Imported Upstream version 1.4upstream/1.4

24 files changed, 6741 insertions, 0 deletions

diff --git a/src/time/example_test.go b/src/time/example_test.go
new file mode 100644
index 000000000..a37e8b86d
--- /dev/null
+++ b/src/time/example_test.go
@@ -0,0 +1,160 @@
+// Copyright 2011 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_test
+
+import (
+	"fmt"
+	"time"
+)
+
+func expensiveCall() {}
+
+func ExampleDuration() {
+	t0 := time.Now()
+	expensiveCall()
+	t1 := time.Now()
+	fmt.Printf("The call took %v to run.\n", t1.Sub(t0))
+}
+
+var c chan int
+
+func handle(int) {}
+
+func ExampleAfter() {
+	select {
+	case m := <-c:
+		handle(m)
+	case <-time.After(5 * time.Minute):
+		fmt.Println("timed out")
+	}
+}
+
+func ExampleSleep() {
+	time.Sleep(100 * time.Millisecond)
+}
+
+func statusUpdate() string { return "" }
+
+func ExampleTick() {
+	c := time.Tick(1 * time.Minute)
+	for now := range c {
+		fmt.Printf("%v %s\n", now, statusUpdate())
+	}
+}
+
+func ExampleMonth() {
+	_, month, day := time.Now().Date()
+	if month == time.November && day == 10 {
+		fmt.Println("Happy Go day!")
+	}
+}
+
+func ExampleDate() {
+	t := time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC)
+	fmt.Printf("Go launched at %s\n", t.Local())
+	// Output: Go launched at 2009-11-10 15:00:00 -0800 PST
+}
+
+func ExampleTime_Format() {
+	// layout shows by example how the reference time should be represented.
+	const layout = "Jan 2, 2006 at 3:04pm (MST)"
+	t := time.Date(2009, time.November, 10, 15, 0, 0, 0, time.Local)
+	fmt.Println(t.Format(layout))
+	fmt.Println(t.UTC().Format(layout))
+	// Output:
+	// Nov 10, 2009 at 3:00pm (PST)
+	// Nov 10, 2009 at 11:00pm (UTC)
+}
+
+func ExampleParse() {
+	// longForm shows by example how the reference time would be represented in
+	// the desired layout.
+	const longForm = "Jan 2, 2006 at 3:04pm (MST)"
+	t, _ := time.Parse(longForm, "Feb 3, 2013 at 7:54pm (PST)")
+	fmt.Println(t)
+
+	// shortForm is another way the reference time would be represented
+	// in the desired layout; it has no time zone present.
+	// Note: without explicit zone, returns time in UTC.
+	const shortForm = "2006-Jan-02"
+	t, _ = time.Parse(shortForm, "2013-Feb-03")
+	fmt.Println(t)
+
+	// Output:
+	// 2013-02-03 19:54:00 -0800 PST
+	// 2013-02-03 00:00:00 +0000 UTC
+}
+
+func ExampleParseInLocation() {
+	loc, _ := time.LoadLocation("Europe/Berlin")
+
+	const longForm = "Jan 2, 2006 at 3:04pm (MST)"
+	t, _ := time.ParseInLocation(longForm, "Jul 9, 2012 at 5:02am (CEST)", loc)
+	fmt.Println(t)
+
+	// Note: without explicit zone, returns time in given location.
+	const shortForm = "2006-Jan-02"
+	t, _ = time.ParseInLocation(shortForm, "2012-Jul-09", loc)
+	fmt.Println(t)
+
+	// Output:
+	// 2012-07-09 05:02:00 +0200 CEST
+	// 2012-07-09 00:00:00 +0200 CEST
+}
+
+func ExampleTime_Round() {
+	t := time.Date(0, 0, 0, 12, 15, 30, 918273645, time.UTC)
+	round := []time.Duration{
+		time.Nanosecond,
+		time.Microsecond,
+		time.Millisecond,
+		time.Second,
+		2 * time.Second,
+		time.Minute,
+		10 * time.Minute,
+		time.Hour,
+	}
+
+	for _, d := range round {
+		fmt.Printf("t.Round(%6s) = %s\n", d, t.Round(d).Format("15:04:05.999999999"))
+	}
+	// Output:
+	// t.Round(   1ns) = 12:15:30.918273645
+	// t.Round(   1µs) = 12:15:30.918274
+	// t.Round(   1ms) = 12:15:30.918
+	// t.Round(    1s) = 12:15:31
+	// t.Round(    2s) = 12:15:30
+	// t.Round(  1m0s) = 12:16:00
+	// t.Round( 10m0s) = 12:20:00
+	// t.Round(1h0m0s) = 12:00:00
+}
+
+func ExampleTime_Truncate() {
+	t, _ := time.Parse("2006 Jan 02 15:04:05", "2012 Dec 07 12:15:30.918273645")
+	trunc := []time.Duration{
+		time.Nanosecond,
+		time.Microsecond,
+		time.Millisecond,
+		time.Second,
+		2 * time.Second,
+		time.Minute,
+		10 * time.Minute,
+		time.Hour,
+	}
+
+	for _, d := range trunc {
+		fmt.Printf("t.Truncate(%6s) = %s\n", d, t.Truncate(d).Format("15:04:05.999999999"))
+	}
+
+	// Output:
+	// t.Truncate(   1ns) = 12:15:30.918273645
+	// t.Truncate(   1µs) = 12:15:30.918273
+	// t.Truncate(   1ms) = 12:15:30.918
+	// t.Truncate(    1s) = 12:15:30
+	// t.Truncate(    2s) = 12:15:30
+	// t.Truncate(  1m0s) = 12:15:00
+	// t.Truncate( 10m0s) = 12:10:00
+	// t.Truncate(1h0m0s) = 12:00:00
+}
diff --git a/src/time/export_test.go b/src/time/export_test.go
new file mode 100644
index 000000000..6cd535f6b
--- /dev/null
+++ b/src/time/export_test.go
@@ -0,0 +1,24 @@
+// Copyright 2013 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 (
+	"sync"
+)
+
+func ResetLocalOnceForTest() {
+	localOnce = sync.Once{}
+	localLoc = Location{}
+}
+
+func ForceUSPacificForTesting() {
+	ResetLocalOnceForTest()
+	localOnce.Do(initTestingZone)
+}
+
+var (
+	ForceZipFileForTesting = forceZipFileForTesting
+	ParseTimeZone          = parseTimeZone
+)
diff --git a/src/time/export_windows_test.go b/src/time/export_windows_test.go
new file mode 100644
index 000000000..7e689b829
--- /dev/null
+++ b/src/time/export_windows_test.go
@@ -0,0 +1,10 @@
+// Copyright 2013 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
+
+func ForceAusForTesting() {
+	ResetLocalOnceForTest()
+	localOnce.Do(initAusTestingZone)
+}
diff --git a/src/time/format.go b/src/time/format.go
new file mode 100644
index 000000000..04e79f32d
--- /dev/null
+++ b/src/time/format.go
@@ -0,0 +1,1248 @@
+// Copyright 2010 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"
+
+// These are predefined layouts for use in Time.Format and Time.Parse.
+// The reference time used in the layouts is the specific time:
+//	Mon Jan 2 15:04:05 MST 2006
+// which is Unix time 1136239445. Since MST is GMT-0700,
+// the reference time can be thought of as
+//	01/02 03:04:05PM '06 -0700
+// To define your own format, write down what the reference time would look
+// like formatted your way; see the values of constants like ANSIC,
+// StampMicro or Kitchen for examples. The model is to demonstrate what the
+// reference time looks like so that the Format and Parse methods can apply
+// the same transformation to a general time value.
+//
+// Within the format string, an underscore _ represents a space that may be
+// replaced by a digit if the following number (a day) has two digits; for
+// compatibility with fixed-width Unix time formats.
+//
+// A decimal point followed by one or more zeros represents a fractional
+// second, printed to the given number of decimal places.  A decimal point
+// followed by one or more nines represents a fractional second, printed to
+// the given number of decimal places, with trailing zeros removed.
+// When parsing (only), the input may contain a fractional second
+// field immediately after the seconds field, even if the layout does not
+// signify its presence. In that case a decimal point followed by a maximal
+// series of digits is parsed as a fractional second.
+//
+// Numeric time zone offsets format as follows:
+//	-0700  ±hhmm
+//	-07:00 ±hh:mm
+// Replacing the sign in the format with a Z triggers
+// the ISO 8601 behavior of printing Z instead of an
+// offset for the UTC zone.  Thus:
+//	Z0700  Z or ±hhmm
+//	Z07:00 Z or ±hh:mm
+const (
+	ANSIC       = "Mon Jan _2 15:04:05 2006"
+	UnixDate    = "Mon Jan _2 15:04:05 MST 2006"
+	RubyDate    = "Mon Jan 02 15:04:05 -0700 2006"
+	RFC822      = "02 Jan 06 15:04 MST"
+	RFC822Z     = "02 Jan 06 15:04 -0700" // RFC822 with numeric zone
+	RFC850      = "Monday, 02-Jan-06 15:04:05 MST"
+	RFC1123     = "Mon, 02 Jan 2006 15:04:05 MST"
+	RFC1123Z    = "Mon, 02 Jan 2006 15:04:05 -0700" // RFC1123 with numeric zone
+	RFC3339     = "2006-01-02T15:04:05Z07:00"
+	RFC3339Nano = "2006-01-02T15:04:05.999999999Z07:00"
+	Kitchen     = "3:04PM"
+	// Handy time stamps.
+	Stamp      = "Jan _2 15:04:05"
+	StampMilli = "Jan _2 15:04:05.000"
+	StampMicro = "Jan _2 15:04:05.000000"
+	StampNano  = "Jan _2 15:04:05.000000000"
+)
+
+const (
+	_                        = iota
+	stdLongMonth             = iota + stdNeedDate  // "January"
+	stdMonth                                       // "Jan"
+	stdNumMonth                                    // "1"
+	stdZeroMonth                                   // "01"
+	stdLongWeekDay                                 // "Monday"
+	stdWeekDay                                     // "Mon"
+	stdDay                                         // "2"
+	stdUnderDay                                    // "_2"
+	stdZeroDay                                     // "02"
+	stdHour                  = iota + stdNeedClock // "15"
+	stdHour12                                      // "3"
+	stdZeroHour12                                  // "03"
+	stdMinute                                      // "4"
+	stdZeroMinute                                  // "04"
+	stdSecond                                      // "5"
+	stdZeroSecond                                  // "05"
+	stdLongYear              = iota + stdNeedDate  // "2006"
+	stdYear                                        // "06"
+	stdPM                    = iota + stdNeedClock // "PM"
+	stdpm                                          // "pm"
+	stdTZ                    = iota                // "MST"
+	stdISO8601TZ                                   // "Z0700"  // prints Z for UTC
+	stdISO8601SecondsTZ                            // "Z070000"
+	stdISO8601ColonTZ                              // "Z07:00" // prints Z for UTC
+	stdISO8601ColonSecondsTZ                       // "Z07:00:00"
+	stdNumTZ                                       // "-0700"  // always numeric
+	stdNumSecondsTz                                // "-070000"
+	stdNumShortTZ                                  // "-07"    // always numeric
+	stdNumColonTZ                                  // "-07:00" // always numeric
+	stdNumColonSecondsTZ                           // "-07:00:00"
+	stdFracSecond0                                 // ".0", ".00", ... , trailing zeros included
+	stdFracSecond9                                 // ".9", ".99", ..., trailing zeros omitted
+
+	stdNeedDate  = 1 << 8             // need month, day, year
+	stdNeedClock = 2 << 8             // need hour, minute, second
+	stdArgShift  = 16                 // extra argument in high bits, above low stdArgShift
+	stdMask      = 1<<stdArgShift - 1 // mask out argument
+)
+
+// std0x records the std values for "01", "02", ..., "06".
+var std0x = [...]int{stdZeroMonth, stdZeroDay, stdZeroHour12, stdZeroMinute, stdZeroSecond, stdYear}
+
+// startsWithLowerCase reports whether the string has a lower-case letter at the beginning.
+// Its purpose is to prevent matching strings like "Month" when looking for "Mon".
+func startsWithLowerCase(str string) bool {
+	if len(str) == 0 {
+		return false
+	}
+	c := str[0]
+	return 'a' <= c && c <= 'z'
+}
+
+// nextStdChunk finds the first occurrence of a std string in
+// layout and returns the text before, the std string, and the text after.
+func nextStdChunk(layout string) (prefix string, std int, suffix string) {
+	for i := 0; i < len(layout); i++ {
+		switch c := int(layout[i]); c {
+		case 'J': // January, Jan
+			if len(layout) >= i+3 && layout[i:i+3] == "Jan" {
+				if len(layout) >= i+7 && layout[i:i+7] == "January" {
+					return layout[0:i], stdLongMonth, layout[i+7:]
+				}
+				if !startsWithLowerCase(layout[i+3:]) {
+					return layout[0:i], stdMonth, layout[i+3:]
+				}
+			}
+
+		case 'M': // Monday, Mon, MST
+			if len(layout) >= i+3 {
+				if layout[i:i+3] == "Mon" {
+					if len(layout) >= i+6 && layout[i:i+6] == "Monday" {
+						return layout[0:i], stdLongWeekDay, layout[i+6:]
+					}
+					if !startsWithLowerCase(layout[i+3:]) {
+						return layout[0:i], stdWeekDay, layout[i+3:]
+					}
+				}
+				if layout[i:i+3] == "MST" {
+					return layout[0:i], stdTZ, layout[i+3:]
+				}
+			}
+
+		case '0': // 01, 02, 03, 04, 05, 06
+			if len(layout) >= i+2 && '1' <= layout[i+1] && layout[i+1] <= '6' {
+				return layout[0:i], std0x[layout[i+1]-'1'], layout[i+2:]
+			}
+
+		case '1': // 15, 1
+			if len(layout) >= i+2 && layout[i+1] == '5' {
+				return layout[0:i], stdHour, layout[i+2:]
+			}
+			return layout[0:i], stdNumMonth, layout[i+1:]
+
+		case '2': // 2006, 2
+			if len(layout) >= i+4 && layout[i:i+4] == "2006" {
+				return layout[0:i], stdLongYear, layout[i+4:]
+			}
+			return layout[0:i], stdDay, layout[i+1:]
+
+		case '_': // _2
+			if len(layout) >= i+2 && layout[i+1] == '2' {
+				return layout[0:i], stdUnderDay, layout[i+2:]
+			}
+
+		case '3':
+			return layout[0:i], stdHour12, layout[i+1:]
+
+		case '4':
+			return layout[0:i], stdMinute, layout[i+1:]
+
+		case '5':
+			return layout[0:i], stdSecond, layout[i+1:]
+
+		case 'P': // PM
+			if len(layout) >= i+2 && layout[i+1] == 'M' {
+				return layout[0:i], stdPM, layout[i+2:]
+			}
+
+		case 'p': // pm
+			if len(layout) >= i+2 && layout[i+1] == 'm' {
+				return layout[0:i], stdpm, layout[i+2:]
+			}
+
+		case '-': // -070000, -07:00:00, -0700, -07:00, -07
+			if len(layout) >= i+7 && layout[i:i+7] == "-070000" {
+				return layout[0:i], stdNumSecondsTz, layout[i+7:]
+			}
+			if len(layout) >= i+9 && layout[i:i+9] == "-07:00:00" {
+				return layout[0:i], stdNumColonSecondsTZ, layout[i+9:]
+			}
+			if len(layout) >= i+5 && layout[i:i+5] == "-0700" {
+				return layout[0:i], stdNumTZ, layout[i+5:]
+			}
+			if len(layout) >= i+6 && layout[i:i+6] == "-07:00" {
+				return layout[0:i], stdNumColonTZ, layout[i+6:]
+			}
+			if len(layout) >= i+3 && layout[i:i+3] == "-07" {
+				return layout[0:i], stdNumShortTZ, layout[i+3:]
+			}
+
+		case 'Z': // Z070000, Z07:00:00, Z0700, Z07:00,
+			if len(layout) >= i+7 && layout[i:i+7] == "Z070000" {
+				return layout[0:i], stdISO8601SecondsTZ, layout[i+7:]
+			}
+			if len(layout) >= i+9 && layout[i:i+9] == "Z07:00:00" {
+				return layout[0:i], stdISO8601ColonSecondsTZ, layout[i+9:]
+			}
+			if len(layout) >= i+5 && layout[i:i+5] == "Z0700" {
+				return layout[0:i], stdISO8601TZ, layout[i+5:]
+			}
+			if len(layout) >= i+6 && layout[i:i+6] == "Z07:00" {
+				return layout[0:i], stdISO8601ColonTZ, layout[i+6:]
+			}
+
+		case '.': // .000 or .999 - repeated digits for fractional seconds.
+			if i+1 < len(layout) && (layout[i+1] == '0' || layout[i+1] == '9') {
+				ch := layout[i+1]
+				j := i + 1
+				for j < len(layout) && layout[j] == ch {
+					j++
+				}
+				// String of digits must end here - only fractional second is all digits.
+				if !isDigit(layout, j) {
+					std := stdFracSecond0
+					if layout[i+1] == '9' {
+						std = stdFracSecond9
+					}
+					std |= (j - (i + 1)) << stdArgShift
+					return layout[0:i], std, layout[j:]
+				}
+			}
+		}
+	}
+	return layout, 0, ""
+}
+
+var longDayNames = []string{
+	"Sunday",
+	"Monday",
+	"Tuesday",
+	"Wednesday",
+	"Thursday",
+	"Friday",
+	"Saturday",
+}
+
+var shortDayNames = []string{
+	"Sun",
+	"Mon",
+	"Tue",
+	"Wed",
+	"Thu",
+	"Fri",
+	"Sat",
+}
+
+var shortMonthNames = []string{
+	"---",
+	"Jan",
+	"Feb",
+	"Mar",
+	"Apr",
+	"May",
+	"Jun",
+	"Jul",
+	"Aug",
+	"Sep",
+	"Oct",
+	"Nov",
+	"Dec",
+}
+
+var longMonthNames = []string{
+	"---",
+	"January",
+	"February",
+	"March",
+	"April",
+	"May",
+	"June",
+	"July",
+	"August",
+	"September",
+	"October",
+	"November",
+	"December",
+}
+
+// match returns true if s1 and s2 match ignoring case.
+// It is assumed s1 and s2 are the same length.
+func match(s1, s2 string) bool {
+	for i := 0; i < len(s1); i++ {
+		c1 := s1[i]
+		c2 := s2[i]
+		if c1 != c2 {
+			// Switch to lower-case; 'a'-'A' is known to be a single bit.
+			c1 |= 'a' - 'A'
+			c2 |= 'a' - 'A'
+			if c1 != c2 || c1 < 'a' || c1 > 'z' {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+func lookup(tab []string, val string) (int, string, error) {
+	for i, v := range tab {
+		if len(val) >= len(v) && match(val[0:len(v)], v) {
+			return i, val[len(v):], nil
+		}
+	}
+	return -1, val, errBad
+}
+
+// appendUint appends the decimal form of x to b and returns the result.
+// If x is a single-digit number and pad != 0, appendUint inserts the pad byte
+// before the digit.
+// Duplicates functionality in strconv, but avoids dependency.
+func appendUint(b []byte, x uint, pad byte) []byte {
+	if x < 10 {
+		if pad != 0 {
+			b = append(b, pad)
+		}
+		return append(b, byte('0'+x))
+	}
+	if x < 100 {
+		b = append(b, byte('0'+x/10))
+		b = append(b, byte('0'+x%10))
+		return b
+	}
+
+	var buf [32]byte
+	n := len(buf)
+	if x == 0 {
+		return append(b, '0')
+	}
+	for x >= 10 {
+		n--
+		buf[n] = byte(x%10 + '0')
+		x /= 10
+	}
+	n--
+	buf[n] = byte(x + '0')
+	return append(b, buf[n:]...)
+}
+
+// Never printed, just needs to be non-nil for return by atoi.
+var atoiError = errors.New("time: invalid number")
+
+// Duplicates functionality in strconv, but avoids dependency.
+func atoi(s string) (x int, err error) {
+	neg := false
+	if s != "" && (s[0] == '-' || s[0] == '+') {
+		neg = s[0] == '-'
+		s = s[1:]
+	}
+	q, rem, err := leadingInt(s)
+	x = int(q)
+	if err != nil || rem != "" {
+		return 0, atoiError
+	}
+	if neg {
+		x = -x
+	}
+	return x, nil
+}
+
+// formatNano appends a fractional second, as nanoseconds, to b
+// and returns the result.
+func formatNano(b []byte, nanosec uint, n int, trim bool) []byte {
+	u := nanosec
+	var buf [9]byte
+	for start := len(buf); start > 0; {
+		start--
+		buf[start] = byte(u%10 + '0')
+		u /= 10
+	}
+
+	if n > 9 {
+		n = 9
+	}
+	if trim {
+		for n > 0 && buf[n-1] == '0' {
+			n--
+		}
+		if n == 0 {
+			return b
+		}
+	}
+	b = append(b, '.')
+	return append(b, buf[:n]...)
+}
+
+// String returns the time formatted using the format string
+//	"2006-01-02 15:04:05.999999999 -0700 MST"
+func (t Time) String() string {
+	return t.Format("2006-01-02 15:04:05.999999999 -0700 MST")
+}
+
+// Format returns a textual representation of the time value formatted
+// according to layout, which defines the format by showing how the reference
+// time, defined to be
+//	Mon Jan 2 15:04:05 -0700 MST 2006
+// would be displayed if it were the value; it serves as an example of the
+// desired output. The same display rules will then be applied to the time
+// value.
+// Predefined layouts ANSIC, UnixDate, RFC3339 and others describe standard
+// and convenient representations of the reference time. For more information
+// about the formats and the definition of the reference time, see the
+// documentation for ANSIC and the other constants defined by this package.
+func (t Time) Format(layout string) string {
+	var (
+		name, offset, abs = t.locabs()
+
+		year  int = -1
+		month Month
+		day   int
+		hour  int = -1
+		min   int
+		sec   int
+
+		b   []byte
+		buf [64]byte
+	)
+	max := len(layout) + 10
+	if max <= len(buf) {
+		b = buf[:0]
+	} else {
+		b = make([]byte, 0, max)
+	}
+	// Each iteration generates one std value.
+	for layout != "" {
+		prefix, std, suffix := nextStdChunk(layout)
+		if prefix != "" {
+			b = append(b, prefix...)
+		}
+		if std == 0 {
+			break
+		}
+		layout = suffix
+
+		// Compute year, month, day if needed.
+		if year < 0 && std&stdNeedDate != 0 {
+			year, month, day, _ = absDate(abs, true)
+		}
+
+		// Compute hour, minute, second if needed.
+		if hour < 0 && std&stdNeedClock != 0 {
+			hour, min, sec = absClock(abs)
+		}
+
+		switch std & stdMask {
+		case stdYear:
+			y := year
+			if y < 0 {
+				y = -y
+			}
+			b = appendUint(b, uint(y%100), '0')
+		case stdLongYear:
+			// Pad year to at least 4 digits.
+			y := year
+			switch {
+			case year <= -1000:
+				b = append(b, '-')
+				y = -y
+			case year <= -100:
+				b = append(b, "-0"...)
+				y = -y
+			case year <= -10:
+				b = append(b, "-00"...)
+				y = -y
+			case year < 0:
+				b = append(b, "-000"...)
+				y = -y
+			case year < 10:
+				b = append(b, "000"...)
+			case year < 100:
+				b = append(b, "00"...)
+			case year < 1000:
+				b = append(b, '0')
+			}
+			b = appendUint(b, uint(y), 0)
+		case stdMonth:
+			b = append(b, month.String()[:3]...)
+		case stdLongMonth:
+			m := month.String()
+			b = append(b, m...)
+		case stdNumMonth:
+			b = appendUint(b, uint(month), 0)
+		case stdZeroMonth:
+			b = appendUint(b, uint(month), '0')
+		case stdWeekDay:
+			b = append(b, absWeekday(abs).String()[:3]...)
+		case stdLongWeekDay:
+			s := absWeekday(abs).String()
+			b = append(b, s...)
+		case stdDay:
+			b = appendUint(b, uint(day), 0)
+		case stdUnderDay:
+			b = appendUint(b, uint(day), ' ')
+		case stdZeroDay:
+			b = appendUint(b, uint(day), '0')
+		case stdHour:
+			b = appendUint(b, uint(hour), '0')
+		case stdHour12:
+			// Noon is 12PM, midnight is 12AM.
+			hr := hour % 12
+			if hr == 0 {
+				hr = 12
+			}
+			b = appendUint(b, uint(hr), 0)
+		case stdZeroHour12:
+			// Noon is 12PM, midnight is 12AM.
+			hr := hour % 12
+			if hr == 0 {
+				hr = 12
+			}
+			b = appendUint(b, uint(hr), '0')
+		case stdMinute:
+			b = appendUint(b, uint(min), 0)
+		case stdZeroMinute:
+			b = appendUint(b, uint(min), '0')
+		case stdSecond:
+			b = appendUint(b, uint(sec), 0)
+		case stdZeroSecond:
+			b = appendUint(b, uint(sec), '0')
+		case stdPM:
+			if hour >= 12 {
+				b = append(b, "PM"...)
+			} else {
+				b = append(b, "AM"...)
+			}
+		case stdpm:
+			if hour >= 12 {
+				b = append(b, "pm"...)
+			} else {
+				b = append(b, "am"...)
+			}
+		case stdISO8601TZ, stdISO8601ColonTZ, stdISO8601SecondsTZ, stdISO8601ColonSecondsTZ, stdNumTZ, stdNumColonTZ, stdNumSecondsTz, stdNumColonSecondsTZ:
+			// Ugly special case.  We cheat and take the "Z" variants
+			// to mean "the time zone as formatted for ISO 8601".
+			if offset == 0 && (std == stdISO8601TZ || std == stdISO8601ColonTZ || std == stdISO8601SecondsTZ || std == stdISO8601ColonSecondsTZ) {
+				b = append(b, 'Z')
+				break
+			}
+			zone := offset / 60 // convert to minutes
+			absoffset := offset
+			if zone < 0 {
+				b = append(b, '-')
+				zone = -zone
+				absoffset = -absoffset
+			} else {
+				b = append(b, '+')
+			}
+			b = appendUint(b, uint(zone/60), '0')
+			if std == stdISO8601ColonTZ || std == stdNumColonTZ || std == stdISO8601ColonSecondsTZ || std == stdNumColonSecondsTZ {
+				b = append(b, ':')
+			}
+			b = appendUint(b, uint(zone%60), '0')
+
+			// append seconds if appropriate
+			if std == stdISO8601SecondsTZ || std == stdNumSecondsTz || std == stdNumColonSecondsTZ || std == stdISO8601ColonSecondsTZ {
+				if std == stdNumColonSecondsTZ || std == stdISO8601ColonSecondsTZ {
+					b = append(b, ':')
+				}
+				b = appendUint(b, uint(absoffset%60), '0')
+			}
+
+		case stdTZ:
+			if name != "" {
+				b = append(b, name...)
+				break
+			}
+			// No time zone known for this time, but we must print one.
+			// Use the -0700 format.
+			zone := offset / 60 // convert to minutes
+			if zone < 0 {
+				b = append(b, '-')
+				zone = -zone
+			} else {
+				b = append(b, '+')
+			}
+			b = appendUint(b, uint(zone/60), '0')
+			b = appendUint(b, uint(zone%60), '0')
+		case stdFracSecond0, stdFracSecond9:
+			b = formatNano(b, uint(t.Nanosecond()), std>>stdArgShift, std&stdMask == stdFracSecond9)
+		}
+	}
+	return string(b)
+}
+
+var errBad = errors.New("bad value for field") // placeholder not passed to user
+
+// ParseError describes a problem parsing a time string.
+type ParseError struct {
+	Layout     string
+	Value      string
+	LayoutElem string
+	ValueElem  string
+	Message    string
+}
+
+func quote(s string) string {
+	return "\"" + s + "\""
+}
+
+// Error returns the string representation of a ParseError.
+func (e *ParseError) Error() string {
+	if e.Message == "" {
+		return "parsing time " +
+			quote(e.Value) + " as " +
+			quote(e.Layout) + ": cannot parse " +
+			quote(e.ValueElem) + " as " +
+			quote(e.LayoutElem)
+	}
+	return "parsing time " +
+		quote(e.Value) + e.Message
+}
+
+// isDigit returns true if s[i] is a decimal digit, false if not or
+// if s[i] is out of range.
+func isDigit(s string, i int) bool {
+	if len(s) <= i {
+		return false
+	}
+	c := s[i]
+	return '0' <= c && c <= '9'
+}
+
+// getnum parses s[0:1] or s[0:2] (fixed forces the latter)
+// as a decimal integer and returns the integer and the
+// remainder of the string.
