Adding upstream version 1.20.14.upstream/1.20.14upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1646 insertions, 0 deletions

diff --git a/src/time/time.go b/src/time/time.go
new file mode 100644
index 0000000..e8aac59
--- /dev/null
+++ b/src/time/time.go
@@ -0,0 +1,1646 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package time provides functionality for measuring and displaying time.
+//
+// The calendrical calculations always assume a Gregorian calendar, with
+// no leap seconds.
+//
+// # Monotonic Clocks
+//
+// Operating systems provide both a “wall clock,” which is subject to
+// changes for clock synchronization, and a “monotonic clock,” which is
+// not. The general rule is that the wall clock is for telling time and
+// the monotonic clock is for measuring time. Rather than split the API,
+// in this package the Time returned by time.Now contains both a wall
+// clock reading and a monotonic clock reading; later time-telling
+// operations use the wall clock reading, but later time-measuring
+// operations, specifically comparisons and subtractions, use the
+// monotonic clock reading.
+//
+// For example, this code always computes a positive elapsed time of
+// approximately 20 milliseconds, even if the wall clock is changed during
+// the operation being timed:
+//
+//	start := time.Now()
+//	... operation that takes 20 milliseconds ...
+//	t := time.Now()
+//	elapsed := t.Sub(start)
+//
+// Other idioms, such as time.Since(start), time.Until(deadline), and
+// time.Now().Before(deadline), are similarly robust against wall clock
+// resets.
+//
+// The rest of this section gives the precise details of how operations
+// use monotonic clocks, but understanding those details is not required
+// to use this package.
+//
+// The Time returned by time.Now contains a monotonic clock reading.
+// If Time t has a monotonic clock reading, t.Add adds the same duration to
+// both the wall clock and monotonic clock readings to compute the result.
+// Because t.AddDate(y, m, d), t.Round(d), and t.Truncate(d) are wall time
+// computations, they always strip any monotonic clock reading from their results.
+// Because t.In, t.Local, and t.UTC are used for their effect on the interpretation
+// of the wall time, they also strip any monotonic clock reading from their results.
+// The canonical way to strip a monotonic clock reading is to use t = t.Round(0).
+//
+// If Times t and u both contain monotonic clock readings, the operations
+// t.After(u), t.Before(u), t.Equal(u), t.Compare(u), and t.Sub(u) are carried out
+// using the monotonic clock readings alone, ignoring the wall clock
+// readings. If either t or u contains no monotonic clock reading, these
+// operations fall back to using the wall clock readings.
+//
+// On some systems the monotonic clock will stop if the computer goes to sleep.
+// On such a system, t.Sub(u) may not accurately reflect the actual
+// time that passed between t and u.
+//
+// Because the monotonic clock reading has no meaning outside
+// the current process, the serialized forms generated by t.GobEncode,
+// t.MarshalBinary, t.MarshalJSON, and t.MarshalText omit the monotonic
+// clock reading, and t.Format provides no format for it. Similarly, the
+// constructors time.Date, time.Parse, time.ParseInLocation, and time.Unix,
+// as well as the unmarshalers t.GobDecode, t.UnmarshalBinary.
+// t.UnmarshalJSON, and t.UnmarshalText always create times with
+// no monotonic clock reading.
+//
+// The monotonic clock reading exists only in Time values. It is not
+// a part of Duration values or the Unix times returned by t.Unix and
+// friends.
+//
+// Note that the Go == operator compares not just the time instant but
+// also the Location and the monotonic clock reading. See the
+// documentation for the Time type for a discussion of equality
+// testing for Time values.
+//
+// For debugging, the result of t.String does include the monotonic
+// clock reading if present. If t != u because of different monotonic clock readings,
+// that difference will be visible when printing t.String() and u.String().
+package time
+
+import (
+	"errors"
+	_ "unsafe" // for go:linkname
+)
+
+// A Time represents an instant in time with nanosecond precision.
+//
+// Programs using times should typically store and pass them as values,
+// not pointers. That is, time variables and struct fields should be of
+// type time.Time, not *time.Time.
+//
+// A Time value can be used by multiple goroutines simultaneously except
+// that the methods GobDecode, UnmarshalBinary, UnmarshalJSON and
+// UnmarshalText are not concurrency-safe.
+//
+// Time instants can be compared using the Before, After, and Equal methods.
+// The Sub method subtracts two instants, producing a Duration.
+// The Add method adds a Time and a Duration, producing a Time.
+//
+// The zero value of type Time is January 1, year 1, 00:00:00.000000000 UTC.
+// As this time is unlikely to come up in practice, the IsZero method gives
+// a simple way of detecting a time that has not been initialized explicitly.
+//
+// Each Time has associated with it a Location, consulted when computing the
+// presentation form of the time, such as in the Format, Hour, and Year methods.
+// The methods Local, UTC, and In return a Time with a specific location.
+// Changing the location in this way changes only the presentation; it does not
+// change the instant in time being denoted and therefore does not affect the
+// computations described in earlier paragraphs.
+//
+// Representations of a Time value saved by the GobEncode, MarshalBinary,
+// MarshalJSON, and MarshalText methods store the Time.Location's offset, but not
+// the location name. They therefore lose information about Daylight Saving Time.
+//
+// In addition to the required “wall clock” reading, a Time may contain an optional
+// reading of the current process's monotonic clock, to provide additional precision
+// for comparison or subtraction.
+// See the “Monotonic Clocks” section in the package documentation for details.
+//
+// Note that the Go == operator compares not just the time instant but also the
+// Location and the monotonic clock reading. Therefore, Time values should not
+// be used as map or database keys without first guaranteeing that the
+// identical Location has been set for all values, which can be achieved
+// through use of the UTC or Local method, and that the monotonic clock reading
+// has been stripped by setting t = t.Round(0). In general, prefer t.Equal(u)
+// to t == u, since t.Equal uses the most accurate comparison available and
+// correctly handles the case when only one of its arguments has a monotonic
+// clock reading.
+type Time struct {
+	// wall and ext encode the wall time seconds, wall time nanoseconds,
+	// and optional monotonic clock reading in nanoseconds.
+	//
+	// From high to low bit position, wall encodes a 1-bit flag (hasMonotonic),
+	// a 33-bit seconds field, and a 30-bit wall time nanoseconds field.
+	// The nanoseconds field is in the range [0, 999999999].
+	// If the hasMonotonic bit is 0, then the 33-bit field must be zero
+	// and the full signed 64-bit wall seconds since Jan 1 year 1 is stored in ext.
+	// If the hasMonotonic bit is 1, then the 33-bit field holds a 33-bit
+	// unsigned wall seconds since Jan 1 year 1885, and ext holds a
+	// signed 64-bit monotonic clock reading, nanoseconds since process start.
+	wall uint64
+	ext  int64
+
+	// loc specifies the Location that should be used to
+	// determine the minute, hour, month, day, and year
+	// that correspond to this Time.
+	// The nil location means UTC.
+	// All UTC times are represented with loc==nil, never loc==&utcLoc.
