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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [time/] [zoneinfo_plan9.go] - Blame information for rev 774

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Line No. Rev Author Line
1 747 jeremybenn 
// 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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// Parse Plan 9 timezone(2) files.
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package time
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import (
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        "errors"
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        "syscall"
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)
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var badData = errors.New("malformed time zone information")
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func isSpace(r rune) bool {
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        return r == ' ' || r == '\t' || r == '\n'
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}
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// Copied from strings to avoid a dependency.
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func fields(s string) []string {
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        // First count the fields.
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        n := 0
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        inField := false
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        for _, rune := range s {
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                wasInField := inField
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                inField = !isSpace(rune)
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                if inField && !wasInField {
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                        n++
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                }
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        }
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        // Now create them.
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        a := make([]string, n)
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        na := 0
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        fieldStart := -1 // Set to -1 when looking for start of field.
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        for i, rune := range s {
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                if isSpace(rune) {
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                        if fieldStart >= 0 {
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                                a[na] = s[fieldStart:i]
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                                na++
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                                fieldStart = -1
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                        }
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                } else if fieldStart == -1 {
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                        fieldStart = i
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                }
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        }
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        if fieldStart >= 0 { // Last field might end at EOF.
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                a[na] = s[fieldStart:]
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        }
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        return a
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}
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func loadZoneData(s string) (l *Location, err error) {
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        f := fields(s)
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        if len(f) < 4 {
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                if len(f) == 2 && f[0] == "GMT" {
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                        return UTC, nil
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                }
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                return nil, badData
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        }
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        var zones [2]zone
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        // standard timezone offset
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        o, err := atoi(f[1])
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        if err != nil {
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                return nil, badData
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        }
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        zones[0] = zone{name: f[0], offset: o, isDST: false}
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        // alternate timezone offset
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        o, err = atoi(f[3])
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        if err != nil {
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                return nil, badData
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        }
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        zones[1] = zone{name: f[2], offset: o, isDST: true}
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        // transition time pairs
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        var tx []zoneTrans
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        f = f[4:]
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        for i := 0; i < len(f); i++ {
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                zi := 0
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                if i%2 == 0 {
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                        zi = 1
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                }
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                t, err := atoi(f[i])
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                if err != nil {
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                        return nil, badData
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                }
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                t -= zones[0].offset
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                tx = append(tx, zoneTrans{when: int64(t), index: uint8(zi)})
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        }
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        // Committed to succeed.
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        l = &Location{zone: zones[:], tx: tx}
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        // Fill in the cache with information about right now,
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        // since that will be the most common lookup.
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        sec, _ := now()
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        for i := range tx {
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                if tx[i].when <= sec && (i+1 == len(tx) || sec < tx[i+1].when) {
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                        l.cacheStart = tx[i].when
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                        l.cacheEnd = 1<<63 - 1
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                        if i+1 < len(tx) {
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                                l.cacheEnd = tx[i+1].when
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                        }
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                        l.cacheZone = &l.zone[tx[i].index]
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                }
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        }
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        return l, nil
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}
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func loadZoneFile(name string) (*Location, error) {
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        b, err := readFile(name)
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        if err != nil {
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                return nil, err
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        }
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        return loadZoneData(string(b))
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}
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func initTestingZone() {
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        if z, err := loadZoneFile("/adm/timezone/US_Pacific"); err == nil {
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                localLoc = *z
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                return
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        }
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        // Fall back to UTC.
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        localLoc.name = "UTC"
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}
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func initLocal() {
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        t, ok := syscall.Getenv("timezone")
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        if ok {
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                if z, err := loadZoneData(t); err == nil {
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                        localLoc = *z
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                        return
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                }
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        } else {
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                if z, err := loadZoneFile("/adm/timezone/local"); err == nil {
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                        localLoc = *z
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                        localLoc.name = "Local"
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                        return
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                }
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        }
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        // Fall back to UTC.
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        localLoc.name = "UTC"
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}
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func loadLocation(name string) (*Location, error) {
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        if z, err := loadZoneFile("/adm/timezone/" + name); err == nil {
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                return z, nil
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        }
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        return nil, errors.New("unknown time zone " + name)
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}

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