+func getnum(s string, fixed bool) (int, string, error) {
+	if !isDigit(s, 0) {
+		return 0, s, errBad
+	}
+	if !isDigit(s, 1) {
+		if fixed {
+			return 0, s, errBad
+		}
+		return int(s[0] - '0'), s[1:], nil
+	}
+	return int(s[0]-'0')*10 + int(s[1]-'0'), s[2:], nil
+}
+
+func cutspace(s string) string {
+	for len(s) > 0 && s[0] == ' ' {
+		s = s[1:]
+	}
+	return s
+}
+
+// skip removes the given prefix from value,
+// treating runs of space characters as equivalent.
+func skip(value, prefix string) (string, error) {
+	for len(prefix) > 0 {
+		if prefix[0] == ' ' {
+			if len(value) > 0 && value[0] != ' ' {
+				return value, errBad
+			}
+			prefix = cutspace(prefix)
+			value = cutspace(value)
+			continue
+		}
+		if len(value) == 0 || value[0] != prefix[0] {
+			return value, errBad
+		}
+		prefix = prefix[1:]
+		value = value[1:]
+	}
+	return value, nil
+}
+
+// Parse parses a formatted string and returns the time value it represents.
+// The layout  defines the format by showing how the reference time,
+// defined to be
+//	Mon Jan 2 15:04:05 -0700 MST 2006
+// would be interpreted if it were the value; it serves as an example of
+// the input format. The same interpretation will then be made to the
+// input string.
+// Predefined layouts ANSIC, UnixDate, RFC3339 and others describe standard
+// and convenient representations of the reference time. For more information
+// about the formats and the definition of the reference time, see the
+// documentation for ANSIC and the other constants defined by this package.
+//
+// Elements omitted from the value are assumed to be zero or, when
+// zero is impossible, one, so parsing "3:04pm" returns the time
+// corresponding to Jan 1, year 0, 15:04:00 UTC (note that because the year is
+// 0, this time is before the zero Time).
+// Years must be in the range 0000..9999. The day of the week is checked
+// for syntax but it is otherwise ignored.
+//
+// In the absence of a time zone indicator, Parse returns a time in UTC.
+//
+// When parsing a time with a zone offset like -0700, if the offset corresponds
+// to a time zone used by the current location (Local), then Parse uses that
+// location and zone in the returned time. Otherwise it records the time as
+// being in a fabricated location with time fixed at the given zone offset.
+//
+// When parsing a time with a zone abbreviation like MST, if the zone abbreviation
+// has a defined offset in the current location, then that offset is used.
+// The zone abbreviation "UTC" is recognized as UTC regardless of location.
+// If the zone abbreviation is unknown, Parse records the time as being
+// in a fabricated location with the given zone abbreviation and a zero offset.
+// This choice means that such a time can be parsed and reformatted with the
+// same layout losslessly, but the exact instant used in the representation will
+// differ by the actual zone offset. To avoid such problems, prefer time layouts
+// that use a numeric zone offset, or use ParseInLocation.
+func Parse(layout, value string) (Time, error) {
+	return parse(layout, value, UTC, Local)
+}
+
+// ParseInLocation is like Parse but differs in two important ways.
+// First, in the absence of time zone information, Parse interprets a time as UTC;
+// ParseInLocation interprets the time as in the given location.
+// Second, when given a zone offset or abbreviation, Parse tries to match it
+// against the Local location; ParseInLocation uses the given location.
+func ParseInLocation(layout, value string, loc *Location) (Time, error) {
+	return parse(layout, value, loc, loc)
+}
+
+func parse(layout, value string, defaultLocation, local *Location) (Time, error) {
+	alayout, avalue := layout, value
+	rangeErrString := "" // set if a value is out of range
+	amSet := false       // do we need to subtract 12 from the hour for midnight?
+	pmSet := false       // do we need to add 12 to the hour?
+
+	// Time being constructed.
+	var (
+		year       int
+		month      int = 1 // January
+		day        int = 1
+		hour       int
+		min        int
+		sec        int
+		nsec       int
+		z          *Location
+		zoneOffset int = -1
+		zoneName   string
+	)
+
+	// Each iteration processes one std value.
+	for {
+		var err error
+		prefix, std, suffix := nextStdChunk(layout)
+		stdstr := layout[len(prefix) : len(layout)-len(suffix)]
+		value, err = skip(value, prefix)
+		if err != nil {
+			return Time{}, &ParseError{alayout, avalue, prefix, value, ""}
+		}
+		if std == 0 {
+			if len(value) != 0 {
+				return Time{}, &ParseError{alayout, avalue, "", value, ": extra text: " + value}
+			}
+			break
+		}
+		layout = suffix
+		var p string
+		switch std & stdMask {
+		case stdYear:
+			if len(value) < 2 {
+				err = errBad
+				break
+			}
+			p, value = value[0:2], value[2:]
+			year, err = atoi(p)
+			if year >= 69 { // Unix time starts Dec 31 1969 in some time zones
+				year += 1900
+			} else {
+				year += 2000
+			}
+		case stdLongYear:
+			if len(value) < 4 || !isDigit(value, 0) {
+				err = errBad
+				break
+			}
+			p, value = value[0:4], value[4:]
+			year, err = atoi(p)
+		case stdMonth:
+			month, value, err = lookup(shortMonthNames, value)
+		case stdLongMonth:
+			month, value, err = lookup(longMonthNames, value)
+		case stdNumMonth, stdZeroMonth:
+			month, value, err = getnum(value, std == stdZeroMonth)
+			if month <= 0 || 12 < month {
+				rangeErrString = "month"
+			}
+		case stdWeekDay:
+			// Ignore weekday except for error checking.
+			_, value, err = lookup(shortDayNames, value)
+		case stdLongWeekDay:
+			_, value, err = lookup(longDayNames, value)
+		case stdDay, stdUnderDay, stdZeroDay:
+			if std == stdUnderDay && len(value) > 0 && value[0] == ' ' {
+				value = value[1:]
+			}
+			day, value, err = getnum(value, std == stdZeroDay)
+			if day < 0 || 31 < day {
+				rangeErrString = "day"
+			}
+		case stdHour:
+			hour, value, err = getnum(value, false)
+			if hour < 0 || 24 <= hour {
+				rangeErrString = "hour"
+			}
+		case stdHour12, stdZeroHour12:
+			hour, value, err = getnum(value, std == stdZeroHour12)
+			if hour < 0 || 12 < hour {
+				rangeErrString = "hour"
+			}
+		case stdMinute, stdZeroMinute:
+			min, value, err = getnum(value, std == stdZeroMinute)
+			if min < 0 || 60 <= min {
+				rangeErrString = "minute"
+			}
+		case stdSecond, stdZeroSecond:
+			sec, value, err = getnum(value, std == stdZeroSecond)
+			if sec < 0 || 60 <= sec {
+				rangeErrString = "second"
+			}
+			// Special case: do we have a fractional second but no
+			// fractional second in the format?
+			if len(value) >= 2 && value[0] == '.' && isDigit(value, 1) {
+				_, std, _ = nextStdChunk(layout)
+				std &= stdMask
+				if std == stdFracSecond0 || std == stdFracSecond9 {
+					// Fractional second in the layout; proceed normally
+					break
+				}
+				// No fractional second in the layout but we have one in the input.
+				n := 2
+				for ; n < len(value) && isDigit(value, n); n++ {
+				}
+				nsec, rangeErrString, err = parseNanoseconds(value, n)
+				value = value[n:]
+			}
+		case stdPM:
+			if len(value) < 2 {
+				err = errBad
+				break
+			}
+			p, value = value[0:2], value[2:]
+			switch p {
+			case "PM":
+				pmSet = true
+			case "AM":
+				amSet = true
+			default:
+				err = errBad
+			}
+		case stdpm:
+			if len(value) < 2 {
+				err = errBad
+				break
+			}
+			p, value = value[0:2], value[2:]
+			switch p {
+			case "pm":
+				pmSet = true
+			case "am":
+				amSet = true
+			default:
+				err = errBad
+			}
+		case stdISO8601TZ, stdISO8601ColonTZ, stdISO8601SecondsTZ, stdISO8601ColonSecondsTZ, stdNumTZ, stdNumShortTZ, stdNumColonTZ, stdNumSecondsTz, stdNumColonSecondsTZ:
+			if (std == stdISO8601TZ || std == stdISO8601ColonTZ) && len(value) >= 1 && value[0] == 'Z' {
+				value = value[1:]
+				z = UTC
+				break
+			}
+			var sign, hour, min, seconds string
+			if std == stdISO8601ColonTZ || std == stdNumColonTZ {
+				if len(value) < 6 {
+					err = errBad
+					break
+				}
+				if value[3] != ':' {
+					err = errBad
+					break
+				}
+				sign, hour, min, seconds, value = value[0:1], value[1:3], value[4:6], "00", value[6:]
+			} else if std == stdNumShortTZ {
+				if len(value) < 3 {
+					err = errBad
+					break
+				}
+				sign, hour, min, seconds, value = value[0:1], value[1:3], "00", "00", value[3:]
+			} else if std == stdISO8601ColonSecondsTZ || std == stdNumColonSecondsTZ {
+				if len(value) < 9 {
+					err = errBad
+					break
+				}
+				if value[3] != ':' || value[6] != ':' {
+					err = errBad
+					break
+				}
+				sign, hour, min, seconds, value = value[0:1], value[1:3], value[4:6], value[7:9], value[9:]
+			} else if std == stdISO8601SecondsTZ || std == stdNumSecondsTz {
+				if len(value) < 7 {
+					err = errBad
+					break
+				}
+				sign, hour, min, seconds, value = value[0:1], value[1:3], value[3:5], value[5:7], value[7:]
+			} else {
+				if len(value) < 5 {
+					err = errBad
+					break
+				}
+				sign, hour, min, seconds, value = value[0:1], value[1:3], value[3:5], "00", value[5:]
+			}
+			var hr, mm, ss int
+			hr, err = atoi(hour)
+			if err == nil {
+				mm, err = atoi(min)
+			}
+			if err == nil {
+				ss, err = atoi(seconds)
+			}
+			zoneOffset = (hr*60+mm)*60 + ss // offset is in seconds
+			switch sign[0] {
+			case '+':
+			case '-':
+				zoneOffset = -zoneOffset
+			default:
+				err = errBad
+			}
+		case stdTZ:
+			// Does it look like a time zone?
+			if len(value) >= 3 && value[0:3] == "UTC" {
+				z = UTC
+				value = value[3:]
+				break
+			}
+			n, ok := parseTimeZone(value)
+			if !ok {
+				err = errBad
+				break
+			}
+			zoneName, value = value[:n], value[n:]
+
+		case stdFracSecond0:
+			// stdFracSecond0 requires the exact number of digits as specified in
+			// the layout.
+			ndigit := 1 + (std >> stdArgShift)
+			if len(value) < ndigit {
+				err = errBad
+				break
+			}
+			nsec, rangeErrString, err = parseNanoseconds(value, ndigit)
+			value = value[ndigit:]
+
+		case stdFracSecond9:
+			if len(value) < 2 || value[0] != '.' || value[1] < '0' || '9' < value[1] {
+				// Fractional second omitted.
+				break
+			}
+			// Take any number of digits, even more than asked for,
+			// because it is what the stdSecond case would do.
+			i := 0
+			for i < 9 && i+1 < len(value) && '0' <= value[i+1] && value[i+1] <= '9' {
+				i++
+			}
+			nsec, rangeErrString, err = parseNanoseconds(value, 1+i)
+			value = value[1+i:]
+		}
+		if rangeErrString != "" {
+			return Time{}, &ParseError{alayout, avalue, stdstr, value, ": " + rangeErrString + " out of range"}
+		}
+		if err != nil {
+			return Time{}, &ParseError{alayout, avalue, stdstr, value, ""}
+		}
+	}
+	if pmSet && hour < 12 {
+		hour += 12
+	} else if amSet && hour == 12 {
+		hour = 0
+	}
+
+	if z != nil {
+		return Date(year, Month(month), day, hour, min, sec, nsec, z), nil
+	}
+
+	if zoneOffset != -1 {
+		t := Date(year, Month(month), day, hour, min, sec, nsec, UTC)
+		t.sec -= int64(zoneOffset)
+
+		// Look for local zone with the given offset.
+		// If that zone was in effect at the given time, use it.
+		name, offset, _, _, _ := local.lookup(t.sec + internalToUnix)
+		if offset == zoneOffset && (zoneName == "" || name == zoneName) {
+			t.loc = local
+			return t, nil
+		}
+
+		// Otherwise create fake zone to record offset.
+		t.loc = FixedZone(zoneName, zoneOffset)
+		return t, nil
+	}
+
+	if zoneName != "" {
+		t := Date(year, Month(month), day, hour, min, sec, nsec, UTC)
+		// Look for local zone with the given offset.
+		// If that zone was in effect at the given time, use it.
+		offset, _, ok := local.lookupName(zoneName, t.sec+internalToUnix)
+		if ok {
+			t.sec -= int64(offset)
+			t.loc = local
+			return t, nil
+		}
+
+		// Otherwise, create fake zone with unknown offset.
+		if len(zoneName) > 3 && zoneName[:3] == "GMT" {
+			offset, _ = atoi(zoneName[3:]) // Guaranteed OK by parseGMT.
+			offset *= 3600
+		}
+		t.loc = FixedZone(zoneName, offset)
+		return t, nil
+	}
+
+	// Otherwise, fall back to default.
+	return Date(year, Month(month), day, hour, min, sec, nsec, defaultLocation), nil
+}
+
+// parseTimeZone parses a time zone string and returns its length. Time zones
+// are human-generated and unpredictable. We can't do precise error checking.
+// On the other hand, for a correct parse there must be a time zone at the
+// beginning of the string, so it's almost always true that there's one
+// there. We look at the beginning of the string for a run of upper-case letters.
+// If there are more than 5, it's an error.
+// If there are 4 or 5 and the last is a T, it's a time zone.
+// If there are 3, it's a time zone.
+// Otherwise, other than special cases, it's not a time zone.
+// GMT is special because it can have an hour offset.
+func parseTimeZone(value string) (length int, ok bool) {
+	if len(value) < 3 {
+		return 0, false
+	}
+	// Special case 1: ChST and MeST are the only zones with a lower-case letter.
+	if len(value) >= 4 && (value[:4] == "ChST" || value[:4] == "MeST") {
+		return 4, true
+	}
+	// Special case 2: GMT may have an hour offset; treat it specially.
+	if value[:3] == "GMT" {
+		length = parseGMT(value)
+		return length, true
+	}
+	// How many upper-case letters are there? Need at least three, at most five.
+	var nUpper int
+	for nUpper = 0; nUpper < 6; nUpper++ {
+		if nUpper >= len(value) {
+			break
+		}
+		if c := value[nUpper]; c < 'A' || 'Z' < c {
+			break
+		}
+	}
+	switch nUpper {
+	case 0, 1, 2, 6:
+		return 0, false
+	case 5: // Must end in T to match.
+		if value[4] == 'T' {
+			return 5, true
+		}
+	case 4: // Must end in T to match.
+		if value[3] == 'T' {
+			return 4, true
+		}
+	case 3:
+		return 3, true
+	}
+	return 0, false
+}
+
+// parseGMT parses a GMT time zone. The input string is known to start "GMT".
+// The function checks whether that is followed by a sign and a number in the
+// range -14 through 12 excluding zero.
+func parseGMT(value string) int {
+	value = value[3:]
+	if len(value) == 0 {
+		return 3
+	}
+	sign := value[0]
+	if sign != '-' && sign != '+' {
+		return 3
+	}
+	x, rem, err := leadingInt(value[1:])
+	if err != nil {
+		return 3
+	}
+	if sign == '-' {
+		x = -x
+	}
+	if x == 0 || x < -14 || 12 < x {
+		return 3
+	}
+	return 3 + len(value) - len(rem)
+}
+
+func parseNanoseconds(value string, nbytes int) (ns int, rangeErrString string, err error) {
+	if value[0] != '.' {
+		err = errBad
+		return
+	}
+	if ns, err = atoi(value[1:nbytes]); err != nil {
+		return
+	}
+	if ns < 0 || 1e9 <= ns {
+		rangeErrString = "fractional second"
+		return
+	}
+	// We need nanoseconds, which means scaling by the number
+	// of missing digits in the format, maximum length 10. If it's
+	// longer than 10, we won't scale.
+	scaleDigits := 10 - nbytes
+	for i := 0; i < scaleDigits; i++ {
+		ns *= 10
+	}
+	return
+}
+
+var errLeadingInt = errors.New("time: bad [0-9]*") // never printed
+
+// leadingInt consumes the leading [0-9]* from s.
+func leadingInt(s string) (x int64, rem string, err error) {
+	i := 0
+	for ; i < len(s); i++ {
+		c := s[i]
+		if c < '0' || c > '9' {
+			break
+		}
+		if x >= (1<<63-10)/10 {
+			// overflow
+			return 0, "", errLeadingInt
+		}
+		x = x*10 + int64(c) - '0'
+	}
+	return x, s[i:], nil
+}
+
+var unitMap = map[string]float64{
+	"ns": float64(Nanosecond),
+	"us": float64(Microsecond),
+	"µs": float64(Microsecond), // U+00B5 = micro symbol
+	"μs": float64(Microsecond), // U+03BC = Greek letter mu
+	"ms": float64(Millisecond),
+	"s":  float64(Second),
+	"m":  float64(Minute),
+	"h":  float64(Hour),
+}
+
+// ParseDuration parses a duration string.
+// A duration string is a possibly signed sequence of
+// decimal numbers, each with optional fraction and a unit suffix,
+// such as "300ms", "-1.5h" or "2h45m".
+// Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
+func ParseDuration(s string) (Duration, error) {
+	// [-+]?([0-9]*(\.[0-9]*)?[a-z]+)+
+	orig := s
+	f := float64(0)
+	neg := false
+
+	// Consume [-+]?
+	if s != "" {
+		c := s[0]
+		if c == '-' || c == '+' {
+			neg = c == '-'
+			s = s[1:]
+		}
+	}
+	// Special case: if all that is left is "0", this is zero.
+	if s == "0" {
+		return 0, nil
+	}
+	if s == "" {
+		return 0, errors.New("time: invalid duration " + orig)
+	}
+	for s != "" {
+		g := float64(0) // this element of the sequence
+
+		var x int64
+		var err error
+
+		// The next character must be [0-9.]
+		if !(s[0] == '.' || ('0' <= s[0] && s[0] <= '9')) {
+			return 0, errors.New("time: invalid duration " + orig)
+		}
+		// Consume [0-9]*
+		pl := len(s)
+		x, s, err = leadingInt(s)
+		if err != nil {
+			return 0, errors.New("time: invalid duration " + orig)
+		}
+		g = float64(x)
+		pre := pl != len(s) // whether we consumed anything before a period
+
+		// Consume (\.[0-9]*)?
+		post := false
+		if s != "" && s[0] == '.' {
+			s = s[1:]
+			pl := len(s)
+			x, s, err = leadingInt(s)
+			if err != nil {
+				return 0, errors.New("time: invalid duration " + orig)
+			}
+			scale := 1.0
+			for n := pl - len(s); n > 0; n-- {
+				scale *= 10
+			}
+			g += float64(x) / scale
+			post = pl != len(s)
+		}
+		if !pre && !post {
+			// no digits (e.g. ".s" or "-.s")
+			return 0, errors.New("time: invalid duration " + orig)
+		}
+
+		// Consume unit.
+		i := 0
+		for ; i < len(s); i++ {
+			c := s[i]
+			if c == '.' || ('0' <= c && c <= '9') {
+				break
+			}
+		}
+		if i == 0 {
+			return 0, errors.New("time: missing unit in duration " + orig)
+		}
+		u := s[:i]
+		s = s[i:]
+		unit, ok := unitMap[u]
+		if !ok {
+			return 0, errors.New("time: unknown unit " + u + " in duration " + orig)
+		}
+
+		f += g * unit
+	}
+
+	if neg {
+		f = -f
+	}
+	if f < float64(-1<<63) || f > float64(1<<63-1) {
+		return 0, errors.New("time: overflow parsing duration")
+	}
+	return Duration(f), nil
+}
diff --git a/src/time/format_test.go b/src/time/format_test.go
new file mode 100644
index 000000000..ecc5c8f28
--- /dev/null
+++ b/src/time/format_test.go
@@ -0,0 +1,518 @@
+// 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_test
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"testing"
+	"testing/quick"
+	. "time"
+)
+
+type TimeFormatTest struct {
+	time           Time
+	formattedValue string
+}
+
+var rfc3339Formats = []TimeFormatTest{
+	{Date(2008, 9, 17, 20, 4, 26, 0, UTC), "2008-09-17T20:04:26Z"},
+	{Date(1994, 9, 17, 20, 4, 26, 0, FixedZone("EST", -18000)), "1994-09-17T20:04:26-05:00"},
+	{Date(2000, 12, 26, 1, 15, 6, 0, FixedZone("OTO", 15600)), "2000-12-26T01:15:06+04:20"},
+}
+
+func TestRFC3339Conversion(t *testing.T) {
+	for _, f := range rfc3339Formats {
+		if f.time.Format(RFC3339) != f.formattedValue {
+			t.Error("RFC3339:")
+			t.Errorf("  want=%+v", f.formattedValue)
+			t.Errorf("  have=%+v", f.time.Format(RFC3339))
+		}
+	}
+}
+
+type FormatTest struct {
+	name   string
+	format string
+	result string
+}
+
+var formatTests = []FormatTest{
+	{"ANSIC", ANSIC, "Wed Feb  4 21:00:57 2009"},
+	{"UnixDate", UnixDate, "Wed Feb  4 21:00:57 PST 2009"},
+	{"RubyDate", RubyDate, "Wed Feb 04 21:00:57 -0800 2009"},
+	{"RFC822", RFC822, "04 Feb 09 21:00 PST"},
+	{"RFC850", RFC850, "Wednesday, 04-Feb-09 21:00:57 PST"},
+	{"RFC1123", RFC1123, "Wed, 04 Feb 2009 21:00:57 PST"},
+	{"RFC1123Z", RFC1123Z, "Wed, 04 Feb 2009 21:00:57 -0800"},
+	{"RFC3339", RFC3339, "2009-02-04T21:00:57-08:00"},
+	{"RFC3339Nano", RFC3339Nano, "2009-02-04T21:00:57.0123456-08:00"},
+	{"Kitchen", Kitchen, "9:00PM"},
+	{"am/pm", "3pm", "9pm"},
+	{"AM/PM", "3PM", "9PM"},
+	{"two-digit year", "06 01 02", "09 02 04"},
+	// Three-letter months and days must not be followed by lower-case letter.
+	{"Janet", "Hi Janet, the Month is January", "Hi Janet, the Month is February"},
+	// Time stamps, Fractional seconds.
+	{"Stamp", Stamp, "Feb  4 21:00:57"},
+	{"StampMilli", StampMilli, "Feb  4 21:00:57.012"},
+	{"StampMicro", StampMicro, "Feb  4 21:00:57.012345"},
+	{"StampNano", StampNano, "Feb  4 21:00:57.012345600"},
+}
+
+func TestFormat(t *testing.T) {
+	// The numeric time represents Thu Feb  4 21:00:57.012345600 PST 2010
+	time := Unix(0, 1233810057012345600)
+	for _, test := range formatTests {
+		result := time.Format(test.format)
+		if result != test.result {
+			t.Errorf("%s expected %q got %q", test.name, test.result, result)
+		}
+	}
+}
+
+func TestFormatShortYear(t *testing.T) {
+	years := []int{
+		-100001, -100000, -99999,
+		-10001, -10000, -9999,
+		-1001, -1000, -999,
+		-101, -100, -99,
+		-11, -10, -9,
+		-1, 0, 1,
+		9, 10, 11,
+		99, 100, 101,
+		999, 1000, 1001,
+		9999, 10000, 10001,
+		99999, 100000, 100001,
+	}
+
+	for _, y := range years {
+		time := Date(y, January, 1, 0, 0, 0, 0, UTC)
+		result := time.Format("2006.01.02")
+		var want string
+		if y < 0 {
+			// The 4 in %04d counts the - sign, so print -y instead
+			// and introduce our own - sign.
+			want = fmt.Sprintf("-%04d.%02d.%02d", -y, 1, 1)
+		} else {
+			want = fmt.Sprintf("%04d.%02d.%02d", y, 1, 1)
+		}
+		if result != want {
+			t.Errorf("(jan 1 %d).Format(\"2006.01.02\") = %q, want %q", y, result, want)
+		}
+	}
+}
+
+type ParseTest struct {
+	name       string
+	format     string
+	value      string
+	hasTZ      bool // contains a time zone
+	hasWD      bool // contains a weekday
+	yearSign   int  // sign of year, -1 indicates the year is not present in the format
+	fracDigits int  // number of digits of fractional second
+}
+
+var parseTests = []ParseTest{
+	{"ANSIC", ANSIC, "Thu Feb  4 21:00:57 2010", false, true, 1, 0},
+	{"UnixDate", UnixDate, "Thu Feb  4 21:00:57 PST 2010", true, true, 1, 0},
+	{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0800 2010", true, true, 1, 0},
+	{"RFC850", RFC850, "Thursday, 04-Feb-10 21:00:57 PST", true, true, 1, 0},
+	{"RFC1123", RFC1123, "Thu, 04 Feb 2010 21:00:57 PST", true, true, 1, 0},
+	{"RFC1123", RFC1123, "Thu, 04 Feb 2010 22:00:57 PDT", true, true, 1, 0},
+	{"RFC1123Z", RFC1123Z, "Thu, 04 Feb 2010 21:00:57 -0800", true, true, 1, 0},
+	{"RFC3339", RFC3339, "2010-02-04T21:00:57-08:00", true, false, 1, 0},
+	{"custom: \"2006-01-02 15:04:05-07\"", "2006-01-02 15:04:05-07", "2010-02-04 21:00:57-08", true, false, 1, 0},
+	// Optional fractional seconds.
+	{"ANSIC", ANSIC, "Thu Feb  4 21:00:57.0 2010", false, true, 1, 1},
+	{"UnixDate", UnixDate, "Thu Feb  4 21:00:57.01 PST 2010", true, true, 1, 2},
+	{"RubyDate", RubyDate, "Thu Feb 04 21:00:57.012 -0800 2010", true, true, 1, 3},
+	{"RFC850", RFC850, "Thursday, 04-Feb-10 21:00:57.0123 PST", true, true, 1, 4},
+	{"RFC1123", RFC1123, "Thu, 04 Feb 2010 21:00:57.01234 PST", true, true, 1, 5},
+	{"RFC1123Z", RFC1123Z, "Thu, 04 Feb 2010 21:00:57.01234 -0800", true, true, 1, 5},
+	{"RFC3339", RFC3339, "2010-02-04T21:00:57.012345678-08:00", true, false, 1, 9},
+	{"custom: \"2006-01-02 15:04:05\"", "2006-01-02 15:04:05", "2010-02-04 21:00:57.0", false, false, 1, 0},
+	// Amount of white space should not matter.
+	{"ANSIC", ANSIC, "Thu Feb 4 21:00:57 2010", false, true, 1, 0},
+	{"ANSIC", ANSIC, "Thu      Feb     4     21:00:57     2010", false, true, 1, 0},
+	// Case should not matter
+	{"ANSIC", ANSIC, "THU FEB 4 21:00:57 2010", false, true, 1, 0},
+	{"ANSIC", ANSIC, "thu feb 4 21:00:57 2010", false, true, 1, 0},
+	// Fractional seconds.
+	{"millisecond", "Mon Jan _2 15:04:05.000 2006", "Thu Feb  4 21:00:57.012 2010", false, true, 1, 3},
+	{"microsecond", "Mon Jan _2 15:04:05.000000 2006", "Thu Feb  4 21:00:57.012345 2010", false, true, 1, 6},
+	{"nanosecond", "Mon Jan _2 15:04:05.000000000 2006", "Thu Feb  4 21:00:57.012345678 2010", false, true, 1, 9},
+	// Leading zeros in other places should not be taken as fractional seconds.
+	{"zero1", "2006.01.02.15.04.05.0", "2010.02.04.21.00.57.0", false, false, 1, 1},
+	{"zero2", "2006.01.02.15.04.05.00", "2010.02.04.21.00.57.01", false, false, 1, 2},
+	// Month and day names only match when not followed by a lower-case letter.
+	{"Janet", "Hi Janet, the Month is January: Jan _2 15:04:05 2006", "Hi Janet, the Month is February: Feb  4 21:00:57 2010", false, true, 1, 0},
+
+	// GMT with offset.