+	loc *Location
+}
+
+const (
+	hasMonotonic = 1 << 63
+	maxWall      = wallToInternal + (1<<33 - 1) // year 2157
+	minWall      = wallToInternal               // year 1885
+	nsecMask     = 1<<30 - 1
+	nsecShift    = 30
+)
+
+// These helpers for manipulating the wall and monotonic clock readings
+// take pointer receivers, even when they don't modify the time,
+// to make them cheaper to call.
+
+// nsec returns the time's nanoseconds.
+func (t *Time) nsec() int32 {
+	return int32(t.wall & nsecMask)
+}
+
+// sec returns the time's seconds since Jan 1 year 1.
+func (t *Time) sec() int64 {
+	if t.wall&hasMonotonic != 0 {
+		return wallToInternal + int64(t.wall<<1>>(nsecShift+1))
+	}
+	return t.ext
+}
+
+// unixSec returns the time's seconds since Jan 1 1970 (Unix time).
+func (t *Time) unixSec() int64 { return t.sec() + internalToUnix }
+
+// addSec adds d seconds to the time.
+func (t *Time) addSec(d int64) {
+	if t.wall&hasMonotonic != 0 {
+		sec := int64(t.wall << 1 >> (nsecShift + 1))
+		dsec := sec + d
+		if 0 <= dsec && dsec <= 1<<33-1 {
+			t.wall = t.wall&nsecMask | uint64(dsec)<<nsecShift | hasMonotonic
+			return
+		}
+		// Wall second now out of range for packed field.
+		// Move to ext.
+		t.stripMono()
+	}
+
+	// Check if the sum of t.ext and d overflows and handle it properly.
+	sum := t.ext + d
+	if (sum > t.ext) == (d > 0) {
+		t.ext = sum
+	} else if d > 0 {
+		t.ext = 1<<63 - 1
+	} else {
+		t.ext = -(1<<63 - 1)
+	}
+}
+
+// setLoc sets the location associated with the time.
+func (t *Time) setLoc(loc *Location) {
+	if loc == &utcLoc {
+		loc = nil
+	}
+	t.stripMono()
+	t.loc = loc
+}
+
+// stripMono strips the monotonic clock reading in t.
+func (t *Time) stripMono() {
+	if t.wall&hasMonotonic != 0 {
+		t.ext = t.sec()
+		t.wall &= nsecMask
+	}
+}
+
+// setMono sets the monotonic clock reading in t.
+// If t cannot hold a monotonic clock reading,
+// because its wall time is too large,
+// setMono is a no-op.
+func (t *Time) setMono(m int64) {
+	if t.wall&hasMonotonic == 0 {
+		sec := t.ext
+		if sec < minWall || maxWall < sec {
+			return
+		}
+		t.wall |= hasMonotonic | uint64(sec-minWall)<<nsecShift
+	}
+	t.ext = m
+}
+
+// mono returns t's monotonic clock reading.
+// It returns 0 for a missing reading.
+// This function is used only for testing,
+// so it's OK that technically 0 is a valid
+// monotonic clock reading as well.
+func (t *Time) mono() int64 {
+	if t.wall&hasMonotonic == 0 {
+		return 0
+	}
+	return t.ext
+}
+
+// After reports whether the time instant t is after u.
+func (t Time) After(u Time) bool {
+	if t.wall&u.wall&hasMonotonic != 0 {
+		return t.ext > u.ext
+	}
+	ts := t.sec()
+	us := u.sec()
+	return ts > us || ts == us && t.nsec() > u.nsec()
+}
+
+// Before reports whether the time instant t is before u.
+func (t Time) Before(u Time) bool {
+	if t.wall&u.wall&hasMonotonic != 0 {
+		return t.ext < u.ext
+	}
+	ts := t.sec()
+	us := u.sec()
+	return ts < us || ts == us && t.nsec() < u.nsec()
+}
+
+// Compare compares the time instant t with u. If t is before u, it returns -1;
+// if t is after u, it returns +1; if they're the same, it returns 0.
+func (t Time) Compare(u Time) int {
+	var tc, uc int64
+	if t.wall&u.wall&hasMonotonic != 0 {
+		tc, uc = t.ext, u.ext
+	} else {
+		tc, uc = t.sec(), u.sec()
+		if tc == uc {
+			tc, uc = int64(t.nsec()), int64(u.nsec())
+		}
+	}
+	switch {
+	case tc < uc:
+		return -1
+	case tc > uc:
+		return +1
+	}
+	return 0
+}
+
+// Equal reports whether t and u represent the same time instant.
+// Two times can be equal even if they are in different locations.
+// For example, 6:00 +0200 and 4:00 UTC are Equal.
+// See the documentation on the Time type for the pitfalls of using == with
+// Time values; most code should use Equal instead.
+func (t Time) Equal(u Time) bool {
+	if t.wall&u.wall&hasMonotonic != 0 {
+		return t.ext == u.ext
+	}
+	return t.sec() == u.sec() && t.nsec() == u.nsec()
+}
+
+// A Month specifies a month of the year (January = 1, ...).
+type Month int
+
+const (
+	January Month = 1 + iota
+	February
+	March
+	April
+	May
+	June
+	July
+	August
+	September
+	October
+	November
+	December
+)
+
+// String returns the English name of the month ("January", "February", ...).
+func (m Month) String() string {
+	if January <= m && m <= December {
+		return longMonthNames[m-1]
+	}
+	buf := make([]byte, 20)
+	n := fmtInt(buf, uint64(m))
+	return "%!Month(" + string(buf[n:]) + ")"
+}
+
+// A Weekday specifies a day of the week (Sunday = 0, ...).
+type Weekday int
+
+const (
+	Sunday Weekday = iota
+	Monday
+	Tuesday
+	Wednesday
+	Thursday
+	Friday
+	Saturday
+)
+
+// String returns the English name of the day ("Sunday", "Monday", ...).
+func (d Weekday) String() string {
+	if Sunday <= d && d <= Saturday {
+		return longDayNames[d]
+	}
+	buf := make([]byte, 20)
+	n := fmtInt(buf, uint64(d))
+	return "%!Weekday(" + string(buf[n:]) + ")"
+}
+
+// Computations on time.
+//
+// The zero value for a Time is defined to be
+//	January 1, year 1, 00:00:00.000000000 UTC
+// which (1) looks like a zero, or as close as you can get in a date
+// (1-1-1 00:00:00 UTC), (2) is unlikely enough to arise in practice to
+// be a suitable "not set" sentinel, unlike Jan 1 1970, and (3) has a
+// non-negative year even in time zones west of UTC, unlike 1-1-0
+// 00:00:00 UTC, which would be 12-31-(-1) 19:00:00 in New York.
+//
+// The zero Time value does not force a specific epoch for the time
+// representation. For example, to use the Unix epoch internally, we
+// could define that to distinguish a zero value from Jan 1 1970, that
+// time would be represented by sec=-1, nsec=1e9. However, it does
+// suggest a representation, namely using 1-1-1 00:00:00 UTC as the
+// epoch, and that's what we do.
+//
+// The Add and Sub computations are oblivious to the choice of epoch.
