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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef builtin_temporal_TemporalTypes_h
#define builtin_temporal_TemporalTypes_h
#include "mozilla/Assertions.h"
#include "mozilla/CheckedInt.h"
#include <stdint.h>
#include "builtin/temporal/TemporalUnit.h"
namespace js::temporal {
// Use __builtin_assume when available, otherwise fall back to
// __builtin_unreachable.
#if defined __has_builtin
# if __has_builtin(__builtin_assume)
# define JS_ASSUME(x) __builtin_assume(x)
# elif __has_builtin(__builtin_unreachable)
# define JS_ASSUME(x) \
if (!(x)) __builtin_unreachable()
# else
# endif
#endif
// Fallback to no-op if neither built-in is available.
#ifndef JS_ASSUME
# define JS_ASSUME(x) \
do { \
} while (false)
#endif
/**
* Struct to represent a seconds and nanoseconds value. The nanoseconds value
* is normalized to the range [0, 999'999'999].
*/
template <typename Derived>
struct SecondsAndNanoseconds {
// Seconds part in the range allowed by the derived class.
int64_t seconds = 0;
// Nanoseconds part in the range [0, 999'999'999].
int32_t nanoseconds = 0;
constexpr bool operator==(const SecondsAndNanoseconds& other) const {
return seconds == other.seconds && nanoseconds == other.nanoseconds;
}
constexpr bool operator<(const SecondsAndNanoseconds& other) const {
// The compiler can optimize expressions like |instant < Instant{}| to a
// single right-shift operation when we propagate the range of nanoseconds.
JS_ASSUME(nanoseconds >= 0);
JS_ASSUME(other.nanoseconds >= 0);
return (seconds < other.seconds) ||
(seconds == other.seconds && nanoseconds < other.nanoseconds);
}
// Other operators are implemented in terms of operator== and operator<.
constexpr bool operator!=(const SecondsAndNanoseconds& other) const {
return !(*this == other);
}
constexpr bool operator>(const SecondsAndNanoseconds& other) const {
return other < *this;
}
constexpr bool operator<=(const SecondsAndNanoseconds& other) const {
return !(other < *this);
}
constexpr bool operator>=(const SecondsAndNanoseconds& other) const {
return !(*this < other);
}
protected:
template <typename T, typename U, class R = Derived>
static constexpr R add(const SecondsAndNanoseconds<T>& self,
const SecondsAndNanoseconds<U>& other) {
// The caller needs to make sure integer overflow won't happen. CheckedInt
// will assert on overflow and we intentionally don't try to recover from
// overflow in this method.
mozilla::CheckedInt64 secs = self.seconds;
secs += other.seconds;
mozilla::CheckedInt32 nanos = self.nanoseconds;
nanos += other.nanoseconds;
if (nanos.value() >= 1'000'000'000) {
secs += 1;
nanos -= 1'000'000'000;
}
MOZ_ASSERT(0 <= nanos.value() && nanos.value() < 1'000'000'000);
return {secs.value(), nanos.value()};
}
template <class T, class U, class R = Derived>
static constexpr R subtract(const SecondsAndNanoseconds<T>& self,
const SecondsAndNanoseconds<U>& other) {
// The caller needs to make sure integer underflow won't happen. CheckedInt
// will assert on underflow and we intentionally don't try to recover from
// underflow in this method.
mozilla::CheckedInt64 secs = self.seconds;
secs -= other.seconds;
mozilla::CheckedInt32 nanos = self.nanoseconds;
nanos -= other.nanoseconds;
if (nanos.value() < 0) {
secs -= 1;
nanos += 1'000'000'000;
}
MOZ_ASSERT(0 <= nanos.value() && nanos.value() < 1'000'000'000);
return {secs.value(), nanos.value()};
}
static constexpr Derived negate(const Derived& self) {
return subtract(Derived{}, self);
}
public:
/**
* Return the absolute value.
*/
constexpr Derived abs() const {
int64_t sec = seconds;
int32_t nanos = nanoseconds;
if (sec < 0) {
if (nanos > 0) {
sec += 1;
nanos -= 1'000'000'000;
}
sec = -sec;
nanos = -nanos;
}
return {sec, nanos};
}
/**
* Return the seconds value, rounded towards zero.
*/
constexpr int64_t toSeconds() const {
int64_t sec = seconds;
int32_t nanos = nanoseconds;
if (sec < 0 && nanos > 0) {
sec += 1;
}
return sec;
}
/**
* Return the milliseconds value, rounded towards zero.
*/
constexpr int64_t toMilliseconds() const {
int64_t sec = seconds;
int32_t nanos = nanoseconds;
if (sec < 0 && nanos > 0) {
sec += 1;
nanos -= 1'000'000'000;
}
return (sec * 1'000) + (nanos / 1'000'000);
}
/**
* Return the microseconds value, rounded towards zero.
