libgo: Update to weekly.2011-11-18.

From-SVN: r182266

11 files changed, 233 insertions, 355 deletions

diff --git a/libgo/go/time/sleep.go b/libgo/go/time/sleep.go
index 314622d0dc9..967fca09b99 100644
--- a/libgo/go/time/sleep.go
+++ b/libgo/go/time/sleep.go
@@ -4,54 +4,60 @@
 
 package time
 
-import (
-	"container/heap"
-	"sync"
-)
+// Interface to timers implemented in package runtime.
+// Must be in sync with ../runtime/runtime.h:/^struct.Timer$
+type runtimeTimer struct {
+	i      int32
+	when   int64
+	period int64
+	f      func(int64, interface{})
+	arg    interface{}
+}
+
+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 represents an AfterFunc event.
+// When the Timer expires, the current time will be sent on C,
+// unless the Timer was created by AfterFunc.
 type Timer struct {
 	C <-chan int64
-	t int64       // The absolute time that the event should fire.
-	f func(int64) // The function to call when the event fires.
-	i int         // The event's index inside eventHeap.
+	r runtimeTimer
 }
 
-type timerHeap []*Timer
-
-// forever is the absolute time (in ns) of an event that is forever away.
-const forever = 1 << 62
-
-// maxSleepTime is the maximum length of time that a sleeper
-// sleeps for before checking if it is defunct.
-const maxSleepTime = 1e9
-
-var (
-	// timerMutex guards the variables inside this var group.
-	timerMutex sync.Mutex
-
-	// timers holds a binary heap of pending events, terminated with a sentinel.
-	timers timerHeap
-
-	// currentSleeper is an ever-incrementing counter which represents
-	// the current sleeper. It allows older sleepers to detect that they are
-	// defunct and exit.
-	currentSleeper int64
-)
-
-func init() {
-	timers.Push(&Timer{t: forever}) // sentinel
+// Stop prevents the Timer from firing.
+// It returns true if the call stops the timer, false if the timer has already
+// expired or stopped.
+func (t *Timer) Stop() (ok bool) {
+	return stopTimer(&t.r)
 }
 
 // NewTimer creates a new Timer that will send
 // the current time on its channel after at least ns nanoseconds.
 func NewTimer(ns int64) *Timer {
 	c := make(chan int64, 1)
-	e := after(ns, func(t int64) { c <- t })
-	e.C = c
-	return e
+	t := &Timer{
+		C: c,
+		r: runtimeTimer{
+			when: Nanoseconds() + ns,
+			f:    sendTime,
+			arg:  c,
+		},
+	}
+	startTimer(&t.r)
+	return t
+}
+
+func sendTime(now int64, c interface{}) {
+	// 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 int64) <- now:
+	default:
+	}
 }
 
