#include "Python.h"
#ifdef MS_WINDOWS
#include <winsock2.h> /* struct timeval */
#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() */
#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(&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 */

#ifdef _AIX
 /* bpo-34373: AIX does not return NULL if t is too small or too large */
 if (t < -2145916800 /* 1902年01月01日 */
 || t > 2145916800 /* 2038年01月01日 */) {
 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 */
}