*/
constexpr int64_t toMicroseconds() const {
int64_t sec = seconds;
int32_t nanos = nanoseconds;
if (sec < 0 && nanos > 0) {
sec += 1;
nanos -= 1'000'000'000;
}
return (sec * 1'000'000) + (nanos / 1'000);
}
/**
* Return the nanoseconds value.
*
* The returned nanoseconds amount can be invalid on overflow. The caller is
* responsible for handling the overflow case.
*/
constexpr mozilla::CheckedInt64 toNanoseconds() const {
mozilla::CheckedInt64 nanos = seconds;
nanos *= ToNanoseconds(TemporalUnit::Second);
nanos += nanoseconds;
return nanos;
}
/**
* Create from a minutes value.
*/
static constexpr Derived fromMinutes(int64_t minutes) {
return {minutes * 60, 0};
}
/**
* Create from a seconds value.
*/
static constexpr Derived fromSeconds(int64_t seconds) { return {seconds, 0}; }
/**
* Create from a milliseconds value.
*/
static constexpr Derived fromMilliseconds(int64_t milliseconds) {
int64_t seconds = milliseconds / 1'000;
int32_t millis = milliseconds % 1'000;
if (millis < 0) {
seconds -= 1;
millis += 1'000;
}
return {seconds, millis * 1'000'000};
}
/**
* Create from a microseconds value.
*/
static constexpr Derived fromMicroseconds(int64_t microseconds) {
int64_t seconds = microseconds / 1'000'000;
int32_t micros = microseconds % 1'000'000;
if (micros < 0) {
seconds -= 1;
micros += 1'000'000;
}
return {seconds, micros * 1'000};
}
/**
* Create from a nanoseconds value.
*/
static constexpr Derived fromNanoseconds(int64_t nanoseconds) {
int64_t seconds = nanoseconds / 1'000'000'000;
int32_t nanos = nanoseconds % 1'000'000'000;
if (nanos < 0) {
seconds -= 1;
nanos += 1'000'000'000;
}
return {seconds, nanos};
}
};
#undef JS_ASSUME
/**
* InstantSpan represents a span of time between two Instants, measured in
* nanoseconds.
*/
struct InstantSpan final : SecondsAndNanoseconds<InstantSpan> {
constexpr InstantSpan& operator+=(const InstantSpan& other) {
*this = add(*this, other);
return *this;
}
constexpr InstantSpan& operator-=(const InstantSpan& other) {
*this = subtract(*this, other);
return *this;
}
constexpr InstantSpan operator+(const InstantSpan& other) const {
return add(*this, other);
}
constexpr InstantSpan operator-(const InstantSpan& other) const {
return subtract(*this, other);
}
constexpr InstantSpan operator-() const { return negate(*this); }
/**
* Returns the maximum instant span value.
*/
static constexpr InstantSpan max() {
// The limit is 2×8.64 × 10^21 nanoseconds, which is 2×8.64 × 10^12 seconds.
constexpr int64_t seconds = 2 * 8'640'000'000'000;
constexpr int64_t nanos = 0;
return {seconds, nanos};
}
/**
* Returns the minimum instant span value.
*/
static constexpr InstantSpan min() { return -max(); }
};
/**
* Instant represents a time since the epoch value, measured in nanoseconds.
*
* Instant supports a range of ±8.64 × 10^21 nanoseconds, covering ±10^8 days
* in either direction relative to midnight at the beginning of 1 January 1970
* UTC. The range also exactly matches the supported range of JavaScript Date
* objects.
*
* C++ doesn't provide a built-in type capable of storing an integer in the
* range ±8.64 × 10^21, therefore we need to create our own abstraction. This
* struct follows the design of `std::timespec` and splits the instant into a
* signed seconds part and an unsigned nanoseconds part.
*/
struct Instant final : SecondsAndNanoseconds<Instant> {
constexpr Instant& operator+=(const InstantSpan& other) {
*this = add(*this, other);
return *this;
}
constexpr Instant& operator-=(const InstantSpan& other) {
*this = subtract(*this, other);
return *this;
}
constexpr Instant operator+(const InstantSpan& other) const {
return add(*this, other);
}
constexpr Instant operator-(const InstantSpan& other) const {
return subtract(*this, other);
}
constexpr InstantSpan operator-(const Instant& other) const {
return subtract<Instant, Instant, InstantSpan>(*this, other);
}
constexpr Instant operator-() const { return negate(*this); }
/**
* Return this instant as microseconds from the start of the epoch. (Rounds
* towards negative infinity.)
*/
constexpr int64_t floorToMicroseconds() const {
return (seconds * 1'000'000) + (nanoseconds / 1'000);
}
/**
* Return this instant as milliseconds from the start of the epoch. (Rounds
* towards negative infinity.)
