// Copyright 2016 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. // Parse the "tzdata" packed timezone file used on Android. // The format is lifted from ZoneInfoDB.java and ZoneInfo.java in // java/libcore/util in the AOSP. package time import ( "errors" "runtime" ) var zoneSources = []string{ "/system/usr/share/zoneinfo/tzdata", "/data/misc/zoneinfo/current/tzdata", runtime.GOROOT() + "/lib/time/zoneinfo.zip", } func initLocal() { // TODO(elias.naur): getprop persist.sys.timezone localLoc = *UTC } func init() { loadTzinfoFromTzdata = androidLoadTzinfoFromTzdata } func androidLoadTzinfoFromTzdata(file, name string) ([]byte, error) { const ( headersize = 12 + 3*4 namesize = 40 entrysize = namesize + 3*4 ) if len(name) > namesize { return nil, errors.New(name + " is longer than the maximum zone name length (40 bytes)") } fd, err := open(file) if err != nil { return nil, err } defer closefd(fd) buf := make([]byte, headersize) if err := preadn(fd, buf, 0); err != nil { return nil, errors.New("corrupt tzdata file " + file) } d := dataIO{buf, false} if magic := d.read(6); string(magic) != "tzdata" { return nil, errors.New("corrupt tzdata file " + file) } d = dataIO{buf[12:], false} indexOff, _ := d.big4() dataOff, _ := d.big4() indexSize := dataOff - indexOff entrycount := indexSize / entrysize buf = make([]byte, indexSize) if err := preadn(fd, buf, int(indexOff)); err != nil { return nil, errors.New("corrupt tzdata file " + file) } for i := 0; i < int(entrycount); i++ { entry := buf[i*entrysize : (i+1)*entrysize] // len(name) <= namesize is checked at function entry if string(entry[:len(name)]) != name { continue } d := dataIO{entry[namesize:], false} off, _ := d.big4() size, _ := d.big4() buf := make([]byte, size) if err := preadn(fd, buf, int(off+dataOff)); err != nil { return nil, errors.New("corrupt tzdata file " + file) } return buf, nil } return nil, errors.New("cannot find " + name + " in tzdata file " + file) }