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bpo-41710: Add pytime_add() and pytime_mul() (GH-28642)
Add pytime_add() and pytime_mul() functions to pytime.c to compute t+t2 and t*k with clamping to [_PyTime_MIN; _PyTime_MAX]. Fix pytime.h: _PyTime_FromTimeval() is not implemented on Windows.
This commit is contained in:
Victor Stinner
GitHub
parent
09796f2f14
commit
d62d925823
2 changed files with 101 additions and 102 deletions
195
Python/pytime.c
195
Python/pytime.c
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@ -13,11 +13,6 @@
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#endif
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#endif
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#define _PyTime_check_mul_overflow(a, b) \
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(assert(b > 0), \
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(_PyTime_t)(a) < _PyTime_MIN / (_PyTime_t)(b) \
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|| _PyTime_MAX / (_PyTime_t)(b) < (_PyTime_t)(a))
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/* To millisecond (10^-3) */
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#define SEC_TO_MS 1000
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@ -78,6 +73,49 @@ pytime_as_nanoseconds(_PyTime_t t)
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}
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// Compute t + t2. Clamp to [_PyTime_MIN; _PyTime_MAX] on overflow.
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static inline _PyTime_t
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pytime_add(_PyTime_t *t, _PyTime_t t2)
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{
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if (t2 > 0 && *t > _PyTime_MAX - t2) {
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*t = _PyTime_MAX;
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return -1;
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}
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else if (t2 < 0 && *t < _PyTime_MIN - t2) {
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*t = _PyTime_MIN;
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return -1;
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}
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else {
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*t += t2;
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return 0;
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}
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}
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static inline int
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_PyTime_check_mul_overflow(_PyTime_t a, _PyTime_t b)
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{
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assert(b > 0);
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return ((a < _PyTime_MIN / b) || (_PyTime_MAX / b < a));
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}
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// Compute t * k. Clamp to [_PyTime_MIN; _PyTime_MAX] on overflow.
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static inline _PyTime_t
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pytime_mul(_PyTime_t *t, _PyTime_t k)
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{
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assert(k > 0);
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if (_PyTime_check_mul_overflow(*t, k)) {
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*t = (*t >= 0) ? _PyTime_MAX : _PyTime_MIN;
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return -1;
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}
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else {
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*t *= k;
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return 0;
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}
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}
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_PyTime_t
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_PyTime_MulDiv(_PyTime_t ticks, _PyTime_t mul, _PyTime_t div)
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{
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@ -371,41 +409,25 @@ _PyTime_FromNanosecondsObject(_PyTime_t *tp, PyObject *obj)
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#ifdef HAVE_CLOCK_GETTIME
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static int
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pytime_fromtimespec(_PyTime_t *tp, struct timespec *ts, int raise)
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pytime_fromtimespec(_PyTime_t *tp, struct timespec *ts, int raise_exc)
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{
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_PyTime_t t, tv_nsec;
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int res = 0;
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Py_BUILD_ASSERT(sizeof(ts->tv_sec) <= sizeof(_PyTime_t));
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t = (_PyTime_t)ts->tv_sec;
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if (_PyTime_check_mul_overflow(t, SEC_TO_NS)) {
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if (raise) {
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pytime_overflow();
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res = -1;
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}
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t = (t > 0) ? _PyTime_MAX : _PyTime_MIN;
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}
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else {
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t = t * SEC_TO_NS;
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}
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int res1 = pytime_mul(&t, SEC_TO_NS);
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tv_nsec = ts->tv_nsec;
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/* The following test is written for positive only tv_nsec */
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assert(tv_nsec >= 0);
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if (t > _PyTime_MAX - tv_nsec) {
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if (raise) {
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pytime_overflow();
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res = -1;
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}
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t = _PyTime_MAX;
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}
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else {
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t += tv_nsec;
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}
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int res2 = pytime_add(&t, tv_nsec);
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*tp = pytime_from_nanoseconds(t);
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return res;
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if (raise_exc && (res1 < 0 || res2 < 0)) {
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pytime_overflow();
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return -1;
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}
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return 0;
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}
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int
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@ -416,43 +438,25 @@ _PyTime_FromTimespec(_PyTime_t *tp, struct timespec *ts)
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#endif
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#if !defined(MS_WINDOWS)
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#ifndef MS_WINDOWS
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static int
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pytime_fromtimeval(_PyTime_t *tp, struct timeval *tv, int raise)
