1 files changed, 365 insertions, 0 deletions
diff --git a/src/lib/time/time.go b/src/lib/time/time.go
new file mode 100644
index 000000000..715ba4276
--- /dev/null
+++ b/src/lib/time/time.go
@@ -0,0 +1,365 @@
+// 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 (
+	"os";
+	"time"
+)
+
+// Seconds since January 1, 1970 00:00:00 GMT
+export func Seconds() (sec int64, err *os.Error) {
+	var nsec int64;
+	sec, nsec, err = os.Time()
+	return sec, err
+}
+
+// Nanoseconds since January 1, 1970 00:00:00 GMT
+export func Nanoseconds() (nsec int64, err *os.Error) {
+	var sec int64;
+	sec, nsec, err = os.Time()
+	return sec*1e9 + nsec, err
+}
+
+export const (
+	Sunday = iota;
+	Monday;
+	Tuesday;
+	Wednesday;
+	Thursday;
+	Friday;
+	Saturday;
+)
+
+export type Time struct {
+	year int64;	// 2008 is 2008
+	month, day int;	// Sep-17 is 9, 17
+	hour, minute, second int;	// 10:43:12 is 10, 43, 12
+	weekday int;		// Sunday = 0, Monday = 1, ...
+	zoneoffset int;	// seconds west of UTC
+	zone string;
+}
+
+var RegularMonths = []int{
+	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+}
+var LeapMonths = []int{
+	31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+}
+
+func Months(year int64) *[]int {
+	if year%4 == 0 && (year%100 != 0 || year%400 == 0) {
+		return &LeapMonths
+	} else {
+		return &RegularMonths
+	}
+	return nil	// not reached
+}
+
+const (
+	SecondsPerDay = 24*60*60;
+
+	DaysPer400Years = 365*400+97;
+	DaysPer100Years = 365*100+24;
+	DaysPer4Years = 365*4+1;
+
+	Days1970To2001 = 31*365+8;
+)
+
+export func SecondsToUTC(sec int64) *Time {
+	t := new(Time);
+
+	// Split into time and day.
+	day := sec/SecondsPerDay;
+	sec -= day*SecondsPerDay;
+	if sec < 0 {
+		day--
+		sec += SecondsPerDay
+	}
+
+	// Time
+	t.hour = int(sec/3600);
+	t.minute = int((sec/60)%60);
+	t.second = int(sec%60);
+
+	// Day 0 = January 1, 1970 was a Thursday
+	t.weekday = int((day + Thursday) % 7)
+	if t.weekday < 0 {
+		t.weekday += 7
+	}
+
+	// Change day from 0 = 1970 to 0 = 2001,
+	// to make leap year calculations easier
+	// (2001 begins 4-, 100-, and 400-year cycles ending in a leap year.)
+	day -= Days1970To2001;
+
+	year := int64(2001)
+	if day < 0 {
+		// Go back enough 400 year cycles to make day positive.
+		n := -day/DaysPer400Years + 1;
+		year -= 400*n;
+		day += DaysPer400Years*n;
+	} else {
+		// Cut off 400 year cycles.
+		n := day/DaysPer400Years;
+		year += 400*n;
+		day -= DaysPer400Years*n;
+	}
+
+	// Cut off 100-year cycles
+	n := day/DaysPer100Years;
+	year += 100*n;
+	day -= DaysPer100Years*n;
+
+	// Cut off 4-year cycles
+	n = day/DaysPer4Years;
+	year += 4*n;
+	day -= DaysPer4Years*n;
+
+	// Cut off non-leap years.
+	n = day/365;
+	year += n;
+	day -= 365*n;
+
+	t.year = year;
+
+	// If someone ever needs yearday,
+	// tyearday = day (+1?)
+
+	months := Months(year);
+	var m int;
+	yday := int(day);
+	for m = 0; m < 12 && yday >= months[m]; m++ {
+		yday -= months[m]
+	}
+	t.month = m+1;
+	t.day = yday+1;
+	t.zone = "GMT";
+
+	return t;
+}
+
+export func UTC() (t *Time, err *os.Error) {
+	var sec int64;
+	sec, err = Seconds()
+	if err != nil {
+		return nil, err
+	}
+	return SecondsToUTC(sec), nil
+}
+
+// TODO: Should this return an error?
+export func SecondsToLocalTime(sec int64) *Time {
+	zone, offset, ok := time.LookupTimezone(sec)
+	if !ok {
+		return SecondsToUTC(sec)
+	}
+	t := SecondsToUTC(sec+int64(offset));
+	t.zone = zone;
+	t.zoneoffset = offset;
+	return t
+}
+
+export func LocalTime() (t *Time, err *os.Error) {
+	var sec int64;
+	sec, err = Seconds()
+	if err != nil {
+		return nil, err
+	}
+	return SecondsToLocalTime(sec), nil
+}
+
+// Compute number of seconds since January 1, 1970.
+func (t *Time) Seconds() int64 {
+	// First, accumulate days since January 1, 2001.
