Fix time_point to string conversion for large and negative values #37
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heifner
suggested changes
Oct 30, 2018
src/time.cpp
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| // negative time_points are non-sensical but expressible with the current constraints | ||
| uint64_t secs = (uint64_t)(-count) / 1000000ULL; | ||
| uint64_t msec = ((uint64_t)(-count) % 1000000ULL) / 1000ULL; | ||
| return string("-") + to_string(secs) + "." + padded_ms(msec) + "s"; |
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Appends an "s" to the end of negative time point. All the examples I see with boost posix time and iso specs, none include a trailing s.
https://www.boost.org/doc/libs/1_68_0/doc/html/date_time/posix_time.html
heifner
approved these changes
Oct 30, 2018
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This fixes two issues:
time_points which were more than 32bits of seconds from the epoch would wrap due to the silent integer narrowing that happens in
uint32_t time_point::sec_since_epoch() constas a result those time points would translate to the wrong ISO string.negative time_points are representable due to being composed of the
fc::microsecondtype which can store negative values. However, these have no representable ISO string so they now degrade to a duration in terms of seconds with 3-digits of precision for millisecond output. Effectively providing the same base unit as the ISO string (seconds) and the extra resolution.Note: it is probably worthwhile to consider if changing
::sec_since_epoch() constand removing the express-ability of negative points in time is worthwhile formaster. This is being made against a patch release of a downstream product so, it should not make breaking changes to the data types.