*/
constexpr int64_t floorToMilliseconds() const {
return (seconds * 1'000) + (nanoseconds / 1'000'000);
}
/**
* Return this instant as milliseconds from the start of the epoch. (Rounds
* towards positive infinity.)
*/
constexpr int64_t ceilToMilliseconds() const {
return floorToMilliseconds() + int64_t(nanoseconds % 1'000'000 != 0);
}
/**
* Returns the maximum instant value.
*/
static constexpr Instant max() {
// The limit is 8.64 × 10^21 nanoseconds, which is 8.64 × 10^12 seconds.
constexpr int64_t seconds = 8'640'000'000'000;
constexpr int64_t nanos = 0;
return {seconds, nanos};
}
/**
* Returns the minimum instant value.
*/
static constexpr Instant min() { return -max(); }
};
/**
* Plain date represents a date in the ISO 8601 calendar.
*/
struct PlainDate final {
// [-271821, 275760]
//
// Dates are limited to the range of ±100'000'000 days relative to midnight at
// the beginning of 1 January 1970 UTC. This limits valid years to [-271821,
// 275760].
int32_t year = 0;
// [1, 12]
int32_t month = 0;
// [1, 31]
int32_t day = 0;
bool operator==(const PlainDate& other) const {
return year == other.year && month == other.month && day == other.day;
}
bool operator!=(const PlainDate& other) const { return !(*this == other); }
};
/**
* Plain time represents a time value on a 24-hour clock. Leap seconds aren't
* supported.
*/
struct PlainTime final {
// [0, 23]
int32_t hour = 0;
// [0, 59]
int32_t minute = 0;
// [0, 59]
int32_t second = 0;
// [0, 999]
int32_t millisecond = 0;
// [0, 999]
int32_t microsecond = 0;
// [0, 999]
int32_t nanosecond = 0;
bool operator==(const PlainTime& other) const {
return hour == other.hour && minute == other.minute &&
second == other.second && millisecond == other.millisecond &&
microsecond == other.microsecond && nanosecond == other.nanosecond;
}
bool operator!=(const PlainTime& other) const { return !(*this == other); }
};
/**
* Plain date-time represents a date-time value in the ISO 8601 calendar.
*/
struct PlainDateTime final {
PlainDate date;
PlainTime time;
bool operator==(const PlainDateTime& other) const {
return date == other.date && time == other.time;
}
bool operator!=(const PlainDateTime& other) const {
return !(*this == other);
}
};
/**
* Duration represents the difference between dates or times. Each duration
* component is an integer and all components must have the same sign.
*/
struct Duration final {
double years = 0;
double months = 0;
double weeks = 0;
double days = 0;
double hours = 0;
double minutes = 0;
double seconds = 0;
double milliseconds = 0;
double microseconds = 0;
double nanoseconds = 0;
bool operator==(const Duration& other) const {
return years == other.years && months == other.months &&
weeks == other.weeks && days == other.days && hours == other.hours &&
minutes == other.minutes && seconds == other.seconds &&
milliseconds == other.milliseconds &&
microseconds == other.microseconds &&
nanoseconds == other.nanoseconds;
}
bool operator!=(const Duration& other) const { return !(*this == other); }
/**
* Return the date components of this duration.
*/
Duration date() const { return {years, months, weeks, days}; }
/**
* Return the time components of this duration.
*/
Duration time() const {
return {
0,
0,
0,
0,
hours,
minutes,
seconds,
milliseconds,
microseconds,
nanoseconds,
};
}
/**
* Return a new duration with every component negated.
*/
Duration negate() const {
// Add zero to convert -0 to +0.
return {
-years + (+0.0), -months + (+0.0), -weeks + (+0.0),
-days + (+0.0), -hours + (+0.0), -minutes + (+0.0),
-seconds + (+0.0), -milliseconds + (+0.0), -microseconds + (+0.0),
-nanoseconds + (+0.0),
};
}
};
/**
* Date duration represents the difference between dates. Each duration
* component is an integer and all components must have the same sign.
*/
struct DateDuration final {
double years = 0;
double months = 0;
double weeks = 0;
double days = 0;
Duration toDuration() { return {years, months, weeks, days}; }
};
/**
* Time duration represents the difference between times. Each duration
* component is an integer and all components must have the same sign.
*/
struct TimeDuration final {
double days = 0;
double hours = 0;
double minutes = 0;
double seconds = 0;
double milliseconds = 0;
double microseconds = 0;
double nanoseconds = 0;
Duration toDuration() {
return {0,
0,
0,
days,
hours,
minutes,
seconds,
milliseconds,
microseconds,
nanoseconds};
}
};
} /* namespace js::temporal */
#endif /* builtin_temporal_TemporalTypes_h */