diff options
Diffstat (limited to 'Python/pytime.c')
| -rw-r--r-- | Python/pytime.c | 274 |
1 files changed, 179 insertions, 95 deletions
diff --git a/Python/pytime.c b/Python/pytime.c index 7f65824..81682ca 100644 --- a/Python/pytime.c +++ b/Python/pytime.c @@ -7,6 +7,11 @@ #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 @@ -38,7 +43,7 @@ _PyLong_AsTime_t(PyObject *obj) val = PyLong_AsLongLong(obj); #else long val; - assert(sizeof(time_t) <= sizeof(long)); + Py_BUILD_ASSERT(sizeof(time_t) <= sizeof(long)); val = PyLong_AsLong(obj); #endif if (val == -1 && PyErr_Occurred()) { @@ -55,55 +60,88 @@ _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)); + 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 + d = floor(d); + return d; +} + static int -_PyTime_ObjectToDenominator(PyObject *obj, time_t *sec, long *numerator, +_PyTime_DoubleToDenominator(double d, 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; + double intpart, err; + /* volatile avoids optimization changing how numbers are rounded */ + volatile double floatpart; - d = PyFloat_AsDouble(obj); - floatpart = modf(d, &intpart); - if (floatpart < 0) { - floatpart = 1.0 + floatpart; - intpart -= 1.0; - } + floatpart = modf(d, &intpart); - floatpart *= denominator; - if (round == _PyTime_ROUND_CEILING) { - floatpart = ceil(floatpart); - if (floatpart >= denominator) { - floatpart = 0.0; - intpart += 1.0; - } - } - else { - floatpart = floor(floatpart); - } + 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; - err = intpart - (double)*sec; - if (err <= -1.0 || err >= 1.0) { - error_time_t_overflow(); - return -1; - } + *sec = (time_t)intpart; + *numerator = (long)floatpart; - *numerator = (long)floatpart; - return 0; + 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; - *numerator = 0; return 0; } } @@ -112,13 +150,12 @@ int _PyTime_ObjectToTime_t(PyObject *obj, time_t *sec, _PyTime_round_t round) { if (PyFloat_Check(obj)) { - double d, intpart, err; + double intpart, err; + /* volatile avoids optimization changing how numbers are rounded */ + volatile double d; d = PyFloat_AsDouble(obj); - if (round == _PyTime_ROUND_CEILING) - d = ceil(d); - else - d = floor(d); + d = _PyTime_Round(d, round); (void)modf(d, &intpart); *sec = (time_t)intpart; @@ -141,14 +178,20 @@ int _PyTime_ObjectToTimespec(PyObject *obj, time_t *sec, long *nsec, _PyTime_round_t round) { - return _PyTime_ObjectToDenominator(obj, sec, nsec, 1e9, 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) { - return _PyTime_ObjectToDenominator(obj, sec, usec, 1e6, round); + int res; + res = _PyTime_ObjectToDenominator(obj, sec, usec, 1e6, round); + assert(0 <= *usec && *usec < SEC_TO_US); + return res; } static void @@ -162,12 +205,15 @@ _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((seconds >= 0 && seconds <= _PyTime_MAX / SEC_TO_NS) - || (seconds < 0 && seconds >= _PyTime_MIN / SEC_TO_NS)); - t = (_PyTime_t)seconds * SEC_TO_NS; + Py_BUILD_ASSERT(INT_MAX <= _PyTime_MAX / SEC_TO_NS); + Py_BUILD_ASSERT(INT_MIN >= _PyTime_MIN / SEC_TO_NS); + assert((t >= 0 && t <= _PyTime_MAX / SEC_TO_NS) + || (t < 0 && t >= _PyTime_MIN / SEC_TO_NS)); + t *= SEC_TO_NS; return t; } @@ -175,7 +221,7 @@ _PyTime_t _PyTime_FromNanoseconds(PY_LONG_LONG ns) { _PyTime_t t; - assert(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t)); + Py_BUILD_ASSERT(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t)); t = Py_SAFE_DOWNCAST(ns, PY_LONG_LONG, _PyTime_t); return t; } @@ -187,12 +233,15 @@ _PyTime_FromTimespec(_PyTime_t *tp, struct timespec *ts, int raise) _PyTime_t t; int res = 0; - t = (_PyTime_t)ts->tv_sec * SEC_TO_NS; - if (t / SEC_TO_NS != ts->tv_sec) { + 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 * SEC_TO_NS; t += ts->tv_nsec; @@ -206,12 +255,15 @@ _PyTime_FromTimeval(_PyTime_t *tp, struct timeval *tv, int raise) _PyTime_t t; int res = 0; - t = (_PyTime_t)tv->tv_sec * SEC_TO_NS; - if (t / SEC_TO_NS != tv->tv_sec) { + 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 * SEC_TO_NS; t += (_PyTime_t)tv->tv_usec * US_TO_NS; @@ -221,50 +273,59 @@ _PyTime_FromTimeval(_PyTime_t *tp, struct timeval *tv, int raise) #endif static int -_PyTime_FromObject(_PyTime_t *t, PyObject *obj, _PyTime_round_t round, - long to_nanoseconds) +_PyTime_FromFloatObject(_PyTime_t *t, double value, _PyTime_round_t round, + long unit_to_ns) { - if (PyFloat_Check(obj)) { - /* volatile avoids unsafe optimization on float enabled by gcc -O3 */ - volatile double d, err; + double err; + /* volatile avoids optimization changing how numbers are rounded */ + volatile double d; - /* convert to a number of nanoseconds */ - d = PyFloat_AsDouble(obj); - d *= to_nanoseconds; + /* convert to a number of nanoseconds */ + d = value; + d *= (double)unit_to_ns; + d = _PyTime_Round(d, round); - if (round == _PyTime_ROUND_CEILING) - d = ceil(d); - else - d = floor(d); + *t = (_PyTime_t)d; + err = d - (double)*t; + if (fabs(err) >= 1.0) { + _PyTime_overflow(); + return -1; + } + return 0; +} - *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; + Py_BUILD_ASSERT(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t)); + sec = PyLong_AsLongLong(obj); - assert(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t)); #else long sec; + Py_BUILD_ASSERT(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t)); + sec = PyLong_AsLong(obj); - assert(sizeof(PY_LONG_LONG) <= sizeof(_PyTime_t)); #endif if (sec == -1 && PyErr_Occurred()) { if (PyErr_ExceptionMatches(PyExc_OverflowError)) _PyTime_overflow(); return -1; } - *t = sec * to_nanoseconds; - if (*t / to_nanoseconds != sec) { + + if (_PyTime_check_mul_overflow(sec, unit_to_ns)) { _PyTime_overflow(); return -1; } + *t = sec * unit_to_ns; return 0; } } @@ -284,22 +345,31 @@ _PyTime_FromMillisecondsObject(_PyTime_t *t, PyObject *obj, _PyTime_round_t roun double _PyTime_AsSecondsDouble(_PyTime_t t) { - _PyTime_t sec, ns; - /* Divide using integers to avoid rounding issues on the integer part. - 1e-9 cannot be stored exactly in IEEE 64-bit. */ - sec = t / SEC_TO_NS; - ns = t % SEC_TO_NS; - return (double)sec + (double)ns * 1e-9; + /* 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)); + Py_BUILD_ASSERT(sizeof(PY_LONG_LONG) >= sizeof(_PyTime_t)); return PyLong_FromLongLong((PY_LONG_LONG)t); #else - assert(sizeof(long) >= sizeof(_PyTime_t)); + Py_BUILD_ASSERT(sizeof(long) >= sizeof(_PyTime_t)); return PyLong_FromLong((long)t); #endif } @@ -309,7 +379,20 @@ _PyTime_Divide(const _PyTime_t t, const _PyTime_t k, const _PyTime_round_t round) { assert(k > 1); - if (round == _PyTime_ROUND_CEILING) { + 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 @@ -373,7 +456,7 @@ static int _PyTime_AsTimevalStruct_impl(_PyTime_t t, struct timeval *tv, _PyTime_round_t round, int raise) { - _PyTime_t secs; + _PyTime_t secs, secs2; int us; int res; @@ -386,7 +469,8 @@ _PyTime_AsTimevalStruct_impl(_PyTime_t t, struct timeval *tv, #endif tv->tv_usec = us; - if (res < 0 || (_PyTime_t)tv->tv_sec != secs) { + secs2 = (_PyTime_t)tv->tv_sec; + if (res < 0 || secs2 != secs) { if (raise) error_time_t_overflow(); return -1; @@ -424,6 +508,7 @@ _PyTime_AsTimevalTime_t(_PyTime_t t, time_t *p_secs, int *us, return 0; } + #if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_KQUEUE) int _PyTime_AsTimespec(_PyTime_t t, struct timespec *ts) @@ -437,13 +522,13 @@ _PyTime_AsTimespec(_PyTime_t t, struct timespec *ts) 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) { - _PyTime_overflow(); + error_time_t_overflow(); return -1; } - ts->tv_nsec = nsec; - - assert(0 <= ts->tv_nsec && ts->tv_nsec <= 999999999); return 0; } #endif @@ -557,19 +642,20 @@ _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 result; + ULONGLONG ticks; + _PyTime_t t; assert(info == NULL || raise); - result = GetTickCount64(); + ticks = GetTickCount64(); + Py_BUILD_ASSERT(sizeof(ticks) <= sizeof(_PyTime_t)); + t = (_PyTime_t)ticks; - *tp = result * MS_TO_NS; - if (*tp / MS_TO_NS != result) { + if (_PyTime_check_mul_overflow(t, MS_TO_NS)) { if (raise) { _PyTime_overflow(); return -1; @@ -577,6 +663,7 @@ pymonotonic(_PyTime_t *tp, _Py_clock_info_t *info, int raise) /* Hello, time traveler! */ assert(0); } + *tp = t * MS_TO_NS; if (info) { DWORD timeAdjustment, timeIncrement; @@ -689,8 +776,5 @@ _PyTime_Init(void) 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; } |