+//
+// The presentation computations - year, month, minute, and so on - all
+// rely heavily on division and modulus by positive constants. For
+// calendrical calculations we want these divisions to round down, even
+// for negative values, so that the remainder is always positive, but
+// Go's division (like most hardware division instructions) rounds to
+// zero. We can still do those computations and then adjust the result
+// for a negative numerator, but it's annoying to write the adjustment
+// over and over. Instead, we can change to a different epoch so long
+// ago that all the times we care about will be positive, and then round
+// to zero and round down coincide. These presentation routines already
+// have to add the zone offset, so adding the translation to the
+// alternate epoch is cheap. For example, having a non-negative time t
+// means that we can write
+//
+//	sec = t % 60
+//
+// instead of
+//
+//	sec = t % 60
+//	if sec < 0 {
+//		sec += 60
+//	}
+//
+// everywhere.
+//
+// The calendar runs on an exact 400 year cycle: a 400-year calendar
+// printed for 1970-2369 will apply as well to 2370-2769. Even the days
+// of the week match up. It simplifies the computations to choose the
+// cycle boundaries so that the exceptional years are always delayed as
+// long as possible. That means choosing a year equal to 1 mod 400, so
+// that the first leap year is the 4th year, the first missed leap year
+// is the 100th year, and the missed missed leap year is the 400th year.
+// So we'd prefer instead to print a calendar for 2001-2400 and reuse it
+// for 2401-2800.
+//
+// Finally, it's convenient if the delta between the Unix epoch and
+// long-ago epoch is representable by an int64 constant.
+//
+// These three considerations—choose an epoch as early as possible, that
+// uses a year equal to 1 mod 400, and that is no more than 2⁶³ seconds
+// earlier than 1970—bring us to the year -292277022399. We refer to
+// this year as the absolute zero year, and to times measured as a uint64
+// seconds since this year as absolute times.
+//
+// Times measured as an int64 seconds since the year 1—the representation
+// used for Time's sec field—are called internal times.
+//
+// Times measured as an int64 seconds since the year 1970 are called Unix
+// times.
+//
+// It is tempting to just use the year 1 as the absolute epoch, defining
+// that the routines are only valid for years >= 1. However, the
+// routines would then be invalid when displaying the epoch in time zones
+// west of UTC, since it is year 0. It doesn't seem tenable to say that
+// printing the zero time correctly isn't supported in half the time
+// zones. By comparison, it's reasonable to mishandle some times in
+// the year -292277022399.
+//
+// All this is opaque to clients of the API and can be changed if a
+// better implementation presents itself.
+
+const (
+	// The unsigned zero year for internal calculations.
+	// Must be 1 mod 400, and times before it will not compute correctly,
+	// but otherwise can be changed at will.
+	absoluteZeroYear = -292277022399
+
+	// The year of the zero Time.
+	// Assumed by the unixToInternal computation below.
+	internalYear = 1
+
+	// Offsets to convert between internal and absolute or Unix times.
+	absoluteToInternal int64 = (absoluteZeroYear - internalYear) * 365.2425 * secondsPerDay
+	internalToAbsolute       = -absoluteToInternal
+
+	unixToInternal int64 = (1969*365 + 1969/4 - 1969/100 + 1969/400) * secondsPerDay
+	internalToUnix int64 = -unixToInternal
+
+	wallToInternal int64 = (1884*365 + 1884/4 - 1884/100 + 1884/400) * secondsPerDay
+)
+
+// IsZero reports whether t represents the zero time instant,
+// January 1, year 1, 00:00:00 UTC.
+func (t Time) IsZero() bool {
+	return t.sec() == 0 && t.nsec() == 0
+}
+
+// abs returns the time t as an absolute time, adjusted by the zone offset.
+// It is called when computing a presentation property like Month or Hour.
+func (t Time) abs() uint64 {
+	l := t.loc
+	// Avoid function calls when possible.
+	if l == nil || l == &localLoc {
+		l = l.get()
+	}
+	sec := t.unixSec()
+	if l != &utcLoc {
+		if l.cacheZone != nil && l.cacheStart <= sec && sec < l.cacheEnd {
+			sec += int64(l.cacheZone.offset)
+		} else {
+			_, offset, _, _, _ := l.lookup(sec)
+			sec += int64(offset)
+		}
+	}
+	return uint64(sec + (unixToInternal + internalToAbsolute))
+}
+
+// locabs is a combination of the Zone and abs methods,
+// extracting both return values from a single zone lookup.
+func (t Time) locabs() (name string, offset int, abs uint64) {
+	l := t.loc
+	if l == nil || l == &localLoc {
+		l = l.get()
+	}
+	// Avoid function call if we hit the local time cache.
+	sec := t.unixSec()
+	if l != &utcLoc {
+		if l.cacheZone != nil && l.cacheStart <= sec && sec < l.cacheEnd {
+			name = l.cacheZone.name
+			offset = l.cacheZone.offset
+		} else {
+			name, offset, _, _, _ = l.lookup(sec)
+		}
+		sec += int64(offset)
+	} else {
+		name = "UTC"
+	}
+	abs = uint64(sec + (unixToInternal + internalToAbsolute))
+	return
+}
+
+// Date returns the year, month, and day in which t occurs.
+func (t Time) Date() (year int, month Month, day int) {
+	year, month, day, _ = t.date(true)
+	return
+}
+
+// Year returns the year in which t occurs.
+func (t Time) Year() int {
+	year, _, _, _ := t.date(false)
+	return year
+}
+
+// Month returns the month of the year specified by t.
+func (t Time) Month() Month {
+	_, month, _, _ := t.date(true)
+	return month
+}
+
+// Day returns the day of the month specified by t.
+func (t Time) Day() int {
+	_, _, day, _ := t.date(true)
+	return day
+}
+
+// Weekday returns the day of the week specified by t.
+func (t Time) Weekday() Weekday {
+	return absWeekday(t.abs())
+}
+
+// absWeekday is like Weekday but operates on an absolute time.
+func absWeekday(abs uint64) Weekday {
+	// January 1 of the absolute year, like January 1 of 2001, was a Monday.
+	sec := (abs + uint64(Monday)*secondsPerDay) % secondsPerWeek
+	return Weekday(int(sec) / secondsPerDay)
+}
+
+// ISOWeek returns the ISO 8601 year and week number in which t occurs.
+// Week ranges from 1 to 53. Jan 01 to Jan 03 of year n might belong to
+// week 52 or 53 of year n-1, and Dec 29 to Dec 31 might belong to week 1
+// of year n+1.
+func (t Time) ISOWeek() (year, week int) {
+	// According to the rule that the first calendar week of a calendar year is
+	// the week including the first Thursday of that year, and that the last one is
+	// the week immediately preceding the first calendar week of the next calendar year.
+	// See https://www.iso.org/obp/ui#iso:std:iso:8601:-1:ed-1:v1:en:term:3.1.1.23 for details.
+
+	// weeks start with Monday
+	// Monday Tuesday Wednesday Thursday Friday Saturday Sunday
+	// 1      2       3         4        5      6        7
+	// +3     +2      +1        0        -1     -2       -3
+	// the offset to Thursday
+	abs := t.abs()
+	d := Thursday - absWeekday(abs)
+	// handle Sunday
+	if d == 4 {
+		d = -3
+	}
+	// find the Thursday of the calendar week
+	abs += uint64(d) * secondsPerDay
+	year, _, _, yday := absDate(abs, false)
+	return year, yday/7 + 1
+}
+
+// Clock returns the hour, minute, and second within the day specified by t.