+	{"GMT-8", UnixDate, "Fri Feb  5 05:00:57 GMT-8 2010", true, true, 1, 0},
+
+	// Accept any number of fractional second digits (including none) for .999...
+	// In Go 1, .999... was completely ignored in the format, meaning the first two
+	// cases would succeed, but the next four would not. Go 1.1 accepts all six.
+	{"", "2006-01-02 15:04:05.9999 -0700 MST", "2010-02-04 21:00:57 -0800 PST", true, false, 1, 0},
+	{"", "2006-01-02 15:04:05.999999999 -0700 MST", "2010-02-04 21:00:57 -0800 PST", true, false, 1, 0},
+	{"", "2006-01-02 15:04:05.9999 -0700 MST", "2010-02-04 21:00:57.0123 -0800 PST", true, false, 1, 4},
+	{"", "2006-01-02 15:04:05.999999999 -0700 MST", "2010-02-04 21:00:57.0123 -0800 PST", true, false, 1, 4},
+	{"", "2006-01-02 15:04:05.9999 -0700 MST", "2010-02-04 21:00:57.012345678 -0800 PST", true, false, 1, 9},
+	{"", "2006-01-02 15:04:05.999999999 -0700 MST", "2010-02-04 21:00:57.012345678 -0800 PST", true, false, 1, 9},
+
+	// issue 4502.
+	{"", StampNano, "Feb  4 21:00:57.012345678", false, false, -1, 9},
+	{"", "Jan _2 15:04:05.999", "Feb  4 21:00:57.012300000", false, false, -1, 4},
+	{"", "Jan _2 15:04:05.999", "Feb  4 21:00:57.012345678", false, false, -1, 9},
+	{"", "Jan _2 15:04:05.999999999", "Feb  4 21:00:57.0123", false, false, -1, 4},
+	{"", "Jan _2 15:04:05.999999999", "Feb  4 21:00:57.012345678", false, false, -1, 9},
+}
+
+func TestParse(t *testing.T) {
+	for _, test := range parseTests {
+		time, err := Parse(test.format, test.value)
+		if err != nil {
+			t.Errorf("%s error: %v", test.name, err)
+		} else {
+			checkTime(time, &test, t)
+		}
+	}
+}
+
+func TestParseInLocation(t *testing.T) {
+	// Check that Parse (and ParseInLocation) understand that
+	// Feb 01 AST (Arabia Standard Time) and Feb 01 AST (Atlantic Standard Time)
+	// are in different time zones even though both are called AST
+
+	baghdad, err := LoadLocation("Asia/Baghdad")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t1, err := ParseInLocation("Jan 02 2006 MST", "Feb 01 2013 AST", baghdad)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t2 := Date(2013, February, 1, 00, 00, 00, 0, baghdad)
+	if t1 != t2 {
+		t.Fatalf("ParseInLocation(Feb 01 2013 AST, Baghdad) = %v, want %v", t1, t2)
+	}
+	_, offset := t1.Zone()
+	if offset != 3*60*60 {
+		t.Fatalf("ParseInLocation(Feb 01 2013 AST, Baghdad).Zone = _, %d, want _, %d", offset, 3*60*60)
+	}
+
+	blancSablon, err := LoadLocation("America/Blanc-Sablon")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t1, err = ParseInLocation("Jan 02 2006 MST", "Feb 01 2013 AST", blancSablon)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t2 = Date(2013, February, 1, 00, 00, 00, 0, blancSablon)
+	if t1 != t2 {
+		t.Fatalf("ParseInLocation(Feb 01 2013 AST, Blanc-Sablon) = %v, want %v", t1, t2)
+	}
+	_, offset = t1.Zone()
+	if offset != -4*60*60 {
+		t.Fatalf("ParseInLocation(Feb 01 2013 AST, Blanc-Sablon).Zone = _, %d, want _, %d", offset, -4*60*60)
+	}
+}
+
+func TestLoadLocationZipFile(t *testing.T) {
+	ForceZipFileForTesting(true)
+	defer ForceZipFileForTesting(false)
+
+	_, err := LoadLocation("Australia/Sydney")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+var rubyTests = []ParseTest{
+	{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0800 2010", true, true, 1, 0},
+	// Ignore the time zone in the test. If it parses, it'll be OK.
+	{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0000 2010", false, true, 1, 0},
+	{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 +0000 2010", false, true, 1, 0},
+	{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 +1130 2010", false, true, 1, 0},
+}
+
+// Problematic time zone format needs special tests.
+func TestRubyParse(t *testing.T) {
+	for _, test := range rubyTests {
+		time, err := Parse(test.format, test.value)
+		if err != nil {
+			t.Errorf("%s error: %v", test.name, err)
+		} else {
+			checkTime(time, &test, t)
+		}
+	}
+}
+
+func checkTime(time Time, test *ParseTest, t *testing.T) {
+	// The time should be Thu Feb  4 21:00:57 PST 2010
+	if test.yearSign >= 0 && test.yearSign*time.Year() != 2010 {
+		t.Errorf("%s: bad year: %d not %d", test.name, time.Year(), 2010)
+	}
+	if time.Month() != February {
+		t.Errorf("%s: bad month: %s not %s", test.name, time.Month(), February)
+	}
+	if time.Day() != 4 {
+		t.Errorf("%s: bad day: %d not %d", test.name, time.Day(), 4)
+	}
+	if time.Hour() != 21 {
+		t.Errorf("%s: bad hour: %d not %d", test.name, time.Hour(), 21)
+	}
+	if time.Minute() != 0 {
+		t.Errorf("%s: bad minute: %d not %d", test.name, time.Minute(), 0)
+	}
+	if time.Second() != 57 {
+		t.Errorf("%s: bad second: %d not %d", test.name, time.Second(), 57)
+	}
+	// Nanoseconds must be checked against the precision of the input.
+	nanosec, err := strconv.ParseUint("012345678"[:test.fracDigits]+"000000000"[:9-test.fracDigits], 10, 0)
+	if err != nil {
+		panic(err)
+	}
+	if time.Nanosecond() != int(nanosec) {
+		t.Errorf("%s: bad nanosecond: %d not %d", test.name, time.Nanosecond(), nanosec)
+	}
+	name, offset := time.Zone()
+	if test.hasTZ && offset != -28800 {
+		t.Errorf("%s: bad tz offset: %s %d not %d", test.name, name, offset, -28800)
+	}
+	if test.hasWD && time.Weekday() != Thursday {
+		t.Errorf("%s: bad weekday: %s not %s", test.name, time.Weekday(), Thursday)
+	}
+}
+
+func TestFormatAndParse(t *testing.T) {
+	const fmt = "Mon MST " + RFC3339 // all fields
+	f := func(sec int64) bool {
+		t1 := Unix(sec, 0)
+		if t1.Year() < 1000 || t1.Year() > 9999 {
+			// not required to work
+			return true
+		}
+		t2, err := Parse(fmt, t1.Format(fmt))
+		if err != nil {
+			t.Errorf("error: %s", err)
+			return false
+		}
+		if t1.Unix() != t2.Unix() || t1.Nanosecond() != t2.Nanosecond() {
+			t.Errorf("FormatAndParse %d: %q(%d) %q(%d)", sec, t1, t1.Unix(), t2, t2.Unix())
+			return false
+		}
+		return true
+	}
+	f32 := func(sec int32) bool { return f(int64(sec)) }
+	cfg := &quick.Config{MaxCount: 10000}
+
+	// Try a reasonable date first, then the huge ones.
+	if err := quick.Check(f32, cfg); err != nil {
+		t.Fatal(err)
+	}
+	if err := quick.Check(f, cfg); err != nil {
+		t.Fatal(err)
+	}
+}
+
+type ParseTimeZoneTest struct {
+	value  string
+	length int
+	ok     bool
+}
+
+var parseTimeZoneTests = []ParseTimeZoneTest{
+	{"gmt hi there", 0, false},
+	{"GMT hi there", 3, true},
+	{"GMT+12 hi there", 6, true},
+	{"GMT+00 hi there", 3, true}, // 0 or 00 is not a legal offset.
+	{"GMT-5 hi there", 5, true},
+	{"GMT-51 hi there", 3, true},
+	{"ChST hi there", 4, true},
+	{"MeST hi there", 4, true},
+	{"MSDx", 3, true},
+	{"MSDY", 0, false}, // four letters must end in T.
+	{"ESAST hi", 5, true},
+	{"ESASTT hi", 0, false}, // run of upper-case letters too long.
+	{"ESATY hi", 0, false},  // five letters must end in T.
+}
+
+func TestParseTimeZone(t *testing.T) {
+	for _, test := range parseTimeZoneTests {
+		length, ok := ParseTimeZone(test.value)
+		if ok != test.ok {
+			t.Errorf("expected %t for %q got %t", test.ok, test.value, ok)
+		} else if length != test.length {
+			t.Errorf("expected %d for %q got %d", test.length, test.value, length)
+		}
+	}
+}
+
+type ParseErrorTest struct {
+	format string
+	value  string
+	expect string // must appear within the error
+}
+
+var parseErrorTests = []ParseErrorTest{
+	{ANSIC, "Feb  4 21:00:60 2010", "cannot parse"}, // cannot parse Feb as Mon
+	{ANSIC, "Thu Feb  4 21:00:57 @2010", "cannot parse"},
+	{ANSIC, "Thu Feb  4 21:00:60 2010", "second out of range"},
+	{ANSIC, "Thu Feb  4 21:61:57 2010", "minute out of range"},
+	{ANSIC, "Thu Feb  4 24:00:60 2010", "hour out of range"},
+	{"Mon Jan _2 15:04:05.000 2006", "Thu Feb  4 23:00:59x01 2010", "cannot parse"},
+	{"Mon Jan _2 15:04:05.000 2006", "Thu Feb  4 23:00:59.xxx 2010", "cannot parse"},
+	{"Mon Jan _2 15:04:05.000 2006", "Thu Feb  4 23:00:59.-123 2010", "fractional second out of range"},
+	// issue 4502. StampNano requires exactly 9 digits of precision.
+	{StampNano, "Dec  7 11:22:01.000000", `cannot parse ".000000" as ".000000000"`},
+	{StampNano, "Dec  7 11:22:01.0000000000", "extra text: 0"},
+	// issue 4493. Helpful errors.
+	{RFC3339, "2006-01-02T15:04:05Z07:00", `parsing time "2006-01-02T15:04:05Z07:00": extra text: 07:00`},
+	{RFC3339, "2006-01-02T15:04_abc", `parsing time "2006-01-02T15:04_abc" as "2006-01-02T15:04:05Z07:00": cannot parse "_abc" as ":"`},
+	{RFC3339, "2006-01-02T15:04:05_abc", `parsing time "2006-01-02T15:04:05_abc" as "2006-01-02T15:04:05Z07:00": cannot parse "_abc" as "Z07:00"`},
+	{RFC3339, "2006-01-02T15:04:05Z_abc", `parsing time "2006-01-02T15:04:05Z_abc": extra text: _abc`},
+}
+
+func TestParseErrors(t *testing.T) {
+	for _, test := range parseErrorTests {
+		_, err := Parse(test.format, test.value)
+		if err == nil {
+			t.Errorf("expected error for %q %q", test.format, test.value)
+		} else if strings.Index(err.Error(), test.expect) < 0 {
+			t.Errorf("expected error with %q for %q %q; got %s", test.expect, test.format, test.value, err)
+		}
+	}
+}
+
+func TestNoonIs12PM(t *testing.T) {
+	noon := Date(0, January, 1, 12, 0, 0, 0, UTC)
+	const expect = "12:00PM"
+	got := noon.Format("3:04PM")
+	if got != expect {
+		t.Errorf("got %q; expect %q", got, expect)
+	}
+	got = noon.Format("03:04PM")
+	if got != expect {
+		t.Errorf("got %q; expect %q", got, expect)
+	}
+}
+
+func TestMidnightIs12AM(t *testing.T) {
+	midnight := Date(0, January, 1, 0, 0, 0, 0, UTC)
+	expect := "12:00AM"
+	got := midnight.Format("3:04PM")
+	if got != expect {
+		t.Errorf("got %q; expect %q", got, expect)
+	}
+	got = midnight.Format("03:04PM")
+	if got != expect {
+		t.Errorf("got %q; expect %q", got, expect)
+	}
+}
+
+func Test12PMIsNoon(t *testing.T) {
+	noon, err := Parse("3:04PM", "12:00PM")
+	if err != nil {
+		t.Fatal("error parsing date:", err)
+	}
+	if noon.Hour() != 12 {
+		t.Errorf("got %d; expect 12", noon.Hour())
+	}
+	noon, err = Parse("03:04PM", "12:00PM")
+	if err != nil {
+		t.Fatal("error parsing date:", err)
+	}
+	if noon.Hour() != 12 {
+		t.Errorf("got %d; expect 12", noon.Hour())
+	}
+}
+
+func Test12AMIsMidnight(t *testing.T) {
+	midnight, err := Parse("3:04PM", "12:00AM")
+	if err != nil {
+		t.Fatal("error parsing date:", err)
+	}
+	if midnight.Hour() != 0 {
+		t.Errorf("got %d; expect 0", midnight.Hour())
+	}
+	midnight, err = Parse("03:04PM", "12:00AM")
+	if err != nil {
+		t.Fatal("error parsing date:", err)
+	}
+	if midnight.Hour() != 0 {
+		t.Errorf("got %d; expect 0", midnight.Hour())
+	}
+}
+
+// Check that a time without a Zone still produces a (numeric) time zone
+// when formatted with MST as a requested zone.
+func TestMissingZone(t *testing.T) {
+	time, err := Parse(RubyDate, "Thu Feb 02 16:10:03 -0500 2006")
+	if err != nil {
+		t.Fatal("error parsing date:", err)
+	}
+	expect := "Thu Feb  2 16:10:03 -0500 2006" // -0500 not EST
+	str := time.Format(UnixDate)               // uses MST as its time zone
+	if str != expect {
+		t.Errorf("got %s; expect %s", str, expect)
+	}
+}
+
+func TestMinutesInTimeZone(t *testing.T) {
+	time, err := Parse(RubyDate, "Mon Jan 02 15:04:05 +0123 2006")
+	if err != nil {
+		t.Fatal("error parsing date:", err)
+	}
+	expected := (1*60 + 23) * 60
+	_, offset := time.Zone()
+	if offset != expected {
+		t.Errorf("ZoneOffset = %d, want %d", offset, expected)
+	}
+}
+
+type SecondsTimeZoneOffsetTest struct {
+	format         string
+	value          string
+	expectedoffset int
+}
+
+var secondsTimeZoneOffsetTests = []SecondsTimeZoneOffsetTest{
+	{"2006-01-02T15:04:05-070000", "1871-01-01T05:33:02-003408", -(34*60 + 8)},
+	{"2006-01-02T15:04:05-07:00:00", "1871-01-01T05:33:02-00:34:08", -(34*60 + 8)},
+	{"2006-01-02T15:04:05-070000", "1871-01-01T05:33:02+003408", 34*60 + 8},
+	{"2006-01-02T15:04:05-07:00:00", "1871-01-01T05:33:02+00:34:08", 34*60 + 8},
+	{"2006-01-02T15:04:05Z070000", "1871-01-01T05:33:02-003408", -(34*60 + 8)},
+	{"2006-01-02T15:04:05Z07:00:00", "1871-01-01T05:33:02+00:34:08", 34*60 + 8},
+}
+
+func TestParseSecondsInTimeZone(t *testing.T) {
+	// should accept timezone offsets with seconds like: Zone America/New_York   -4:56:02 -      LMT     1883 Nov 18 12:03:58
+	for _, test := range secondsTimeZoneOffsetTests {
+		time, err := Parse(test.format, test.value)
+		if err != nil {
+			t.Fatal("error parsing date:", err)
+		}
+		_, offset := time.Zone()
+		if offset != test.expectedoffset {
+			t.Errorf("ZoneOffset = %d, want %d", offset, test.expectedoffset)
+		}
+	}
+}
+
+func TestFormatSecondsInTimeZone(t *testing.T) {
+	for _, test := range secondsTimeZoneOffsetTests {
+		d := Date(1871, 1, 1, 5, 33, 2, 0, FixedZone("LMT", test.expectedoffset))
+		timestr := d.Format(test.format)
+		if timestr != test.value {
+			t.Errorf("Format = %s, want %s", timestr, test.value)
+		}
+	}
+}
diff --git a/src/time/genzabbrs.go b/src/time/genzabbrs.go
new file mode 100644
index 000000000..9eb0728a4
--- /dev/null
+++ b/src/time/genzabbrs.go
@@ -0,0 +1,159 @@
+// Copyright 2013 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.
+
+// +build ignore
+
+//
+// usage:
+//
+// go run genzabbrs.go -output zoneinfo_abbrs_windows.go
+//
+
+package main
+
+import (
+	"bytes"
+	"encoding/xml"
+	"flag"
+	"go/format"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"sort"
+	"text/template"
+	"time"
+)
+
+var filename = flag.String("output", "zoneinfo_abbrs_windows.go", "output file name")
+
+// getAbbrs finds timezone abbreviations (standard and daylight saving time)
+// for location l.
+func getAbbrs(l *time.Location) (st, dt string) {
+	t := time.Date(time.Now().Year(), 0, 0, 0, 0, 0, 0, l)
+	abbr1, off1 := t.Zone()
+	for i := 0; i < 12; i++ {
+		t = t.AddDate(0, 1, 0)
+		abbr2, off2 := t.Zone()
+		if abbr1 != abbr2 {
+			if off2-off1 < 0 { // southern hemisphere
+				abbr1, abbr2 = abbr2, abbr1
+			}
+			return abbr1, abbr2
+		}
+	}
+	return abbr1, abbr1
+}
+
+type zone struct {
+	WinName  string
+	UnixName string
+	StTime   string
+	DSTime   string
+}
+
+type zones []*zone
+
+func (zs zones) Len() int           { return len(zs) }
+func (zs zones) Swap(i, j int)      { zs[i], zs[j] = zs[j], zs[i] }
+func (zs zones) Less(i, j int) bool { return zs[i].UnixName < zs[j].UnixName }
+
+const wzURL = "http://unicode.org/cldr/data/common/supplemental/windowsZones.xml"
+
+type MapZone struct {
+	Other     string `xml:"other,attr"`
+	Territory string `xml:"territory,attr"`
+	Type      string `xml:"type,attr"`
+}
+
+type SupplementalData struct {
+	Zones []MapZone `xml:"windowsZones>mapTimezones>mapZone"`
+}
+
+func readWindowsZones() (zones, error) {
+	r, err := http.Get(wzURL)
+	if err != nil {
+		return nil, err
+	}
+	defer r.Body.Close()
+
+	data, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var sd SupplementalData
+	err = xml.Unmarshal(data, &sd)
+	if err != nil {
+		return nil, err
+	}
+	zs := make(zones, 0)
+	for _, z := range sd.Zones {
+		if z.Territory != "001" {
+			// to avoid dups. I don't know why.
+			continue
+		}
+		l, err := time.LoadLocation(z.Type)
+		if err != nil {
+			return nil, err
+		}
+		st, dt := getAbbrs(l)
+		zs = append(zs, &zone{
+			WinName:  z.Other,
+			UnixName: z.Type,
+			StTime:   st,
+			DSTime:   dt,
+		})
+	}
+	return zs, nil
+}
+
+func main() {
+	flag.Parse()
+	zs, err := readWindowsZones()
+	if err != nil {
+		log.Fatal(err)
+	}
+	sort.Sort(zs)
+	var v = struct {
+		URL string
+		Zs  zones
+	}{
+		wzURL,
+		zs,
+	}
+	var buf bytes.Buffer
+	err = template.Must(template.New("prog").Parse(prog)).Execute(&buf, v)
+	if err != nil {
+		log.Fatal(err)
+	}
+	data, err := format.Source(buf.Bytes())
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = ioutil.WriteFile(*filename, data, 0644)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+const prog = `
+// Copyright 2013 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.
+
+// generated by genzabbrs.go from
+// {{.URL}}
+
+package time
+
+type abbr struct {
+	std string
+	dst string
+}
+
+var abbrs = map[string]abbr{
+{{range .Zs}}	"{{.WinName}}": {"{{.StTime}}", "{{.DSTime}}"}, // {{.UnixName}}
+{{end}}}
+
+`
diff --git a/src/time/internal_test.go b/src/time/internal_test.go
new file mode 100644
index 000000000..edd523bc8
--- /dev/null
+++ b/src/time/internal_test.go
@@ -0,0 +1,59 @@
+// Copyright 2011 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
+
+func init() {
+	// force US/Pacific for time zone tests
+	ForceUSPacificForTesting()
+}
+
+var Interrupt = interrupt
+var DaysIn = daysIn
+
+func empty(arg interface{}, seq uintptr) {}
+
+// Test that a runtimeTimer with a duration so large it overflows
+// does not cause other timers to hang.
+//
+// This test has to be in internal_test.go since it fiddles with
+// unexported data structures.
+func CheckRuntimeTimerOverflow() {
+	// We manually create a runtimeTimer to bypass the overflow
+	// detection logic in NewTimer: we're testing the underlying
+	// runtime.addtimer function.
+	r := &runtimeTimer{
+		when: runtimeNano() + (1<<63 - 1),
+		f:    empty,
+		arg:  nil,
+	}
+	startTimer(r)
+
+	// Start a goroutine that should send on t.C right away.
+	t := NewTimer(1)
+
+	defer func() {
+		// Subsequent tests won't work correctly if we don't stop the
+		// overflow timer and kick the timer proc back into service.
+		//
+		// The timer proc is now sleeping and can only be awoken by
+		// adding a timer to the *beginning* of the heap. We can't
+		// wake it up by calling NewTimer since other tests may have
+		// left timers running that should have expired before ours.
+		// Instead we zero the overflow timer duration and start it
+		// once more.
+		stopTimer(r)
+		t.Stop()
+		r.when = 0
+		startTimer(r)
+	}()
+
+	// If the test fails, we will hang here until the timeout in the testing package
+	// fires, which is 10 minutes. It would be nice to catch the problem sooner,
+	// but there is no reliable way to guarantee that timerproc schedules without
+	// doing something involving timerproc itself. Previous failed attempts have
+	// tried calling runtime.Gosched and runtime.GC, but neither is reliable.
+	// So we fall back to hope: We hope we don't hang here.
+	<-t.C
+}
diff --git a/src/time/sleep.go b/src/time/sleep.go
new file mode 100644
index 000000000..e7a2ee205
--- /dev/null
+++ b/src/time/sleep.go
@@ -0,0 +1,130 @@
+// 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
+
+// Sleep pauses the current goroutine for at least the duration d.
+// A negative or zero duration causes Sleep to return immediately.
+func Sleep(d Duration)
+
+// runtimeNano returns the current value of the runtime clock in nanoseconds.
+func runtimeNano() int64
+
+// Interface to timers implemented in package runtime.
+// Must be in sync with ../runtime/runtime.h:/^struct.Timer$
+type runtimeTimer struct {
+	i      int
+	when   int64
+	period int64
+	f      func(interface{}, uintptr) // NOTE: must not be closure
+	arg    interface{}
+	seq    uintptr
+}
+
+// when is a helper function for setting the 'when' field of a runtimeTimer.
+// It returns what the time will be, in nanoseconds, Duration d in the future.
+// If d is negative, it is ignored.  If the returned value would be less than
+// zero because of an overflow, MaxInt64 is returned.
+func when(d Duration) int64 {
+	if d <= 0 {
+		return runtimeNano()
+	}
+	t := runtimeNano() + int64(d)
+	if t < 0 {
+		t = 1<<63 - 1 // math.MaxInt64
+	}
+	return t
+}
+
+func startTimer(*runtimeTimer)
+func stopTimer(*runtimeTimer) bool
+
+// The Timer type represents a single event.
+// When the Timer expires, the current time will be sent on C,
+// unless the Timer was created by AfterFunc.
+// A Timer must be created with NewTimer or AfterFunc.
+type Timer struct {
+	C <-chan Time
+	r runtimeTimer
+}
+
+// Stop prevents the Timer from firing.
+// It returns true if the call stops the timer, false if the timer has already
+// expired or been stopped.
+// Stop does not close the channel, to prevent a read from the channel succeeding
+// incorrectly.
+func (t *Timer) Stop() bool {
+	if t.r.f == nil {
+		panic("time: Stop called on uninitialized Timer")
+	}
+	return stopTimer(&t.r)
+}
+
+// NewTimer creates a new Timer that will send
+// the current time on its channel after at least duration d.
+func NewTimer(d Duration) *Timer {
+	c := make(chan Time, 1)
+	t := &Timer{
+		C: c,
+		r: runtimeTimer{
+			when: when(d),
+			f:    sendTime,
+			arg:  c,
+		},
+	}
+	startTimer(&t.r)
+	return t
+}
+
+// Reset changes the timer to expire after duration d.
+// It returns true if the timer had been active, false if the timer had
+// expired or been stopped.
+func (t *Timer) Reset(d Duration) bool {
+	if t.r.f == nil {
+		panic("time: Reset called on uninitialized Timer")
+	}
+	w := when(d)
+	active := stopTimer(&t.r)
+	t.r.when = w
+	startTimer(&t.r)
+	return active
+}
+
+func sendTime(c interface{}, seq uintptr) {
+	// Non-blocking send of time on c.
+	// Used in NewTimer, it cannot block anyway (buffer).
+	// Used in NewTicker, dropping sends on the floor is
+	// the desired behavior when the reader gets behind,
+	// because the sends are periodic.
+	select {
+	case c.(chan Time) <- Now():
+	default:
+	}
+}
+
+// After waits for the duration to elapse and then sends the current time
+// on the returned channel.
+// It is equivalent to NewTimer(d).C.
+func After(d Duration) <-chan Time {
+	return NewTimer(d).C
+}
+
+// AfterFunc waits for the duration to elapse and then calls f
+// in its own goroutine. It returns a Timer that can
+// be used to cancel the call using its Stop method.
+func AfterFunc(d Duration, f func()) *Timer {
+	t := &Timer{
+		r: runtimeTimer{
+			when: when(d),
+			f:    goFunc,
+			arg:  f,
+		},
+	}
+	startTimer(&t.r)
+	return t
+}
+
+func goFunc(arg interface{}, seq uintptr) {
+	go arg.(func())()
+}
diff --git a/src/time/sleep_test.go b/src/time/sleep_test.go
new file mode 100644
index 000000000..c9b2956b7
--- /dev/null
+++ b/src/time/sleep_test.go
@@ -0,0 +1,430 @@
+// 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_test
+
+import (
+	"errors"
+	"fmt"
+	"runtime"
+	"sort"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	. "time"
+)
+
+// Go runtime uses different Windows timers for time.Now and sleeping.
+// These can tick at different frequencies and can arrive out of sync.
+// The effect can be seen, for example, as time.Sleep(100ms) is actually
+// shorter then 100ms when measured as difference between time.Now before and
+// after time.Sleep call. This was observed on Windows XP SP3 (windows/386).
+// windowsInaccuracy is to ignore such errors.
+const windowsInaccuracy = 17 * Millisecond
+
+func TestSleep(t *testing.T) {
+	const delay = 100 * Millisecond
+	go func() {
+		Sleep(delay / 2)
+		Interrupt()
+	}()
+	start := Now()
+	Sleep(delay)
+	delayadj := delay
+	if runtime.GOOS == "windows" {
+		delayadj -= windowsInaccuracy
+	}
+	duration := Now().Sub(start)
+	if duration < delayadj {
+		t.Fatalf("Sleep(%s) slept for only %s", delay, duration)
+	}
+}
+
+// Test the basic function calling behavior. Correct queueing
+// behavior is tested elsewhere, since After and AfterFunc share
+// the same code.
+func TestAfterFunc(t *testing.T) {
+	i := 10
+	c := make(chan bool)
+	var f func()
+	f = func() {
+		i--
+		if i >= 0 {
+			AfterFunc(0, f)
+			Sleep(1 * Second)
+		} else {
+			c <- true
+		}
+	}
+
+	AfterFunc(0, f)
+	<-c
+}
+
+func TestAfterStress(t *testing.T) {
+	stop := uint32(0)
+	go func() {
+		for atomic.LoadUint32(&stop) == 0 {
+			runtime.GC()
+			// Yield so that the OS can wake up the timer thread,
+			// so that it can generate channel sends for the main goroutine,
+			// which will eventually set stop = 1 for us.
