1 files changed, 272 insertions, 0 deletions
diff --git a/src/time/zoneinfo_windows.go b/src/time/zoneinfo_windows.go
new file mode 100644
index 000000000..02d8e0edc
--- /dev/null
+++ b/src/time/zoneinfo_windows.go
@@ -0,0 +1,272 @@
+// Copyright 2009 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 (
+	"errors"
+	"runtime"
+	"syscall"
+	"unsafe"
+)
+
+//go:generate go run genzabbrs.go -output zoneinfo_abbrs_windows.go
+
+// TODO(rsc): Fall back to copy of zoneinfo files.
+
+// BUG(brainman,rsc): On Windows, the operating system does not provide complete
+// time zone information.
+// The implementation assumes that this year's rules for daylight savings
+// time apply to all previous and future years as well.
+
+// getKeyValue retrieves the string value kname associated with the open registry key kh.
+func getKeyValue(kh syscall.Handle, kname string) (string, error) {
+	var buf [50]uint16 // buf needs to be large enough to fit zone descriptions
+	var typ uint32
+	n := uint32(len(buf) * 2) // RegQueryValueEx's signature expects array of bytes, not uint16
+	p, _ := syscall.UTF16PtrFromString(kname)
+	if err := syscall.RegQueryValueEx(kh, p, nil, &typ, (*byte)(unsafe.Pointer(&buf[0])), &n); err != nil {
+		return "", err
+	}
+	if typ != syscall.REG_SZ { // null terminated strings only
+		return "", errors.New("Key is not string")
+	}
+	return syscall.UTF16ToString(buf[:]), nil
+}
+
+// matchZoneKey checks if stdname and dstname match the corresponding "Std"
+// and "Dlt" key values in the kname key stored under the open registry key zones.
+func matchZoneKey(zones syscall.Handle, kname string, stdname, dstname string) (matched bool, err2 error) {
+	var h syscall.Handle
+	p, _ := syscall.UTF16PtrFromString(kname)
+	if err := syscall.RegOpenKeyEx(zones, p, 0, syscall.KEY_READ, &h); err != nil {
+		return false, err
+	}
+	defer syscall.RegCloseKey(h)
+
+	s, err := getKeyValue(h, "Std")
+	if err != nil {
+		return false, err
+	}
+	if s != stdname {
+		return false, nil
+	}
+	s, err = getKeyValue(h, "Dlt")
+	if err != nil {
+		return false, err
+	}
+	if s != dstname && dstname != stdname {
+		return false, nil
+	}
+	return true, nil
+}
+
+// toEnglishName searches the registry for an English name of a time zone
+// whose zone names are stdname and dstname and returns the English name.
+func toEnglishName(stdname, dstname string) (string, error) {
+	var zones syscall.Handle
+	p, _ := syscall.UTF16PtrFromString(`SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones`)
+	if err := syscall.RegOpenKeyEx(syscall.HKEY_LOCAL_MACHINE, p, 0, syscall.KEY_READ, &zones); err != nil {
+		return "", err
+	}
+	defer syscall.RegCloseKey(zones)
+
+	var count uint32
+	if err := syscall.RegQueryInfoKey(zones, nil, nil, nil, &count, nil, nil, nil, nil, nil, nil, nil); err != nil {
+		return "", err
+	}
+
+	var buf [50]uint16 // buf needs to be large enough to fit zone descriptions
+	for i := uint32(0); i < count; i++ {
+		n := uint32(len(buf))
+		if syscall.RegEnumKeyEx(zones, i, &buf[0], &n, nil, nil, nil, nil) != nil {
+			continue
+		}
+		kname := syscall.UTF16ToString(buf[:])
+		matched, err := matchZoneKey(zones, kname, stdname, dstname)
+		if err == nil && matched {
+			return kname, nil
+		}
+	}
+	return "", errors.New(`English name for time zone "` + stdname + `" not found in registry`)
+}
+
+// extractCAPS extracts capital letters from description desc.
+func extractCAPS(desc string) string {
+	var short []rune
+	for _, c := range desc {
+		if 'A' <= c && c <= 'Z' {
+			short = append(short, rune(c))
+		}
+	}
+	return string(short)
+}
+
+// abbrev returns the abbreviations to use for the given zone z.
+func abbrev(z *syscall.Timezoneinformation) (std, dst string) {
+	stdName := syscall.UTF16ToString(z.StandardName[:])
+	a, ok := abbrs[stdName]
+	if !ok {
+		dstName := syscall.UTF16ToString(z.DaylightName[:])
+		// Perhaps stdName is not English. Try to convert it.
+		englishName, err := toEnglishName(stdName, dstName)
+		if err == nil {
+			a, ok = abbrs[englishName]
+			if ok {
+				return a.std, a.dst
+			}
+		}
+		// fallback to using capital letters
+		return extractCAPS(stdName), extractCAPS(dstName)
+	}
+	return a.std, a.dst
+}
+
+// pseudoUnix returns the pseudo-Unix time (seconds since Jan 1 1970 *LOCAL TIME*)
+// denoted by the system date+time d in the given year.
+// It is up to the caller to convert this local time into a UTC-based time.