+	// Using 2001 instead of 1970 makes the leap-year
+	// handling easier (see SecondsToUTC), because 
+	// it is at the beginning of the 4-, 100-, and 400-year cycles.
+	day := int64(0);
+
+	// Rewrite year to be >= 2001.
+	year := t.year;
+	if year < 2001 {
+		n := (2001 - year)/400 + 1;
+		year += 400*n;
+		day -= DaysPer400Years*n;
+	}
+
+	// Add in days from 400-year cycles.
+	n := (year - 2001) / 400;
+	year -= 400*n;
+	day += DaysPer400Years*n;
+
+	// Add in 100-year cycles.
+	n = (year - 2001) / 100;
+	year -= 100*n;
+	day += DaysPer100Years*n;
+
+	// Add in 4-year cycles.
+	n = (year - 2001) / 4;
+	year -= 4*n;
+	day += DaysPer4Years*n;
+
+	// Add in non-leap years.
+	n = year - 2001;
+	day += 365*n;
+
+	// Add in days this year.
+	months := Months(t.year);
+	for m := 0; m < t.month-1; m++ {
+		day += int64(months[m])
+	}
+	day += int64(t.day - 1);
+
+	// Convert days to seconds since January 1, 2001.
+	sec := day * SecondsPerDay;
+
+	// Add in time elapsed today.
+	sec += int64(t.hour) * 3600;
+	sec += int64(t.minute) * 60;
+	sec += int64(t.second);
+
+	// Convert from seconds since 2001 to seconds since 1970.
+	sec += Days1970To2001 * SecondsPerDay;
+
+	// Account for local time zone.
+	sec -= int64(t.zoneoffset)
+	return sec
+}
+
+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"
+}
+
+func Copy(dst *[]byte, s string) {
+	for i := 0; i < len(s); i++ {
+		dst[i] = s[i]
+	}
+}
+
+func Decimal(dst *[]byte, n int) {
+	if n < 0 {
+		n = 0
+	}
+	for i := len(dst)-1; i >= 0; i-- {
+		dst[i] = byte(n%10 + '0');
+		n /= 10
+	}
+}
+
+func AddString(buf *[]byte, bp int, s string) int {
+	n := len(s);
+	Copy(buf[bp:bp+n], s)
+	return bp+n
+}
+
+// Just enough of strftime to implement the date formats below.
+// Not exported.
+func Format(t *Time, fmt string) string {
+	buf := new([]byte, 128);
+	bp := 0
+
+	for i := 0; i < len(fmt); i++ {
+		if fmt[i] == '%' {
+			i++
+			switch fmt[i] {
+			case 'A':	// %A full weekday name
+				bp = AddString(buf, bp, LongDayNames[t.weekday])
+			case 'a':	// %a abbreviated weekday name
+				bp = AddString(buf, bp, ShortDayNames[t.weekday])
+			case 'b':	// %b abbreviated month name
+				bp = AddString(buf, bp, ShortMonthNames[t.month-1])
+			case 'd':	// %d day of month (01-31)
+				Decimal(buf[bp:bp+2], t.day);
+				bp += 2
+			case 'e':	// %e day of month ( 1-31)
+				if t.day >= 10 {
+					Decimal(buf[bp:bp+2], t.day)
+				} else {
+					buf[bp] = ' ';
+					buf[bp+1] = byte(t.day + '0')
+				}
+				bp += 2
+			case 'H':	// %H hour 00-23
+				Decimal(buf[bp:bp+2], t.hour);
+				bp += 2
+			case 'M':	// %M minute 00-59
+				Decimal(buf[bp:bp+2], t.minute);
+				bp += 2
+			case 'S':	// %S second 00-59
+				Decimal(buf[bp:bp+2], t.second);
+				bp += 2
+			case 'Y':	// %Y year 2008
+				Decimal(buf[bp:bp+4], int(t.year));
+				bp += 4
+			case 'y':	// %y year 08
+				Decimal(buf[bp:bp+2], int(t.year%100));
+				bp += 2
+			case 'Z':
+				bp = AddString(buf, bp, t.zone)
+			default:
+				buf[bp] = '%';
+				buf[bp+1] = fmt[i];
+				bp += 2
+			}
+		} else {
+			buf[bp] = fmt[i];
+			bp++
+		}
+	}
+	return string(buf[0:bp])
+}
+
+// ANSI C asctime: Sun Nov  6 08:49:37 1994
+func (t *Time) Asctime() string {
+	return Format(t, "%a %b %e %H:%M:%S %Y")
+}
+
+// RFC 850: Sunday, 06-Nov-94 08:49:37 GMT
+func (t *Time) RFC850() string {
+	return Format(t, "%A, %d-%b-%y %H:%M:%S %Z")
+}
+
+// RFC 1123: Sun, 06 Nov 1994 08:49:37 GMT
+func (t *Time) RFC1123() string {
+	return Format(t, "%a, %d %b %Y %H:%M:%S %Z")
+}
+
+// date(1) - Sun Nov  6 08:49:37 GMT 1994
+func (t *Time) String() string {
+	return Format(t, "%a %b %e %H:%M:%S %Z %Y")
+}
+