65 lines
1.6 KiB
Go
65 lines
1.6 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin freebsd linux openbsd plan9
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package time
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import "sync"
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// Parsed representation
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type zone struct {
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utcoff int
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isdst bool
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name string
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}
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type zonetime struct {
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time int32 // transition time, in seconds since 1970 GMT
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zone *zone // the zone that goes into effect at that time
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isstd, isutc bool // ignored - no idea what these mean
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}
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var zones []zonetime
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var onceSetupZone sync.Once
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// Look up the correct time zone (daylight savings or not) for the given unix time, in the current location.
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func lookupTimezone(sec int64) (zone string, offset int) {
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onceSetupZone.Do(setupZone)
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if len(zones) == 0 {
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return "UTC", 0
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}
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// Binary search for entry with largest time <= sec
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tz := zones
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for len(tz) > 1 {
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m := len(tz) / 2
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if sec < int64(tz[m].time) {
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tz = tz[0:m]
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} else {
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tz = tz[m:]
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}
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}
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z := tz[0].zone
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return z.name, z.utcoff
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}
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// lookupByName returns the time offset for the
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// time zone with the given abbreviation. It only considers
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// time zones that apply to the current system.
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// For example, for a system configured as being in New York,
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// it only recognizes "EST" and "EDT".
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// For a system in San Francisco, "PST" and "PDT".
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// For a system in Sydney, "EST" and "EDT", though they have
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// different meanings than they do in New York.
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func lookupByName(name string) (off int, found bool) {
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onceSetupZone.Do(setupZone)
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for _, z := range zones {
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if name == z.zone.name {
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return z.zone.utcoff, true
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}
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}
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return 0, false
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}
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