+func (t Time) Clock() (hour, min, sec int) {
+	return absClock(t.abs())
+}
+
+// absClock is like clock but operates on an absolute time.
+func absClock(abs uint64) (hour, min, sec int) {
+	sec = int(abs % secondsPerDay)
+	hour = sec / secondsPerHour
+	sec -= hour * secondsPerHour
+	min = sec / secondsPerMinute
+	sec -= min * secondsPerMinute
+	return
+}
+
+// Hour returns the hour within the day specified by t, in the range [0, 23].
+func (t Time) Hour() int {
+	return int(t.abs()%secondsPerDay) / secondsPerHour
+}
+
+// Minute returns the minute offset within the hour specified by t, in the range [0, 59].
+func (t Time) Minute() int {
+	return int(t.abs()%secondsPerHour) / secondsPerMinute
+}
+
+// Second returns the second offset within the minute specified by t, in the range [0, 59].
+func (t Time) Second() int {
+	return int(t.abs() % secondsPerMinute)
+}
+
+// Nanosecond returns the nanosecond offset within the second specified by t,
+// in the range [0, 999999999].
+func (t Time) Nanosecond() int {
+	return int(t.nsec())
+}
+
+// YearDay returns the day of the year specified by t, in the range [1,365] for non-leap years,
+// and [1,366] in leap years.
+func (t Time) YearDay() int {
+	_, _, _, yday := t.date(false)
+	return yday + 1
+}
+
+// A Duration represents the elapsed time between two instants
+// as an int64 nanosecond count. The representation limits the
+// largest representable duration to approximately 290 years.
+type Duration int64
+
+const (
+	minDuration Duration = -1 << 63
+	maxDuration Duration = 1<<63 - 1
+)
+
+// Common durations. There is no definition for units of Day or larger
+// to avoid confusion across daylight savings time zone transitions.
+//
+// To count the number of units in a Duration, divide:
+//
+//	second := time.Second
+//	fmt.Print(int64(second/time.Millisecond)) // prints 1000
+//
+// To convert an integer number of units to a Duration, multiply:
+//
+//	seconds := 10
+//	fmt.Print(time.Duration(seconds)*time.Second) // prints 10s
+const (
+	Nanosecond  Duration = 1
+	Microsecond          = 1000 * Nanosecond
+	Millisecond          = 1000 * Microsecond
+	Second               = 1000 * Millisecond
+	Minute               = 60 * Second
+	Hour                 = 60 * Minute
+)
+
+// String returns a string representing the duration in the form "72h3m0.5s".
+// Leading zero units are omitted. As a special case, durations less than one
+// second format use a smaller unit (milli-, micro-, or nanoseconds) to ensure
+// that the leading digit is non-zero. The zero duration formats as 0s.
+func (d Duration) String() string {
+	// Largest time is 2540400h10m10.000000000s
+	var buf [32]byte
+	w := len(buf)
+
+	u := uint64(d)
+	neg := d < 0
+	if neg {
+		u = -u
+	}
+
+	if u < uint64(Second) {
+		// Special case: if duration is smaller than a second,
+		// use smaller units, like 1.2ms
+		var prec int
+		w--
+		buf[w] = 's'
+		w--
+		switch {
+		case u == 0:
+			return "0s"
+		case u < uint64(Microsecond):
+			// print nanoseconds
+			prec = 0
+			buf[w] = 'n'
+		case u < uint64(Millisecond):
+			// print microseconds
+			prec = 3
+			// U+00B5 'µ' micro sign == 0xC2 0xB5
+			w-- // Need room for two bytes.
+			copy(buf[w:], "µ")
+		default:
+			// print milliseconds
+			prec = 6
+			buf[w] = 'm'
+		}
+		w, u = fmtFrac(buf[:w], u, prec)
+		w = fmtInt(buf[:w], u)
+	} else {
+		w--
+		buf[w] = 's'
+
+		w, u = fmtFrac(buf[:w], u, 9)
+
+		// u is now integer seconds
+		w = fmtInt(buf[:w], u%60)
+		u /= 60
+
+		// u is now integer minutes
+		if u > 0 {
+			w--
+			buf[w] = 'm'
+			w = fmtInt(buf[:w], u%60)
+			u /= 60
+
+			// u is now integer hours
+			// Stop at hours because days can be different lengths.
+			if u > 0 {
+				w--
+				buf[w] = 'h'
+				w = fmtInt(buf[:w], u)
+			}
+		}
+	}
+
+	if neg {
+		w--
+		buf[w] = '-'
+	}
+
+	return string(buf[w:])
+}
+
+// fmtFrac formats the fraction of v/10**prec (e.g., ".12345") into the
+// tail of buf, omitting trailing zeros. It omits the decimal
+// point too when the fraction is 0. It returns the index where the
+// output bytes begin and the value v/10**prec.
+func fmtFrac(buf []byte, v uint64, prec int) (nw int, nv uint64) {
+	// Omit trailing zeros up to and including decimal point.
+	w := len(buf)
+	print := false
+	for i := 0; i < prec; i++ {
+		digit := v % 10
+		print = print || digit != 0
+		if print {
+			w--
+			buf[w] = byte(digit) + '0'
+		}
+		v /= 10
+	}
+	if print {
+		w--
+		buf[w] = '.'
+	}
+	return w, v
+}
+
+// fmtInt formats v into the tail of buf.
+// It returns the index where the output begins.
+func fmtInt(buf []byte, v uint64) int {
+	w := len(buf)
+	if v == 0 {
+		w--
+		buf[w] = '0'
+	} else {
+		for v > 0 {
+			w--
+			buf[w] = byte(v%10) + '0'
+			v /= 10
+		}
+	}
+	return w
+}
+
+// Nanoseconds returns the duration as an integer nanosecond count.
+func (d Duration) Nanoseconds() int64 { return int64(d) }
+
+// Microseconds returns the duration as an integer microsecond count.
+func (d Duration) Microseconds() int64 { return int64(d) / 1e3 }
+
+// Milliseconds returns the duration as an integer millisecond count.
+func (d Duration) Milliseconds() int64 { return int64(d) / 1e6 }
+
+// These methods return float64 because the dominant
+// use case is for printing a floating point number like 1.5s, and
+// a truncation to integer would make them not useful in those cases.
+// Splitting the integer and fraction ourselves guarantees that
+// converting the returned float64 to an integer rounds the same
+// way that a pure integer conversion would have, even in cases
+// where, say, float64(d.Nanoseconds())/1e9 would have rounded
+// differently.
+
+// Seconds returns the duration as a floating point number of seconds.
+func (d Duration) Seconds() float64 {
+	sec := d / Second
+	nsec := d % Second
+	return float64(sec) + float64(nsec)/1e9
+}
+
+// Minutes returns the duration as a floating point number of minutes.
+func (d Duration) Minutes() float64 {
+	min := d / Minute
+	nsec := d % Minute
+	return float64(min) + float64(nsec)/(60*1e9)
+}
+
+// Hours returns the duration as a floating point number of hours.
