shithub: riscv

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ref: 56e869ac7004a635a7d63596ee751275484f28c3
parent: 3ba1d83d2026ebac616ab17a2126df97c0a7a24c
author: Ori Bernstein <[email protected]>
date: Sun Aug 9 14:58:44 EDT 2020

libc: new date apis

The current date and time APIs on Plan 9 are not good. They're
inflexible, non-threadsafe, and don't expose timezone information.

This commit adds new time APIs that allow parsing arbitrary
dates, work from multiple threads, and can handle timezones
effectively.

--- a/sys/include/libc.h
+++ b/sys/include/libc.h
@@ -314,21 +314,43 @@
 /*
  * Time-of-day
  */
+typedef struct Tzone Tzone;
+#pragma incomplete Tzone
 
+
 typedef
 struct Tm
 {
-	int	sec;
-	int	min;
-	int	hour;
-	int	mday;
-	int	mon;
-	int	year;
-	int	wday;
-	int	yday;
-	char	zone[4];
-	int	tzoff;
+	int	nsec;		/* nseconds (range 0...1e9) */
+	int	sec;		/* seconds (range 0..60) */
+	int	min;		/* minutes (0..59) */
+	int	hour;		/* hours (0..23) */
+	int	mday;		/* day of the month (1..31) */
+	int	mon;		/* month of the year (0..11) */
+	int	year;		/* year A.D. */
+	int	wday;		/* day of week (0..6, Sunday = 0) */
+	int	yday;		/* day of year (0..365) */
+	char	zone[16];	/* time zone name */
+	int	tzoff;		/* time zone delta from GMT */
+	Tzone	*tz;		/* time zone associated with this date */
 } Tm;
+
+typedef
+struct Tmfmt {
+	char	*fmt;
+	Tm	*tm;
+} Tmfmt;
+
+#pragma varargck	type	"τ"	Tmfmt
+
+extern	Tzone*	tzload(char *name);
+extern	Tm*	tmnow(Tm*, Tzone*);
+extern	Tm*	tmtime(Tm*, vlong, Tzone*);
+extern	Tm*	tmtimens(Tm*, vlong, int, Tzone*);
+extern	Tm*	tmparse(Tm*, char*, char*, Tzone*, char **ep);
+extern	vlong	tmnorm(Tm*);
+extern	Tmfmt	tmfmt(Tm*, char*);
+extern	void	tmfmtinstall(void);
 
