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path: root/src/pkg/time/time.go
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Diffstat (limited to 'src/pkg/time/time.go')
-rw-r--r--src/pkg/time/time.go124
1 files changed, 90 insertions, 34 deletions
diff --git a/src/pkg/time/time.go b/src/pkg/time/time.go
index d291672af..c504df740 100644
--- a/src/pkg/time/time.go
+++ b/src/pkg/time/time.go
@@ -39,7 +39,14 @@ type Time struct {
// nsec specifies a non-negative nanosecond
// offset within the second named by Seconds.
// It must be in the range [0, 999999999].
- nsec int32
+ //
+ // It is declared as uintptr instead of int32 or uint32
+ // to avoid garbage collector aliasing in the case where
+ // on a 64-bit system the int32 or uint32 field is written
+ // over the low half of a pointer, creating another pointer.
+ // TODO(rsc): When the garbage collector is completely
+ // precise, change back to int32.
+ nsec uintptr
// loc specifies the Location that should be used to
// determine the minute, hour, month, day, and year
@@ -424,6 +431,11 @@ func (t Time) YearDay() int {
// 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.
//
@@ -600,21 +612,33 @@ func (d Duration) Hours() float64 {
// Add returns the time t+d.
func (t Time) Add(d Duration) Time {
t.sec += int64(d / 1e9)
- t.nsec += int32(d % 1e9)
- if t.nsec >= 1e9 {
+ nsec := int32(t.nsec) + int32(d%1e9)
+ if nsec >= 1e9 {
t.sec++
- t.nsec -= 1e9
- } else if t.nsec < 0 {
+ nsec -= 1e9
+ } else if nsec < 0 {
t.sec--
- t.nsec += 1e9
+ nsec += 1e9
}
+ t.nsec = uintptr(nsec)
return t
}
-// Sub returns the duration t-u.
+// 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 {
- return Duration(t.sec-u.sec)*Second + Duration(t.nsec-u.nsec)
+ 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.
@@ -645,7 +669,6 @@ const (
daysPer400Years = 365*400 + 97
daysPer100Years = 365*100 + 24
daysPer4Years = 365*4 + 1
- days1970To2001 = 31*365 + 8
)
// date computes the year, day of year, and when full=true,
@@ -760,7 +783,7 @@ func now() (sec int64, nsec int32)
// Now returns the current local time.
func Now() Time {
sec, nsec := now()
- return Time{sec + unixToInternal, nsec, Local}
+ return Time{sec + unixToInternal, uintptr(nsec), Local}
}
// UTC returns t with the location set to UTC.
@@ -816,10 +839,10 @@ func (t Time) UnixNano() int64 {
return (t.sec+internalToUnix)*1e9 + int64(t.nsec)
}
-const timeGobVersion byte = 1
+const timeBinaryVersion byte = 1
-// GobEncode implements the gob.GobEncoder interface.
-func (t Time) GobEncode() ([]byte, error) {
+// 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 {
@@ -827,17 +850,17 @@ func (t Time) GobEncode() ([]byte, error) {
} else {
_, offset := t.Zone()
if offset%60 != 0 {
- return nil, errors.New("Time.GobEncode: zone offset has fractional minute")
+ 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.GobEncode: unexpected zone offset")
+ return nil, errors.New("Time.MarshalBinary: unexpected zone offset")
}
offsetMin = int16(offset)
}
enc := []byte{
- timeGobVersion, // byte 0 : version
+ timeBinaryVersion, // byte 0 : version
byte(t.sec >> 56), // bytes 1-8: seconds
byte(t.sec >> 48),
byte(t.sec >> 40),
@@ -857,18 +880,19 @@ func (t Time) GobEncode() ([]byte, error) {
return enc, nil
}
-// GobDecode implements the gob.GobDecoder interface.
-func (t *Time) GobDecode(buf []byte) error {
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+func (t *Time) UnmarshalBinary(data []byte) error {
+ buf := data
if len(buf) == 0 {
- return errors.New("Time.GobDecode: no data")
+ return errors.New("Time.UnmarshalBinary: no data")
}
- if buf[0] != timeGobVersion {
- return errors.New("Time.GobDecode: unsupported version")
+ 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.GobDecode: invalid length")
+ return errors.New("Time.UnmarshalBinary: invalid length")
}
buf = buf[1:]
@@ -876,7 +900,7 @@ func (t *Time) GobDecode(buf []byte) error {
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
+ t.nsec = uintptr(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
@@ -892,8 +916,22 @@ func (t *Time) GobDecode(buf []byte) error {
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.
-// Time is formatted as RFC3339.
+// 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 {
return nil, errors.New("Time.MarshalJSON: year outside of range [0,9999]")
@@ -902,13 +940,30 @@ func (t Time) MarshalJSON() ([]byte, error) {
}
// UnmarshalJSON implements the json.Unmarshaler interface.
-// Time is expected in RFC3339 format.
+// 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].
@@ -922,7 +977,7 @@ func Unix(sec int64, nsec int64) Time {
sec--
}
}
- return Time{sec + unixToInternal, int32(nsec), Local}
+ return Time{sec + unixToInternal, uintptr(nsec), Local}
}
func isLeap(year int) bool {
@@ -1031,7 +1086,7 @@ func Date(year int, month Month, day, hour, min, sec, nsec int, loc *Location) T
unix -= int64(offset)
}
- return Time{unix + unixToInternal, int32(nsec), loc}
+ return Time{unix + unixToInternal, uintptr(nsec), loc}
}
// Truncate returns the result of rounding t down to a multiple of d (since the zero time).
@@ -1063,13 +1118,14 @@ func (t Time) Round(d Duration) Time {
// 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
- t.nsec = -t.nsec
- if t.nsec < 0 {
- t.nsec += 1e9
+ nsec = -nsec
+ if nsec < 0 {
+ nsec += 1e9
t.sec-- // t.sec >= 1 before the -- so safe
}
}
@@ -1077,14 +1133,14 @@ func div(t Time, d Duration) (qmod2 int, r Duration) {
switch {
// Special case: 2d divides 1 second.
case d < Second && Second%(d+d) == 0:
- qmod2 = int(t.nsec/int32(d)) & 1
- r = Duration(t.nsec % int32(d))
+ 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(t.nsec)
+ r = Duration(t.sec%d1)*Second + Duration(nsec)
// General case.
// This could be faster if more cleverness were applied,
@@ -1101,7 +1157,7 @@ func div(t Time, d Duration) (qmod2 int, r Duration) {
if u0 < u0x {
u1++
}
- u0x, u0 = u0, u0+uint64(t.nsec)
+ u0x, u0 = u0, u0+uint64(nsec)
if u0 < u0x {
u1++
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-01 16:48:19 +0000