+func (d Duration) Hours() float64 {
+	hour := d / Hour
+	nsec := d % Hour
+	return float64(hour) + float64(nsec)/(60*60*1e9)
+}
+
+// Truncate returns the result of rounding d toward zero to a multiple of m.
+// If m <= 0, Truncate returns d unchanged.
+func (d Duration) Truncate(m Duration) Duration {
+	if m <= 0 {
+		return d
+	}
+	return d - d%m
+}
+
+// lessThanHalf reports whether x+x < y but avoids overflow,
+// assuming x and y are both positive (Duration is signed).
+func lessThanHalf(x, y Duration) bool {
+	return uint64(x)+uint64(x) < uint64(y)
+}
+
+// Round returns the result of rounding d to the nearest multiple of m.
+// The rounding behavior for halfway values is to round away from zero.
+// If the result exceeds the maximum (or minimum)
+// value that can be stored in a Duration,
+// Round returns the maximum (or minimum) duration.
+// If m <= 0, Round returns d unchanged.
+func (d Duration) Round(m Duration) Duration {
+	if m <= 0 {
+		return d
+	}
+	r := d % m
+	if d < 0 {
+		r = -r
+		if lessThanHalf(r, m) {
+			return d + r
+		}
+		if d1 := d - m + r; d1 < d {
+			return d1
+		}
+		return minDuration // overflow
+	}
+	if lessThanHalf(r, m) {
+		return d - r
+	}
+	if d1 := d + m - r; d1 > d {
+		return d1
+	}
+	return maxDuration // overflow
+}
+
+// Abs returns the absolute value of d.
+// As a special case, math.MinInt64 is converted to math.MaxInt64.
+func (d Duration) Abs() Duration {
+	switch {
+	case d >= 0:
+		return d
+	case d == minDuration:
+		return maxDuration
+	default:
+		return -d
+	}
+}
+
+// Add returns the time t+d.
+func (t Time) Add(d Duration) Time {
+	dsec := int64(d / 1e9)
+	nsec := t.nsec() + int32(d%1e9)
+	if nsec >= 1e9 {
+		dsec++
+		nsec -= 1e9
+	} else if nsec < 0 {
+		dsec--
+		nsec += 1e9
+	}
+	t.wall = t.wall&^nsecMask | uint64(nsec) // update nsec
+	t.addSec(dsec)
+	if t.wall&hasMonotonic != 0 {
+		te := t.ext + int64(d)
+		if d < 0 && te > t.ext || d > 0 && te < t.ext {
+			// Monotonic clock reading now out of range; degrade to wall-only.
+			t.stripMono()
+		} else {
+			t.ext = te
+		}
+	}
+	return t
+}
+
+// Sub returns the duration t-u. If the result exceeds the maximum (or minimum)
+// value that can be stored in a Duration, the maximum (or minimum) duration
+// will be returned.
+// To compute t-d for a duration d, use t.Add(-d).
+func (t Time) Sub(u Time) Duration {
+	if t.wall&u.wall&hasMonotonic != 0 {
+		te := t.ext
+		ue := u.ext
+		d := Duration(te - ue)
+		if d < 0 && te > ue {
+			return maxDuration // t - u is positive out of range
+		}
+		if d > 0 && te < ue {
+			return minDuration // t - u is negative out of range
+		}
+		return d
+	}
+	d := Duration(t.sec()-u.sec())*Second + Duration(t.nsec()-u.nsec())
+	// Check for overflow or underflow.
+	switch {
+	case u.Add(d).Equal(t):
+		return d // d is correct
+	case t.Before(u):
+		return minDuration // t - u is negative out of range
+	default:
+		return maxDuration // t - u is positive out of range
+	}
+}
+
+// Since returns the time elapsed since t.
+// It is shorthand for time.Now().Sub(t).
+func Since(t Time) Duration {
+	var now Time
+	if t.wall&hasMonotonic != 0 {
+		// Common case optimization: if t has monotonic time, then Sub will use only it.
+		now = Time{hasMonotonic, runtimeNano() - startNano, nil}
+	} else {
+		now = Now()
+	}
+	return now.Sub(t)
+}
+
+// Until returns the duration until t.
+// It is shorthand for t.Sub(time.Now()).
+func Until(t Time) Duration {
+	var now Time
+	if t.wall&hasMonotonic != 0 {
+		// Common case optimization: if t has monotonic time, then Sub will use only it.
+		now = Time{hasMonotonic, runtimeNano() - startNano, nil}
+	} else {
+		now = Now()
+	}
+	return t.Sub(now)
+}
+
+// AddDate returns the time corresponding to adding the
+// given number of years, months, and days to t.
+// For example, AddDate(-1, 2, 3) applied to January 1, 2011
+// returns March 4, 2010.
+//
+// AddDate normalizes its result in the same way that Date does,
+// so, for example, adding one month to October 31 yields
+// December 1, the normalized form for November 31.
+func (t Time) AddDate(years int, months int, days int) Time {
+	year, month, day := t.Date()
+	hour, min, sec := t.Clock()
+	return Date(year+years, month+Month(months), day+days, hour, min, sec, int(t.nsec()), t.Location())
+}
+
+const (
+	secondsPerMinute = 60
+	secondsPerHour   = 60 * secondsPerMinute
+	secondsPerDay    = 24 * secondsPerHour
+	secondsPerWeek   = 7 * secondsPerDay
+	daysPer400Years  = 365*400 + 97
+	daysPer100Years  = 365*100 + 24
+	daysPer4Years    = 365*4 + 1
+)
+
+// date computes the year, day of year, and when full=true,
+// the month and day in which t occurs.
+func (t Time) date(full bool) (year int, month Month, day int, yday int) {
+	return absDate(t.abs(), full)
+}
+
+// absDate is like date but operates on an absolute time.
+func absDate(abs uint64, full bool) (year int, month Month, day int, yday int) {
+	// Split into time and day.
+	d := abs / secondsPerDay
+
+	// Account for 400 year cycles.
+	n := d / daysPer400Years
+	y := 400 * n
+	d -= daysPer400Years * n
+
+	// Cut off 100-year cycles.
+	// The last cycle has one extra leap year, so on the last day
+	// of that year, day / daysPer100Years will be 4 instead of 3.
+	// Cut it back down to 3 by subtracting n>>2.
+	n = d / daysPer100Years
+	n -= n >> 2
+	y += 100 * n
+	d -= daysPer100Years * n
+
+	// Cut off 4-year cycles.
+	// The last cycle has a missing leap year, which does not
+	// affect the computation.
+	n = d / daysPer4Years
+	y += 4 * n
+	d -= daysPer4Years * n
+
+	// Cut off years within a 4-year cycle.
+	// The last year is a leap year, so on the last day of that year,
+	// day / 365 will be 4 instead of 3. Cut it back down to 3
+	// by subtracting n>>2.
+	n = d / 365
+	n -= n >> 2
+	y += n
+	d -= 365 * n
+
+	year = int(int64(y) + absoluteZeroYear)
+	yday = int(d)
+
+	if !full {
+		return
+	}
+
+	day = yday
+	if isLeap(year) {
+		// Leap year
+		switch {
+		case day > 31+29-1:
+			// After leap day; pretend it wasn't there.
+			day--
+		case day == 31+29-1:
+			// Leap day.