 extern	Tm*	gmtime(long);
 extern	Tm*	localtime(long);
--- /dev/null
+++ b/sys/man/2/tmdate
@@ -1,0 +1,275 @@
+.TH TMDATE 2
+.SH NAME
+tmnow, tzload, tmtime, tmparse, tmfmt, tmnorm - convert date and time
+.SH SYNOPSIS
+.B #include <u.h>
+.br
+.B #include <libc.h>
+.PP
+.ft L
+.nf
+.EX
+typedef struct Tmd Tmd;
+typedef struct Tmfmt Tmfmt;
+
+struct {
+	int	nsec;	/* nanoseconds (range 0..1e9) */
+	int	sec;	/* seconds (range 0..59) */
+	int	min;	/* minutes (0..59) */
+	int	hour;	/* hours (0..23) */
+	int	mday;	/* day of the month (1..31) */
+	int	mon;	/* month of the year (0..11) */
+	int	year;	/* C.E year - 1900 */
+	int	wday;	/* day of week (0..6, Sunday = 0) */
+	int	yday;	/* day of year (0..365) */
+	char	zone[];	/* time zone name */
+	int	tzoff;	/* time	zone delta from GMT, seconds */
+};
+
+Tzone *tzload(char *name);
+Tm    *tmnow(Tm *tm, char *tz);
+Tm    *tmtime(Tm *tm, vlong abs, Tzone *tz);
+Tm    *tmtimens(Tm *tm, vlong abs, int ns, Tzone *tz);
+Tm    *tmparse(Tm *dst, char *fmt, char *tm, Tzone *zone, char **ep);
+vlong  tmnorm(Tm *tm);
+Tmfmt  tmfmt(Tm *tm, char *fmt);
+void   tmfmtinstall(void);
+.EE
+.SH DESCRIPTION
+.PP
+This family of functions handles simple date and time manipulation.
+.PP
+Time zones are loaded by name.
+They can be specified as the abbreviated timezone name,
+the full timezone name, the path to a timezone file,
+or an absolute offset in the HHMM form.
+.PP
+When given as a timezone, any instant-dependent adjustments such as leap
+seconds and daylight savings time will be applied to the derived fields of
+struct Tm, but will not affect the absolute time.
+The time zone name local always refers to the time in /env/timezone.
+The nil timezone always refers to GMT.
+.PP
+Tzload loads a timezone by name. The returned timezone is
+cached for the lifetime of the program, and should not be freed.
+Loading a timezone repeatedly by name loads from the cache, and
+does not leak.
+.PP
+Tmnow gets the current time of day in the requested time zone.
+.PP
+Tmtime converts the millisecond-resolution timestamp 'abs'
+into a Tm struct in the requested timezone.
+Tmtimens does the same, but with a nanosecond accuracy.
+.PP
+Tmstime is identical to tmtime, but accepts the time in sec-
+onds.
+.PP
+Tmparse parses a time from a string according to the format argument.
+The point at which the parsing stopped is returned in
+.IR ep .
+If
+.I ep
+is nil, trailing garbage is ignored.
+The result is returned in the timezone requested.
+If there is a timezone in the date, and a timezone is provided
+when parsing, then the zone is shifted to the provided timezone.
+Parsing is case-insensitive
+.PP
+The format argument contains zero or more of the following components:
+.TP
+.B Y, YY, YYYY
+Represents the year.
+.I YY
+prints the year in 2 digit form.
+.TP
+.B M, MM, MMM, MMMM
+The month of the year, in unpadded numeric, padded numeric, short name, or long name,
+respectively.
+.TP
+.B D, DD
+The day of month in unpadded or padded numeric form, respectively.
+.TP
+.B W, WW, WWW
+The day of week in numeric, short or long name form, respectively.
+.TP
+.B h, hh
+The hour in unpadded or padded form, respectively
+.TP
+.B m, mm
+The minute in unpadded or padded form, respectively
+.TP
+.B s, ss
+The second in unpadded or padded form, respectively
+.TP
+.B t, tt
+The milliseconds in unpadded and padded form, respectively.
+.B u, uu, uuu, uuuu
+The microseconds in unpadded. padded form modulo milliseconds,
+or unpadded, padded forms of the complete value, respectively.
+.B n, nn, nnn, nnnn, nnnnn, nnnnnn
+The nanoseconds in unpadded and padded form modulo milliseconds,
+the unpadded and padded form modulo microseconds,
+and the unpadded and padded complete value, respectively.
+.TP
+.B Z, ZZ, ZZZ
+The timezone in [+-]HHMM and [+-]HH:MM, and named form, respectively.
+.TP
+.B a, A
+Lower and uppercase 'am' and 'pm' specifiers, respectively.
+.TP
+.B [...]
+Quoted text, copied directly to the output.
+.TP
+.B _
+When formatting, this inserts padding into the date format.
+The padded width of a field is the sum of format and specifier
+characters combined. When
+For example,
+.I __h
+will format to a width of 3. When parsing, this acts as whitespace.
+.TP
+.B ?
+When parsing, this makes the following argument match fuzzily.
+Fuzzy matching means that all formats are tried, from most to least specific.
+For example, 
+.I ?M
+will match 
+.IR January ,
+.IR Jan ,
+.IR 01 ,
+and 
+.IR 1 ,
+in that order of preference.
+.TP
+.B ~
+When parsing a date, this slackens range enforcement, accepting
+out of range values such as January
+.IR 32 ,
+which would get normalized to February 1st.
+.PP
+Any characters not specified above are copied directly to output,
+without modification.
+
+
+
+.PP
+If the format argument is nil, it makes an
+attempt to parse common human readable date formats.  These
+formats include ISO-8601, RFC3339 and RFC2822 dates.
+.
+.PP
+Tmfmt produces a format description structure suitable for passing
+to
+.IR fmtprint (2) .
+If fmt is nil, we default to the format used in
+.IR ctime (2).
+The format of the format string is identical to
+.IR tmparse.
+
+.PP
+When parsing, any amount of whitespace is treated as a single token.
+All string matches are case insensitive, and zero padding is optional.
+
+.PP
+Tmnorm takes a manually adjusted Tm structure, and normalizes it,
+returning the absolute timestamp that the date represents.
+Normalizing recomputes the
+.I year, mon, mday, hr, min, sec
+and
+.I tzoff
+fields.
+If
+.I tz
+is non-nil, then
+.I tzoff
+will be recomputed, taking into account daylight savings
+for the absolute time.
+The values not used in the computation are recomputed for
+the resulting absolute time.
+All out of range values are wrapped.
+For example, December 32 will roll over to Jan 1 of the
+following year.
+.PP
+Tmfmtinstall installs a time format specifier %τ. The time
+format behaves as in tmfmt
+
+.SH EXAMPLES
+.PP
+All examples assume tmfmtinstall has been called.
+.PP
+Get the current date in the local timezone, UTC, and
+US_Pacific time. Print it using the default format.
+
+.IP
+.EX
+Tm t;
+Tzone *zl, *zp;
+if((zl = tzload("local") == nil)
+	sysfatal("load zone: %r");
+if((zp = tzload("US_Pacific") == nil)
+	sysfatal("load zone: %r");
+print("local: %τ\\n", tmfmt(tmnow(&t, zl), nil));
+print("gmt: %τ\\n", tmfmt(tmnow(&t, nil), nil));
+print("eastern: %τ\\n", tmfmt(tmnow(&t, zp), nil));
+.EE
+.PP
+Compare if two times are the same, regardless of timezone.
+Done with full, strict error checking.
+
+.IP
+.EX
+Tm a, b;
+
+if(tmparse(&a, nil, "Tue Dec 10 12:36:00 PST 2019", &e) == nil)
+	sysfatal("failed to parse: %r");
+if(*e != '\0')
+	sysfatal("trailing junk %s", e);
+if(tmparse(&b, nil, "Tue Dec 10 15:36:00 EST 2019", &e) == nil)
+	sysfata("failed to parse: %r");
+if(*e != '\0')
+	sysfatal("trailing junk %s", e);
+if(tmnorm(a) == tmnorm(b) && a.nsec == b.nsec)
+	print("same\\n");
+else
+	print("different\\n");
+.EE
+
+.PP
+Convert from one timezone to another.
+
+.IP
+.EX
+Tm here, there;
+Tzone *zl, *zp;
+if((zl = tzload("local")) == nil)
+	sysfatal("load zone: %r");
+if((zp = tzload("US_Pacific")) == nil)
+	sysfatal("load zone: %r");
+if(tmnow(&here, zl) == nil)
+	sysfatal("get time: %r");
+if(tmtime(&there, tmnorm(&tm), zp) == nil)
+	sysfatal("shift time: %r");
+.EE
+
+.PP
+Add a day. Because cross daylight savings, only 23 hours are added.
+
+.EX
+Tm t;
+char *date = "Sun Nov 2 13:11:11 PST 2019";
+if(tmparse(&t, "W MMM D hh:mm:ss z YYYY, date, &e) == nil)
+	print("failed top parse");
+tm.day++;
+tmnorm(&t);
+print("%τ", &t); /*  Mon Nov 3 13:11:11 PST 2019 */
+.EE
+
+.SH BUGS
+.PP
+There is no way to format specifier for subsecond precision.
+.PP
+The timezone information that we ship is out of date.
+.PP
+The Plan 9 timezone format has no way to express leap seconds.
+.PP
+We provide no way to manipulate timezones.
--- a/sys/src/libc/9sys/ctime.c
+++ b/sys/src/libc/9sys/ctime.c
@@ -1,301 +1,39 @@
-/*
- * This routine converts time as follows.
- * The epoch is 0000 Jan 1 1970 GMT.
- * The argument time is in seconds since then.
- * The localtime(t) entry returns a pointer to an array
- * containing
- *
- *	seconds (0-59)
- *	minutes (0-59)
- *	hours (0-23)
- *	day of month (1-31)
- *	month (0-11)
- *	year-1970
- *	weekday (0-6, Sun is 0)
- *	day of the year
- *	daylight savings flag
- *
- * The routine gets the daylight savings time from the environment.
- *
- * asctime(tvec))
- * where tvec is produced by localtime
- * returns a ptr to a character string
- * that has the ascii time in the form
- *
- *	                            \\
- *	Thu Jan 01 00:00:00 GMT 1970n0
- *	012345678901234567890123456789
- *	0	  1	    2
- *
- * ctime(t) just calls localtime, then asctime.
- */
-
 #include <u.h>
 #include <libc.h>
 
