inline std::ostream& operator<<(std::ostream& stream, const Duration& duration_) { // Output the duration in full double precision and save the old precision. std::streamsize precision = stream.precision(std::numeric_limits<double>::digits10); // Parse the duration as the sign and the absolute value. Duration duration = duration_; if (duration_ < Duration::zero()) { stream << "-"; // Duration::min() may not be representable as a positive Duration. if (duration_ == Duration::min()) { duration = Duration::max(); } else { duration = duration_ * -1; } } // First determine which bucket of time unit the duration falls into // then check whether the duration can be represented as a whole // number with this time unit or a smaller one. // e.g. 1.42857142857143weeks falls into the 'Weeks' bucket but // reads better with a smaller unit: '10days'. So we use 'days' // instead of 'weeks' to output the duration. int64_t nanoseconds = duration.ns(); if (duration < Microseconds(1)) { stream << duration.ns() << Nanoseconds::units(); } else if (duration < Milliseconds(1)) { if (nanoseconds % Duration::MICROSECONDS != 0) { // We can't get a whole number using this unit but we can at // one level down. stream << duration.ns() << Nanoseconds::units(); } else { stream << duration.us() << Microseconds::units(); } } else if (duration < Seconds(1)) { if (nanoseconds % Duration::MILLISECONDS != 0 && nanoseconds % Duration::MICROSECONDS == 0) { stream << duration.us() << Microseconds::units(); } else { stream << duration.ms() << Milliseconds::units(); } } else if (duration < Minutes(1)) { if (nanoseconds % Duration::SECONDS != 0 && nanoseconds % Duration::MILLISECONDS == 0) { stream << duration.ms() << Milliseconds::units(); } else { stream << duration.secs() << Seconds::units(); } } else if (duration < Hours(1)) { if (nanoseconds % Duration::MINUTES != 0 && nanoseconds % Duration::SECONDS == 0) { stream << duration.secs() << Seconds::units(); } else { stream << duration.mins() << Minutes::units(); } } else if (duration < Days(1)) { if (nanoseconds % Duration::HOURS != 0 && nanoseconds % Duration::MINUTES == 0) { stream << duration.mins() << Minutes::units(); } else { stream << duration.hrs() << Hours::units(); } } else if (duration < Weeks(1)) { if (nanoseconds % Duration::DAYS != 0 && nanoseconds % Duration::HOURS == 0) { stream << duration.hrs() << Hours::units(); } else { stream << duration.days() << Days::units(); } } else { if (nanoseconds % Duration::WEEKS != 0 && nanoseconds % Duration::DAYS == 0) { stream << duration.days() << Days::units(); } else { stream << duration.weeks() << Weeks::units(); } } // Return the stream to original formatting state. stream.precision(precision); return stream; }