--- /dev/null
+// 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 tzdataPaths = []string{
+ "/system/usr/share/zoneinfo/tzdata",
+ "/data/misc/zoneinfo/current/tzdata",
+ runtime.GOROOT() + "/lib/time/zoneinfo.zip",
+}
+
+var origTzdataPaths = tzdataPaths
+
+func forceZipFileForTesting(zipOnly bool) {
+ tzdataPaths = make([]string, len(origTzdataPaths))
+ copy(tzdataPaths, origTzdataPaths)
+ if zipOnly {
+ for i := 0; i < len(tzdataPaths)-1; i++ {
+ tzdataPaths[i] = "/XXXNOEXIST"
+ }
+ }
+}
+
+func initTestingZone() {
+ z, err := loadLocation("America/Los_Angeles")
+ if err != nil {
+ panic("cannot load America/Los_Angeles for testing: " + err.Error())
+ }
+ z.name = "Local"
+ localLoc = *z
+}
+
+func initLocal() {
+ // TODO(elias.naur): getprop persist.sys.timezone
+ localLoc = *UTC
+}
+
+func loadLocation(name string) (*Location, error) {
+ var firstErr error
+ for _, path := range tzdataPaths {
+ var z *Location
+ var err error
+ if len(path) > 4 && path[len(path)-4:] == ".zip" {
+ z, err = loadZoneZip(path, name)
+ } else {
+ z, err = loadTzdataFile(path, name)
+ }
+ if err == nil {
+ z.name = name
+ return z, nil
+ } else if firstErr == nil && !isNotExist(err) {
+ firstErr = err
+ }
+ }
+ if firstErr != nil {
+ return nil, firstErr
+ }
+ return nil, errors.New("unknown time zone " + name)
+}
+
+func loadTzdataFile(file, name string) (*Location, 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 := data{buf, false}
+ if magic := d.read(6); string(magic) != "tzdata" {
+ return nil, errors.New("corrupt tzdata file " + file)
+ }
+ d = data{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 := data{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 loadZoneData(buf)
+ }
+ return nil, errors.New("cannot find " + name + " in tzdata file " + file)
+}