leapsecond.go

/*
Package leapsecond is the tool of leap seconds.
*/
package leapsecond

import (
	"time"
)

var seconds = []int64{
	1483228799, // 2016-12-31T23:59:59Z
	1435708799, // 2015-06-30T23:59:59Z
	1341100799, // 2012-06-30T23:59:59Z
	1230767999, // 2008-12-31T23:59:59Z
	1136073599, // 2005-12-31T23:59:59Z
	915148799,  // 1998-12-31T23:59:59Z
	867715199,  // 1997-06-30T23:59:59Z
	820454399,  // 1995-12-31T23:59:59Z
	773020799,  // 1994-06-30T23:59:59Z
	741484799,  // 1993-06-30T23:59:59Z
	709948799,  // 1992-06-30T23:59:59Z
	662687999,  // 1990-12-31T23:59:59Z
	631151999,  // 1989-12-31T23:59:59Z
	567993599,  // 1987-12-31T23:59:59Z
	489023999,  // 1985-06-30T23:59:59Z
	425865599,  // 1983-06-30T23:59:59Z
	394329599,  // 1982-06-30T23:59:59Z
	362793599,  // 1981-06-30T23:59:59Z
	315532799,  // 1979-12-31T23:59:59Z
	283996799,  // 1978-12-31T23:59:59Z
	252460799,  // 1977-12-31T23:59:59Z
	220924799,  // 1976-12-31T23:59:59Z
	189302399,  // 1975-12-31T23:59:59Z
	157766399,  // 1974-12-31T23:59:59Z
	126230399,  // 1973-12-31T23:59:59Z
	94694399,   // 1972-12-31T23:59:59Z
	78796799,   // 1972-06-30T23:59:59Z
}

// Have get times of leap seconds by time
func Have(t time.Time) time.Duration {
	for i, s := range seconds {
		if t.Unix() > s {
			return time.Duration(len(seconds)-i) * time.Second
		}
	}

	return 0
}

// Diff get times of leap seconds between two times
func Diff(t1 time.Time, t2 time.Time) time.Duration {
	d := Have(t1) - Have(t2)
	y := d >> 63

	return (d ^ y) - y
}