+			Sleep(Nanosecond)
+		}
+	}()
+	ticker := NewTicker(1)
+	for i := 0; i < 100; i++ {
+		<-ticker.C
+	}
+	ticker.Stop()
+	atomic.StoreUint32(&stop, 1)
+}
+
+func benchmark(b *testing.B, bench func(n int)) {
+	garbage := make([]*Timer, 1<<17)
+	for i := 0; i < len(garbage); i++ {
+		garbage[i] = AfterFunc(Hour, nil)
+	}
+	b.ResetTimer()
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			bench(1000)
+		}
+	})
+
+	b.StopTimer()
+	for i := 0; i < len(garbage); i++ {
+		garbage[i].Stop()
+	}
+}
+
+func BenchmarkAfterFunc(b *testing.B) {
+	benchmark(b, func(n int) {
+		c := make(chan bool)
+		var f func()
+		f = func() {
+			n--
+			if n >= 0 {
+				AfterFunc(0, f)
+			} else {
+				c <- true
+			}
+		}
+
+		AfterFunc(0, f)
+		<-c
+	})
+}
+
+func BenchmarkAfter(b *testing.B) {
+	benchmark(b, func(n int) {
+		for i := 0; i < n; i++ {
+			<-After(1)
+		}
+	})
+}
+
+func BenchmarkStop(b *testing.B) {
+	benchmark(b, func(n int) {
+		for i := 0; i < n; i++ {
+			NewTimer(1 * Second).Stop()
+		}
+	})
+}
+
+func BenchmarkSimultaneousAfterFunc(b *testing.B) {
+	benchmark(b, func(n int) {
+		var wg sync.WaitGroup
+		wg.Add(n)
+		for i := 0; i < n; i++ {
+			AfterFunc(0, wg.Done)
+		}
+		wg.Wait()
+	})
+}
+
+func BenchmarkStartStop(b *testing.B) {
+	benchmark(b, func(n int) {
+		timers := make([]*Timer, n)
+		for i := 0; i < n; i++ {
+			timers[i] = AfterFunc(Hour, nil)
+		}
+
+		for i := 0; i < n; i++ {
+			timers[i].Stop()
+		}
+	})
+}
+
+func TestAfter(t *testing.T) {
+	const delay = 100 * Millisecond
+	start := Now()
+	end := <-After(delay)
+	delayadj := delay
+	if runtime.GOOS == "windows" {
+		delayadj -= windowsInaccuracy
+	}
+	if duration := Now().Sub(start); duration < delayadj {
+		t.Fatalf("After(%s) slept for only %d ns", delay, duration)
+	}
+	if min := start.Add(delayadj); end.Before(min) {
+		t.Fatalf("After(%s) expect >= %s, got %s", delay, min, end)
+	}
+}
+
+func TestAfterTick(t *testing.T) {
+	const Count = 10
+	Delta := 100 * Millisecond
+	if testing.Short() {
+		Delta = 10 * Millisecond
+	}
+	t0 := Now()
+	for i := 0; i < Count; i++ {
+		<-After(Delta)
+	}
+	t1 := Now()
+	d := t1.Sub(t0)
+	target := Delta * Count
+	if d < target*9/10 {
+		t.Fatalf("%d ticks of %s too fast: took %s, expected %s", Count, Delta, d, target)
+	}
+	if !testing.Short() && d > target*30/10 {
+		t.Fatalf("%d ticks of %s too slow: took %s, expected %s", Count, Delta, d, target)
+	}
+}
+
+func TestAfterStop(t *testing.T) {
+	AfterFunc(100*Millisecond, func() {})
+	t0 := NewTimer(50 * Millisecond)
+	c1 := make(chan bool, 1)
+	t1 := AfterFunc(150*Millisecond, func() { c1 <- true })
+	c2 := After(200 * Millisecond)
+	if !t0.Stop() {
+		t.Fatalf("failed to stop event 0")
+	}
+	if !t1.Stop() {
+		t.Fatalf("failed to stop event 1")
+	}
+	<-c2
+	select {
+	case <-t0.C:
+		t.Fatalf("event 0 was not stopped")
+	case <-c1:
+		t.Fatalf("event 1 was not stopped")
+	default:
+	}
+	if t1.Stop() {
+		t.Fatalf("Stop returned true twice")
+	}
+}
+
+func TestAfterQueuing(t *testing.T) {
+	// This test flakes out on some systems,
+	// so we'll try it a few times before declaring it a failure.
+	const attempts = 3
+	err := errors.New("!=nil")
+	for i := 0; i < attempts && err != nil; i++ {
+		if err = testAfterQueuing(t); err != nil {
+			t.Logf("attempt %v failed: %v", i, err)
+		}
+	}
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+var slots = []int{5, 3, 6, 6, 6, 1, 1, 2, 7, 9, 4, 8, 0}
+
+type afterResult struct {
+	slot int
+	t    Time
+}
+
+func await(slot int, result chan<- afterResult, ac <-chan Time) {
+	result <- afterResult{slot, <-ac}
+}
+
+func testAfterQueuing(t *testing.T) error {
+	Delta := 100 * Millisecond
+	if testing.Short() {
+		Delta = 20 * Millisecond
+	}
+	// make the result channel buffered because we don't want
+	// to depend on channel queueing semantics that might
+	// possibly change in the future.
+	result := make(chan afterResult, len(slots))
+
+	t0 := Now()
+	for _, slot := range slots {
+		go await(slot, result, After(Duration(slot)*Delta))
+	}
+	sort.Ints(slots)
+	for _, slot := range slots {
+		r := <-result
+		if r.slot != slot {
+			return fmt.Errorf("after slot %d, expected %d", r.slot, slot)
+		}
+		dt := r.t.Sub(t0)
+		target := Duration(slot) * Delta
+		if dt < target-Delta/2 || dt > target+Delta*10 {
+			return fmt.Errorf("After(%s) arrived at %s, expected [%s,%s]", target, dt, target-Delta/2, target+Delta*10)
+		}
+	}
+	return nil
+}
+
+func TestTimerStopStress(t *testing.T) {
+	if testing.Short() {
+		return
+	}
+	for i := 0; i < 100; i++ {
+		go func(i int) {
+			timer := AfterFunc(2*Second, func() {
+				t.Fatalf("timer %d was not stopped", i)
+			})
+			Sleep(1 * Second)
+			timer.Stop()
+		}(i)
+	}
+	Sleep(3 * Second)
+}
+
+func TestSleepZeroDeadlock(t *testing.T) {
+	// Sleep(0) used to hang, the sequence of events was as follows.
+	// Sleep(0) sets G's status to Gwaiting, but then immediately returns leaving the status.
+	// Then the goroutine calls e.g. new and falls down into the scheduler due to pending GC.
+	// After the GC nobody wakes up the goroutine from Gwaiting status.
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
+	c := make(chan bool)
+	go func() {
+		for i := 0; i < 100; i++ {
+			runtime.GC()
+		}
+		c <- true
+	}()
+	for i := 0; i < 100; i++ {
+		Sleep(0)
+		tmp := make(chan bool, 1)
+		tmp <- true
+		<-tmp
+	}
+	<-c
+}
+
+func testReset(d Duration) error {
+	t0 := NewTimer(2 * d)
+	Sleep(d)
+	if t0.Reset(3*d) != true {
+		return errors.New("resetting unfired timer returned false")
+	}
+	Sleep(2 * d)
+	select {
+	case <-t0.C:
+		return errors.New("timer fired early")
+	default:
+	}
+	Sleep(2 * d)
+	select {
+	case <-t0.C:
+	default:
+		return errors.New("reset timer did not fire")
+	}
+
+	if t0.Reset(50*Millisecond) != false {
+		return errors.New("resetting expired timer returned true")
+	}
+	return nil
+}
+
+func TestReset(t *testing.T) {
+	// We try to run this test with increasingly larger multiples
+	// until one works so slow, loaded hardware isn't as flaky,
+	// but without slowing down fast machines unnecessarily.
+	const unit = 25 * Millisecond
+	tries := []Duration{
+		1 * unit,
+		3 * unit,
+		7 * unit,
+		15 * unit,
+	}
+	var err error
+	for _, d := range tries {
+		err = testReset(d)
+		if err == nil {
+			t.Logf("passed using duration %v", d)
+			return
+		}
+	}
+	t.Error(err)
+}
+
+// Test that sleeping for an interval so large it overflows does not
+// result in a short sleep duration.
+func TestOverflowSleep(t *testing.T) {
+	const big = Duration(int64(1<<63 - 1))
+	select {
+	case <-After(big):
+		t.Fatalf("big timeout fired")
+	case <-After(25 * Millisecond):
+		// OK
+	}
+	const neg = Duration(-1 << 63)
+	select {
+	case <-After(neg):
+		// OK
+	case <-After(1 * Second):
+		t.Fatalf("negative timeout didn't fire")
+	}
+}
+
+// Test that a panic while deleting a timer does not leave
+// the timers mutex held, deadlocking a ticker.Stop in a defer.
+func TestIssue5745(t *testing.T) {
+	ticker := NewTicker(Hour)
+	defer func() {
+		// would deadlock here before the fix due to
+		// lock taken before the segfault.
+		ticker.Stop()
+
+		if r := recover(); r == nil {
+			t.Error("Expected panic, but none happened.")
+		}
+	}()
+
+	// cause a panic due to a segfault
+	var timer *Timer
+	timer.Stop()
+	t.Error("Should be unreachable.")
+}
+
+func TestOverflowRuntimeTimer(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode, see issue 6874")
+	}
+	// This may hang forever if timers are broken. See comment near
+	// the end of CheckRuntimeTimerOverflow in internal_test.go.
+	CheckRuntimeTimerOverflow()
+}
+
+func checkZeroPanicString(t *testing.T) {
+	e := recover()
+	s, _ := e.(string)
+	if want := "called on uninitialized Timer"; !strings.Contains(s, want) {
+		t.Errorf("panic = %v; want substring %q", e, want)
+	}
+}
+
+func TestZeroTimerResetPanics(t *testing.T) {
+	defer checkZeroPanicString(t)
+	var tr Timer
+	tr.Reset(1)
+}
+
+func TestZeroTimerStopPanics(t *testing.T) {
+	defer checkZeroPanicString(t)
+	var tr Timer
+	tr.Stop()
+}
diff --git a/src/time/sys_plan9.go b/src/time/sys_plan9.go
new file mode 100644
index 000000000..848472944
--- /dev/null
+++ b/src/time/sys_plan9.go
@@ -0,0 +1,76 @@
+// Copyright 2011 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.
+
+// +build plan9
+
+package time
+
+import (
+	"errors"
+	"syscall"
+)
+
+// for testing: whatever interrupts a sleep
+func interrupt() {
+	// cannot predict pid, don't want to kill group
+}
+
+// readFile reads and returns the content of the named file.
+// It is a trivial implementation of ioutil.ReadFile, reimplemented
+// here to avoid depending on io/ioutil or os.
+func readFile(name string) ([]byte, error) {
+	f, err := syscall.Open(name, syscall.O_RDONLY)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.Close(f)
+	var (
+		buf [4096]byte
+		ret []byte
+		n   int
+	)
+	for {
+		n, err = syscall.Read(f, buf[:])
+		if n > 0 {
+			ret = append(ret, buf[:n]...)
+		}
+		if n == 0 || err != nil {
+			break
+		}
+	}
+	return ret, err
+}
+
+func open(name string) (uintptr, error) {
+	fd, err := syscall.Open(name, syscall.O_RDONLY)
+	if err != nil {
+		return 0, err
+	}
+	return uintptr(fd), nil
+}
+
+func closefd(fd uintptr) {
+	syscall.Close(int(fd))
+}
+
+func preadn(fd uintptr, buf []byte, off int) error {
+	whence := 0
+	if off < 0 {
+		whence = 2
+	}
+	if _, err := syscall.Seek(int(fd), int64(off), whence); err != nil {
+		return err
+	}
+	for len(buf) > 0 {
+		m, err := syscall.Read(int(fd), buf)
+		if m <= 0 {
+			if err == nil {
+				return errors.New("short read")
+			}
+			return err
+		}
+		buf = buf[m:]
+	}
+	return nil
+}
diff --git a/src/time/sys_unix.go b/src/time/sys_unix.go
new file mode 100644
index 000000000..379e13d6a
--- /dev/null
+++ b/src/time/sys_unix.go
@@ -0,0 +1,76 @@
+// Copyright 2011 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.
+
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+
+package time
+
+import (
+	"errors"
+	"syscall"
+)
+
+// for testing: whatever interrupts a sleep
+func interrupt() {
+	syscall.Kill(syscall.Getpid(), syscall.SIGCHLD)
+}
+
+// readFile reads and returns the content of the named file.
+// It is a trivial implementation of ioutil.ReadFile, reimplemented
+// here to avoid depending on io/ioutil or os.
+func readFile(name string) ([]byte, error) {
+	f, err := syscall.Open(name, syscall.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.Close(f)
+	var (
+		buf [4096]byte
+		ret []byte
+		n   int
+	)
+	for {
+		n, err = syscall.Read(f, buf[:])
+		if n > 0 {
+			ret = append(ret, buf[:n]...)
+		}
+		if n == 0 || err != nil {
+			break
+		}
+	}
+	return ret, err
+}
+
+func open(name string) (uintptr, error) {
+	fd, err := syscall.Open(name, syscall.O_RDONLY, 0)
+	if err != nil {
+		return 0, err
+	}
+	return uintptr(fd), nil
+}
+
+func closefd(fd uintptr) {
+	syscall.Close(int(fd))
+}
+
+func preadn(fd uintptr, buf []byte, off int) error {
+	whence := 0
+	if off < 0 {
+		whence = 2
+	}
+	if _, err := syscall.Seek(int(fd), int64(off), whence); err != nil {
+		return err
+	}
+	for len(buf) > 0 {
+		m, err := syscall.Read(int(fd), buf)
+		if m <= 0 {
+			if err == nil {
+				return errors.New("short read")
+			}
+			return err
+		}
+		buf = buf[m:]
+	}
+	return nil
+}
diff --git a/src/time/sys_windows.go b/src/time/sys_windows.go
new file mode 100644
index 000000000..de63b4bf4
--- /dev/null
+++ b/src/time/sys_windows.go
@@ -0,0 +1,73 @@
+// Copyright 2011 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"
+	"syscall"
+)
+
+// for testing: whatever interrupts a sleep
+func interrupt() {
+}
+
+// readFile reads and returns the content of the named file.
+// It is a trivial implementation of ioutil.ReadFile, reimplemented
+// here to avoid depending on io/ioutil or os.
+func readFile(name string) ([]byte, error) {
+	f, err := syscall.Open(name, syscall.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.Close(f)
+	var (
+		buf [4096]byte
+		ret []byte
+		n   int
+	)
+	for {
+		n, err = syscall.Read(f, buf[:])
+		if n > 0 {
+			ret = append(ret, buf[:n]...)
+		}
+		if n == 0 || err != nil {
+			break
+		}
+	}
+	return ret, err
+}
+
+func open(name string) (uintptr, error) {
+	fd, err := syscall.Open(name, syscall.O_RDONLY, 0)
+	if err != nil {
+		return 0, err
+	}
+	return uintptr(fd), nil
+}
+
+func closefd(fd uintptr) {
+	syscall.Close(syscall.Handle(fd))
+}
+
+func preadn(fd uintptr, buf []byte, off int) error {
+	whence := 0
+	if off < 0 {
+		whence = 2
+	}
+	if _, err := syscall.Seek(syscall.Handle(fd), int64(off), whence); err != nil {
+		return err
+	}
+	for len(buf) > 0 {
+		m, err := syscall.Read(syscall.Handle(fd), buf)
+		if m <= 0 {
+			if err == nil {
+				return errors.New("short read")
+			}
+			return err
+		}
+		buf = buf[m:]
+	}
+	return nil
+}
diff --git a/src/time/tick.go b/src/time/tick.go
new file mode 100644
index 000000000..19007841e
--- /dev/null
+++ b/src/time/tick.go
@@ -0,0 +1,56 @@
+// 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"
+
+// A Ticker holds a channel that delivers `ticks' of a clock
+// at intervals.
+type Ticker struct {
+	C <-chan Time // The channel on which the ticks are delivered.
+	r runtimeTimer
+}
+
+// NewTicker returns a new Ticker containing a channel that will send the
+// time with a period specified by the duration argument.
+// It adjusts the intervals or drops ticks to make up for slow receivers.
+// The duration d must be greater than zero; if not, NewTicker will panic.
+// Stop the ticker to release associated resources.
+func NewTicker(d Duration) *Ticker {
+	if d <= 0 {
+		panic(errors.New("non-positive interval for NewTicker"))
+	}
+	// Give the channel a 1-element time buffer.
+	// If the client falls behind while reading, we drop ticks
+	// on the floor until the client catches up.
+	c := make(chan Time, 1)
+	t := &Ticker{
+		C: c,
+		r: runtimeTimer{
+			when:   when(d),
+			period: int64(d),
+			f:      sendTime,
+			arg:    c,
+		},
+	}
+	startTimer(&t.r)
+	return t
+}
+
+// Stop turns off a ticker.  After Stop, no more ticks will be sent.
+// Stop does not close the channel, to prevent a read from the channel succeeding
+// incorrectly.
+func (t *Ticker) Stop() {
+	stopTimer(&t.r)
+}
+
+// Tick is a convenience wrapper for NewTicker providing access to the ticking
+// channel only.  Useful for clients that have no need to shut down the ticker.
+func Tick(d Duration) <-chan Time {
+	if d <= 0 {
+		return nil
+	}
+	return NewTicker(d).C
+}
diff --git a/src/time/tick_test.go b/src/time/tick_test.go
new file mode 100644
index 000000000..32f4740ad
--- /dev/null
+++ b/src/time/tick_test.go
@@ -0,0 +1,78 @@
+// 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_test
+
+import (
+	"testing"
+	. "time"
+)
+
+func TestTicker(t *testing.T) {
+	const Count = 10
+	Delta := 100 * Millisecond
+	ticker := NewTicker(Delta)
+	t0 := Now()
+	for i := 0; i < Count; i++ {
+		<-ticker.C
+	}
+	ticker.Stop()
+	t1 := Now()
+	dt := t1.Sub(t0)
+	target := Delta * Count
+	slop := target * 2 / 10
+	if dt < target-slop || (!testing.Short() && dt > target+slop) {
+		t.Fatalf("%d %s ticks took %s, expected [%s,%s]", Count, Delta, dt, target-slop, target+slop)
+	}
+	// Now test that the ticker stopped
+	Sleep(2 * Delta)
+	select {
+	case <-ticker.C:
+		t.Fatal("Ticker did not shut down")
+	default:
+		// ok
+	}
+}
+
+// Test that a bug tearing down a ticker has been fixed.  This routine should not deadlock.
+func TestTeardown(t *testing.T) {
+	Delta := 100 * Millisecond
+	if testing.Short() {
+		Delta = 20 * Millisecond
+	}
+	for i := 0; i < 3; i++ {
+		ticker := NewTicker(Delta)
+		<-ticker.C
+		ticker.Stop()
+	}
+}
+
+// Test the Tick convenience wrapper.
+func TestTick(t *testing.T) {
+	// Test that giving a negative duration returns nil.
+	if got := Tick(-1); got != nil {
+		t.Errorf("Tick(-1) = %v; want nil", got)
+	}
+}
+
+// Test that NewTicker panics when given a duration less than zero.
+func TestNewTickerLtZeroDuration(t *testing.T) {
+	defer func() {
+		if err := recover(); err == nil {
+			t.Errorf("NewTicker(-1) should have panicked")
+		}
+	}()
+	NewTicker(-1)
+}
+
+func BenchmarkTicker(b *testing.B) {
+	ticker := NewTicker(1)
+	b.ResetTimer()
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		<-ticker.C
+	}
+	b.StopTimer()
+	ticker.Stop()
+}
diff --git a/src/time/time.go b/src/time/time.go
new file mode 100644
index 000000000..0300e846a
--- /dev/null
+++ b/src/time/time.go
@@ -0,0 +1,1203 @@
+// 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 provides functionality for measuring and displaying time.
+//
+// The calendrical calculations always assume a Gregorian calendar.
+package time
+
+import "errors"
+
+// A Time represents an instant in time with nanosecond precision.
+//
+// Programs using times should typically store and pass them as values,
+// not pointers.  That is, time variables and struct fields should be of
+// type time.Time, not *time.Time.  A Time value can be used by
+// multiple goroutines simultaneously.
+//
+// Time instants can be compared using the Before, After, and Equal methods.
+// The Sub method subtracts two instants, producing a Duration.
+// The Add method adds a Time and a Duration, producing a Time.
+//
+// The zero value of type Time is January 1, year 1, 00:00:00.000000000 UTC.
+// As this time is unlikely to come up in practice, the IsZero method gives
+// a simple way of detecting a time that has not been initialized explicitly.
+//
+// Each Time has associated with it a Location, consulted when computing the
+// presentation form of the time, such as in the Format, Hour, and Year methods.
+// The methods Local, UTC, and In return a Time with a specific location.
+// Changing the location in this way changes only the presentation; it does not
+// change the instant in time being denoted and therefore does not affect the
+// computations described in earlier paragraphs.
+//
+// Note that the Go == operator compares not just the time instant but also the
+// Location. Therefore, Time values should not be used as map or database keys
+// without first guaranteeing that the identical Location has been set for all
+// values, which can be achieved through use of the UTC or Local method.
+//
+type Time struct {
+	// sec gives the number of seconds elapsed since
+	// January 1, year 1 00:00:00 UTC.
+	sec int64
+
+	// nsec specifies a non-negative nanosecond
+	// offset within the second named by Seconds.
+	// It must be in the range [0, 999999999].
+	nsec int32
+
+	// loc specifies the Location that should be used to
+	// determine the minute, hour, month, day, and year
+	// that correspond to this Time.
+	// Only the zero Time has a nil Location.
+	// In that case it is interpreted to mean UTC.
+	loc *Location
+}
+
+// After reports whether the time instant t is after u.
+func (t Time) After(u Time) bool {
+	return t.sec > u.sec || t.sec == u.sec && t.nsec > u.nsec
+}
+
+// Before reports whether the time instant t is before u.
+func (t Time) Before(u Time) bool {
+	return t.sec < u.sec || t.sec == u.sec && t.nsec < u.nsec
+}
+
+// Equal reports whether t and u represent the same time instant.
+// Two times can be equal even if they are in different locations.
+// For example, 6:00 +0200 CEST and 4:00 UTC are Equal.
+// This comparison is different from using t == u, which also compares
+// the locations.
+func (t Time) Equal(u Time) bool {
+	return t.sec == u.sec && t.nsec == u.nsec
+}
+
+// A Month specifies a month of the year (January = 1, ...).
+type Month int
+
+const (
+	January Month = 1 + iota
+	February
+	March
+	April
+	May
+	June
+	July
+	August
+	September
+	October
+	November
+	December
+)
+
+var months = [...]string{
+	"January",
+	"February",
+	"March",
+	"April",
+	"May",
+	"June",
+	"July",
+	"August",
+	"September",
+	"October",
+	"November",
+	"December",
+}
+
+// String returns the English name of the month ("January", "February", ...).
+func (m Month) String() string { return months[m-1] }
+
+// A Weekday specifies a day of the week (Sunday = 0, ...).
+type Weekday int
+
+const (
+	Sunday Weekday = iota
+	Monday
+	Tuesday
+	Wednesday
+	Thursday
+	Friday
+	Saturday
+)
+
+var days = [...]string{
+	"Sunday",
+	"Monday",
+	"Tuesday",
+	"Wednesday",
+	"Thursday",
+	"Friday",
+	"Saturday",
+}
+
+// String returns the English name of the day ("Sunday", "Monday", ...).
+func (d Weekday) String() string { return days[d] }
+
+// Computations on time.
+//
+// The zero value for a Time is defined to be
+//	January 1, year 1, 00:00:00.000000000 UTC
+// which (1) looks like a zero, or as close as you can get in a date
+// (1-1-1 00:00:00 UTC), (2) is unlikely enough to arise in practice to
+// be a suitable "not set" sentinel, unlike Jan 1 1970, and (3) has a
+// non-negative year even in time zones west of UTC, unlike 1-1-0
+// 00:00:00 UTC, which would be 12-31-(-1) 19:00:00 in New York.
+//
+// The zero Time value does not force a specific epoch for the time
+// representation.  For example, to use the Unix epoch internally, we
+// could define that to distinguish a zero value from Jan 1 1970, that
+// time would be represented by sec=-1, nsec=1e9.  However, it does
+// suggest a representation, namely using 1-1-1 00:00:00 UTC as the
+// epoch, and that's what we do.
+//
+// The Add and Sub computations are oblivious to the choice of epoch.
+//
+// The presentation computations - year, month, minute, and so on - all
+// rely heavily on division and modulus by positive constants.  For
+// calendrical calculations we want these divisions to round down, even
+// for negative values, so that the remainder is always positive, but
+// Go's division (like most hardware division instructions) rounds to
+// zero.  We can still do those computations and then adjust the result
+// for a negative numerator, but it's annoying to write the adjustment
+// over and over.  Instead, we can change to a different epoch so long
+// ago that all the times we care about will be positive, and then round
+// to zero and round down coincide.  These presentation routines already
+// have to add the zone offset, so adding the translation to the
+// alternate epoch is cheap.  For example, having a non-negative time t
+// means that we can write
+//
+//	sec = t % 60
+//
+// instead of
+//
+//	sec = t % 60
+//	if sec < 0 {
+//		sec += 60
+//	}
+//
+// everywhere.
+//
+// The calendar runs on an exact 400 year cycle: a 400-year calendar
+// printed for 1970-2469 will apply as well to 2470-2869.  Even the days
+// of the week match up.  It simplifies the computations to choose the
+// cycle boundaries so that the exceptional years are always delayed as
+// long as possible.  That means choosing a year equal to 1 mod 400, so
+// that the first leap year is the 4th year, the first missed leap year
+// is the 100th year, and the missed missed leap year is the 400th year.
+// So we'd prefer instead to print a calendar for 2001-2400 and reuse it
+// for 2401-2800.
+//
+// Finally, it's convenient if the delta between the Unix epoch and
+// long-ago epoch is representable by an int64 constant.
+//
+// These three considerations—choose an epoch as early as possible, that
+// uses a year equal to 1 mod 400, and that is no more than 2⁶³ seconds
+// earlier than 1970—bring us to the year -292277022399.  We refer to
+// this year as the absolute zero year, and to times measured as a uint64
+// seconds since this year as absolute times.
+//
+// Times measured as an int64 seconds since the year 1—the representation
+// used for Time's sec field—are called internal times.
+//
+// Times measured as an int64 seconds since the year 1970 are called Unix
+// times.
+//
+// It is tempting to just use the year 1 as the absolute epoch, defining
+// that the routines are only valid for years >= 1.  However, the
+// routines would then be invalid when displaying the epoch in time zones
+// west of UTC, since it is year 0.  It doesn't seem tenable to say that
+// printing the zero time correctly isn't supported in half the time
+// zones.  By comparison, it's reasonable to mishandle some times in
+// the year -292277022399.
+//
+// All this is opaque to clients of the API and can be changed if a
+// better implementation presents itself.
+
+const (
+	// The unsigned zero year for internal calculations.
+	// Must be 1 mod 400, and times before it will not compute correctly,
+	// but otherwise can be changed at will.
+	absoluteZeroYear = -292277022399
+
+	// The year of the zero Time.
+	// Assumed by the unixToInternal computation below.
+	internalYear = 1
+
+	// The year of the zero Unix time.
+	unixYear = 1970
+
+	// Offsets to convert between internal and absolute or Unix times.
+	absoluteToInternal int64 = (absoluteZeroYear - internalYear) * 365.2425 * secondsPerDay
+	internalToAbsolute       = -absoluteToInternal
+
+	unixToInternal int64 = (1969*365 + 1969/4 - 1969/100 + 1969/400) * secondsPerDay
+	internalToUnix int64 = -unixToInternal
+)
+
+// IsZero reports whether t represents the zero time instant,
+// January 1, year 1, 00:00:00 UTC.
+func (t Time) IsZero() bool {
+	return t.sec == 0 && t.nsec == 0
+}
+
+// abs returns the time t as an absolute time, adjusted by the zone offset.
+// It is called when computing a presentation property like Month or Hour.
+func (t Time) abs() uint64 {
+	l := t.loc
+	// Avoid function calls when possible.
+	if l == nil || l == &localLoc {
+		l = l.get()
+	}
+	sec := t.sec + internalToUnix
+	if l != &utcLoc {
+		if l.cacheZone != nil && l.cacheStart <= sec && sec < l.cacheEnd {
+			sec += int64(l.cacheZone.offset)
+		} else {
+			_, offset, _, _, _ := l.lookup(sec)
+			sec += int64(offset)
+		}
+	}
+	return uint64(sec + (unixToInternal + internalToAbsolute))
+}
+
+// locabs is a combination of the Zone and abs methods,
+// extracting both return values from a single zone lookup.
