Initial commit: Go 1.23 release state

src/time/zoneinfo_android.go

@@ -0,0 +1,87 @@
+// 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"
+	"syscall"
+)
+
+var platformZoneSources = []string{
+	"/system/usr/share/zoneinfo/tzdata",
+	"/data/misc/zoneinfo/current/tzdata",
+}
+
+func initLocal() {
+	// TODO(elias.naur): getprop persist.sys.timezone
+	localLoc = *UTC
+}
+
+func init() {
+	loadTzinfoFromTzdata = androidLoadTzinfoFromTzdata
+}
+
+var allowGorootSource = true
+
+func gorootZoneSource(goroot string) (string, bool) {
+	if goroot == "" || !allowGorootSource {
+		return "", false
+	}
+	return goroot + "/lib/time/zoneinfo.zip", true
+}
+
+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, syscall.ENOENT
+}