 // After waits at least ns nanoseconds before sending the current time
@@ -65,113 +71,17 @@ func After(ns int64) <-chan int64 {
 // in its own goroutine. It returns a Timer that can
 // be used to cancel the call using its Stop method.
 func AfterFunc(ns int64, f func()) *Timer {
-	return after(ns, func(_ int64) {
-		go f()
-	})
-}
-
-// Stop prevents the Timer from firing.
-// It returns true if the call stops the timer, false if the timer has already
-// expired or stopped.
-func (e *Timer) Stop() (ok bool) {
-	timerMutex.Lock()
-	// Avoid removing the first event in the queue so that
-	// we don't start a new sleeper unnecessarily.
-	if e.i > 0 {
-		heap.Remove(timers, e.i)
-	}
-	ok = e.f != nil
-	e.f = nil
-	timerMutex.Unlock()
-	return
-}
-
-// after is the implementation of After and AfterFunc.
-// When the current time is after ns, it calls f with the current time.
-// It assumes that f will not block.
-func after(ns int64, f func(int64)) (e *Timer) {
-	now := Nanoseconds()
-	t := now + ns
-	if ns > 0 && t < now {
-		panic("time: time overflow")
-	}
-	timerMutex.Lock()
-	t0 := timers[0].t
-	e = &Timer{nil, t, f, -1}
-	heap.Push(timers, e)
-	// Start a new sleeper if the new event is before
-	// the first event in the queue. If the length of time
-	// until the new event is at least maxSleepTime,
-	// then we're guaranteed that the sleeper will wake up
-	// in time to service it, so no new sleeper is needed.
-	if t0 > t && (t0 == forever || ns < maxSleepTime) {
-		currentSleeper++
-		go sleeper(currentSleeper)
-	}
-	timerMutex.Unlock()
-	return
-}
-
-// sleeper continually looks at the earliest event in the queue, waits until it happens,
-// then removes any events in the queue that are due. It stops when the queue
-// is empty or when another sleeper has been started.
-func sleeper(sleeperId int64) {
-	timerMutex.Lock()
-	e := timers[0]
-	t := Nanoseconds()
-	for e.t != forever {
-		if dt := e.t - t; dt > 0 {
-			if dt > maxSleepTime {
-				dt = maxSleepTime
-			}
-			timerMutex.Unlock()
-			sysSleep(dt)
-			timerMutex.Lock()
-			if currentSleeper != sleeperId {
-				// Another sleeper has been started, making this one redundant.
-				break
-			}
-		}
-		e = timers[0]
-		t = Nanoseconds()
-		for t >= e.t {
-			if e.f != nil {
-				e.f(t)
-				e.f = nil
-			}
-			heap.Pop(timers)
-			e = timers[0]
-		}
+	t := &Timer{
+		r: runtimeTimer{
+			when: Nanoseconds() + ns,
+			f:    goFunc,
+			arg:  f,
+		},
 	}
-	timerMutex.Unlock()
-}
-
-func (timerHeap) Len() int {
-	return len(timers)
-}
-
-func (timerHeap) Less(i, j int) bool {
-	return timers[i].t < timers[j].t
-}
-
-func (timerHeap) Swap(i, j int) {
-	timers[i], timers[j] = timers[j], timers[i]
-	timers[i].i = i
-	timers[j].i = j
-}
-
-func (timerHeap) Push(x interface{}) {
-	e := x.(*Timer)
-	e.i = len(timers)
-	timers = append(timers, e)
+	startTimer(&t.r)
+	return t
 }
 
-func (timerHeap) Pop() interface{} {
-	// TODO: possibly shrink array.
-	n := len(timers) - 1
-	e := timers[n]
-	timers[n] = nil
-	timers = timers[0:n]
-	e.i = -1
-	return e
+func goFunc(now int64, arg interface{}) {
+	go arg.(func())()
 }
diff --git a/libgo/go/time/sleep_test.go b/libgo/go/time/sleep_test.go
index 0662e3359cf..9171da3af1c 100644
--- a/libgo/go/time/sleep_test.go
+++ b/libgo/go/time/sleep_test.go
@@ -7,7 +7,9 @@ package time_test
 import (
 	"errors"
 	"fmt"
+	"runtime"
 	"sort"
+	"sync/atomic"
 	"testing"
 	. "time"
 )
@@ -47,6 +49,23 @@ func TestAfterFunc(t *testing.T) {
 	<-c
 }
 
+func TestAfterStress(t *testing.T) {
+	stop := uint32(0)
+	go func() {
+		for atomic.LoadUint32(&stop) == 0 {
+			runtime.GC()
+			// Need to yield, because otherwise
+			// the main goroutine will never set the stop flag.
+			runtime.Gosched()
+		}
+	}()
+	c := Tick(1)
+	for i := 0; i < 100; i++ {
+		<-c
+	}
+	atomic.StoreUint32(&stop, 1)
+}
+
 func BenchmarkAfterFunc(b *testing.B) {
 	i := b.N
 	c := make(chan bool)
diff --git a/libgo/go/time/sys.go b/libgo/go/time/sys.go
index ca1d334a5b7..a5e529b814a 100644
--- a/libgo/go/time/sys.go
+++ b/libgo/go/time/sys.go
@@ -17,25 +17,4 @@ func Seconds() int64 {
 func Nanoseconds() int64
 
 // Sleep pauses the current goroutine for at least ns nanoseconds.
-// Higher resolution sleeping may be provided by syscall.Nanosleep 
-// on some operating systems.
-func Sleep(ns int64) error {
-	_, err := sleep(Nanoseconds(), ns)
-	return err
-}
-
-// sleep takes the current time and a duration,
-// pauses for at least ns nanoseconds, and
-// returns the current time and an error.
-func sleep(t, ns int64) (int64, error) {
-	// TODO(cw): use monotonic-time once it's available
-	end := t + ns
-	for t < end {
-		err := sysSleep(end - t)
-		if err != nil {
-			return 0, err
-		}
-		t = Nanoseconds()
-	}
-	return t, nil
-}
+func Sleep(ns int64)
diff --git a/libgo/go/time/sys_plan9.go b/libgo/go/time/sys_plan9.go
index a630b3ee030..e58fb519ea3 100644
--- a/libgo/go/time/sys_plan9.go
+++ b/libgo/go/time/sys_plan9.go
@@ -4,19 +4,6 @@
 