+			month = February
+			day = 29
+			return
+		}
+	}
+
+	// Estimate month on assumption that every month has 31 days.
+	// The estimate may be too low by at most one month, so adjust.
+	month = Month(day / 31)
+	end := int(daysBefore[month+1])
+	var begin int
+	if day >= end {
+		month++
+		begin = end
+	} else {
+		begin = int(daysBefore[month])
+	}
+
+	month++ // because January is 1
+	day = day - begin + 1
+	return
+}
+
+// daysBefore[m] counts the number of days in a non-leap year
+// before month m begins. There is an entry for m=12, counting
+// the number of days before January of next year (365).
+var daysBefore = [...]int32{
+	0,
+	31,
+	31 + 28,
+	31 + 28 + 31,
+	31 + 28 + 31 + 30,
+	31 + 28 + 31 + 30 + 31,
+	31 + 28 + 31 + 30 + 31 + 30,
+	31 + 28 + 31 + 30 + 31 + 30 + 31,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 31,
+}
+
+func daysIn(m Month, year int) int {
+	if m == February && isLeap(year) {
+		return 29
+	}
+	return int(daysBefore[m] - daysBefore[m-1])
+}
+
+// daysSinceEpoch takes a year and returns the number of days from
+// the absolute epoch to the start of that year.
+// This is basically (year - zeroYear) * 365, but accounting for leap days.
+func daysSinceEpoch(year int) uint64 {
+	y := uint64(int64(year) - absoluteZeroYear)
+
+	// Add in days from 400-year cycles.
+	n := y / 400
+	y -= 400 * n
+	d := daysPer400Years * n
+
+	// Add in 100-year cycles.
+	n = y / 100
+	y -= 100 * n
+	d += daysPer100Years * n
+
+	// Add in 4-year cycles.
+	n = y / 4
+	y -= 4 * n
+	d += daysPer4Years * n
+
+	// Add in non-leap years.
+	n = y
+	d += 365 * n
+
+	return d
+}
+
+// Provided by package runtime.
+func now() (sec int64, nsec int32, mono int64)
+
+// runtimeNano returns the current value of the runtime clock in nanoseconds.
+//
+//go:linkname runtimeNano runtime.nanotime
+func runtimeNano() int64
+
+// Monotonic times are reported as offsets from startNano.
+// We initialize startNano to runtimeNano() - 1 so that on systems where
+// monotonic time resolution is fairly low (e.g. Windows 2008
+// which appears to have a default resolution of 15ms),
+// we avoid ever reporting a monotonic time of 0.
+// (Callers may want to use 0 as "time not set".)
+var startNano int64 = runtimeNano() - 1
+
+// Now returns the current local time.
+func Now() Time {
+	sec, nsec, mono := now()
+	mono -= startNano
+	sec += unixToInternal - minWall
+	if uint64(sec)>>33 != 0 {
+		// Seconds field overflowed the 33 bits available when
+		// storing a monotonic time. This will be true after
+		// March 16, 2157.
+		return Time{uint64(nsec), sec + minWall, Local}
+	}
+	return Time{hasMonotonic | uint64(sec)<<nsecShift | uint64(nsec), mono, Local}
+}
+
+func unixTime(sec int64, nsec int32) Time {
+	return Time{uint64(nsec), sec + unixToInternal, Local}
+}
+
+// UTC returns t with the location set to UTC.
+func (t Time) UTC() Time {
+	t.setLoc(&utcLoc)
+	return t
+}
+
+// Local returns t with the location set to local time.
+func (t Time) Local() Time {
+	t.setLoc(Local)
+	return t
+}
+
+// In returns a copy of t representing the same time instant, but
+// with the copy's location information set to loc for display
+// purposes.
+//
+// In panics if loc is nil.
+func (t Time) In(loc *Location) Time {
+	if loc == nil {
+		panic("time: missing Location in call to Time.In")
+	}
+	t.setLoc(loc)
+	return t
+}
+
+// Location returns the time zone information associated with t.
+func (t Time) Location() *Location {
+	l := t.loc
+	if l == nil {
+		l = UTC
+	}
+	return l
+}
+
+// Zone computes the time zone in effect at time t, returning the abbreviated
+// name of the zone (such as "CET") and its offset in seconds east of UTC.
+func (t Time) Zone() (name string, offset int) {
+	name, offset, _, _, _ = t.loc.lookup(t.unixSec())
+	return
+}
+
+// ZoneBounds returns the bounds of the time zone in effect at time t.
+// The zone begins at start and the next zone begins at end.
+// If the zone begins at the beginning of time, start will be returned as a zero Time.
+// If the zone goes on forever, end will be returned as a zero Time.
+// The Location of the returned times will be the same as t.
+func (t Time) ZoneBounds() (start, end Time) {
+	_, _, startSec, endSec, _ := t.loc.lookup(t.unixSec())
+	if startSec != alpha {
+		start = unixTime(startSec, 0)
+		start.setLoc(t.loc)
+	}
+	if endSec != omega {
+		end = unixTime(endSec, 0)
+		end.setLoc(t.loc)
+	}
+	return
+}
+
+// Unix returns t as a Unix time, the number of seconds elapsed
+// since January 1, 1970 UTC. The result does not depend on the
+// location associated with t.
+// Unix-like operating systems often record time as a 32-bit
+// count of seconds, but since the method here returns a 64-bit
+// value it is valid for billions of years into the past or future.
+func (t Time) Unix() int64 {
+	return t.unixSec()
+}
+
+// UnixMilli returns t as a Unix time, the number of milliseconds elapsed since
+// January 1, 1970 UTC. The result is undefined if the Unix time in
+// milliseconds cannot be represented by an int64 (a date more than 292 million
+// years before or after 1970). The result does not depend on the
+// location associated with t.
+func (t Time) UnixMilli() int64 {
+	return t.unixSec()*1e3 + int64(t.nsec())/1e6
+}
+
+// UnixMicro returns t as a Unix time, the number of microseconds elapsed since
+// January 1, 1970 UTC. The result is undefined if the Unix time in
+// microseconds cannot be represented by an int64 (a date before year -290307 or
+// after year 294246). The result does not depend on the location associated
+// with t.
+func (t Time) UnixMicro() int64 {
+	return t.unixSec()*1e6 + int64(t.nsec())/1e3
+}
+
+// UnixNano returns t as a Unix time, the number of nanoseconds elapsed
+// since January 1, 1970 UTC. The result is undefined if the Unix time
+// in nanoseconds cannot be represented by an int64 (a date before the year
+// 1678 or after 2262). Note that this means the result of calling UnixNano
+// on the zero Time is undefined. The result does not depend on the
+// location associated with t.
+func (t Time) UnixNano() int64 {
+	return (t.unixSec())*1e9 + int64(t.nsec())
+}
+
+const (
+	timeBinaryVersionV1 byte = iota + 1 // For general situation
+	timeBinaryVersionV2                 // For LMT only
+)
+
+// MarshalBinary implements the encoding.BinaryMarshaler interface.
+func (t Time) MarshalBinary() ([]byte, error) {
+	var offsetMin int16 // minutes east of UTC. -1 is UTC.