+func pseudoUnix(year int, d *syscall.Systemtime) int64 {
+	// Windows specifies daylight savings information in "day in month" format:
+	// d.Month is month number (1-12)
+	// d.DayOfWeek is appropriate weekday (Sunday=0 to Saturday=6)
+	// d.Day is week within the month (1 to 5, where 5 is last week of the month)
+	// d.Hour, d.Minute and d.Second are absolute time
+	day := 1
+	t := Date(year, Month(d.Month), day, int(d.Hour), int(d.Minute), int(d.Second), 0, UTC)
+	i := int(d.DayOfWeek) - int(t.Weekday())
+	if i < 0 {
+		i += 7
+	}
+	day += i
+	if week := int(d.Day) - 1; week < 4 {
+		day += week * 7
+	} else {
+		// "Last" instance of the day.
+		day += 4 * 7
+		if day > daysIn(Month(d.Month), year) {
+			day -= 7
+		}
+	}
+	return t.sec + int64(day-1)*secondsPerDay + internalToUnix
+}
+
+func initLocalFromTZI(i *syscall.Timezoneinformation) {
+	l := &localLoc
+
+	nzone := 1
+	if i.StandardDate.Month > 0 {
+		nzone++
+	}
+	l.zone = make([]zone, nzone)
+
+	stdname, dstname := abbrev(i)
+
+	std := &l.zone[0]
+	std.name = stdname
+	if nzone == 1 {
+		// No daylight savings.
+		std.offset = -int(i.Bias) * 60
+		l.cacheStart = alpha
+		l.cacheEnd = omega
+		l.cacheZone = std
+		l.tx = make([]zoneTrans, 1)
+		l.tx[0].when = l.cacheStart
+		l.tx[0].index = 0
+		return
+	}
+
+	// StandardBias must be ignored if StandardDate is not set,
+	// so this computation is delayed until after the nzone==1
+	// return above.
+	std.offset = -int(i.Bias+i.StandardBias) * 60
+
+	dst := &l.zone[1]
+	dst.name = dstname
+	dst.offset = -int(i.Bias+i.DaylightBias) * 60
+	dst.isDST = true
+
+	// Arrange so that d0 is first transition date, d1 second,
+	// i0 is index of zone after first transition, i1 second.
+	d0 := &i.StandardDate
+	d1 := &i.DaylightDate
+	i0 := 0
+	i1 := 1
+	if d0.Month > d1.Month {
+		d0, d1 = d1, d0
+		i0, i1 = i1, i0
+	}
+
+	// 2 tx per year, 100 years on each side of this year
+	l.tx = make([]zoneTrans, 400)
+
+	t := Now().UTC()
+	year := t.Year()
+	txi := 0
+	for y := year - 100; y < year+100; y++ {
+		tx := &l.tx[txi]
+		tx.when = pseudoUnix(y, d0) - int64(l.zone[i1].offset)
+		tx.index = uint8(i0)
+		txi++
+
+		tx = &l.tx[txi]
+		tx.when = pseudoUnix(y, d1) - int64(l.zone[i0].offset)
+		tx.index = uint8(i1)
+		txi++
+	}
+}
+
+var usPacific = syscall.Timezoneinformation{
+	Bias: 8 * 60,
+	StandardName: [32]uint16{
+		'P', 'a', 'c', 'i', 'f', 'i', 'c', ' ', 'S', 't', 'a', 'n', 'd', 'a', 'r', 'd', ' ', 'T', 'i', 'm', 'e',
+	},
+	StandardDate: syscall.Systemtime{Month: 11, Day: 1, Hour: 2},
+	DaylightName: [32]uint16{
+		'P', 'a', 'c', 'i', 'f', 'i', 'c', ' ', 'D', 'a', 'y', 'l', 'i', 'g', 'h', 't', ' ', 'T', 'i', 'm', 'e',
+	},
+	DaylightDate: syscall.Systemtime{Month: 3, Day: 2, Hour: 2},
+	DaylightBias: -60,
+}
+
+var aus = syscall.Timezoneinformation{
+	Bias: -10 * 60,
+	StandardName: [32]uint16{
+		'A', 'U', 'S', ' ', 'E', 'a', 's', 't', 'e', 'r', 'n', ' ', 'S', 't', 'a', 'n', 'd', 'a', 'r', 'd', ' ', 'T', 'i', 'm', 'e',
+	},
+	StandardDate: syscall.Systemtime{Month: 4, Day: 1, Hour: 3},
+	DaylightName: [32]uint16{
+		'A', 'U', 'S', ' ', 'E', 'a', 's', 't', 'e', 'r', 'n', ' ', 'D', 'a', 'y', 'l', 'i', 'g', 'h', 't', ' ', 'T', 'i', 'm', 'e',
+	},
+	DaylightDate: syscall.Systemtime{Month: 10, Day: 1, Hour: 2},
+	DaylightBias: -60,
+}
+
+func initTestingZone() {
+	initLocalFromTZI(&usPacific)
+}
+
+func initAusTestingZone() {
+	initLocalFromTZI(&aus)
+}
+
+func initLocal() {
+	var i syscall.Timezoneinformation
+	if _, err := syscall.GetTimeZoneInformation(&i); err != nil {
+		localLoc.name = "UTC"
+		return
+	}
+	initLocalFromTZI(&i)
+}
+
+func loadLocation(name string) (*Location, error) {
+	if z, err := loadZoneFile(runtime.GOROOT()+`\lib\time\zoneinfo.zip`, name); err == nil {
+		z.name = name
+		return z, nil
+	}
+	return nil, errors.New("unknown time zone " + name)
+}
+
+func forceZipFileForTesting(zipOnly bool) {
+	// We only use the zip file anyway.
+}