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pytime_fromtimeval(_PyTime_t *tp, struct timeval *tv, int raise_exc)
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{
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_PyTime_t t, usec;
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int res = 0;
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Py_BUILD_ASSERT(sizeof(tv->tv_sec) <= sizeof(_PyTime_t));
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t = (_PyTime_t)tv->tv_sec;
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_PyTime_t t = (_PyTime_t)tv->tv_sec;
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if (_PyTime_check_mul_overflow(t, SEC_TO_NS)) {
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if (raise) {
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pytime_overflow();
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res = -1;
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}
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t = (t > 0) ? _PyTime_MAX : _PyTime_MIN;
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}
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else {
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t = t * SEC_TO_NS;
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}
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int res1 = pytime_mul(&t, SEC_TO_NS);
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usec = (_PyTime_t)tv->tv_usec * US_TO_NS;
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/* The following test is written for positive only usec */
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assert(usec >= 0);
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if (t > _PyTime_MAX - usec) {
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if (raise) {
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pytime_overflow();
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res = -1;
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}
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t = _PyTime_MAX;
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}
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else {
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t += usec;
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}
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_PyTime_t usec = (_PyTime_t)tv->tv_usec * US_TO_NS;
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int res2 = pytime_add(&t, usec);
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*tp = pytime_from_nanoseconds(t);
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return res;
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if (raise_exc && (res1 < 0 || res2 < 0)) {
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pytime_overflow();
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return -1;
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}
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return 0;
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}
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@ -572,7 +576,7 @@ pytime_divide_round_up(const _PyTime_t t, const _PyTime_t k)
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assert(k > 1);
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if (t >= 0) {
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// Don't use (t + k - 1) / k to avoid integer overflow
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// if t=_PyTime_MAX
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// if t is equal to _PyTime_MAX
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_PyTime_t q = t / k;
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if (t % k) {
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q += 1;
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@ -581,7 +585,7 @@ pytime_divide_round_up(const _PyTime_t t, const _PyTime_t k)
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}
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else {
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// Don't use (t - (k - 1)) / k to avoid integer overflow
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// if t=_PyTime_MIN
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// if t is equals to _PyTime_MIN.
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_PyTime_t q = t / k;
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if (t % k) {
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q -= 1;
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@ -804,14 +808,14 @@ _PyTime_AsTimespec(_PyTime_t t, struct timespec *ts)
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static int
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py_get_system_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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py_get_system_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise_exc)
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{
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assert(info == NULL || raise_exc);
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#ifdef MS_WINDOWS
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FILETIME system_time;
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ULARGE_INTEGER large;
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assert(info == NULL || raise);
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GetSystemTimeAsFileTime(&system_time);
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large.u.LowPart = system_time.dwLowDateTime;
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large.u.HighPart = system_time.dwHighDateTime;
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@ -846,8 +850,6 @@ py_get_system_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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struct timeval tv;
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#endif
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assert(info == NULL || raise);
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#ifdef HAVE_CLOCK_GETTIME
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#ifdef HAVE_CLOCK_GETTIME_RUNTIME
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@ -856,12 +858,12 @@ py_get_system_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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err = clock_gettime(CLOCK_REALTIME, &ts);
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if (err) {
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if (raise) {
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if (raise_exc) {
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PyErr_SetFromErrno(PyExc_OSError);
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}
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return -1;
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}
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if (pytime_fromtimespec(tp, &ts, raise) < 0) {
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if (pytime_fromtimespec(tp, &ts, raise_exc) < 0) {
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return -1;
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}
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@ -890,12 +892,12 @@ py_get_system_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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/* test gettimeofday() */
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err = gettimeofday(&tv, (struct timezone *)NULL);
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if (err) {
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if (raise) {
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if (raise_exc) {
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PyErr_SetFromErrno(PyExc_OSError);
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}
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return -1;
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}
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if (pytime_fromtimeval(tp, &tv, raise) < 0) {
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if (pytime_fromtimeval(tp, &tv, raise_exc) < 0) {
