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LibJS: Use nanoseconds to normalize values in IsValidDuration

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This is an editorial change in the Temporal proposal. See:
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Note that we were already performing this calculation using nanoseconds.
This commit is contained in:
Timothy Flynn 2025-11-21 06:56:17 -05:00 • committed by Jelle Raaijmakers
parent 8feabc3158
commit 37f49d5f6d
Notes: github-actions[bot] 2025-11-21 12:54:07 +00:00
1 changed files with 15 additions and 14 deletions
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29
Libraries/LibJS/Runtime/Temporal/Duration.cpp
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@ -508,22 +508,23 @@ bool is_valid_duration(double years, double months, double weeks, double days, d
if (AK::fabs(weeks) > NumericLimits<u32>::max())
return false;
// 6. Let normalizedSeconds be days × 86,400 + hours × 3600 + minutes × 60 + seconds + ℝ(𝔽(milliseconds)) × 10**-3 + ℝ(𝔽(microseconds)) × 10**-6 + ℝ(𝔽(nanoseconds)) × 10**-9.
// 7. NOTE: The above step cannot be implemented directly using floating-point arithmetic. Multiplying by 10**-3,
// 10**-6, and 10**-9 respectively may be imprecise when milliseconds, microseconds, or nanoseconds is an
// unsafe integer. This multiplication can be implemented in C++ with an implementation of std::remquo()
// with sufficient bits in the quotient. String manipulation will also give an exact result, since the
// 6. Let normalizedNanoseconds be days × 86,400 × 10**9 + hours × 3600 × 10**9 + minutes × 60 × 10**9 + seconds × 10**9 + ℝ(𝔽(milliseconds)) × 10**6 + ℝ(𝔽(microseconds)) × 10**3 + ℝ(𝔽(nanoseconds)).
// 7. NOTE: The above step cannot be implemented directly using 64-bit floating-point arithmetic. Multiplying by
// 10**-3, 10**-6, and 10**-9 respectively may be imprecise when milliseconds, microseconds, or nanoseconds
// is an unsafe integer. The step can be implemented by using 128-bit integers and performing all arithmetic
// on nanosecond values. It could also be implemented in C++ with an implementation of std::remquo() with
// sufficient bits in the quotient. String manipulation will also give an exact result, since the
// multiplication is by a power of 10.
auto normalized_seconds = TimeDuration { days }.multiplied_by(NANOSECONDS_PER_DAY);
normalized_seconds = normalized_seconds.plus(TimeDuration { hours }.multiplied_by(NANOSECONDS_PER_HOUR));
normalized_seconds = normalized_seconds.plus(TimeDuration { minutes }.multiplied_by(NANOSECONDS_PER_MINUTE));
normalized_seconds = normalized_seconds.plus(TimeDuration { seconds }.multiplied_by(NANOSECONDS_PER_SECOND));
normalized_seconds = normalized_seconds.plus(TimeDuration { milliseconds }.multiplied_by(NANOSECONDS_PER_MILLISECOND));
normalized_seconds = normalized_seconds.plus(TimeDuration { microseconds }.multiplied_by(NANOSECONDS_PER_MICROSECOND));
normalized_seconds = normalized_seconds.plus(TimeDuration { nanoseconds });
auto normalized_nanoseconds = TimeDuration { days }.multiplied_by(NANOSECONDS_PER_DAY);
normalized_nanoseconds = normalized_nanoseconds.plus(TimeDuration { hours }.multiplied_by(NANOSECONDS_PER_HOUR));
normalized_nanoseconds = normalized_nanoseconds.plus(TimeDuration { minutes }.multiplied_by(NANOSECONDS_PER_MINUTE));
normalized_nanoseconds = normalized_nanoseconds.plus(TimeDuration { seconds }.multiplied_by(NANOSECONDS_PER_SECOND));
normalized_nanoseconds = normalized_nanoseconds.plus(TimeDuration { milliseconds }.multiplied_by(NANOSECONDS_PER_MILLISECOND));
normalized_nanoseconds = normalized_nanoseconds.plus(TimeDuration { microseconds }.multiplied_by(NANOSECONDS_PER_MICROSECOND));
normalized_nanoseconds = normalized_nanoseconds.plus(TimeDuration { nanoseconds });
// 8. If abs(normalizedSeconds) ≥ 2**53, return false.
if (normalized_seconds.unsigned_value() > MAX_TIME_DURATION.unsigned_value())
// 8. If abs(normalizedNanoseconds) ≥ 10**9 × 2**53, return false.
if (normalized_nanoseconds.unsigned_value() > MAX_TIME_DURATION.unsigned_value())
return false;
// 9. Return true.