diff options
Diffstat (limited to 'hrtime.h')
| -rw-r--r-- | hrtime.h | 49 |
1 files changed, 48 insertions, 1 deletions
@@ -8,11 +8,28 @@ /* * Hi-res monotonic clock. It is currently nsec resolution, which has over - * 500 years of range. + * 500 years of range (unsigned). * * TBD: Is nsec even necessary? usec resolution seems enough for userspace * and it'll be suitable for use with devices lasting over 500,000 years * (maybe some devices designed for long-term space travel) + * + * Current API: + * + * * rb_hrtime_now - current clock value (monotonic if available) + * * rb_hrtime_mul - multiply with overflow check + * * rb_hrtime_add - add with overflow check + * * rb_timeval2hrtime - convert from timeval + * * rb_timespec2hrtime - convert from timespec + * * rb_msec2hrtime - convert from millisecond + * * rb_sec2hrtime - convert from time_t (seconds) + * * rb_hrtime2timeval - convert to timeval + * * rb_hrtime2timespec - convert to timespec + * + * Note: no conversion to milliseconds is provided here because different + * functions have different limits (e.g. epoll_wait vs w32_wait_events). + * So we provide RB_HRTIME_PER_MSEC and similar macros for implementing + * this for each use case. */ #define RB_HRTIME_PER_USEC ((rb_hrtime_t)1000) #define RB_HRTIME_PER_MSEC (RB_HRTIME_PER_USEC * (rb_hrtime_t)1000) @@ -30,8 +47,13 @@ typedef uint64_t rb_hrtime_t; #endif /* thread.c */ +/* returns the value of the monotonic clock (if available) */ rb_hrtime_t rb_hrtime_now(void); +/* + * multiply @a and @b with overflow check and return the + * (clamped to RB_HRTIME_MAX) result. + */ static inline rb_hrtime_t rb_hrtime_mul(rb_hrtime_t a, rb_hrtime_t b) { @@ -48,6 +70,10 @@ rb_hrtime_mul(rb_hrtime_t a, rb_hrtime_t b) return c; } +/* + * add @a and @b with overflow check and return the + * (clamped to RB_HRTIME_MAX) result. + */ static inline rb_hrtime_t rb_hrtime_add(rb_hrtime_t a, rb_hrtime_t b) { @@ -64,6 +90,9 @@ rb_hrtime_add(rb_hrtime_t a, rb_hrtime_t b) return c; } +/* + * convert a timeval struct to rb_hrtime_t, clamping at RB_HRTIME_MAX + */ static inline rb_hrtime_t rb_timeval2hrtime(const struct timeval *tv) { @@ -73,6 +102,9 @@ rb_timeval2hrtime(const struct timeval *tv) return rb_hrtime_add(s, u); } +/* + * convert a timespec struct to rb_hrtime_t, clamping at RB_HRTIME_MAX + */ static inline rb_hrtime_t rb_timespec2hrtime(const struct timespec *ts) { @@ -81,12 +113,19 @@ rb_timespec2hrtime(const struct timespec *ts) return rb_hrtime_add(s, (rb_hrtime_t)ts->tv_nsec); } +/* + * convert a millisecond value to rb_hrtime_t, clamping at RB_HRTIME_MAX + */ static inline rb_hrtime_t rb_msec2hrtime(unsigned long msec) { return rb_hrtime_mul((rb_hrtime_t)msec, RB_HRTIME_PER_MSEC); } +/* + * convert a time_t value to rb_hrtime_t, clamping at RB_HRTIME_MAX + * Negative values will be clamped at 0. + */ static inline rb_hrtime_t rb_sec2hrtime(time_t sec) { @@ -95,6 +134,10 @@ rb_sec2hrtime(time_t sec) return rb_hrtime_mul((rb_hrtime_t)sec, RB_HRTIME_PER_SEC); } +/* + * convert a rb_hrtime_t value to a timespec, suitable for calling + * functions like ppoll(2) or kevent(2) + */ static inline struct timespec * rb_hrtime2timespec(struct timespec *ts, const rb_hrtime_t *hrt) { @@ -106,6 +149,10 @@ rb_hrtime2timespec(struct timespec *ts, const rb_hrtime_t *hrt) return 0; } +/* + * convert a rb_hrtime_t value to a timeval, suitable for calling + * functions like select(2) + */ static inline struct timeval * rb_hrtime2timeval(struct timeval *tv, const rb_hrtime_t *hrt) { |