+func (t Time) locabs() (name string, offset int, abs uint64) {
+	l := t.loc
+	if l == nil || l == &localLoc {
+		l = l.get()
+	}
+	// Avoid function call if we hit the local time cache.
+	sec := t.sec + internalToUnix
+	if l != &utcLoc {
+		if l.cacheZone != nil && l.cacheStart <= sec && sec < l.cacheEnd {
+			name = l.cacheZone.name
+			offset = l.cacheZone.offset
+		} else {
+			name, offset, _, _, _ = l.lookup(sec)
+		}
+		sec += int64(offset)
+	} else {
+		name = "UTC"
+	}
+	abs = uint64(sec + (unixToInternal + internalToAbsolute))
+	return
+}
+
+// Date returns the year, month, and day in which t occurs.
+func (t Time) Date() (year int, month Month, day int) {
+	year, month, day, _ = t.date(true)
+	return
+}
+
+// Year returns the year in which t occurs.
+func (t Time) Year() int {
+	year, _, _, _ := t.date(false)
+	return year
+}
+
+// Month returns the month of the year specified by t.
+func (t Time) Month() Month {
+	_, month, _, _ := t.date(true)
+	return month
+}
+
+// Day returns the day of the month specified by t.
+func (t Time) Day() int {
+	_, _, day, _ := t.date(true)
+	return day
+}
+
+// Weekday returns the day of the week specified by t.
+func (t Time) Weekday() Weekday {
+	return absWeekday(t.abs())
+}
+
+// absWeekday is like Weekday but operates on an absolute time.
+func absWeekday(abs uint64) Weekday {
+	// January 1 of the absolute year, like January 1 of 2001, was a Monday.
+	sec := (abs + uint64(Monday)*secondsPerDay) % secondsPerWeek
+	return Weekday(int(sec) / secondsPerDay)
+}
+
+// ISOWeek returns the ISO 8601 year and week number in which t occurs.
+// Week ranges from 1 to 53. Jan 01 to Jan 03 of year n might belong to
+// week 52 or 53 of year n-1, and Dec 29 to Dec 31 might belong to week 1
+// of year n+1.
+func (t Time) ISOWeek() (year, week int) {
+	year, month, day, yday := t.date(true)
+	wday := int(t.Weekday()+6) % 7 // weekday but Monday = 0.
+	const (
+		Mon int = iota
+		Tue
+		Wed
+		Thu
+		Fri
+		Sat
+		Sun
+	)
+
+	// Calculate week as number of Mondays in year up to
+	// and including today, plus 1 because the first week is week 0.
+	// Putting the + 1 inside the numerator as a + 7 keeps the
+	// numerator from being negative, which would cause it to
+	// round incorrectly.
+	week = (yday - wday + 7) / 7
+
+	// The week number is now correct under the assumption
+	// that the first Monday of the year is in week 1.
+	// If Jan 1 is a Tuesday, Wednesday, or Thursday, the first Monday
+	// is actually in week 2.
+	jan1wday := (wday - yday + 7*53) % 7
+	if Tue <= jan1wday && jan1wday <= Thu {
+		week++
+	}
+
+	// If the week number is still 0, we're in early January but in
+	// the last week of last year.
+	if week == 0 {
+		year--
+		week = 52
+		// A year has 53 weeks when Jan 1 or Dec 31 is a Thursday,
+		// meaning Jan 1 of the next year is a Friday
+		// or it was a leap year and Jan 1 of the next year is a Saturday.
+		if jan1wday == Fri || (jan1wday == Sat && isLeap(year)) {
+			week++
+		}
+	}
+
+	// December 29 to 31 are in week 1 of next year if
+	// they are after the last Thursday of the year and
+	// December 31 is a Monday, Tuesday, or Wednesday.
+	if month == December && day >= 29 && wday < Thu {
+		if dec31wday := (wday + 31 - day) % 7; Mon <= dec31wday && dec31wday <= Wed {
+			year++
+			week = 1
+		}
+	}
+
+	return
+}
+
+// Clock returns the hour, minute, and second within the day specified by t.
+func (t Time) Clock() (hour, min, sec int) {
+	return absClock(t.abs())
+}
+
+// absClock is like clock but operates on an absolute time.
+func absClock(abs uint64) (hour, min, sec int) {
+	sec = int(abs % secondsPerDay)
+	hour = sec / secondsPerHour
+	sec -= hour * secondsPerHour
+	min = sec / secondsPerMinute
+	sec -= min * secondsPerMinute
+	return
+}
+
+// Hour returns the hour within the day specified by t, in the range [0, 23].
+func (t Time) Hour() int {
+	return int(t.abs()%secondsPerDay) / secondsPerHour
+}
+
+// Minute returns the minute offset within the hour specified by t, in the range [0, 59].
+func (t Time) Minute() int {
+	return int(t.abs()%secondsPerHour) / secondsPerMinute
+}
+
+// Second returns the second offset within the minute specified by t, in the range [0, 59].
+func (t Time) Second() int {
+	return int(t.abs() % secondsPerMinute)
+}
+
+// Nanosecond returns the nanosecond offset within the second specified by t,
+// in the range [0, 999999999].
+func (t Time) Nanosecond() int {
+	return int(t.nsec)
+}
+
+// YearDay returns the day of the year specified by t, in the range [1,365] for non-leap years,
+// and [1,366] in leap years.
+func (t Time) YearDay() int {
+	_, _, _, yday := t.date(false)
+	return yday + 1
+}
+
+// A Duration represents the elapsed time between two instants
+// as an int64 nanosecond count.  The representation limits the
+// largest representable duration to approximately 290 years.
+type Duration int64
+
+const (
+	minDuration Duration = -1 << 63
+	maxDuration Duration = 1<<63 - 1
+)
+
+// Common durations.  There is no definition for units of Day or larger
+// to avoid confusion across daylight savings time zone transitions.
+//
+// To count the number of units in a Duration, divide:
+//	second := time.Second
+//	fmt.Print(int64(second/time.Millisecond)) // prints 1000
+//
+// To convert an integer number of units to a Duration, multiply:
+//	seconds := 10
+//	fmt.Print(time.Duration(seconds)*time.Second) // prints 10s
+//
+const (
+	Nanosecond  Duration = 1
+	Microsecond          = 1000 * Nanosecond
+	Millisecond          = 1000 * Microsecond
+	Second               = 1000 * Millisecond
+	Minute               = 60 * Second
+	Hour                 = 60 * Minute
+)
+
+// String returns a string representing the duration in the form "72h3m0.5s".
+// Leading zero units are omitted.  As a special case, durations less than one
+// second format use a smaller unit (milli-, micro-, or nanoseconds) to ensure
+// that the leading digit is non-zero.  The zero duration formats as 0,
+// with no unit.
+func (d Duration) String() string {
+	// Largest time is 2540400h10m10.000000000s
+	var buf [32]byte
+	w := len(buf)
+
+	u := uint64(d)
+	neg := d < 0
+	if neg {
+		u = -u
+	}
+
+	if u < uint64(Second) {
+		// Special case: if duration is smaller than a second,
+		// use smaller units, like 1.2ms
+		var prec int
+		w--
+		buf[w] = 's'
+		w--
+		switch {
+		case u == 0:
+			return "0"
+		case u < uint64(Microsecond):
+			// print nanoseconds
+			prec = 0
+			buf[w] = 'n'
+		case u < uint64(Millisecond):
+			// print microseconds
+			prec = 3
+			// U+00B5 'µ' micro sign == 0xC2 0xB5
+			w-- // Need room for two bytes.
+			copy(buf[w:], "µ")
+		default:
+			// print milliseconds
+			prec = 6
+			buf[w] = 'm'
+		}
+		w, u = fmtFrac(buf[:w], u, prec)
+		w = fmtInt(buf[:w], u)
+	} else {
+		w--
+		buf[w] = 's'
+
+		w, u = fmtFrac(buf[:w], u, 9)
+
+		// u is now integer seconds
+		w = fmtInt(buf[:w], u%60)
+		u /= 60
+
+		// u is now integer minutes
+		if u > 0 {
+			w--
+			buf[w] = 'm'
+			w = fmtInt(buf[:w], u%60)
+			u /= 60
+
+			// u is now integer hours
+			// Stop at hours because days can be different lengths.
+			if u > 0 {
+				w--
+				buf[w] = 'h'
+				w = fmtInt(buf[:w], u)
+			}
+		}
+	}
+
+	if neg {
+		w--
+		buf[w] = '-'
+	}
+
+	return string(buf[w:])
+}
+
+// fmtFrac formats the fraction of v/10**prec (e.g., ".12345") into the
+// tail of buf, omitting trailing zeros.  it omits the decimal
+// point too when the fraction is 0.  It returns the index where the
+// output bytes begin and the value v/10**prec.
+func fmtFrac(buf []byte, v uint64, prec int) (nw int, nv uint64) {
+	// Omit trailing zeros up to and including decimal point.
+	w := len(buf)
+	print := false
+	for i := 0; i < prec; i++ {
+		digit := v % 10
+		print = print || digit != 0
+		if print {
+			w--
+			buf[w] = byte(digit) + '0'
+		}
+		v /= 10
+	}
+	if print {
+		w--
+		buf[w] = '.'
+	}
+	return w, v
+}
+
+// fmtInt formats v into the tail of buf.
+// It returns the index where the output begins.
+func fmtInt(buf []byte, v uint64) int {
+	w := len(buf)
+	if v == 0 {
+		w--
+		buf[w] = '0'
+	} else {
+		for v > 0 {
+			w--
+			buf[w] = byte(v%10) + '0'
+			v /= 10
+		}
+	}
+	return w
+}
+
+// Nanoseconds returns the duration as an integer nanosecond count.
+func (d Duration) Nanoseconds() int64 { return int64(d) }
+
+// These methods return float64 because the dominant
+// use case is for printing a floating point number like 1.5s, and
+// a truncation to integer would make them not useful in those cases.
+// Splitting the integer and fraction ourselves guarantees that
+// converting the returned float64 to an integer rounds the same
+// way that a pure integer conversion would have, even in cases
+// where, say, float64(d.Nanoseconds())/1e9 would have rounded
+// differently.
+
+// Seconds returns the duration as a floating point number of seconds.
+func (d Duration) Seconds() float64 {
+	sec := d / Second
+	nsec := d % Second
+	return float64(sec) + float64(nsec)*1e-9
+}
+
+// Minutes returns the duration as a floating point number of minutes.
+func (d Duration) Minutes() float64 {
+	min := d / Minute
+	nsec := d % Minute
+	return float64(min) + float64(nsec)*(1e-9/60)
+}
+
+// Hours returns the duration as a floating point number of hours.
+func (d Duration) Hours() float64 {
+	hour := d / Hour
+	nsec := d % Hour
+	return float64(hour) + float64(nsec)*(1e-9/60/60)
+}
+
+// Add returns the time t+d.
+func (t Time) Add(d Duration) Time {
+	t.sec += int64(d / 1e9)
+	nsec := int32(t.nsec) + int32(d%1e9)
+	if nsec >= 1e9 {
+		t.sec++
+		nsec -= 1e9
+	} else if nsec < 0 {
+		t.sec--
+		nsec += 1e9
+	}
+	t.nsec = nsec
+	return t
+}
+
+// Sub returns the duration t-u. If the result exceeds the maximum (or minimum)
+// value that can be stored in a Duration, the maximum (or minimum) duration
+// will be returned.
+// To compute t-d for a duration d, use t.Add(-d).
+func (t Time) Sub(u Time) Duration {
+	d := Duration(t.sec-u.sec)*Second + Duration(int32(t.nsec)-int32(u.nsec))
+	// Check for overflow or underflow.
+	switch {
+	case u.Add(d).Equal(t):
+		return d // d is correct
+	case t.Before(u):
+		return minDuration // t - u is negative out of range
+	default:
+		return maxDuration // t - u is positive out of range
+	}
+}
+
+// Since returns the time elapsed since t.
+// It is shorthand for time.Now().Sub(t).
+func Since(t Time) Duration {
+	return Now().Sub(t)
+}
+
+// AddDate returns the time corresponding to adding the
+// given number of years, months, and days to t.
+// For example, AddDate(-1, 2, 3) applied to January 1, 2011
+// returns March 4, 2010.
+//
+// AddDate normalizes its result in the same way that Date does,
+// so, for example, adding one month to October 31 yields
+// December 1, the normalized form for November 31.
+func (t Time) AddDate(years int, months int, days int) Time {
+	year, month, day := t.Date()
+	hour, min, sec := t.Clock()
+	return Date(year+years, month+Month(months), day+days, hour, min, sec, int(t.nsec), t.loc)
+}
+
+const (
+	secondsPerMinute = 60
+	secondsPerHour   = 60 * 60
+	secondsPerDay    = 24 * secondsPerHour
+	secondsPerWeek   = 7 * secondsPerDay
+	daysPer400Years  = 365*400 + 97
+	daysPer100Years  = 365*100 + 24
+	daysPer4Years    = 365*4 + 1
+)
+
+// date computes the year, day of year, and when full=true,
+// the month and day in which t occurs.
+func (t Time) date(full bool) (year int, month Month, day int, yday int) {
+	return absDate(t.abs(), full)
+}
+
+// absDate is like date but operates on an absolute time.
+func absDate(abs uint64, full bool) (year int, month Month, day int, yday int) {
+	// Split into time and day.
+	d := abs / secondsPerDay
+
+	// Account for 400 year cycles.
+	n := d / daysPer400Years
+	y := 400 * n
+	d -= daysPer400Years * n
+
+	// Cut off 100-year cycles.
+	// The last cycle has one extra leap year, so on the last day
+	// of that year, day / daysPer100Years will be 4 instead of 3.
+	// Cut it back down to 3 by subtracting n>>2.
+	n = d / daysPer100Years
+	n -= n >> 2
+	y += 100 * n
+	d -= daysPer100Years * n
+
+	// Cut off 4-year cycles.
+	// The last cycle has a missing leap year, which does not
+	// affect the computation.
+	n = d / daysPer4Years
+	y += 4 * n
+	d -= daysPer4Years * n
+
+	// Cut off years within a 4-year cycle.
+	// The last year is a leap year, so on the last day of that year,
+	// day / 365 will be 4 instead of 3.  Cut it back down to 3
+	// by subtracting n>>2.
+	n = d / 365
+	n -= n >> 2
+	y += n
+	d -= 365 * n
+
+	year = int(int64(y) + absoluteZeroYear)
+	yday = int(d)
+
+	if !full {
+		return
+	}
+
+	day = yday
+	if isLeap(year) {
+		// Leap year
+		switch {
+		case day > 31+29-1:
+			// After leap day; pretend it wasn't there.
+			day--
+		case day == 31+29-1:
+			// Leap day.
+			month = February
+			day = 29
+			return
+		}
+	}
+
+	// Estimate month on assumption that every month has 31 days.
+	// The estimate may be too low by at most one month, so adjust.
+	month = Month(day / 31)
+	end := int(daysBefore[month+1])
+	var begin int
+	if day >= end {
+		month++
+		begin = end
+	} else {
+		begin = int(daysBefore[month])
+	}
+
+	month++ // because January is 1
+	day = day - begin + 1
+	return
+}
+
+// daysBefore[m] counts the number of days in a non-leap year
+// before month m begins.  There is an entry for m=12, counting
+// the number of days before January of next year (365).
+var daysBefore = [...]int32{
+	0,
+	31,
+	31 + 28,
+	31 + 28 + 31,
+	31 + 28 + 31 + 30,
+	31 + 28 + 31 + 30 + 31,
+	31 + 28 + 31 + 30 + 31 + 30,
+	31 + 28 + 31 + 30 + 31 + 30 + 31,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30,
+	31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 31,
+}
+
+func daysIn(m Month, year int) int {
+	if m == February && isLeap(year) {
+		return 29
+	}
+	return int(daysBefore[m] - daysBefore[m-1])
+}
+
+// Provided by package runtime.
+func now() (sec int64, nsec int32)
+
+// Now returns the current local time.
+func Now() Time {
+	sec, nsec := now()
+	return Time{sec + unixToInternal, nsec, Local}
+}
+
+// UTC returns t with the location set to UTC.
+func (t Time) UTC() Time {
+	t.loc = UTC
+	return t
+}
+
+// Local returns t with the location set to local time.
+func (t Time) Local() Time {
+	t.loc = Local
+	return t
+}
+
+// In returns t with the location information set to loc.
+//
+// In panics if loc is nil.
+func (t Time) In(loc *Location) Time {
+	if loc == nil {
+		panic("time: missing Location in call to Time.In")
+	}
+	t.loc = loc
+	return t
+}
+
+// Location returns the time zone information associated with t.
+func (t Time) Location() *Location {
+	l := t.loc
+	if l == nil {
+		l = UTC
+	}
+	return l
+}
+
+// Zone computes the time zone in effect at time t, returning the abbreviated
+// name of the zone (such as "CET") and its offset in seconds east of UTC.
+func (t Time) Zone() (name string, offset int) {
+	name, offset, _, _, _ = t.loc.lookup(t.sec + internalToUnix)
+	return
+}
+
+// Unix returns t as a Unix time, the number of seconds elapsed
+// since January 1, 1970 UTC.
+func (t Time) Unix() int64 {
+	return t.sec + internalToUnix
+}
+
+// UnixNano returns t as a Unix time, the number of nanoseconds elapsed
+// since January 1, 1970 UTC. The result is undefined if the Unix time
+// in nanoseconds cannot be represented by an int64. Note that this
+// means the result of calling UnixNano on the zero Time is undefined.
+func (t Time) UnixNano() int64 {
+	return (t.sec+internalToUnix)*1e9 + int64(t.nsec)
+}
+
+const timeBinaryVersion byte = 1
+
+// MarshalBinary implements the encoding.BinaryMarshaler interface.
+func (t Time) MarshalBinary() ([]byte, error) {
+	var offsetMin int16 // minutes east of UTC. -1 is UTC.
+
+	if t.Location() == &utcLoc {
+		offsetMin = -1
+	} else {
+		_, offset := t.Zone()
+		if offset%60 != 0 {
+			return nil, errors.New("Time.MarshalBinary: zone offset has fractional minute")
+		}
+		offset /= 60
+		if offset < -32768 || offset == -1 || offset > 32767 {
+			return nil, errors.New("Time.MarshalBinary: unexpected zone offset")
+		}
+		offsetMin = int16(offset)
+	}
+
+	enc := []byte{
+		timeBinaryVersion, // byte 0 : version
+		byte(t.sec >> 56), // bytes 1-8: seconds
+		byte(t.sec >> 48),
+		byte(t.sec >> 40),
+		byte(t.sec >> 32),
+		byte(t.sec >> 24),
+		byte(t.sec >> 16),
+		byte(t.sec >> 8),
+		byte(t.sec),
+		byte(t.nsec >> 24), // bytes 9-12: nanoseconds
+		byte(t.nsec >> 16),
+		byte(t.nsec >> 8),
+		byte(t.nsec),
+		byte(offsetMin >> 8), // bytes 13-14: zone offset in minutes
+		byte(offsetMin),
+	}
+
+	return enc, nil
+}
+
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+func (t *Time) UnmarshalBinary(data []byte) error {
+	buf := data
+	if len(buf) == 0 {
+		return errors.New("Time.UnmarshalBinary: no data")
+	}
+
+	if buf[0] != timeBinaryVersion {
+		return errors.New("Time.UnmarshalBinary: unsupported version")
+	}
+
+	if len(buf) != /*version*/ 1+ /*sec*/ 8+ /*nsec*/ 4+ /*zone offset*/ 2 {
+		return errors.New("Time.UnmarshalBinary: invalid length")
+	}
+
+	buf = buf[1:]
+	t.sec = int64(buf[7]) | int64(buf[6])<<8 | int64(buf[5])<<16 | int64(buf[4])<<24 |
+		int64(buf[3])<<32 | int64(buf[2])<<40 | int64(buf[1])<<48 | int64(buf[0])<<56
+
+	buf = buf[8:]
+	t.nsec = int32(buf[3]) | int32(buf[2])<<8 | int32(buf[1])<<16 | int32(buf[0])<<24
+
+	buf = buf[4:]
+	offset := int(int16(buf[1])|int16(buf[0])<<8) * 60
+
+	if offset == -1*60 {
+		t.loc = &utcLoc
+	} else if _, localoff, _, _, _ := Local.lookup(t.sec + internalToUnix); offset == localoff {
+		t.loc = Local
+	} else {
+		t.loc = FixedZone("", offset)
+	}
+
+	return nil
+}
+
+// TODO(rsc): Remove GobEncoder, GobDecoder, MarshalJSON, UnmarshalJSON in Go 2.
+// The same semantics will be provided by the generic MarshalBinary, MarshalText,
+// UnmarshalBinary, UnmarshalText.
+
+// GobEncode implements the gob.GobEncoder interface.
+func (t Time) GobEncode() ([]byte, error) {
+	return t.MarshalBinary()
+}
+
+// GobDecode implements the gob.GobDecoder interface.
+func (t *Time) GobDecode(data []byte) error {
+	return t.UnmarshalBinary(data)
+}
+
+// MarshalJSON implements the json.Marshaler interface.
+// The time is a quoted string in RFC 3339 format, with sub-second precision added if present.
+func (t Time) MarshalJSON() ([]byte, error) {
+	if y := t.Year(); y < 0 || y >= 10000 {
+		// RFC 3339 is clear that years are 4 digits exactly.
+		// See golang.org/issue/4556#c15 for more discussion.
+		return nil, errors.New("Time.MarshalJSON: year outside of range [0,9999]")
+	}
+	return []byte(t.Format(`"` + RFC3339Nano + `"`)), nil
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+// The time is expected to be a quoted string in RFC 3339 format.
+func (t *Time) UnmarshalJSON(data []byte) (err error) {
+	// Fractional seconds are handled implicitly by Parse.
+	*t, err = Parse(`"`+RFC3339+`"`, string(data))
+	return
+}
+
+// MarshalText implements the encoding.TextMarshaler interface.
+// The time is formatted in RFC 3339 format, with sub-second precision added if present.
+func (t Time) MarshalText() ([]byte, error) {
+	if y := t.Year(); y < 0 || y >= 10000 {
+		return nil, errors.New("Time.MarshalText: year outside of range [0,9999]")
+	}
+	return []byte(t.Format(RFC3339Nano)), nil
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+// The time is expected to be in RFC 3339 format.
+func (t *Time) UnmarshalText(data []byte) (err error) {
+	// Fractional seconds are handled implicitly by Parse.
+	*t, err = Parse(RFC3339, string(data))
+	return
+}
+
+// Unix returns the local Time corresponding to the given Unix time,
+// sec seconds and nsec nanoseconds since January 1, 1970 UTC.
+// It is valid to pass nsec outside the range [0, 999999999].
+func Unix(sec int64, nsec int64) Time {
+	if nsec < 0 || nsec >= 1e9 {
+		n := nsec / 1e9
+		sec += n
+		nsec -= n * 1e9
+		if nsec < 0 {
+			nsec += 1e9
+			sec--
+		}
+	}
+	return Time{sec + unixToInternal, int32(nsec), Local}
+}
+
+func isLeap(year int) bool {
+	return year%4 == 0 && (year%100 != 0 || year%400 == 0)
+}
+
+// norm returns nhi, nlo such that
+//	hi * base + lo == nhi * base + nlo
+//	0 <= nlo < base
+func norm(hi, lo, base int) (nhi, nlo int) {
+	if lo < 0 {
+		n := (-lo-1)/base + 1
+		hi -= n
+		lo += n * base
+	}
+	if lo >= base {
+		n := lo / base
+		hi += n
+		lo -= n * base
+	}
+	return hi, lo
+}
+
+// Date returns the Time corresponding to
+//	yyyy-mm-dd hh:mm:ss + nsec nanoseconds
+// in the appropriate zone for that time in the given location.
+//
+// The month, day, hour, min, sec, and nsec values may be outside
+// their usual ranges and will be normalized during the conversion.
+// For example, October 32 converts to November 1.
+//
+// A daylight savings time transition skips or repeats times.
+// For example, in the United States, March 13, 2011 2:15am never occurred,
+// while November 6, 2011 1:15am occurred twice.  In such cases, the
+// choice of time zone, and therefore the time, is not well-defined.
+// Date returns a time that is correct in one of the two zones involved
+// in the transition, but it does not guarantee which.
+//
+// Date panics if loc is nil.
+func Date(year int, month Month, day, hour, min, sec, nsec int, loc *Location) Time {
+	if loc == nil {
+		panic("time: missing Location in call to Date")
+	}
+
+	// Normalize month, overflowing into year.
+	m := int(month) - 1
+	year, m = norm(year, m, 12)
+	month = Month(m) + 1
+
+	// Normalize nsec, sec, min, hour, overflowing into day.
+	sec, nsec = norm(sec, nsec, 1e9)
+	min, sec = norm(min, sec, 60)
+	hour, min = norm(hour, min, 60)
+	day, hour = norm(day, hour, 24)
+
+	y := uint64(int64(year) - absoluteZeroYear)
+
+	// Compute days since the absolute epoch.
+
+	// Add in days from 400-year cycles.
+	n := y / 400
+	y -= 400 * n
+	d := daysPer400Years * n
+
+	// Add in 100-year cycles.
+	n = y / 100
+	y -= 100 * n
+	d += daysPer100Years * n
+
+	// Add in 4-year cycles.
+	n = y / 4
+	y -= 4 * n
+	d += daysPer4Years * n
+
+	// Add in non-leap years.
+	n = y
+	d += 365 * n
+
+	// Add in days before this month.
+	d += uint64(daysBefore[month-1])
+	if isLeap(year) && month >= March {
+		d++ // February 29
+	}
+
+	// Add in days before today.
+	d += uint64(day - 1)
+
+	// Add in time elapsed today.
+	abs := d * secondsPerDay
+	abs += uint64(hour*secondsPerHour + min*secondsPerMinute + sec)
+
+	unix := int64(abs) + (absoluteToInternal + internalToUnix)
+
+	// Look for zone offset for t, so we can adjust to UTC.
+	// The lookup function expects UTC, so we pass t in the
+	// hope that it will not be too close to a zone transition,
+	// and then adjust if it is.
+	_, offset, _, start, end := loc.lookup(unix)
+	if offset != 0 {
+		switch utc := unix - int64(offset); {
+		case utc < start:
+			_, offset, _, _, _ = loc.lookup(start - 1)
+		case utc >= end:
+			_, offset, _, _, _ = loc.lookup(end)
+		}
+		unix -= int64(offset)
+	}
+
+	return Time{unix + unixToInternal, int32(nsec), loc}
+}
+
+// Truncate returns the result of rounding t down to a multiple of d (since the zero time).
+// If d <= 0, Truncate returns t unchanged.
+func (t Time) Truncate(d Duration) Time {
+	if d <= 0 {
+		return t
+	}
+	_, r := div(t, d)
+	return t.Add(-r)
+}
+
+// Round returns the result of rounding t to the nearest multiple of d (since the zero time).
+// The rounding behavior for halfway values is to round up.
+// If d <= 0, Round returns t unchanged.
+func (t Time) Round(d Duration) Time {
+	if d <= 0 {
+		return t
+	}
+	_, r := div(t, d)
+	if r+r < d {
+		return t.Add(-r)
+	}
+	return t.Add(d - r)
+}
+
+// div divides t by d and returns the quotient parity and remainder.
+// We don't use the quotient parity anymore (round half up instead of round to even)
+// but it's still here in case we change our minds.
+func div(t Time, d Duration) (qmod2 int, r Duration) {
+	neg := false
+	nsec := int32(t.nsec)
+	if t.sec < 0 {
+		// Operate on absolute value.
+		neg = true
+		t.sec = -t.sec
+		nsec = -nsec
+		if nsec < 0 {
+			nsec += 1e9
+			t.sec-- // t.sec >= 1 before the -- so safe
+		}
+	}
+
+	switch {
+	// Special case: 2d divides 1 second.
+	case d < Second && Second%(d+d) == 0:
+		qmod2 = int(nsec/int32(d)) & 1
+		r = Duration(nsec % int32(d))
+
+	// Special case: d is a multiple of 1 second.
+	case d%Second == 0:
+		d1 := int64(d / Second)
+		qmod2 = int(t.sec/d1) & 1
+		r = Duration(t.sec%d1)*Second + Duration(nsec)
+
+	// General case.
+	// This could be faster if more cleverness were applied,
+	// but it's really only here to avoid special case restrictions in the API.
+	// No one will care about these cases.
+	default:
+		// Compute nanoseconds as 128-bit number.