 package time
 
-import (
-	"os"
-	"syscall"
-)
-
-func sysSleep(t int64) error {
-	err := syscall.Sleep(t)
-	if err != nil {
-		return os.NewSyscallError("sleep", err)
-	}
-	return nil
-}
-
 // for testing: whatever interrupts a sleep
 func interrupt() {
 	// cannot predict pid, don't want to kill group
diff --git a/libgo/go/time/sys_unix.go b/libgo/go/time/sys_unix.go
index 17a6a2d63e0..3d313228b01 100644
--- a/libgo/go/time/sys_unix.go
+++ b/libgo/go/time/sys_unix.go
@@ -11,14 +11,6 @@ import (
 	"syscall"
 )
 
-func sysSleep(t int64) error {
-	errno := syscall.Sleep(t)
-	if errno != 0 && errno != syscall.EINTR {
-		return os.NewSyscallError("sleep", errno)
-	}
-	return nil
-}
-
 // for testing: whatever interrupts a sleep
 func interrupt() {
 	syscall.Kill(os.Getpid(), syscall.SIGCHLD)
diff --git a/libgo/go/time/sys_windows.go b/libgo/go/time/sys_windows.go
index f9d6e89281c..8c7242f4275 100644
--- a/libgo/go/time/sys_windows.go
+++ b/libgo/go/time/sys_windows.go
@@ -4,19 +4,6 @@
 
 package time
 
-import (
-	"os"
-	"syscall"
-)
-
-func sysSleep(t int64) error {
-	errno := syscall.Sleep(t)
-	if errno != 0 && errno != syscall.EINTR {
-		return os.NewSyscallError("sleep", errno)
-	}
-	return nil
-}
-
 // for testing: whatever interrupts a sleep
 func interrupt() {
 }
diff --git a/libgo/go/time/tick.go b/libgo/go/time/tick.go
index 92f9eb893e4..95941a1e819 100644
--- a/libgo/go/time/tick.go
+++ b/libgo/go/time/tick.go
@@ -4,156 +4,15 @@
 
 package time
 
-import (
-	"errors"
-	"sync"
-)
+import "errors"
 
 // A Ticker holds a synchronous channel that delivers `ticks' of a clock
 // at intervals.
 type Ticker struct {
-	C        <-chan int64 // The channel on which the ticks are delivered.
-	c        chan<- int64 // The same channel, but the end we use.
-	ns       int64
-	shutdown chan bool // Buffered channel used to signal shutdown.
-	nextTick int64
-	next     *Ticker
+	C <-chan int64 // The channel on which the ticks are delivered.
+	r runtimeTimer
 }
 