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return -1;
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}
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@ -987,28 +989,21 @@ py_mach_timebase_info(_PyTime_t *pnumer, _PyTime_t *pdenom, int raise)
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static int
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py_get_monotonic_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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py_get_monotonic_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise_exc)
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{
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assert(info == NULL || raise_exc);
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#if defined(MS_WINDOWS)
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ULONGLONG ticks;
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_PyTime_t t;
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assert(info == NULL || raise);
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ticks = GetTickCount64();
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ULONGLONG ticks = GetTickCount64();
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Py_BUILD_ASSERT(sizeof(ticks) <= sizeof(_PyTime_t));
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t = (_PyTime_t)ticks;
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_PyTime_t t = (_PyTime_t)ticks;
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if (_PyTime_check_mul_overflow(t, MS_TO_NS)) {
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if (raise) {
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pytime_overflow();
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return -1;
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}
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// Clamp to _PyTime_MAX silently.
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*tp = _PyTime_MAX;
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}
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else {
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*tp = t * MS_TO_NS;
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int res = pytime_mul(&t, MS_TO_NS);
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*tp = t;
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if (raise_exc && res < 0) {
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pytime_overflow();
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return -1;
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}
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if (info) {
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@ -1030,7 +1025,7 @@ py_get_monotonic_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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static _PyTime_t timebase_numer = 0;
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static _PyTime_t timebase_denom = 0;
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if (timebase_denom == 0) {
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if (py_mach_timebase_info(&timebase_numer, &timebase_denom, raise) < 0) {
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if (py_mach_timebase_info(&timebase_numer, &timebase_denom, raise_exc) < 0) {
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return -1;
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}
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}
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@ -1055,7 +1050,7 @@ py_get_monotonic_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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time = gethrtime();
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if (time == -1) {
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if (raise) {
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if (raise_exc) {
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PyErr_SetFromErrno(PyExc_OSError);
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}
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return -1;
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@ -1071,7 +1066,7 @@ py_get_monotonic_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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}
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#else
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struct timespec ts;
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#ifdef CLOCK_HIGHRES
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const clockid_t clk_id = CLOCK_HIGHRES;
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const char *implementation = "clock_gettime(CLOCK_HIGHRES)";
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@ -1080,30 +1075,30 @@ py_get_monotonic_clock(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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const char *implementation = "clock_gettime(CLOCK_MONOTONIC)";
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#endif
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assert(info == NULL || raise);
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struct timespec ts;
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if (clock_gettime(clk_id, &ts) != 0) {
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if (raise) {
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if (raise_exc) {
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PyErr_SetFromErrno(PyExc_OSError);
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return -1;
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}
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return -1;
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}
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if (pytime_fromtimespec(tp, &ts, raise_exc) < 0) {
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return -1;
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}
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if (info) {
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struct timespec res;
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info->monotonic = 1;
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info->implementation = implementation;
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info->adjustable = 0;
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struct timespec res;
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if (clock_getres(clk_id, &res) != 0) {
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PyErr_SetFromErrno(PyExc_OSError);
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return -1;
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}
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info->resolution = res.tv_sec + res.tv_nsec * 1e-9;
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}
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if (pytime_fromtimespec(tp, &ts, raise) < 0) {
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return -1;
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}
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#endif
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return 0;
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}
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@ -1169,6 +1164,8 @@ py_win_perf_counter_frequency(LONGLONG *pfrequency, int raise)
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static int
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py_get_win_perf_counter(_PyTime_t *tp, _Py_clock_info_t *info, int raise)
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{
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assert(info == NULL || raise_exc);
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static LONGLONG frequency = 0;
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if (frequency == 0) {
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if (py_win_perf_counter_frequency(&frequency, raise) < 0) {
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