+		sec := uint64(t.sec)
+		tmp := (sec >> 32) * 1e9
+		u1 := tmp >> 32
+		u0 := tmp << 32
+		tmp = uint64(sec&0xFFFFFFFF) * 1e9
+		u0x, u0 := u0, u0+tmp
+		if u0 < u0x {
+			u1++
+		}
+		u0x, u0 = u0, u0+uint64(nsec)
+		if u0 < u0x {
+			u1++
+		}
+
+		// Compute remainder by subtracting r<<k for decreasing k.
+		// Quotient parity is whether we subtract on last round.
+		d1 := uint64(d)
+		for d1>>63 != 1 {
+			d1 <<= 1
+		}
+		d0 := uint64(0)
+		for {
+			qmod2 = 0
+			if u1 > d1 || u1 == d1 && u0 >= d0 {
+				// subtract
+				qmod2 = 1
+				u0x, u0 = u0, u0-d0
+				if u0 > u0x {
+					u1--
+				}
+				u1 -= d1
+			}
+			if d1 == 0 && d0 == uint64(d) {
+				break
+			}
+			d0 >>= 1
+			d0 |= (d1 & 1) << 63
+			d1 >>= 1
+		}
+		r = Duration(u0)
+	}
+
+	if neg && r != 0 {
+		// If input was negative and not an exact multiple of d, we computed q, r such that
+		//	q*d + r = -t
+		// But the right answers are given by -(q-1), d-r:
+		//	q*d + r = -t
+		//	-q*d - r = t
+		//	-(q-1)*d + (d - r) = t
+		qmod2 ^= 1
+		r = d - r
+	}
+	return
+}
diff --git a/src/time/time_test.go b/src/time/time_test.go
new file mode 100644
index 000000000..7e31dd78a
--- /dev/null
+++ b/src/time/time_test.go
@@ -0,0 +1,1081 @@
+// 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_test
+
+import (
+	"bytes"
+	"encoding/gob"
+	"encoding/json"
+	"fmt"
+	"math/big"
+	"math/rand"
+	"runtime"
+	"testing"
+	"testing/quick"
+	. "time"
+)
+
+// We should be in PST/PDT, but if the time zone files are missing we
+// won't be. The purpose of this test is to at least explain why some of
+// the subsequent tests fail.
+func TestZoneData(t *testing.T) {
+	lt := Now()
+	// PST is 8 hours west, PDT is 7 hours west.  We could use the name but it's not unique.
+	if name, off := lt.Zone(); off != -8*60*60 && off != -7*60*60 {
+		t.Errorf("Unable to find US Pacific time zone data for testing; time zone is %q offset %d", name, off)
+		t.Error("Likely problem: the time zone files have not been installed.")
+	}
+}
+
+// parsedTime is the struct representing a parsed time value.
+type parsedTime struct {
+	Year                 int
+	Month                Month
+	Day                  int
+	Hour, Minute, Second int // 15:04:05 is 15, 4, 5.
+	Nanosecond           int // Fractional second.
+	Weekday              Weekday
+	ZoneOffset           int    // seconds east of UTC, e.g. -7*60*60 for -0700
+	Zone                 string // e.g., "MST"
+}
+
+type TimeTest struct {
+	seconds int64
+	golden  parsedTime
+}
+
+var utctests = []TimeTest{
+	{0, parsedTime{1970, January, 1, 0, 0, 0, 0, Thursday, 0, "UTC"}},
+	{1221681866, parsedTime{2008, September, 17, 20, 4, 26, 0, Wednesday, 0, "UTC"}},
+	{-1221681866, parsedTime{1931, April, 16, 3, 55, 34, 0, Thursday, 0, "UTC"}},
+	{-11644473600, parsedTime{1601, January, 1, 0, 0, 0, 0, Monday, 0, "UTC"}},
+	{599529660, parsedTime{1988, December, 31, 0, 1, 0, 0, Saturday, 0, "UTC"}},
+	{978220860, parsedTime{2000, December, 31, 0, 1, 0, 0, Sunday, 0, "UTC"}},
+}
+
+var nanoutctests = []TimeTest{
+	{0, parsedTime{1970, January, 1, 0, 0, 0, 1e8, Thursday, 0, "UTC"}},
+	{1221681866, parsedTime{2008, September, 17, 20, 4, 26, 2e8, Wednesday, 0, "UTC"}},
+}
+
+var localtests = []TimeTest{
+	{0, parsedTime{1969, December, 31, 16, 0, 0, 0, Wednesday, -8 * 60 * 60, "PST"}},
+	{1221681866, parsedTime{2008, September, 17, 13, 4, 26, 0, Wednesday, -7 * 60 * 60, "PDT"}},
+}
+
+var nanolocaltests = []TimeTest{
+	{0, parsedTime{1969, December, 31, 16, 0, 0, 1e8, Wednesday, -8 * 60 * 60, "PST"}},
+	{1221681866, parsedTime{2008, September, 17, 13, 4, 26, 3e8, Wednesday, -7 * 60 * 60, "PDT"}},
+}
+
+func same(t Time, u *parsedTime) bool {
+	// Check aggregates.
+	year, month, day := t.Date()
+	hour, min, sec := t.Clock()
+	name, offset := t.Zone()
+	if year != u.Year || month != u.Month || day != u.Day ||
+		hour != u.Hour || min != u.Minute || sec != u.Second ||
+		name != u.Zone || offset != u.ZoneOffset {
+		return false
+	}
+	// Check individual entries.
+	return t.Year() == u.Year &&
+		t.Month() == u.Month &&
+		t.Day() == u.Day &&
+		t.Hour() == u.Hour &&
+		t.Minute() == u.Minute &&
+		t.Second() == u.Second &&
+		t.Nanosecond() == u.Nanosecond &&
+		t.Weekday() == u.Weekday
+}
+
+func TestSecondsToUTC(t *testing.T) {
+	for _, test := range utctests {
+		sec := test.seconds
+		golden := &test.golden
+		tm := Unix(sec, 0).UTC()
+		newsec := tm.Unix()
+		if newsec != sec {
+			t.Errorf("SecondsToUTC(%d).Seconds() = %d", sec, newsec)
+		}
+		if !same(tm, golden) {
+			t.Errorf("SecondsToUTC(%d):  // %#v", sec, tm)
+			t.Errorf("  want=%+v", *golden)
+			t.Errorf("  have=%v", tm.Format(RFC3339+" MST"))
+		}
+	}
+}
+
+func TestNanosecondsToUTC(t *testing.T) {
+	for _, test := range nanoutctests {
+		golden := &test.golden
+		nsec := test.seconds*1e9 + int64(golden.Nanosecond)
+		tm := Unix(0, nsec).UTC()
+		newnsec := tm.Unix()*1e9 + int64(tm.Nanosecond())
+		if newnsec != nsec {
+			t.Errorf("NanosecondsToUTC(%d).Nanoseconds() = %d", nsec, newnsec)
+		}
+		if !same(tm, golden) {
+			t.Errorf("NanosecondsToUTC(%d):", nsec)
+			t.Errorf("  want=%+v", *golden)
+			t.Errorf("  have=%+v", tm.Format(RFC3339+" MST"))
+		}
+	}
+}
+
+func TestSecondsToLocalTime(t *testing.T) {
+	for _, test := range localtests {
+		sec := test.seconds
+		golden := &test.golden
+		tm := Unix(sec, 0)
+		newsec := tm.Unix()
+		if newsec != sec {
+			t.Errorf("SecondsToLocalTime(%d).Seconds() = %d", sec, newsec)
+		}
+		if !same(tm, golden) {
+			t.Errorf("SecondsToLocalTime(%d):", sec)
+			t.Errorf("  want=%+v", *golden)
+			t.Errorf("  have=%+v", tm.Format(RFC3339+" MST"))
+		}
+	}
+}
+
+func TestNanosecondsToLocalTime(t *testing.T) {
+	for _, test := range nanolocaltests {
+		golden := &test.golden
+		nsec := test.seconds*1e9 + int64(golden.Nanosecond)
+		tm := Unix(0, nsec)
+		newnsec := tm.Unix()*1e9 + int64(tm.Nanosecond())
+		if newnsec != nsec {
+			t.Errorf("NanosecondsToLocalTime(%d).Seconds() = %d", nsec, newnsec)
+		}
+		if !same(tm, golden) {
+			t.Errorf("NanosecondsToLocalTime(%d):", nsec)
+			t.Errorf("  want=%+v", *golden)
+			t.Errorf("  have=%+v", tm.Format(RFC3339+" MST"))
+		}
+	}
+}
+
+func TestSecondsToUTCAndBack(t *testing.T) {
+	f := func(sec int64) bool { return Unix(sec, 0).UTC().Unix() == sec }
+	f32 := func(sec int32) bool { return f(int64(sec)) }
+	cfg := &quick.Config{MaxCount: 10000}
+
+	// Try a reasonable date first, then the huge ones.
+	if err := quick.Check(f32, cfg); err != nil {
+		t.Fatal(err)
+	}
+	if err := quick.Check(f, cfg); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestNanosecondsToUTCAndBack(t *testing.T) {
+	f := func(nsec int64) bool {
+		t := Unix(0, nsec).UTC()
+		ns := t.Unix()*1e9 + int64(t.Nanosecond())
+		return ns == nsec
+	}
+	f32 := func(nsec int32) bool { return f(int64(nsec)) }
+	cfg := &quick.Config{MaxCount: 10000}
+
+	// Try a small date first, then the large ones. (The span is only a few hundred years
+	// for nanoseconds in an int64.)
+	if err := quick.Check(f32, cfg); err != nil {
+		t.Fatal(err)
+	}
+	if err := quick.Check(f, cfg); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// The time routines provide no way to get absolute time
+// (seconds since zero), but we need it to compute the right
+// answer for bizarre roundings like "to the nearest 3 ns".
+// Compute as t - year1 = (t - 1970) + (1970 - 2001) + (2001 - 1).
+// t - 1970 is returned by Unix and Nanosecond.
+// 1970 - 2001 is -(31*365+8)*86400 = -978307200 seconds.
+// 2001 - 1 is 2000*365.2425*86400 = 63113904000 seconds.
+const unixToZero = -978307200 + 63113904000
+
+// abs returns the absolute time stored in t, as seconds and nanoseconds.
+func abs(t Time) (sec, nsec int64) {
+	unix := t.Unix()
+	nano := t.Nanosecond()
+	return unix + unixToZero, int64(nano)
+}
+
+// absString returns abs as a decimal string.
+func absString(t Time) string {
+	sec, nsec := abs(t)
+	if sec < 0 {
+		sec = -sec
+		nsec = -nsec
+		if nsec < 0 {
+			nsec += 1e9
+			sec--
+		}
+		return fmt.Sprintf("-%d%09d", sec, nsec)
+	}
+	return fmt.Sprintf("%d%09d", sec, nsec)
+}
+
+var truncateRoundTests = []struct {
+	t Time
+	d Duration
+}{
+	{Date(-1, January, 1, 12, 15, 30, 5e8, UTC), 3},
+	{Date(-1, January, 1, 12, 15, 31, 5e8, UTC), 3},
+	{Date(2012, January, 1, 12, 15, 30, 5e8, UTC), Second},
+	{Date(2012, January, 1, 12, 15, 31, 5e8, UTC), Second},
+}
+
+func TestTruncateRound(t *testing.T) {
+	var (
+		bsec  = new(big.Int)
+		bnsec = new(big.Int)
+		bd    = new(big.Int)
+		bt    = new(big.Int)
+		br    = new(big.Int)
+		bq    = new(big.Int)
+		b1e9  = new(big.Int)
+	)
+
+	b1e9.SetInt64(1e9)
+
+	testOne := func(ti, tns, di int64) bool {
+		t0 := Unix(ti, int64(tns)).UTC()
+		d := Duration(di)
+		if d < 0 {
+			d = -d
+		}
+		if d <= 0 {
+			d = 1
+		}
+
+		// Compute bt = absolute nanoseconds.
+		sec, nsec := abs(t0)
+		bsec.SetInt64(sec)
+		bnsec.SetInt64(nsec)
+		bt.Mul(bsec, b1e9)
+		bt.Add(bt, bnsec)
+
+		// Compute quotient and remainder mod d.
+		bd.SetInt64(int64(d))
+		bq.DivMod(bt, bd, br)
+
+		// To truncate, subtract remainder.
+		// br is < d, so it fits in an int64.
+		r := br.Int64()
+		t1 := t0.Add(-Duration(r))
+
+		// Check that time.Truncate works.
+		if trunc := t0.Truncate(d); trunc != t1 {
+			t.Errorf("Time.Truncate(%s, %s) = %s, want %s\n"+
+				"%v trunc %v =\n%v want\n%v",
+				t0.Format(RFC3339Nano), d, trunc, t1.Format(RFC3339Nano),
+				absString(t0), int64(d), absString(trunc), absString(t1))
+			return false
+		}
+
+		// To round, add d back if remainder r > d/2 or r == exactly d/2.
+		// The commented out code would round half to even instead of up,
+		// but that makes it time-zone dependent, which is a bit strange.
+		if r > int64(d)/2 || r+r == int64(d) /*&& bq.Bit(0) == 1*/ {
+			t1 = t1.Add(Duration(d))
+		}
+
+		// Check that time.Round works.
+		if rnd := t0.Round(d); rnd != t1 {
+			t.Errorf("Time.Round(%s, %s) = %s, want %s\n"+
+				"%v round %v =\n%v want\n%v",
+				t0.Format(RFC3339Nano), d, rnd, t1.Format(RFC3339Nano),
+				absString(t0), int64(d), absString(rnd), absString(t1))
+			return false
+		}
+		return true
+	}
+
+	// manual test cases
+	for _, tt := range truncateRoundTests {
+		testOne(tt.t.Unix(), int64(tt.t.Nanosecond()), int64(tt.d))
+	}
+
+	// exhaustive near 0
+	for i := 0; i < 100; i++ {
+		for j := 1; j < 100; j++ {
+			testOne(unixToZero, int64(i), int64(j))
+			testOne(unixToZero, -int64(i), int64(j))
+			if t.Failed() {
+				return
+			}
+		}
+	}
+
+	if t.Failed() {
+		return
+	}
+
+	// randomly generated test cases
+	cfg := &quick.Config{MaxCount: 100000}
+	if testing.Short() {
+		cfg.MaxCount = 1000
+	}
+
+	// divisors of Second
+	f1 := func(ti int64, tns int32, logdi int32) bool {
+		d := Duration(1)
+		a, b := uint(logdi%9), (logdi>>16)%9
+		d <<= a
+		for i := 0; i < int(b); i++ {
+			d *= 5
+		}
+		return testOne(ti, int64(tns), int64(d))
+	}
+	quick.Check(f1, cfg)
+
+	// multiples of Second
+	f2 := func(ti int64, tns int32, di int32) bool {
+		d := Duration(di) * Second
+		if d < 0 {
+			d = -d
+		}
+		return testOne(ti, int64(tns), int64(d))
+	}
+	quick.Check(f2, cfg)
+
+	// halfway cases
+	f3 := func(tns, di int64) bool {
+		di &= 0xfffffffe
+		if di == 0 {
+			di = 2
+		}
+		tns -= tns % di
+		if tns < 0 {
+			tns += di / 2
+		} else {
+			tns -= di / 2
+		}
+		return testOne(0, tns, di)
+	}
+	quick.Check(f3, cfg)
+
+	// full generality
+	f4 := func(ti int64, tns int32, di int64) bool {
+		return testOne(ti, int64(tns), di)
+	}
+	quick.Check(f4, cfg)
+}
+
+type ISOWeekTest struct {
+	year       int // year
+	month, day int // month and day
+	yex        int // expected year
+	wex        int // expected week
+}
+
+var isoWeekTests = []ISOWeekTest{
+	{1981, 1, 1, 1981, 1}, {1982, 1, 1, 1981, 53}, {1983, 1, 1, 1982, 52},
+	{1984, 1, 1, 1983, 52}, {1985, 1, 1, 1985, 1}, {1986, 1, 1, 1986, 1},
+	{1987, 1, 1, 1987, 1}, {1988, 1, 1, 1987, 53}, {1989, 1, 1, 1988, 52},
+	{1990, 1, 1, 1990, 1}, {1991, 1, 1, 1991, 1}, {1992, 1, 1, 1992, 1},
+	{1993, 1, 1, 1992, 53}, {1994, 1, 1, 1993, 52}, {1995, 1, 2, 1995, 1},
+	{1996, 1, 1, 1996, 1}, {1996, 1, 7, 1996, 1}, {1996, 1, 8, 1996, 2},
+	{1997, 1, 1, 1997, 1}, {1998, 1, 1, 1998, 1}, {1999, 1, 1, 1998, 53},
+	{2000, 1, 1, 1999, 52}, {2001, 1, 1, 2001, 1}, {2002, 1, 1, 2002, 1},
+	{2003, 1, 1, 2003, 1}, {2004, 1, 1, 2004, 1}, {2005, 1, 1, 2004, 53},
+	{2006, 1, 1, 2005, 52}, {2007, 1, 1, 2007, 1}, {2008, 1, 1, 2008, 1},
+	{2009, 1, 1, 2009, 1}, {2010, 1, 1, 2009, 53}, {2010, 1, 1, 2009, 53},
+	{2011, 1, 1, 2010, 52}, {2011, 1, 2, 2010, 52}, {2011, 1, 3, 2011, 1},
+	{2011, 1, 4, 2011, 1}, {2011, 1, 5, 2011, 1}, {2011, 1, 6, 2011, 1},
+	{2011, 1, 7, 2011, 1}, {2011, 1, 8, 2011, 1}, {2011, 1, 9, 2011, 1},
+	{2011, 1, 10, 2011, 2}, {2011, 1, 11, 2011, 2}, {2011, 6, 12, 2011, 23},
+	{2011, 6, 13, 2011, 24}, {2011, 12, 25, 2011, 51}, {2011, 12, 26, 2011, 52},
+	{2011, 12, 27, 2011, 52}, {2011, 12, 28, 2011, 52}, {2011, 12, 29, 2011, 52},
+	{2011, 12, 30, 2011, 52}, {2011, 12, 31, 2011, 52}, {1995, 1, 1, 1994, 52},
+	{2012, 1, 1, 2011, 52}, {2012, 1, 2, 2012, 1}, {2012, 1, 8, 2012, 1},
+	{2012, 1, 9, 2012, 2}, {2012, 12, 23, 2012, 51}, {2012, 12, 24, 2012, 52},
+	{2012, 12, 30, 2012, 52}, {2012, 12, 31, 2013, 1}, {2013, 1, 1, 2013, 1},
+	{2013, 1, 6, 2013, 1}, {2013, 1, 7, 2013, 2}, {2013, 12, 22, 2013, 51},
+	{2013, 12, 23, 2013, 52}, {2013, 12, 29, 2013, 52}, {2013, 12, 30, 2014, 1},
+	{2014, 1, 1, 2014, 1}, {2014, 1, 5, 2014, 1}, {2014, 1, 6, 2014, 2},
+	{2015, 1, 1, 2015, 1}, {2016, 1, 1, 2015, 53}, {2017, 1, 1, 2016, 52},
+	{2018, 1, 1, 2018, 1}, {2019, 1, 1, 2019, 1}, {2020, 1, 1, 2020, 1},
+	{2021, 1, 1, 2020, 53}, {2022, 1, 1, 2021, 52}, {2023, 1, 1, 2022, 52},
+	{2024, 1, 1, 2024, 1}, {2025, 1, 1, 2025, 1}, {2026, 1, 1, 2026, 1},
+	{2027, 1, 1, 2026, 53}, {2028, 1, 1, 2027, 52}, {2029, 1, 1, 2029, 1},
+	{2030, 1, 1, 2030, 1}, {2031, 1, 1, 2031, 1}, {2032, 1, 1, 2032, 1},
+	{2033, 1, 1, 2032, 53}, {2034, 1, 1, 2033, 52}, {2035, 1, 1, 2035, 1},
+	{2036, 1, 1, 2036, 1}, {2037, 1, 1, 2037, 1}, {2038, 1, 1, 2037, 53},
+	{2039, 1, 1, 2038, 52}, {2040, 1, 1, 2039, 52},
+}
+
+func TestISOWeek(t *testing.T) {
+	// Selected dates and corner cases
+	for _, wt := range isoWeekTests {
+		dt := Date(wt.year, Month(wt.month), wt.day, 0, 0, 0, 0, UTC)
+		y, w := dt.ISOWeek()
+		if w != wt.wex || y != wt.yex {
+			t.Errorf("got %d/%d; expected %d/%d for %d-%02d-%02d",
+				y, w, wt.yex, wt.wex, wt.year, wt.month, wt.day)
+		}
+	}
+
+	// The only real invariant: Jan 04 is in week 1
+	for year := 1950; year < 2100; year++ {
+		if y, w := Date(year, January, 4, 0, 0, 0, 0, UTC).ISOWeek(); y != year || w != 1 {
+			t.Errorf("got %d/%d; expected %d/1 for Jan 04", y, w, year)
+		}
+	}
+}
+
+type YearDayTest struct {
+	year, month, day int
+	yday             int
+}
+
+// Test YearDay in several different scenarios
+// and corner cases
+var yearDayTests = []YearDayTest{
+	// Non-leap-year tests
+	{2007, 1, 1, 1},
+	{2007, 1, 15, 15},
+	{2007, 2, 1, 32},
+	{2007, 2, 15, 46},
+	{2007, 3, 1, 60},
+	{2007, 3, 15, 74},
+	{2007, 4, 1, 91},
+	{2007, 12, 31, 365},
+
+	// Leap-year tests
+	{2008, 1, 1, 1},
+	{2008, 1, 15, 15},
+	{2008, 2, 1, 32},
+	{2008, 2, 15, 46},
+	{2008, 3, 1, 61},
+	{2008, 3, 15, 75},
+	{2008, 4, 1, 92},
+	{2008, 12, 31, 366},
+
+	// Looks like leap-year (but isn't) tests
+	{1900, 1, 1, 1},
+	{1900, 1, 15, 15},
+	{1900, 2, 1, 32},
+	{1900, 2, 15, 46},
+	{1900, 3, 1, 60},
+	{1900, 3, 15, 74},
+	{1900, 4, 1, 91},
+	{1900, 12, 31, 365},
+
+	// Year one tests (non-leap)
+	{1, 1, 1, 1},
+	{1, 1, 15, 15},
+	{1, 2, 1, 32},
+	{1, 2, 15, 46},
+	{1, 3, 1, 60},
+	{1, 3, 15, 74},
+	{1, 4, 1, 91},
+	{1, 12, 31, 365},
+
+	// Year minus one tests (non-leap)
+	{-1, 1, 1, 1},
+	{-1, 1, 15, 15},
+	{-1, 2, 1, 32},
+	{-1, 2, 15, 46},
+	{-1, 3, 1, 60},
+	{-1, 3, 15, 74},
+	{-1, 4, 1, 91},
+	{-1, 12, 31, 365},
+
+	// 400 BC tests (leap-year)
+	{-400, 1, 1, 1},
+	{-400, 1, 15, 15},
+	{-400, 2, 1, 32},
+	{-400, 2, 15, 46},
+	{-400, 3, 1, 61},
+	{-400, 3, 15, 75},
+	{-400, 4, 1, 92},
+	{-400, 12, 31, 366},
+
+	// Special Cases
+
+	// Gregorian calendar change (no effect)
+	{1582, 10, 4, 277},
+	{1582, 10, 15, 288},
+}
+
+// Check to see if YearDay is location sensitive
+var yearDayLocations = []*Location{
+	FixedZone("UTC-8", -8*60*60),
+	FixedZone("UTC-4", -4*60*60),
+	UTC,
+	FixedZone("UTC+4", 4*60*60),
+	FixedZone("UTC+8", 8*60*60),
+}
+
+func TestYearDay(t *testing.T) {
+	for _, loc := range yearDayLocations {
+		for _, ydt := range yearDayTests {
+			dt := Date(ydt.year, Month(ydt.month), ydt.day, 0, 0, 0, 0, loc)
+			yday := dt.YearDay()
+			if yday != ydt.yday {
+				t.Errorf("got %d, expected %d for %d-%02d-%02d in %v",
+					yday, ydt.yday, ydt.year, ydt.month, ydt.day, loc)
+			}
+		}
+	}
+}
+
+var durationTests = []struct {
+	str string
+	d   Duration
+}{
+	{"0", 0},
+	{"1ns", 1 * Nanosecond},
+	{"1.1µs", 1100 * Nanosecond},
+	{"2.2ms", 2200 * Microsecond},
+	{"3.3s", 3300 * Millisecond},
+	{"4m5s", 4*Minute + 5*Second},
+	{"4m5.001s", 4*Minute + 5001*Millisecond},
+	{"5h6m7.001s", 5*Hour + 6*Minute + 7001*Millisecond},
+	{"8m0.000000001s", 8*Minute + 1*Nanosecond},
+	{"2562047h47m16.854775807s", 1<<63 - 1},
+	{"-2562047h47m16.854775808s", -1 << 63},
+}
+
+func TestDurationString(t *testing.T) {
+	for _, tt := range durationTests {
+		if str := tt.d.String(); str != tt.str {
+			t.Errorf("Duration(%d).String() = %s, want %s", int64(tt.d), str, tt.str)
+		}
+		if tt.d > 0 {
+			if str := (-tt.d).String(); str != "-"+tt.str {
+				t.Errorf("Duration(%d).String() = %s, want %s", int64(-tt.d), str, "-"+tt.str)
+			}
+		}
+	}
+}
+
+var dateTests = []struct {
+	year, month, day, hour, min, sec, nsec int
+	z                                      *Location
+	unix                                   int64
+}{
+	{2011, 11, 6, 1, 0, 0, 0, Local, 1320566400},   // 1:00:00 PDT
+	{2011, 11, 6, 1, 59, 59, 0, Local, 1320569999}, // 1:59:59 PDT
+	{2011, 11, 6, 2, 0, 0, 0, Local, 1320573600},   // 2:00:00 PST
+
+	{2011, 3, 13, 1, 0, 0, 0, Local, 1300006800},   // 1:00:00 PST
+	{2011, 3, 13, 1, 59, 59, 0, Local, 1300010399}, // 1:59:59 PST
+	{2011, 3, 13, 3, 0, 0, 0, Local, 1300010400},   // 3:00:00 PDT
+	{2011, 3, 13, 2, 30, 0, 0, Local, 1300008600},  // 2:30:00 PDT ≡ 1:30 PST
+
+	// Many names for Fri Nov 18 7:56:35 PST 2011
+	{2011, 11, 18, 7, 56, 35, 0, Local, 1321631795},                 // Nov 18 7:56:35
+	{2011, 11, 19, -17, 56, 35, 0, Local, 1321631795},               // Nov 19 -17:56:35
+	{2011, 11, 17, 31, 56, 35, 0, Local, 1321631795},                // Nov 17 31:56:35
+	{2011, 11, 18, 6, 116, 35, 0, Local, 1321631795},                // Nov 18 6:116:35
+	{2011, 10, 49, 7, 56, 35, 0, Local, 1321631795},                 // Oct 49 7:56:35
+	{2011, 11, 18, 7, 55, 95, 0, Local, 1321631795},                 // Nov 18 7:55:95
+	{2011, 11, 18, 7, 56, 34, 1e9, Local, 1321631795},               // Nov 18 7:56:34 + 10⁹ns
+	{2011, 12, -12, 7, 56, 35, 0, Local, 1321631795},                // Dec -21 7:56:35
+	{2012, 1, -43, 7, 56, 35, 0, Local, 1321631795},                 // Jan -52 7:56:35 2012
+	{2012, int(January - 2), 18, 7, 56, 35, 0, Local, 1321631795},   // (Jan-2) 18 7:56:35 2012
+	{2010, int(December + 11), 18, 7, 56, 35, 0, Local, 1321631795}, // (Dec+11) 18 7:56:35 2010
+}
+
+func TestDate(t *testing.T) {
+	for _, tt := range dateTests {
+		time := Date(tt.year, Month(tt.month), tt.day, tt.hour, tt.min, tt.sec, tt.nsec, tt.z)
+		want := Unix(tt.unix, 0)
+		if !time.Equal(want) {
+			t.Errorf("Date(%d, %d, %d, %d, %d, %d, %d, %s) = %v, want %v",
+				tt.year, tt.month, tt.day, tt.hour, tt.min, tt.sec, tt.nsec, tt.z,
+				time, want)
+		}
+	}
+}
+
+// Several ways of getting from
+// Fri Nov 18 7:56:35 PST 2011
+// to
+// Thu Mar 19 7:56:35 PST 2016
+var addDateTests = []struct {
+	years, months, days int
+}{
+	{4, 4, 1},
+	{3, 16, 1},
+	{3, 15, 30},
+	{5, -6, -18 - 30 - 12},
+}
+
+func TestAddDate(t *testing.T) {
+	t0 := Date(2011, 11, 18, 7, 56, 35, 0, UTC)
+	t1 := Date(2016, 3, 19, 7, 56, 35, 0, UTC)
+	for _, at := range addDateTests {
+		time := t0.AddDate(at.years, at.months, at.days)
+		if !time.Equal(t1) {
+			t.Errorf("AddDate(%d, %d, %d) = %v, want %v",
+				at.years, at.months, at.days,
+				time, t1)
+		}
+	}
+}
+
+var daysInTests = []struct {
+	year, month, di int
+}{
+	{2011, 1, 31},  // January, first month, 31 days
+	{2011, 2, 28},  // February, non-leap year, 28 days
+	{2012, 2, 29},  // February, leap year, 29 days
+	{2011, 6, 30},  // June, 30 days
+	{2011, 12, 31}, // December, last month, 31 days
+}
+
+func TestDaysIn(t *testing.T) {
+	// The daysIn function is not exported.