-// Stop turns off a ticker.  After Stop, no more ticks will be sent.
-func (t *Ticker) Stop() {
-	select {
-	case t.shutdown <- true:
-		// ok
-	default:
-		// Stop in progress already
-	}
-}
-
-// 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(ns int64) <-chan int64 {
-	if ns <= 0 {
-		return nil
-	}
-	return NewTicker(ns).C
-}
-
-type alarmer struct {
-	wakeUp   chan bool // wakeup signals sent/received here
-	wakeMeAt chan int64
-	wakeTime int64
-}
-
-// Set alarm to go off at time ns, if not already set earlier.
-func (a *alarmer) set(ns int64) {
-	switch {
-	case a.wakeTime > ns:
-		// Next tick we expect is too late; shut down the late runner
-		// and (after fallthrough) start a new wakeLoop.
-		close(a.wakeMeAt)
-		fallthrough
-	case a.wakeMeAt == nil:
-		// There's no wakeLoop, start one.
-		a.wakeMeAt = make(chan int64)
-		a.wakeUp = make(chan bool, 1)
-		go wakeLoop(a.wakeMeAt, a.wakeUp)
-		fallthrough
-	case a.wakeTime == 0:
-		// Nobody else is waiting; it's just us.
-		a.wakeTime = ns
-		a.wakeMeAt <- ns
-	default:
-		// There's already someone scheduled.
-	}
-}
-
-// Channel to notify tickerLoop of new Tickers being created.
-var newTicker chan *Ticker
-
-func startTickerLoop() {
-	newTicker = make(chan *Ticker)
-	go tickerLoop()
-}
-
-// wakeLoop delivers ticks at scheduled times, sleeping until the right moment.
-// If another, earlier Ticker is created while it sleeps, tickerLoop() will start a new
-// wakeLoop and signal that this one is done by closing the wakeMeAt channel.
-func wakeLoop(wakeMeAt chan int64, wakeUp chan bool) {
-	for wakeAt := range wakeMeAt {
-		Sleep(wakeAt - Nanoseconds())
-		wakeUp <- true
-	}
-}
-
-// A single tickerLoop serves all ticks to Tickers.  It waits for two events:
-// either the creation of a new Ticker or a tick from the alarm,
-// signaling a time to wake up one or more Tickers.
-func tickerLoop() {
-	// Represents the next alarm to be delivered.
-	var alarm alarmer
-	var now, wakeTime int64
-	var tickers *Ticker
-	for {
-		select {
-		case t := <-newTicker:
-			// Add Ticker to list
-			t.next = tickers
-			tickers = t
-			// Arrange for a new alarm if this one precedes the existing one.
-			alarm.set(t.nextTick)
-		case <-alarm.wakeUp:
-			now = Nanoseconds()
-			wakeTime = now + 1e15 // very long in the future
-			var prev *Ticker = nil
-			// Scan list of tickers, delivering updates to those
-			// that need it and determining the next wake time.
-			// TODO(r): list should be sorted in time order.
-			for t := tickers; t != nil; t = t.next {
-				select {
-				case <-t.shutdown:
-					// Ticker is done; remove it from list.
-					if prev == nil {
-						tickers = t.next
-					} else {
-						prev.next = t.next
-					}
-					continue
-				default:
-				}
-				if t.nextTick <= now {
-					if len(t.c) == 0 {
-						// Only send if there's room.  We must not block.
-						// The channel is allocated with a one-element
-						// buffer, which is sufficient: if he hasn't picked
-						// up the last tick, no point in sending more.
-						t.c <- now
-					}
-					t.nextTick += t.ns
-					if t.nextTick <= now {
-						// Still behind; advance in one big step.
-						t.nextTick += (now - t.nextTick + t.ns) / t.ns * t.ns
-					}
-				}
-				if t.nextTick < wakeTime {
-					wakeTime = t.nextTick
-				}
-				prev = t
-			}
-			if tickers != nil {
-				// Please send wakeup at earliest required time.
-				// If there are no tickers, don't bother.
-				alarm.wakeTime = wakeTime
-				alarm.wakeMeAt <- wakeTime
-			} else {
-				alarm.wakeTime = 0
-			}
-		}
-	}
-}
-
-var onceStartTickerLoop sync.Once
-
 // NewTicker returns a new Ticker containing a channel that will
 // send the time, in nanoseconds, every ns nanoseconds.  It adjusts the
 // intervals to make up for pauses in delivery of the ticks. The value of
@@ -162,16 +21,33 @@ func NewTicker(ns int64) *Ticker {
 	if ns <= 0 {
 		panic(errors.New("non-positive interval for NewTicker"))
 	}
-	c := make(chan int64, 1) //  See comment on send in tickerLoop
+	// 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 int64, 1)
 	t := &Ticker{
-		C:        c,
-		c:        c,
-		ns:       ns,
-		shutdown: make(chan bool, 1),
-		nextTick: Nanoseconds() + ns,
+		C: c,
+		r: runtimeTimer{
+			when:   Nanoseconds() + ns,
+			period: ns,
+			f:      sendTime,
+			arg:    c,
+		},
 	}
-	onceStartTickerLoop.Do(startTickerLoop)
-	// must be run in background so global Tickers can be created
-	go func() { newTicker <- t }()
+	startTimer(&t.r)
 	return t
 }
+
+// Stop turns off a ticker.  After Stop, no more ticks will be sent.
+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(ns int64) <-chan int64 {
+	if ns <= 0 {
+		return nil
+	}
+	return NewTicker(ns).C
+}
diff --git a/libgo/go/time/time.go b/libgo/go/time/time.go
index 859b3167278..e11d17731b4 100644
--- a/libgo/go/time/time.go
+++ b/libgo/go/time/time.go
@@ -237,3 +237,63 @@ func (t *Time) Weekday() int {
 	}
 	return weekday
 }
+
+// julianDayNumber returns the time's Julian Day Number
+// relative to the epoch 12:00 January 1, 4713 BC, Monday.
+func julianDayNumber(year int64, month, day int) int64 {
+	a := int64(14-month) / 12
+	y := year + 4800 - a
+	m := int64(month) + 12*a - 3
+	return int64(day) + (153*m+2)/5 + 365*y + y/4 - y/100 + y/400 - 32045
+}
+
+// startOfFirstWeek returns the julian day number of the first day
+// of the first week of the given year.
+func startOfFirstWeek(year int64) (d int64) {
+	jan01 := julianDayNumber(year, 1, 1)
+	weekday := (jan01 % 7) + 1
+	if weekday <= 4 {
+		d = jan01 - weekday + 1
+	} else {
+		d = jan01 + 8 - weekday
+	}
+	return
+}
+
+// dayOfWeek returns the weekday of the given date.
+func dayOfWeek(year int64, month, day int) int {
+	t := Time{Year: year, Month: month, Day: day}
+	return t.Weekday()
+}
+
+// ISOWeek returns the time's year and week number according to ISO 8601. 
+// 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 int64, week int) {
+	d := julianDayNumber(t.Year, t.Month, t.Day)
+	week1Start := startOfFirstWeek(t.Year)
+
+	if d < week1Start {
+		// Previous year, week 52 or 53
+		year = t.Year - 1
+		if dayOfWeek(t.Year-1, 1, 1) == 4 || dayOfWeek(t.Year-1, 12, 31) == 4 {
+			week = 53
+		} else {
+			week = 52
+		}
+		return
+	}
+
+	if d < startOfFirstWeek(t.Year+1) {
+		// Current year, week 01..52(,53)
+		year = t.Year
+		week = int((d-week1Start)/7 + 1)
+		return
+	}
+
+	// Next year, week 1
+	year = t.Year + 1
+	week = 1
+	return
+}
diff --git a/libgo/go/time/time_test.go b/libgo/go/time/time_test.go
index 8b373a13bc2..01b8bea4aad 100644
--- a/libgo/go/time/time_test.go
+++ b/libgo/go/time/time_test.go
@@ -478,6 +478,68 @@ func TestMinutesInTimeZone(t *testing.T) {
 	}
 }
 