+	var offsetSec int8
+	version := timeBinaryVersionV1
+
+	if t.Location() == UTC {
+		offsetMin = -1
+	} else {
+		_, offset := t.Zone()
+		if offset%60 != 0 {
+			version = timeBinaryVersionV2
+			offsetSec = int8(offset % 60)
+		}
+
+		offset /= 60
+		if offset < -32768 || offset == -1 || offset > 32767 {
+			return nil, errors.New("Time.MarshalBinary: unexpected zone offset")
+		}
+		offsetMin = int16(offset)
+	}
+
+	sec := t.sec()
+	nsec := t.nsec()
+	enc := []byte{
+		version,         // byte 0 : version
+		byte(sec >> 56), // bytes 1-8: seconds
+		byte(sec >> 48),
+		byte(sec >> 40),
+		byte(sec >> 32),
+		byte(sec >> 24),
+		byte(sec >> 16),
+		byte(sec >> 8),
+		byte(sec),
+		byte(nsec >> 24), // bytes 9-12: nanoseconds
+		byte(nsec >> 16),
+		byte(nsec >> 8),
+		byte(nsec),
+		byte(offsetMin >> 8), // bytes 13-14: zone offset in minutes
+		byte(offsetMin),
+	}
+	if version == timeBinaryVersionV2 {
+		enc = append(enc, byte(offsetSec))
+	}
+
+	return enc, nil
+}
+
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+func (t *Time) UnmarshalBinary(data []byte) error {
+	buf := data
+	if len(buf) == 0 {
+		return errors.New("Time.UnmarshalBinary: no data")
+	}
+
+	version := buf[0]
+	if version != timeBinaryVersionV1 && version != timeBinaryVersionV2 {
+		return errors.New("Time.UnmarshalBinary: unsupported version")
+	}
+
+	wantLen := /*version*/ 1 + /*sec*/ 8 + /*nsec*/ 4 + /*zone offset*/ 2
+	if version == timeBinaryVersionV2 {
+		wantLen++
+	}
+	if len(buf) != wantLen {
+		return errors.New("Time.UnmarshalBinary: invalid length")
+	}
+
+	buf = buf[1:]
+	sec := int64(buf[7]) | int64(buf[6])<<8 | int64(buf[5])<<16 | int64(buf[4])<<24 |
+		int64(buf[3])<<32 | int64(buf[2])<<40 | int64(buf[1])<<48 | int64(buf[0])<<56
+
+	buf = buf[8:]
+	nsec := int32(buf[3]) | int32(buf[2])<<8 | int32(buf[1])<<16 | int32(buf[0])<<24
+
+	buf = buf[4:]
+	offset := int(int16(buf[1])|int16(buf[0])<<8) * 60
+	if version == timeBinaryVersionV2 {
+		offset += int(buf[2])
+	}
+
+	*t = Time{}
+	t.wall = uint64(nsec)
+	t.ext = sec
+
+	if offset == -1*60 {
+		t.setLoc(&utcLoc)
+	} else if _, localoff, _, _, _ := Local.lookup(t.unixSec()); offset == localoff {
+		t.setLoc(Local)
+	} else {
+		t.setLoc(FixedZone("", offset))
+	}
+
+	return nil
+}
+
+// TODO(rsc): Remove GobEncoder, GobDecoder, MarshalJSON, UnmarshalJSON in Go 2.
+// The same semantics will be provided by the generic MarshalBinary, MarshalText,
+// UnmarshalBinary, UnmarshalText.
+
+// GobEncode implements the gob.GobEncoder interface.
+func (t Time) GobEncode() ([]byte, error) {
+	return t.MarshalBinary()
+}
+
+// GobDecode implements the gob.GobDecoder interface.
+func (t *Time) GobDecode(data []byte) error {
+	return t.UnmarshalBinary(data)
+}
+
+// MarshalJSON implements the json.Marshaler interface.
+// The time is a quoted string in the RFC 3339 format with sub-second precision.
+// If the timestamp cannot be represented as valid RFC 3339
+// (e.g., the year is out of range), then an error is reported.
+func (t Time) MarshalJSON() ([]byte, error) {
+	b := make([]byte, 0, len(RFC3339Nano)+len(`""`))
+	b = append(b, '"')
+	b, err := t.appendStrictRFC3339(b)
+	b = append(b, '"')
+	if err != nil {
+		return nil, errors.New("Time.MarshalJSON: " + err.Error())
+	}
+	return b, nil
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+// The time must be a quoted string in the RFC 3339 format.
+func (t *Time) UnmarshalJSON(data []byte) error {
+	if string(data) == "null" {
+		return nil
+	}
+	// TODO(https://go.dev/issue/47353): Properly unescape a JSON string.
+	if len(data) < 2 || data[0] != '"' || data[len(data)-1] != '"' {
+		return errors.New("Time.UnmarshalJSON: input is not a JSON string")
+	}
+	data = data[len(`"`) : len(data)-len(`"`)]
+	var err error
+	*t, err = parseStrictRFC3339(data)
+	return err
+}
+
+// MarshalText implements the encoding.TextMarshaler interface.
+// The time is formatted in RFC 3339 format with sub-second precision.
+// If the timestamp cannot be represented as valid RFC 3339
+// (e.g., the year is out of range), then an error is reported.
+func (t Time) MarshalText() ([]byte, error) {
+	b := make([]byte, 0, len(RFC3339Nano))
+	b, err := t.appendStrictRFC3339(b)
+	if err != nil {
+		return nil, errors.New("Time.MarshalText: " + err.Error())
+	}
+	return b, nil
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+// The time must be in the RFC 3339 format.
+func (t *Time) UnmarshalText(data []byte) error {
+	var err error
+	*t, err = parseStrictRFC3339(data)
+	return err
+}
+
+// Unix returns the local Time corresponding to the given Unix time,
+// sec seconds and nsec nanoseconds since January 1, 1970 UTC.
+// It is valid to pass nsec outside the range [0, 999999999].
+// Not all sec values have a corresponding time value. One such
+// value is 1<<63-1 (the largest int64 value).
+func Unix(sec int64, nsec int64) Time {
+	if nsec < 0 || nsec >= 1e9 {
+		n := nsec / 1e9
+		sec += n
+		nsec -= n * 1e9
+		if nsec < 0 {
+			nsec += 1e9
+			sec--
+		}
+	}
+	return unixTime(sec, int32(nsec))
+}
+
+// UnixMilli returns the local Time corresponding to the given Unix time,
+// msec milliseconds since January 1, 1970 UTC.
+func UnixMilli(msec int64) Time {
+	return Unix(msec/1e3, (msec%1e3)*1e6)
+}
+
+// UnixMicro returns the local Time corresponding to the given Unix time,
+// usec microseconds since January 1, 1970 UTC.
+func UnixMicro(usec int64) Time {
+	return Unix(usec/1e6, (usec%1e6)*1e3)
+}
+
+// IsDST reports whether the time in the configured location is in Daylight Savings Time.