+	// Test the daysIn function via the `var DaysIn = daysIn`
+	// statement in the internal_test.go file.
+	for _, tt := range daysInTests {
+		di := DaysIn(Month(tt.month), tt.year)
+		if di != tt.di {
+			t.Errorf("got %d; expected %d for %d-%02d",
+				di, tt.di, tt.year, tt.month)
+		}
+	}
+}
+
+func TestAddToExactSecond(t *testing.T) {
+	// Add an amount to the current time to round it up to the next exact second.
+	// This test checks that the nsec field still lies within the range [0, 999999999].
+	t1 := Now()
+	t2 := t1.Add(Second - Duration(t1.Nanosecond()))
+	sec := (t1.Second() + 1) % 60
+	if t2.Second() != sec || t2.Nanosecond() != 0 {
+		t.Errorf("sec = %d, nsec = %d, want sec = %d, nsec = 0", t2.Second(), t2.Nanosecond(), sec)
+	}
+}
+
+func equalTimeAndZone(a, b Time) bool {
+	aname, aoffset := a.Zone()
+	bname, boffset := b.Zone()
+	return a.Equal(b) && aoffset == boffset && aname == bname
+}
+
+var gobTests = []Time{
+	Date(0, 1, 2, 3, 4, 5, 6, UTC),
+	Date(7, 8, 9, 10, 11, 12, 13, FixedZone("", 0)),
+	Unix(81985467080890095, 0x76543210), // Time.sec: 0x0123456789ABCDEF
+	{}, // nil location
+	Date(1, 2, 3, 4, 5, 6, 7, FixedZone("", 32767*60)),
+	Date(1, 2, 3, 4, 5, 6, 7, FixedZone("", -32768*60)),
+}
+
+func TestTimeGob(t *testing.T) {
+	var b bytes.Buffer
+	enc := gob.NewEncoder(&b)
+	dec := gob.NewDecoder(&b)
+	for _, tt := range gobTests {
+		var gobtt Time
+		if err := enc.Encode(&tt); err != nil {
+			t.Errorf("%v gob Encode error = %q, want nil", tt, err)
+		} else if err := dec.Decode(&gobtt); err != nil {
+			t.Errorf("%v gob Decode error = %q, want nil", tt, err)
+		} else if !equalTimeAndZone(gobtt, tt) {
+			t.Errorf("Decoded time = %v, want %v", gobtt, tt)
+		}
+		b.Reset()
+	}
+}
+
+var invalidEncodingTests = []struct {
+	bytes []byte
+	want  string
+}{
+	{[]byte{}, "Time.UnmarshalBinary: no data"},
+	{[]byte{0, 2, 3}, "Time.UnmarshalBinary: unsupported version"},
+	{[]byte{1, 2, 3}, "Time.UnmarshalBinary: invalid length"},
+}
+
+func TestInvalidTimeGob(t *testing.T) {
+	for _, tt := range invalidEncodingTests {
+		var ignored Time
+		err := ignored.GobDecode(tt.bytes)
+		if err == nil || err.Error() != tt.want {
+			t.Errorf("time.GobDecode(%#v) error = %v, want %v", tt.bytes, err, tt.want)
+		}
+		err = ignored.UnmarshalBinary(tt.bytes)
+		if err == nil || err.Error() != tt.want {
+			t.Errorf("time.UnmarshalBinary(%#v) error = %v, want %v", tt.bytes, err, tt.want)
+		}
+	}
+}
+
+var notEncodableTimes = []struct {
+	time Time
+	want string
+}{
+	{Date(0, 1, 2, 3, 4, 5, 6, FixedZone("", 1)), "Time.MarshalBinary: zone offset has fractional minute"},
+	{Date(0, 1, 2, 3, 4, 5, 6, FixedZone("", -1*60)), "Time.MarshalBinary: unexpected zone offset"},
+	{Date(0, 1, 2, 3, 4, 5, 6, FixedZone("", -32769*60)), "Time.MarshalBinary: unexpected zone offset"},
+	{Date(0, 1, 2, 3, 4, 5, 6, FixedZone("", 32768*60)), "Time.MarshalBinary: unexpected zone offset"},
+}
+
+func TestNotGobEncodableTime(t *testing.T) {
+	for _, tt := range notEncodableTimes {
+		_, err := tt.time.GobEncode()
+		if err == nil || err.Error() != tt.want {
+			t.Errorf("%v GobEncode error = %v, want %v", tt.time, err, tt.want)
+		}
+		_, err = tt.time.MarshalBinary()
+		if err == nil || err.Error() != tt.want {
+			t.Errorf("%v MarshalBinary error = %v, want %v", tt.time, err, tt.want)
+		}
+	}
+}
+
+var jsonTests = []struct {
+	time Time
+	json string
+}{
+	{Date(9999, 4, 12, 23, 20, 50, 520*1e6, UTC), `"9999-04-12T23:20:50.52Z"`},
+	{Date(1996, 12, 19, 16, 39, 57, 0, Local), `"1996-12-19T16:39:57-08:00"`},
+	{Date(0, 1, 1, 0, 0, 0, 1, FixedZone("", 1*60)), `"0000-01-01T00:00:00.000000001+00:01"`},
+}
+
+func TestTimeJSON(t *testing.T) {
+	for _, tt := range jsonTests {
+		var jsonTime Time
+
+		if jsonBytes, err := json.Marshal(tt.time); err != nil {
+			t.Errorf("%v json.Marshal error = %v, want nil", tt.time, err)
+		} else if string(jsonBytes) != tt.json {
+			t.Errorf("%v JSON = %#q, want %#q", tt.time, string(jsonBytes), tt.json)
+		} else if err = json.Unmarshal(jsonBytes, &jsonTime); err != nil {
+			t.Errorf("%v json.Unmarshal error = %v, want nil", tt.time, err)
+		} else if !equalTimeAndZone(jsonTime, tt.time) {
+			t.Errorf("Unmarshaled time = %v, want %v", jsonTime, tt.time)
+		}
+	}
+}
+
+func TestInvalidTimeJSON(t *testing.T) {
+	var tt Time
+	err := json.Unmarshal([]byte(`{"now is the time":"buddy"}`), &tt)
+	_, isParseErr := err.(*ParseError)
+	if !isParseErr {
+		t.Errorf("expected *time.ParseError unmarshaling JSON, got %v", err)
+	}
+}
+
+var notJSONEncodableTimes = []struct {
+	time Time
+	want string
+}{
+	{Date(10000, 1, 1, 0, 0, 0, 0, UTC), "Time.MarshalJSON: year outside of range [0,9999]"},
+	{Date(-1, 1, 1, 0, 0, 0, 0, UTC), "Time.MarshalJSON: year outside of range [0,9999]"},
+}
+
+func TestNotJSONEncodableTime(t *testing.T) {
+	for _, tt := range notJSONEncodableTimes {
+		_, err := tt.time.MarshalJSON()
+		if err == nil || err.Error() != tt.want {
+			t.Errorf("%v MarshalJSON error = %v, want %v", tt.time, err, tt.want)
+		}
+	}
+}
+
+var parseDurationTests = []struct {
+	in   string
+	ok   bool
+	want Duration
+}{
+	// simple
+	{"0", true, 0},
+	{"5s", true, 5 * Second},
+	{"30s", true, 30 * Second},
+	{"1478s", true, 1478 * Second},
+	// sign
+	{"-5s", true, -5 * Second},
+	{"+5s", true, 5 * Second},
+	{"-0", true, 0},
+	{"+0", true, 0},
+	// decimal
+	{"5.0s", true, 5 * Second},
+	{"5.6s", true, 5*Second + 600*Millisecond},
+	{"5.s", true, 5 * Second},
+	{".5s", true, 500 * Millisecond},
+	{"1.0s", true, 1 * Second},
+	{"1.00s", true, 1 * Second},
+	{"1.004s", true, 1*Second + 4*Millisecond},
+	{"1.0040s", true, 1*Second + 4*Millisecond},
+	{"100.00100s", true, 100*Second + 1*Millisecond},
+	// different units
+	{"10ns", true, 10 * Nanosecond},
+	{"11us", true, 11 * Microsecond},
+	{"12µs", true, 12 * Microsecond}, // U+00B5
+	{"12μs", true, 12 * Microsecond}, // U+03BC
+	{"13ms", true, 13 * Millisecond},
+	{"14s", true, 14 * Second},
+	{"15m", true, 15 * Minute},
+	{"16h", true, 16 * Hour},
+	// composite durations
+	{"3h30m", true, 3*Hour + 30*Minute},
+	{"10.5s4m", true, 4*Minute + 10*Second + 500*Millisecond},
+	{"-2m3.4s", true, -(2*Minute + 3*Second + 400*Millisecond)},
+	{"1h2m3s4ms5us6ns", true, 1*Hour + 2*Minute + 3*Second + 4*Millisecond + 5*Microsecond + 6*Nanosecond},
+	{"39h9m14.425s", true, 39*Hour + 9*Minute + 14*Second + 425*Millisecond},
+	// large value
+	{"52763797000ns", true, 52763797000 * Nanosecond},
+	// more than 9 digits after decimal point, see http://golang.org/issue/6617
+	{"0.3333333333333333333h", true, 20 * Minute},
+
+	// errors
+	{"", false, 0},
+	{"3", false, 0},
+	{"-", false, 0},
+	{"s", false, 0},
+	{".", false, 0},
+	{"-.", false, 0},
+	{".s", false, 0},
+	{"+.s", false, 0},
+	{"3000000h", false, 0}, // overflow
+}
+
+func TestParseDuration(t *testing.T) {
+	for _, tc := range parseDurationTests {
+		d, err := ParseDuration(tc.in)
+		if tc.ok && (err != nil || d != tc.want) {
+			t.Errorf("ParseDuration(%q) = %v, %v, want %v, nil", tc.in, d, err, tc.want)
+		} else if !tc.ok && err == nil {
+			t.Errorf("ParseDuration(%q) = _, nil, want _, non-nil", tc.in)
+		}
+	}
+}
+
+func TestParseDurationRoundTrip(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		// Resolutions finer than milliseconds will result in
+		// imprecise round-trips.
+		d0 := Duration(rand.Int31()) * Millisecond
+		s := d0.String()
+		d1, err := ParseDuration(s)
+		if err != nil || d0 != d1 {
+			t.Errorf("round-trip failed: %d => %q => %d, %v", d0, s, d1, err)
+		}
+	}
+}
+
+// golang.org/issue/4622
+func TestLocationRace(t *testing.T) {
+	ResetLocalOnceForTest() // reset the Once to trigger the race
+
+	c := make(chan string, 1)
+	go func() {
+		c <- Now().String()
+	}()
+	Now().String()
+	<-c
+	Sleep(100 * Millisecond)
+
+	// Back to Los Angeles for subsequent tests:
+	ForceUSPacificForTesting()
+}
+
+var (
+	t Time
+	u int64
+)
+
+var mallocTest = []struct {
+	count int
+	desc  string
+	fn    func()
+}{
+	{0, `time.Now()`, func() { t = Now() }},
+	{0, `time.Now().UnixNano()`, func() { u = Now().UnixNano() }},
+}
+
+func TestCountMallocs(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping malloc count in short mode")
+	}
+	if runtime.GOMAXPROCS(0) > 1 {
+		t.Skip("skipping; GOMAXPROCS>1")
+	}
+	for _, mt := range mallocTest {
+		allocs := int(testing.AllocsPerRun(100, mt.fn))
+		if allocs > mt.count {
+			t.Errorf("%s: %d allocs, want %d", mt.desc, allocs, mt.count)
+		}
+	}
+}
+
+func TestLoadFixed(t *testing.T) {
+	// Issue 4064: handle locations without any zone transitions.
+	loc, err := LoadLocation("Etc/GMT+1")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// The tzdata name Etc/GMT+1 uses "east is negative",
+	// but Go and most other systems use "east is positive".
+	// So GMT+1 corresponds to -3600 in the Go zone, not +3600.
+	name, offset := Now().In(loc).Zone()
+	if name != "GMT+1" || offset != -1*60*60 {
+		t.Errorf("Now().In(loc).Zone() = %q, %d, want %q, %d", name, offset, "GMT+1", -1*60*60)
+	}
+}
+
+const (
+	minDuration Duration = -1 << 63
+	maxDuration Duration = 1<<63 - 1
+)
+
+var subTests = []struct {
+	t Time
+	u Time
+	d Duration
+}{
+	{Time{}, Time{}, Duration(0)},
+	{Date(2009, 11, 23, 0, 0, 0, 1, UTC), Date(2009, 11, 23, 0, 0, 0, 0, UTC), Duration(1)},
+	{Date(2009, 11, 23, 0, 0, 0, 0, UTC), Date(2009, 11, 24, 0, 0, 0, 0, UTC), -24 * Hour},
+	{Date(2009, 11, 24, 0, 0, 0, 0, UTC), Date(2009, 11, 23, 0, 0, 0, 0, UTC), 24 * Hour},
+	{Date(-2009, 11, 24, 0, 0, 0, 0, UTC), Date(-2009, 11, 23, 0, 0, 0, 0, UTC), 24 * Hour},
+	{Time{}, Date(2109, 11, 23, 0, 0, 0, 0, UTC), Duration(minDuration)},
+	{Date(2109, 11, 23, 0, 0, 0, 0, UTC), Time{}, Duration(maxDuration)},
+	{Time{}, Date(-2109, 11, 23, 0, 0, 0, 0, UTC), Duration(maxDuration)},
+	{Date(-2109, 11, 23, 0, 0, 0, 0, UTC), Time{}, Duration(minDuration)},
+	{Date(2290, 1, 1, 0, 0, 0, 0, UTC), Date(2000, 1, 1, 0, 0, 0, 0, UTC), 290*365*24*Hour + 71*24*Hour},
+	{Date(2300, 1, 1, 0, 0, 0, 0, UTC), Date(2000, 1, 1, 0, 0, 0, 0, UTC), Duration(maxDuration)},
+	{Date(2000, 1, 1, 0, 0, 0, 0, UTC), Date(2290, 1, 1, 0, 0, 0, 0, UTC), -290*365*24*Hour - 71*24*Hour},
+	{Date(2000, 1, 1, 0, 0, 0, 0, UTC), Date(2300, 1, 1, 0, 0, 0, 0, UTC), Duration(minDuration)},
+}
+
+func TestSub(t *testing.T) {
+	for i, st := range subTests {
+		got := st.t.Sub(st.u)
+		if got != st.d {
+			t.Errorf("#%d: Sub(%v, %v): got %v; want %v", i, st.t, st.u, got, st.d)
+		}
+	}
+}
+
+var nsDurationTests = []struct {
+	d    Duration
+	want int64
+}{
+	{Duration(-1000), -1000},
+	{Duration(-1), -1},
+	{Duration(1), 1},
+	{Duration(1000), 1000},
+}
+
+func TestDurationNanoseconds(t *testing.T) {
+	for _, tt := range nsDurationTests {
+		if got := tt.d.Nanoseconds(); got != tt.want {
+			t.Errorf("d.Nanoseconds() = %d; want: %d", got, tt.want)
+		}
+	}
+}
+
+var minDurationTests = []struct {
+	d    Duration
+	want float64
+}{
+	{Duration(-60000000000), -1},
+	{Duration(-1), -1 / 60e9},
+	{Duration(1), 1 / 60e9},
+	{Duration(60000000000), 1},
+}
+
+func TestDurationMinutes(t *testing.T) {
+	for _, tt := range minDurationTests {
+		if got := tt.d.Minutes(); got != tt.want {
+			t.Errorf("d.Minutes() = %g; want: %g", got, tt.want)
+		}
+	}
+}
+
+var hourDurationTests = []struct {
+	d    Duration
+	want float64
+}{
+	{Duration(-3600000000000), -1},
+	{Duration(-1), -1 / 3600e9},
+	{Duration(1), 1 / 3600e9},
+	{Duration(3600000000000), 1},
+}
+
+func TestDurationHours(t *testing.T) {
+	for _, tt := range hourDurationTests {
+		if got := tt.d.Hours(); got != tt.want {
+			t.Errorf("d.Hours() = %g; want: %g", got, tt.want)
+		}
+	}
+}
+
+func BenchmarkNow(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		t = Now()
+	}
+}
+
+func BenchmarkNowUnixNano(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		u = Now().UnixNano()
+	}
+}
+
+func BenchmarkFormat(b *testing.B) {
+	t := Unix(1265346057, 0)
+	for i := 0; i < b.N; i++ {
+		t.Format("Mon Jan  2 15:04:05 2006")
+	}
+}
+
+func BenchmarkFormatNow(b *testing.B) {
+	// Like BenchmarkFormat, but easier, because the time zone
+	// lookup cache is optimized for the present.
+	t := Now()
+	for i := 0; i < b.N; i++ {
+		t.Format("Mon Jan  2 15:04:05 2006")
+	}
+}
+
+func BenchmarkParse(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		Parse(ANSIC, "Mon Jan  2 15:04:05 2006")
+	}
+}
+
+func BenchmarkHour(b *testing.B) {
+	t := Now()
+	for i := 0; i < b.N; i++ {
+		_ = t.Hour()
+	}
+}
+
+func BenchmarkSecond(b *testing.B) {
+	t := Now()
+	for i := 0; i < b.N; i++ {
+		_ = t.Second()
+	}
+}
+
+func BenchmarkYear(b *testing.B) {
+	t := Now()
+	for i := 0; i < b.N; i++ {
+		_ = t.Year()
+	}
+}
+
+func BenchmarkDay(b *testing.B) {
+	t := Now()
+	for i := 0; i < b.N; i++ {
+		_ = t.Day()
+	}
+}
diff --git a/src/time/zoneinfo.go b/src/time/zoneinfo.go
new file mode 100644
index 000000000..c8e53a27c
--- /dev/null
+++ b/src/time/zoneinfo.go
@@ -0,0 +1,287 @@
+// Copyright 2011 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 (
+	"sync"
+	"syscall"
+)
+
+// A Location maps time instants to the zone in use at that time.
+// Typically, the Location represents the collection of time offsets
+// in use in a geographical area, such as CEST and CET for central Europe.
+type Location struct {
+	name string
+	zone []zone
+	tx   []zoneTrans
+
+	// Most lookups will be for the current time.
+	// To avoid the binary search through tx, keep a
+	// static one-element cache that gives the correct
+	// zone for the time when the Location was created.
+	// if cacheStart <= t <= cacheEnd,
+	// lookup can return cacheZone.
+	// The units for cacheStart and cacheEnd are seconds
+	// since January 1, 1970 UTC, to match the argument
+	// to lookup.
+	cacheStart int64
+	cacheEnd   int64
+	cacheZone  *zone
+}
+
+// A zone represents a single time zone such as CEST or CET.
+type zone struct {
+	name   string // abbreviated name, "CET"
+	offset int    // seconds east of UTC
+	isDST  bool   // is this zone Daylight Savings Time?
+}
+
+// A zoneTrans represents a single time zone transition.
+type zoneTrans struct {
+	when         int64 // transition time, in seconds since 1970 GMT
+	index        uint8 // the index of the zone that goes into effect at that time
+	isstd, isutc bool  // ignored - no idea what these mean
+}
+
+// alpha and omega are the beginning and end of time for zone
+// transitions.
+const (
+	alpha = -1 << 63  // math.MinInt64
+	omega = 1<<63 - 1 // math.MaxInt64
+)
+
+// UTC represents Universal Coordinated Time (UTC).
+var UTC *Location = &utcLoc
+
+// utcLoc is separate so that get can refer to &utcLoc
+// and ensure that it never returns a nil *Location,
+// even if a badly behaved client has changed UTC.
+var utcLoc = Location{name: "UTC"}
+
+// Local represents the system's local time zone.
+var Local *Location = &localLoc
+
+// localLoc is separate so that initLocal can initialize
+// it even if a client has changed Local.
+var localLoc Location
+var localOnce sync.Once
+
+func (l *Location) get() *Location {
+	if l == nil {
+		return &utcLoc
+	}
+	if l == &localLoc {
+		localOnce.Do(initLocal)
+	}
+	return l
+}
+
+// String returns a descriptive name for the time zone information,
+// corresponding to the argument to LoadLocation.
+func (l *Location) String() string {
+	return l.get().name
+}
+
+// FixedZone returns a Location that always uses
+// the given zone name and offset (seconds east of UTC).
+func FixedZone(name string, offset int) *Location {
+	l := &Location{
+		name:       name,
+		zone:       []zone{{name, offset, false}},
+		tx:         []zoneTrans{{alpha, 0, false, false}},
+		cacheStart: alpha,
+		cacheEnd:   omega,
+	}
+	l.cacheZone = &l.zone[0]
+	return l
+}
+
+// lookup returns information about the time zone in use at an
+// instant in time expressed as seconds since January 1, 1970 00:00:00 UTC.
+//
+// The returned information gives the name of the zone (such as "CET"),
+// the start and end times bracketing sec when that zone is in effect,
+// the offset in seconds east of UTC (such as -5*60*60), and whether
+// the daylight savings is being observed at that time.
+func (l *Location) lookup(sec int64) (name string, offset int, isDST bool, start, end int64) {
+	l = l.get()
+
+	if len(l.zone) == 0 {
+		name = "UTC"
+		offset = 0
+		isDST = false
+		start = alpha
+		end = omega
+		return
+	}
+
+	if zone := l.cacheZone; zone != nil && l.cacheStart <= sec && sec < l.cacheEnd {
+		name = zone.name
+		offset = zone.offset
+		isDST = zone.isDST
+		start = l.cacheStart
+		end = l.cacheEnd
+		return
+	}
+
+	if len(l.tx) == 0 || sec < l.tx[0].when {
+		zone := &l.zone[l.lookupFirstZone()]
+		name = zone.name
+		offset = zone.offset
+		isDST = zone.isDST
+		start = alpha
+		if len(l.tx) > 0 {
+			end = l.tx[0].when
+		} else {
+			end = omega
+		}
+		return
+	}
+
+	// Binary search for entry with largest time <= sec.
+	// Not using sort.Search to avoid dependencies.
+	tx := l.tx
+	end = omega
+	lo := 0
+	hi := len(tx)
+	for hi-lo > 1 {
+		m := lo + (hi-lo)/2
+		lim := tx[m].when
+		if sec < lim {
+			end = lim
+			hi = m
+		} else {
+			lo = m
+		}
+	}
+	zone := &l.zone[tx[lo].index]
+	name = zone.name
+	offset = zone.offset
+	isDST = zone.isDST
+	start = tx[lo].when
+	// end = maintained during the search
+	return
+}
+
+// lookupFirstZone returns the index of the time zone to use for times
+// before the first transition time, or when there are no transition
+// times.
+//
+// The reference implementation in localtime.c from
+// http://www.iana.org/time-zones/repository/releases/tzcode2013g.tar.gz
+// implements the following algorithm for these cases:
+// 1) If the first zone is unused by the transitions, use it.
+// 2) Otherwise, if there are transition times, and the first
+//    transition is to a zone in daylight time, find the first
+//    non-daylight-time zone before and closest to the first transition
+//    zone.
+// 3) Otherwise, use the first zone that is not daylight time, if
+//    there is one.
+// 4) Otherwise, use the first zone.
+func (l *Location) lookupFirstZone() int {
+	// Case 1.
+	if !l.firstZoneUsed() {
+		return 0
+	}
+
+	// Case 2.
+	if len(l.tx) > 0 && l.zone[l.tx[0].index].isDST {
+		for zi := int(l.tx[0].index) - 1; zi >= 0; zi-- {
+			if !l.zone[zi].isDST {
+				return zi
+			}
+		}
+	}
+
+	// Case 3.
+	for zi := range l.zone {
+		if !l.zone[zi].isDST {
+			return zi
+		}
+	}
+
+	// Case 4.
+	return 0
+}
+
+// firstZoneUsed returns whether the first zone is used by some
+// transition.
+func (l *Location) firstZoneUsed() bool {
+	for _, tx := range l.tx {
+		if tx.index == 0 {
+			return true
+		}
+	}
+	return false
+}
+
+// lookupName returns information about the time zone with
+// the given name (such as "EST") at the given pseudo-Unix time
+// (what the given time of day would be in UTC).
+func (l *Location) lookupName(name string, unix int64) (offset int, isDST bool, ok bool) {
+	l = l.get()
+
+	// First try for a zone with the right name that was actually
+	// in effect at the given time. (In Sydney, Australia, both standard
+	// and daylight-savings time are abbreviated "EST". Using the
+	// offset helps us pick the right one for the given time.
+	// It's not perfect: during the backward transition we might pick
+	// either one.)
+	for i := range l.zone {
+		zone := &l.zone[i]
+		if zone.name == name {
+			nam, offset, isDST, _, _ := l.lookup(unix - int64(zone.offset))
+			if nam == zone.name {
+				return offset, isDST, true
+			}
+		}
+	}
+
+	// Otherwise fall back to an ordinary name match.
+	for i := range l.zone {
+		zone := &l.zone[i]
+		if zone.name == name {
+			return zone.offset, zone.isDST, true
+		}
+	}
+
+	// Otherwise, give up.
+	return
+}
+
+// NOTE(rsc): Eventually we will need to accept the POSIX TZ environment
+// syntax too, but I don't feel like implementing it today.
+
+var zoneinfo, _ = syscall.Getenv("ZONEINFO")
+
+// LoadLocation returns the Location with the given name.
+//
+// If the name is "" or "UTC", LoadLocation returns UTC.
+// If the name is "Local", LoadLocation returns Local.
+//
+// Otherwise, the name is taken to be a location name corresponding to a file
+// in the IANA Time Zone database, such as "America/New_York".
+//
+// The time zone database needed by LoadLocation may not be
+// present on all systems, especially non-Unix systems.
+// LoadLocation looks in the directory or uncompressed zip file
+// named by the ZONEINFO environment variable, if any, then looks in
+// known installation locations on Unix systems,
+// and finally looks in $GOROOT/lib/time/zoneinfo.zip.
+func LoadLocation(name string) (*Location, error) {
+	if name == "" || name == "UTC" {
+		return UTC, nil
+	}
+	if name == "Local" {
+		return Local, nil
+	}
+	if zoneinfo != "" {
+		if z, err := loadZoneFile(zoneinfo, name); err == nil {
+			z.name = name
+			return z, nil
+		}
+	}
+	return loadLocation(name)
+}
diff --git a/src/time/zoneinfo_abbrs_windows.go b/src/time/zoneinfo_abbrs_windows.go
new file mode 100644
index 000000000..51a1a2f66
--- /dev/null
+++ b/src/time/zoneinfo_abbrs_windows.go
@@ -0,0 +1,116 @@
+// Copyright 2013 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.
