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