+func (t Time) IsDST() bool {
+	_, _, _, _, isDST := t.loc.lookup(t.Unix())
+	return isDST
+}
+
+func isLeap(year int) bool {
+	return year%4 == 0 && (year%100 != 0 || year%400 == 0)
+}
+
+// norm returns nhi, nlo such that
+//
+//	hi * base + lo == nhi * base + nlo
+//	0 <= nlo < base
+func norm(hi, lo, base int) (nhi, nlo int) {
+	if lo < 0 {
+		n := (-lo-1)/base + 1
+		hi -= n
+		lo += n * base
+	}
+	if lo >= base {
+		n := lo / base
+		hi += n
+		lo -= n * base
+	}
+	return hi, lo
+}
+
+// Date returns the Time corresponding to
+//
+//	yyyy-mm-dd hh:mm:ss + nsec nanoseconds
+//
+// in the appropriate zone for that time in the given location.
+//
+// The month, day, hour, min, sec, and nsec values may be outside
+// their usual ranges and will be normalized during the conversion.
+// For example, October 32 converts to November 1.
+//
+// A daylight savings time transition skips or repeats times.
+// For example, in the United States, March 13, 2011 2:15am never occurred,
+// while November 6, 2011 1:15am occurred twice. In such cases, the
+// choice of time zone, and therefore the time, is not well-defined.
+// Date returns a time that is correct in one of the two zones involved
+// in the transition, but it does not guarantee which.
+//
+// Date panics if loc is nil.
+func Date(year int, month Month, day, hour, min, sec, nsec int, loc *Location) Time {
+	if loc == nil {
+		panic("time: missing Location in call to Date")
+	}
+
+	// Normalize month, overflowing into year.
+	m := int(month) - 1
+	year, m = norm(year, m, 12)
+	month = Month(m) + 1
+
+	// Normalize nsec, sec, min, hour, overflowing into day.
+	sec, nsec = norm(sec, nsec, 1e9)
+	min, sec = norm(min, sec, 60)
+	hour, min = norm(hour, min, 60)
+	day, hour = norm(day, hour, 24)
+
+	// Compute days since the absolute epoch.
+	d := daysSinceEpoch(year)
+
+	// Add in days before this month.
+	d += uint64(daysBefore[month-1])
+	if isLeap(year) && month >= March {
+		d++ // February 29
+	}
+
+	// Add in days before today.
+	d += uint64(day - 1)
+
+	// Add in time elapsed today.
+	abs := d * secondsPerDay
+	abs += uint64(hour*secondsPerHour + min*secondsPerMinute + sec)
+
+	unix := int64(abs) + (absoluteToInternal + internalToUnix)
+
+	// Look for zone offset for expected time, so we can adjust to UTC.
+	// The lookup function expects UTC, so first we pass unix in the
+	// hope that it will not be too close to a zone transition,
+	// and then adjust if it is.
+	_, offset, start, end, _ := loc.lookup(unix)
+	if offset != 0 {
+		utc := unix - int64(offset)
+		// If utc is valid for the time zone we found, then we have the right offset.
+		// If not, we get the correct offset by looking up utc in the location.
+		if utc < start || utc >= end {
+			_, offset, _, _, _ = loc.lookup(utc)
+		}
+		unix -= int64(offset)
+	}
+
+	t := unixTime(unix, int32(nsec))
+	t.setLoc(loc)
+	return t
+}
+
+// Truncate returns the result of rounding t down to a multiple of d (since the zero time).
+// If d <= 0, Truncate returns t stripped of any monotonic clock reading but otherwise unchanged.
+//
+// Truncate operates on the time as an absolute duration since the
+// zero time; it does not operate on the presentation form of the
+// time. Thus, Truncate(Hour) may return a time with a non-zero
+// minute, depending on the time's Location.
+func (t Time) Truncate(d Duration) Time {
+	t.stripMono()
+	if d <= 0 {
+		return t
+	}
+	_, r := div(t, d)
+	return t.Add(-r)
+}
+
+// Round returns the result of rounding t to the nearest multiple of d (since the zero time).
+// The rounding behavior for halfway values is to round up.
+// If d <= 0, Round returns t stripped of any monotonic clock reading but otherwise unchanged.
+//
+// Round operates on the time as an absolute duration since the
+// zero time; it does not operate on the presentation form of the
+// time. Thus, Round(Hour) may return a time with a non-zero
+// minute, depending on the time's Location.
+func (t Time) Round(d Duration) Time {
+	t.stripMono()
+	if d <= 0 {
+		return t
+	}
+	_, r := div(t, d)
+	if lessThanHalf(r, d) {
+		return t.Add(-r)
+	}
+	return t.Add(d - r)
+}
+
+// div divides t by d and returns the quotient parity and remainder.
+// We don't use the quotient parity anymore (round half up instead of round to even)
+// but it's still here in case we change our minds.
+func div(t Time, d Duration) (qmod2 int, r Duration) {
+	neg := false
+	nsec := t.nsec()
+	sec := t.sec()
+	if sec < 0 {
+		// Operate on absolute value.
+		neg = true
+		sec = -sec
+		nsec = -nsec
+		if nsec < 0 {
+			nsec += 1e9
+			sec-- // sec >= 1 before the -- so safe
+		}
+	}
+
+	switch {
+	// Special case: 2d divides 1 second.
+	case d < Second && Second%(d+d) == 0:
+		qmod2 = int(nsec/int32(d)) & 1
+		r = Duration(nsec % int32(d))
+
+	// Special case: d is a multiple of 1 second.
+	case d%Second == 0:
+		d1 := int64(d / Second)
+		qmod2 = int(sec/d1) & 1
+		r = Duration(sec%d1)*Second + Duration(nsec)
+
+	// General case.
+	// This could be faster if more cleverness were applied,
+	// but it's really only here to avoid special case restrictions in the API.
+	// No one will care about these cases.
+	default:
+		// Compute nanoseconds as 128-bit number.
+		sec := uint64(sec)
+		tmp := (sec >> 32) * 1e9
+		u1 := tmp >> 32
+		u0 := tmp << 32
+		tmp = (sec & 0xFFFFFFFF) * 1e9
+		u0x, u0 := u0, u0+tmp
+		if u0 < u0x {
+			u1++
+		}
+		u0x, u0 = u0, u0+uint64(nsec)
+		if u0 < u0x {
+			u1++
+		}
+
+		// Compute remainder by subtracting r<<k for decreasing k.
+		// Quotient parity is whether we subtract on last round.
+		d1 := uint64(d)
+		for d1>>63 != 1 {
+			d1 <<= 1
+		}
+		d0 := uint64(0)
+		for {
+			qmod2 = 0
+			if u1 > d1 || u1 == d1 && u0 >= d0 {
+				// subtract
+				qmod2 = 1
+				u0x, u0 = u0, u0-d0
+				if u0 > u0x {
+					u1--
+				}
+				u1 -= d1
+			}
+			if d1 == 0 && d0 == uint64(d) {
+				break
+			}
+			d0 >>= 1
+			d0 |= (d1 & 1) << 63
+			d1 >>= 1
+		}
+		r = Duration(u0)
+	}
+
+	if neg && r != 0 {
+		// If input was negative and not an exact multiple of d, we computed q, r such that
+		//	q*d + r = -t
+		// But the right answers are given by -(q-1), d-r:
+		//	q*d + r = -t
+		//	-q*d - r = t
+		//	-(q-1)*d + (d - r) = t
+		qmod2 ^= 1
+		r = d - r
+	}
+	return
+}