_NS);

return 0;

}

cpython/Python/pytime.c at 51b93984449ec79908036cc7a1a5922458f87690 · python/cpython · GitHub

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