+
+// generated by genzabbrs.go from
+// http://unicode.org/cldr/data/common/supplemental/windowsZones.xml
+
+package time
+
+type abbr struct {
+	std string
+	dst string
+}
+
+var abbrs = map[string]abbr{
+	"Egypt Standard Time":             {"EET", "EET"},    // Africa/Cairo
+	"Morocco Standard Time":           {"WET", "WEST"},   // Africa/Casablanca
+	"South Africa Standard Time":      {"SAST", "SAST"},  // Africa/Johannesburg
+	"W. Central Africa Standard Time": {"WAT", "WAT"},    // Africa/Lagos
+	"E. Africa Standard Time":         {"EAT", "EAT"},    // Africa/Nairobi
+	"Libya Standard Time":             {"EET", "EET"},    // Africa/Tripoli
+	"Namibia Standard Time":           {"WAT", "WAST"},   // Africa/Windhoek
+	"Alaskan Standard Time":           {"AKST", "AKDT"},  // America/Anchorage
+	"Paraguay Standard Time":          {"PYT", "PYST"},   // America/Asuncion
+	"Bahia Standard Time":             {"BRT", "BRST"},   // America/Bahia
+	"SA Pacific Standard Time":        {"COT", "COT"},    // America/Bogota
+	"Argentina Standard Time":         {"ART", "ART"},    // America/Buenos_Aires
+	"Venezuela Standard Time":         {"VET", "VET"},    // America/Caracas
+	"SA Eastern Standard Time":        {"GFT", "GFT"},    // America/Cayenne
+	"Central Standard Time":           {"CST", "CDT"},    // America/Chicago
+	"Mountain Standard Time (Mexico)": {"MST", "MDT"},    // America/Chihuahua
+	"Central Brazilian Standard Time": {"AMT", "AMST"},   // America/Cuiaba
+	"Mountain Standard Time":          {"MST", "MDT"},    // America/Denver
+	"Greenland Standard Time":         {"WGT", "WGST"},   // America/Godthab
+	"Central America Standard Time":   {"CST", "CST"},    // America/Guatemala
+	"Atlantic Standard Time":          {"AST", "ADT"},    // America/Halifax
+	"US Eastern Standard Time":        {"EST", "EDT"},    // America/Indianapolis
+	"SA Western Standard Time":        {"BOT", "BOT"},    // America/La_Paz
+	"Pacific Standard Time":           {"PST", "PDT"},    // America/Los_Angeles
+	"Central Standard Time (Mexico)":  {"CST", "CDT"},    // America/Mexico_City
+	"Montevideo Standard Time":        {"UYT", "UYST"},   // America/Montevideo
+	"Eastern Standard Time":           {"EST", "EDT"},    // America/New_York
+	"US Mountain Standard Time":       {"MST", "MST"},    // America/Phoenix
+	"Canada Central Standard Time":    {"CST", "CST"},    // America/Regina
+	"Pacific Standard Time (Mexico)":  {"PST", "PDT"},    // America/Santa_Isabel
+	"Pacific SA Standard Time":        {"CLT", "CLST"},   // America/Santiago
+	"E. South America Standard Time":  {"BRT", "BRST"},   // America/Sao_Paulo
+	"Newfoundland Standard Time":      {"NST", "NDT"},    // America/St_Johns
+	"Central Asia Standard Time":      {"ALMT", "ALMT"},  // Asia/Almaty
+	"Jordan Standard Time":            {"EET", "EEST"},   // Asia/Amman
+	"Arabic Standard Time":            {"AST", "AST"},    // Asia/Baghdad
+	"Azerbaijan Standard Time":        {"AZT", "AZST"},   // Asia/Baku
+	"SE Asia Standard Time":           {"ICT", "ICT"},    // Asia/Bangkok
+	"Middle East Standard Time":       {"EET", "EEST"},   // Asia/Beirut
+	"India Standard Time":             {"IST", "IST"},    // Asia/Calcutta
+	"Sri Lanka Standard Time":         {"IST", "IST"},    // Asia/Colombo
+	"Syria Standard Time":             {"EET", "EEST"},   // Asia/Damascus
+	"Bangladesh Standard Time":        {"BDT", "BDT"},    // Asia/Dhaka
+	"Arabian Standard Time":           {"GST", "GST"},    // Asia/Dubai
+	"North Asia East Standard Time":   {"IRKT", "IRKT"},  // Asia/Irkutsk
+	"Israel Standard Time":            {"IST", "IDT"},    // Asia/Jerusalem
+	"Afghanistan Standard Time":       {"AFT", "AFT"},    // Asia/Kabul
+	"Pakistan Standard Time":          {"PKT", "PKT"},    // Asia/Karachi
+	"Nepal Standard Time":             {"NPT", "NPT"},    // Asia/Katmandu
+	"North Asia Standard Time":        {"KRAT", "KRAT"},  // Asia/Krasnoyarsk
+	"Magadan Standard Time":           {"MAGT", "MAGT"},  // Asia/Magadan
+	"N. Central Asia Standard Time":   {"NOVT", "NOVT"},  // Asia/Novosibirsk
+	"Myanmar Standard Time":           {"MMT", "MMT"},    // Asia/Rangoon
+	"Arab Standard Time":              {"AST", "AST"},    // Asia/Riyadh
+	"Korea Standard Time":             {"KST", "KST"},    // Asia/Seoul
+	"China Standard Time":             {"CST", "CST"},    // Asia/Shanghai
+	"Singapore Standard Time":         {"SGT", "SGT"},    // Asia/Singapore
+	"Taipei Standard Time":            {"CST", "CST"},    // Asia/Taipei
+	"West Asia Standard Time":         {"UZT", "UZT"},    // Asia/Tashkent
+	"Georgian Standard Time":          {"GET", "GET"},    // Asia/Tbilisi
+	"Iran Standard Time":              {"IRST", "IRDT"},  // Asia/Tehran
+	"Tokyo Standard Time":             {"JST", "JST"},    // Asia/Tokyo
+	"Ulaanbaatar Standard Time":       {"ULAT", "ULAT"},  // Asia/Ulaanbaatar
+	"Vladivostok Standard Time":       {"VLAT", "VLAT"},  // Asia/Vladivostok
+	"Yakutsk Standard Time":           {"YAKT", "YAKT"},  // Asia/Yakutsk
+	"Ekaterinburg Standard Time":      {"YEKT", "YEKT"},  // Asia/Yekaterinburg
+	"Caucasus Standard Time":          {"AMT", "AMT"},    // Asia/Yerevan
+	"Azores Standard Time":            {"AZOT", "AZOST"}, // Atlantic/Azores
+	"Cape Verde Standard Time":        {"CVT", "CVT"},    // Atlantic/Cape_Verde
+	"Greenwich Standard Time":         {"GMT", "GMT"},    // Atlantic/Reykjavik
+	"Cen. Australia Standard Time":    {"CST", "CST"},    // Australia/Adelaide
+	"E. Australia Standard Time":      {"EST", "EST"},    // Australia/Brisbane
+	"AUS Central Standard Time":       {"CST", "CST"},    // Australia/Darwin
+	"Tasmania Standard Time":          {"EST", "EST"},    // Australia/Hobart
+	"W. Australia Standard Time":      {"WST", "WST"},    // Australia/Perth
+	"AUS Eastern Standard Time":       {"EST", "EST"},    // Australia/Sydney
+	"UTC":                            {"GMT", "GMT"},       // Etc/GMT
+	"UTC-11":                         {"GMT+11", "GMT+11"}, // Etc/GMT+11
+	"Dateline Standard Time":         {"GMT+12", "GMT+12"}, // Etc/GMT+12
+	"UTC-02":                         {"GMT+2", "GMT+2"},   // Etc/GMT+2
+	"UTC+12":                         {"GMT-12", "GMT-12"}, // Etc/GMT-12
+	"W. Europe Standard Time":        {"CET", "CEST"},      // Europe/Berlin
+	"GTB Standard Time":              {"EET", "EEST"},      // Europe/Bucharest
+	"Central Europe Standard Time":   {"CET", "CEST"},      // Europe/Budapest
+	"Turkey Standard Time":           {"EET", "EEST"},      // Europe/Istanbul
+	"Kaliningrad Standard Time":      {"FET", "FET"},       // Europe/Kaliningrad
+	"FLE Standard Time":              {"EET", "EEST"},      // Europe/Kiev
+	"GMT Standard Time":              {"GMT", "BST"},       // Europe/London
+	"Russian Standard Time":          {"MSK", "MSK"},       // Europe/Moscow
+	"Romance Standard Time":          {"CET", "CEST"},      // Europe/Paris
+	"Central European Standard Time": {"CET", "CEST"},      // Europe/Warsaw
+	"Mauritius Standard Time":        {"MUT", "MUT"},       // Indian/Mauritius
+	"Samoa Standard Time":            {"WST", "WST"},       // Pacific/Apia
+	"New Zealand Standard Time":      {"NZST", "NZDT"},     // Pacific/Auckland
+	"Fiji Standard Time":             {"FJT", "FJT"},       // Pacific/Fiji
+	"Central Pacific Standard Time":  {"SBT", "SBT"},       // Pacific/Guadalcanal
+	"Hawaiian Standard Time":         {"HST", "HST"},       // Pacific/Honolulu
+	"Line Islands Standard Time":     {"LINT", "LINT"},     // Pacific/Kiritimati
+	"West Pacific Standard Time":     {"PGT", "PGT"},       // Pacific/Port_Moresby
+	"Tonga Standard Time":            {"TOT", "TOT"},       // Pacific/Tongatapu
+}
diff --git a/src/time/zoneinfo_plan9.go b/src/time/zoneinfo_plan9.go
new file mode 100644
index 000000000..4bb0cb390
--- /dev/null
+++ b/src/time/zoneinfo_plan9.go
@@ -0,0 +1,160 @@
+// Copyright 2011 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 Plan 9 timezone(2) files.
+
+package time
+
+import (
+	"errors"
+	"runtime"
+	"syscall"
+)
+
+func isSpace(r rune) bool {
+	return r == ' ' || r == '\t' || r == '\n'
+}
+
+// Copied from strings to avoid a dependency.
+func fields(s string) []string {
+	// First count the fields.
+	n := 0
+	inField := false
+	for _, rune := range s {
+		wasInField := inField
+		inField = !isSpace(rune)
+		if inField && !wasInField {
+			n++
+		}
+	}
+
+	// Now create them.
+	a := make([]string, n)
+	na := 0
+	fieldStart := -1 // Set to -1 when looking for start of field.
+	for i, rune := range s {
+		if isSpace(rune) {
+			if fieldStart >= 0 {
+				a[na] = s[fieldStart:i]
+				na++
+				fieldStart = -1
+			}
+		} else if fieldStart == -1 {
+			fieldStart = i
+		}
+	}
+	if fieldStart >= 0 { // Last field might end at EOF.
+		a[na] = s[fieldStart:]
+	}
+	return a
+}
+
+func loadZoneDataPlan9(s string) (l *Location, err error) {
+	f := fields(s)
+	if len(f) < 4 {
+		if len(f) == 2 && f[0] == "GMT" {
+			return UTC, nil
+		}
+		return nil, badData
+	}
+
+	var zones [2]zone
+
+	// standard timezone offset
+	o, err := atoi(f[1])
+	if err != nil {
+		return nil, badData
+	}
+	zones[0] = zone{name: f[0], offset: o, isDST: false}
+
+	// alternate timezone offset
+	o, err = atoi(f[3])
+	if err != nil {
+		return nil, badData
+	}
+	zones[1] = zone{name: f[2], offset: o, isDST: true}
+
+	// transition time pairs
+	var tx []zoneTrans
+	f = f[4:]
+	for i := 0; i < len(f); i++ {
+		zi := 0
+		if i%2 == 0 {
+			zi = 1
+		}
+		t, err := atoi(f[i])
+		if err != nil {
+			return nil, badData
+		}
+		t -= zones[0].offset
+		tx = append(tx, zoneTrans{when: int64(t), index: uint8(zi)})
+	}
+
+	// Committed to succeed.
+	l = &Location{zone: zones[:], tx: tx}
+
+	// Fill in the cache with information about right now,
+	// since that will be the most common lookup.
+	sec, _ := now()
+	for i := range tx {
+		if tx[i].when <= sec && (i+1 == len(tx) || sec < tx[i+1].when) {
+			l.cacheStart = tx[i].when
+			l.cacheEnd = omega
+			if i+1 < len(tx) {
+				l.cacheEnd = tx[i+1].when
+			}
+			l.cacheZone = &l.zone[tx[i].index]
+		}
+	}
+
+	return l, nil
+}
+
+func loadZoneFilePlan9(name string) (*Location, error) {
+	b, err := readFile(name)
+	if err != nil {
+		return nil, err
+	}
+	return loadZoneDataPlan9(string(b))
+}
+
+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() {
+	t, ok := syscall.Getenv("timezone")
+	if ok {
+		if z, err := loadZoneDataPlan9(t); err == nil {
+			localLoc = *z
+			return
+		}
+	} else {
+		if z, err := loadZoneFilePlan9("/adm/timezone/local"); err == nil {
+			localLoc = *z
+			localLoc.name = "Local"
+			return
+		}
+	}
+
+	// Fall back to UTC.
+	localLoc.name = "UTC"
+}
+
+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.
+}
diff --git a/src/time/zoneinfo_read.go b/src/time/zoneinfo_read.go
new file mode 100644
index 000000000..de9ebb41c
--- /dev/null
+++ b/src/time/zoneinfo_read.go
@@ -0,0 +1,343 @@
+// 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.
+
+// Parse "zoneinfo" time zone file.
+// This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.
+// See tzfile(5), http://en.wikipedia.org/wiki/Zoneinfo,
+// and ftp://munnari.oz.au/pub/oldtz/
+
+package time
+
+import "errors"
+
+// Simple I/O interface to binary blob of data.
+type data struct {
+	p     []byte
+	error bool
+}
+
+func (d *data) read(n int) []byte {
+	if len(d.p) < n {
+		d.p = nil
+		d.error = true
+		return nil
+	}
+	p := d.p[0:n]
+	d.p = d.p[n:]
+	return p
+}
+
+func (d *data) big4() (n uint32, ok bool) {
+	p := d.read(4)
+	if len(p) < 4 {
+		d.error = true
+		return 0, false
+	}
+	return uint32(p[0])<<24 | uint32(p[1])<<16 | uint32(p[2])<<8 | uint32(p[3]), true
+}
+
+func (d *data) byte() (n byte, ok bool) {
+	p := d.read(1)
+	if len(p) < 1 {
+		d.error = true
+		return 0, false
+	}
+	return p[0], true
+}
+
+// Make a string by stopping at the first NUL
+func byteString(p []byte) string {
+	for i := 0; i < len(p); i++ {
+		if p[i] == 0 {
+			return string(p[0:i])
+		}
+	}
+	return string(p)
+}
+
+var badData = errors.New("malformed time zone information")
+
+func loadZoneData(bytes []byte) (l *Location, err error) {
+	d := data{bytes, false}
+
+	// 4-byte magic "TZif"
+	if magic := d.read(4); string(magic) != "TZif" {
+		return nil, badData
+	}
+
+	// 1-byte version, then 15 bytes of padding
+	var p []byte
+	if p = d.read(16); len(p) != 16 || p[0] != 0 && p[0] != '2' && p[0] != '3' {
+		return nil, badData
+	}
+
+	// six big-endian 32-bit integers:
+	//	number of UTC/local indicators
+	//	number of standard/wall indicators
+	//	number of leap seconds
+	//	number of transition times
+	//	number of local time zones
+	//	number of characters of time zone abbrev strings
+	const (
+		NUTCLocal = iota
+		NStdWall
+		NLeap
+		NTime
+		NZone
+		NChar
+	)
+	var n [6]int
+	for i := 0; i < 6; i++ {
+		nn, ok := d.big4()
+		if !ok {
+			return nil, badData
+		}
+		n[i] = int(nn)
+	}
+
+	// Transition times.
+	txtimes := data{d.read(n[NTime] * 4), false}
+
+	// Time zone indices for transition times.
+	txzones := d.read(n[NTime])
+
+	// Zone info structures
+	zonedata := data{d.read(n[NZone] * 6), false}
+
+	// Time zone abbreviations.
+	abbrev := d.read(n[NChar])
+
+	// Leap-second time pairs
+	d.read(n[NLeap] * 8)
+
+	// Whether tx times associated with local time types
+	// are specified as standard time or wall time.
+	isstd := d.read(n[NStdWall])
+
+	// Whether tx times associated with local time types
+	// are specified as UTC or local time.
+	isutc := d.read(n[NUTCLocal])
+
+	if d.error { // ran out of data
+		return nil, badData
+	}
+
+	// If version == 2 or 3, the entire file repeats, this time using
+	// 8-byte ints for txtimes and leap seconds.
+	// We won't need those until 2106.
+
+	// Now we can build up a useful data structure.
+	// First the zone information.
+	//	utcoff[4] isdst[1] nameindex[1]
+	zone := make([]zone, n[NZone])
+	for i := range zone {
+		var ok bool
+		var n uint32
+		if n, ok = zonedata.big4(); !ok {
+			return nil, badData
+		}
+		zone[i].offset = int(int32(n))
+		var b byte
+		if b, ok = zonedata.byte(); !ok {
+			return nil, badData
+		}
+		zone[i].isDST = b != 0
+		if b, ok = zonedata.byte(); !ok || int(b) >= len(abbrev) {
+			return nil, badData
+		}
+		zone[i].name = byteString(abbrev[b:])
+	}
+
+	// Now the transition time info.
+	tx := make([]zoneTrans, n[NTime])
+	for i := range tx {
+		var ok bool
+		var n uint32
+		if n, ok = txtimes.big4(); !ok {
+			return nil, badData
+		}
+		tx[i].when = int64(int32(n))
+		if int(txzones[i]) >= len(zone) {
+			return nil, badData
+		}
+		tx[i].index = txzones[i]
+		if i < len(isstd) {
+			tx[i].isstd = isstd[i] != 0
+		}
+		if i < len(isutc) {
+			tx[i].isutc = isutc[i] != 0
+		}
+	}
+
+	if len(tx) == 0 {
+		// Build fake transition to cover all time.
+		// This happens in fixed locations like "Etc/GMT0".
+		tx = append(tx, zoneTrans{when: alpha, index: 0})
+	}
+
+	// Committed to succeed.
+	l = &Location{zone: zone, tx: tx}
+
+	// Fill in the cache with information about right now,
+	// since that will be the most common lookup.
+	sec, _ := now()
+	for i := range tx {
+		if tx[i].when <= sec && (i+1 == len(tx) || sec < tx[i+1].when) {
+			l.cacheStart = tx[i].when
+			l.cacheEnd = omega
+			if i+1 < len(tx) {
+				l.cacheEnd = tx[i+1].when
+			}
+			l.cacheZone = &l.zone[tx[i].index]
+		}
+	}
+
+	return l, nil
+}
+
+func loadZoneFile(dir, name string) (l *Location, err error) {
+	if len(dir) > 4 && dir[len(dir)-4:] == ".zip" {
+		return loadZoneZip(dir, name)
+	}
+	if dir != "" {
+		name = dir + "/" + name
+	}
+	buf, err := readFile(name)
+	if err != nil {
+		return
+	}
+	return loadZoneData(buf)
+}
+
+// There are 500+ zoneinfo files.  Rather than distribute them all
+// individually, we ship them in an uncompressed zip file.
+// Used this way, the zip file format serves as a commonly readable
+// container for the individual small files.  We choose zip over tar
+// because zip files have a contiguous table of contents, making
+// individual file lookups faster, and because the per-file overhead
+// in a zip file is considerably less than tar's 512 bytes.
+
+// get4 returns the little-endian 32-bit value in b.
+func get4(b []byte) int {
+	if len(b) < 4 {
+		return 0
+	}
+	return int(b[0]) | int(b[1])<<8 | int(b[2])<<16 | int(b[3])<<24
+}
+
+// get2 returns the little-endian 16-bit value in b.
+func get2(b []byte) int {
+	if len(b) < 2 {
+		return 0
+	}
+	return int(b[0]) | int(b[1])<<8
+}
+
+func loadZoneZip(zipfile, name string) (l *Location, err error) {
+	fd, err := open(zipfile)
+	if err != nil {
+		return nil, errors.New("open " + zipfile + ": " + err.Error())
+	}
+	defer closefd(fd)
+
+	const (
+		zecheader = 0x06054b50
+		zcheader  = 0x02014b50
+		ztailsize = 22
+
+		zheadersize = 30
+		zheader     = 0x04034b50
+	)
+
+	buf := make([]byte, ztailsize)
+	if err := preadn(fd, buf, -ztailsize); err != nil || get4(buf) != zecheader {
+		return nil, errors.New("corrupt zip file " + zipfile)
+	}
+	n := get2(buf[10:])
+	size := get4(buf[12:])
+	off := get4(buf[16:])
+
+	buf = make([]byte, size)
+	if err := preadn(fd, buf, off); err != nil {
+		return nil, errors.New("corrupt zip file " + zipfile)
+	}
+
+	for i := 0; i < n; i++ {
+		// zip entry layout:
+		//	0	magic[4]
+		//	4	madevers[1]
+		//	5	madeos[1]
+		//	6	extvers[1]
+		//	7	extos[1]
+		//	8	flags[2]
+		//	10	meth[2]
+		//	12	modtime[2]
+		//	14	moddate[2]
+		//	16	crc[4]
+		//	20	csize[4]
+		//	24	uncsize[4]
+		//	28	namelen[2]
+		//	30	xlen[2]
+		//	32	fclen[2]
+		//	34	disknum[2]
+		//	36	iattr[2]
+		//	38	eattr[4]
+		//	42	off[4]
+		//	46	name[namelen]
+		//	46+namelen+xlen+fclen - next header
+		//
+		if get4(buf) != zcheader {
+			break
+		}
+		meth := get2(buf[10:])
+		size := get4(buf[24:])
+		namelen := get2(buf[28:])
+		xlen := get2(buf[30:])
+		fclen := get2(buf[32:])
+		off := get4(buf[42:])
+		zname := buf[46 : 46+namelen]
+		buf = buf[46+namelen+xlen+fclen:]
+		if string(zname) != name {
+			continue
+		}
+		if meth != 0 {
+			return nil, errors.New("unsupported compression for " + name + " in " + zipfile)
+		}
+
+		// zip per-file header layout:
+		//	0	magic[4]
+		//	4	extvers[1]
+		//	5	extos[1]
+		//	6	flags[2]
+		//	8	meth[2]
+		//	10	modtime[2]
+		//	12	moddate[2]
+		//	14	crc[4]
+		//	18	csize[4]
+		//	22	uncsize[4]
+		//	26	namelen[2]
+		//	28	xlen[2]
+		//	30	name[namelen]
+		//	30+namelen+xlen - file data
+		//
+		buf = make([]byte, zheadersize+namelen)
+		if err := preadn(fd, buf, off); err != nil ||
+			get4(buf) != zheader ||
+			get2(buf[8:]) != meth ||
+			get2(buf[26:]) != namelen ||
+			string(buf[30:30+namelen]) != name {
+			return nil, errors.New("corrupt zip file " + zipfile)
+		}
+		xlen = get2(buf[28:])
+
+		buf = make([]byte, size)
+		if err := preadn(fd, buf, off+30+namelen+xlen); err != nil {
+			return nil, errors.New("corrupt zip file " + zipfile)
+		}
+
+		return loadZoneData(buf)
+	}
+
+	return nil, errors.New("cannot find " + name + " in zip file " + zipfile)
+}
diff --git a/src/time/zoneinfo_test.go b/src/time/zoneinfo_test.go
new file mode 100644
index 000000000..4ca7fad93
--- /dev/null
+++ b/src/time/zoneinfo_test.go
@@ -0,0 +1,63 @@
+// Copyright 2014 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_test
+
+import (
+	"testing"
+	"time"
+)
+
+func TestVersion3(t *testing.T) {
+	time.ForceZipFileForTesting(true)
+	defer time.ForceZipFileForTesting(false)
+	_, err := time.LoadLocation("Asia/Jerusalem")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Test that we get the correct results for times before the first
+// transition time.  To do this we explicitly check early dates in a
+// couple of specific timezones.
+func TestFirstZone(t *testing.T) {
+	time.ForceZipFileForTesting(true)
+	defer time.ForceZipFileForTesting(false)
+
+	const format = "Mon, 02 Jan 2006 15:04:05 -0700 (MST)"
+	var tests = []struct {
+		zone  string
+		unix  int64
+		want1 string
+		want2 string
+	}{
+		{
+			"PST8PDT",
+			-1633269601,
+			"Sun, 31 Mar 1918 01:59:59 -0800 (PST)",
+			"Sun, 31 Mar 1918 03:00:00 -0700 (PDT)",
+		},
+		{
+			"Pacific/Fakaofo",
+			1325242799,
+			"Thu, 29 Dec 2011 23:59:59 -1100 (TKT)",
+			"Sat, 31 Dec 2011 00:00:00 +1300 (TKT)",
+		},
+	}
+
+	for _, test := range tests {
+		z, err := time.LoadLocation(test.zone)
+		if err != nil {
+			t.Fatal(err)
+		}
+		s := time.Unix(test.unix, 0).In(z).Format(format)
+		if s != test.want1 {
+			t.Errorf("for %s %d got %q want %q", test.zone, test.unix, s, test.want1)
+		}
+		s = time.Unix(test.unix+1, 0).In(z).Format(format)
+		if s != test.want2 {
+			t.Errorf("for %s %d got %q want %q", test.zone, test.unix, s, test.want2)
+		}
+	}
+}
diff --git a/src/time/zoneinfo_unix.go b/src/time/zoneinfo_unix.go
new file mode 100644
index 000000000..ab7e4612e
--- /dev/null
+++ b/src/time/zoneinfo_unix.go
@@ -0,0 +1,84 @@
+// 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.
+
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+
+// Parse "zoneinfo" time zone file.
+// This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.
+// See tzfile(5), http://en.wikipedia.org/wiki/Zoneinfo,
+// and ftp://munnari.oz.au/pub/oldtz/
+
+package time
+
+import (
+	"errors"
+	"runtime"
+	"syscall"
+)
+
+func initTestingZone() {
+	z, err := loadZoneFile(runtime.GOROOT()+"/lib/time/zoneinfo.zip", "America/Los_Angeles")
+	if err != nil {
+		panic("cannot load America/Los_Angeles for testing: " + err.Error())
+	}
+	z.name = "Local"
+	localLoc = *z
+}
+
+// Many systems use /usr/share/zoneinfo, Solaris 2 has
+// /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ.
+var zoneDirs = []string{
+	"/usr/share/zoneinfo/",
+	"/usr/share/lib/zoneinfo/",
+	"/usr/lib/locale/TZ/",
+	runtime.GOROOT() + "/lib/time/zoneinfo.zip",
+}
+
+var origZoneDirs = zoneDirs
+
+func forceZipFileForTesting(zipOnly bool) {
+	zoneDirs = make([]string, len(origZoneDirs))
+	copy(zoneDirs, origZoneDirs)
+	if zipOnly {
+		for i := 0; i < len(zoneDirs)-1; i++ {
+			zoneDirs[i] = "/XXXNOEXIST"
+		}
+	}
+}
+
+func initLocal() {
+	// consult $TZ to find the time zone to use.
+	// no $TZ means use the system default /etc/localtime.
+	// $TZ="" means use UTC.
+	// $TZ="foo" means use /usr/share/zoneinfo/foo.
+
+	tz, ok := syscall.Getenv("TZ")
+	switch {
+	case !ok:
+		z, err := loadZoneFile("", "/etc/localtime")
+		if err == nil {
+			localLoc = *z
+			localLoc.name = "Local"
+			return
+		}
+	case tz != "" && tz != "UTC":
+		if z, err := loadLocation(tz); err == nil {
+			localLoc = *z
+			return
+		}
+	}
+
+	// Fall back to UTC.
+	localLoc.name = "UTC"
+}
+
+func loadLocation(name string) (*Location, error) {
+	for _, zoneDir := range zoneDirs {
+		if z, err := loadZoneFile(zoneDir, name); err == nil {
+			z.name = name
+			return z, nil
+		}
+	}
+	return nil, errors.New("unknown time zone " + name)
+}
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.
+}
diff --git a/src/time/zoneinfo_windows_test.go b/src/time/zoneinfo_windows_test.go
new file mode 100644
index 000000000..9db81b7cf
--- /dev/null
+++ b/src/time/zoneinfo_windows_test.go
@@ -0,0 +1,35 @@
+// Copyright 2013 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_test
+
+import (
+	"testing"
+	. "time"
+)
+
+func testZoneAbbr(t *testing.T) {
+	t1 := Now()
+	// discard nsec
+	t1 = Date(t1.Year(), t1.Month(), t1.Day(), t1.Hour(), t1.Minute(), t1.Second(), 0, t1.Location())
+	t2, err := Parse(RFC1123, t1.Format(RFC1123))
+	if err != nil {
+		t.Fatalf("Parse failed: %v", err)
+	}
+	if t1 != t2 {
+		t.Fatalf("t1 (%v) is not equal to t2 (%v)", t1, t2)
+	}
+}
+
+func TestLocalZoneAbbr(t *testing.T) {
+	ResetLocalOnceForTest() // reset the Once to trigger the race
+	defer ForceUSPacificForTesting()
+	testZoneAbbr(t)
+}
+
+func TestAusZoneAbbr(t *testing.T) {
+	ForceAusForTesting()
+	defer ForceUSPacificForTesting()
+	testZoneAbbr(t)
+}