+type ISOWeekTest struct {
+	year       int64 // year
+	month, day int   // month and day
+	yex        int64 // 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 := &Time{Year: wt.year, Month: wt.month, Day: wt.day}
+		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 := int64(1950); year < 2100; year++ {
+		if y, w := (&Time{Year: year, Month: 1, Day: 4}).ISOWeek(); y != year || w != 1 {
+			t.Errorf("got %d/%d; expected %d/1 for Jan 04", y, w, year)
+		}
+	}
+}
+
 func BenchmarkSeconds(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		Seconds()
diff --git a/libgo/go/time/zoneinfo_unix.go b/libgo/go/time/zoneinfo_unix.go
index 0dc42353136..b552e589aa9 100644
--- a/libgo/go/time/zoneinfo_unix.go
+++ b/libgo/go/time/zoneinfo_unix.go
@@ -12,7 +12,7 @@
 package time
 
 import (
-	"io/ioutil"
+	"bytes"
 	"os"
 )
 
@@ -180,11 +180,17 @@ func parseinfo(bytes []byte) (zt []zonetime, ok bool) {
 }
 
 func readinfofile(name string) ([]zonetime, bool) {
-	buf, err := ioutil.ReadFile(name)
+	var b bytes.Buffer
+
+	f, err := os.Open(name)
 	if err != nil {
 		return nil, false
 	}
-	return parseinfo(buf)
+	defer f.Close()
+	if _, err := b.ReadFrom(f); err != nil {
+		return nil, false
+	}
+	return parseinfo(b.Bytes())
 }
 
 func setupTestingZone() {
diff --git a/libgo/go/time/zoneinfo_windows.go b/libgo/go/time/zoneinfo_windows.go
index ba152e0882a..995fd44dc06 100644
--- a/libgo/go/time/zoneinfo_windows.go
+++ b/libgo/go/time/zoneinfo_windows.go
@@ -161,7 +161,7 @@ var onceSetupZone sync.Once
 
 func setupZone() {
 	var i syscall.Timezoneinformation
-	if _, e := syscall.GetTimeZoneInformation(&i); e != 0 {
+	if _, e := syscall.GetTimeZoneInformation(&i); e != nil {
 		initError = os.NewSyscallError("GetTimeZoneInformation", e)
 		return
 	}