-static	char	dmsize[12] =
-{
-	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
-};
-
-/*
- * The following table is used for 1974 and 1975 and
- * gives the day number of the first day after the Sunday of the
- * change.
- */
-
-static	int	dysize(int);
-static	void	ct_numb(char*, int);
-
-#define	TZSIZE	150
-static	void	readtimezone(void);
-static	int	rd_name(char**, char*);
-static	int	rd_long(char**, long*);
-static
-struct
-{
-	char	stname[4];
-	char	dlname[4];
-	long	stdiff;
-	long	dldiff;
-	long	dlpairs[TZSIZE];
-} timezone;
-
-char*
-ctime(long t)
-{
-	return asctime(localtime(t));
-}
-
 Tm*
 localtime(long tim)
 {
-	Tm *ct;
-	long t, *p;
-	int dlflag;
+	static Tm tm;
+	Tzone *tz;
 
-	if(timezone.stname[0] == 0)
-		readtimezone();
-	t = tim + timezone.stdiff;
-	dlflag = 0;
-	for(p = timezone.dlpairs; *p; p += 2)
-		if(t >= p[0])
-		if(t < p[1]) {
-			t = tim + timezone.dldiff;
-			dlflag++;
-			break;
-		}
-	ct = gmtime(t);
-	if(dlflag){
-		strcpy(ct->zone, timezone.dlname);
-		ct->tzoff = timezone.dldiff;
-	} else {
-		strcpy(ct->zone, timezone.stname);
-		ct->tzoff = timezone.stdiff;
-	}
-	return ct;
+	/*
+	 * We have no way to report errors,
+	 * so we just ignore them here.
+	 */
+	tz = tzload("local");
+	tmtime(&tm, tim, tz);
+	return &tm;
 }
 
 Tm*
-gmtime(long tim)
+gmtime(long abs)
 {
-	int d0, d1;
-	long hms, day;
-	static Tm xtime;
-
-	/*
-	 * break initial number into days
-	 */
-	hms = tim % 86400L;
-	day = tim / 86400L;
-	if(hms < 0) {
-		hms += 86400L;
-		day -= 1;
-	}
-
-	/*
-	 * generate hours:minutes:seconds
-	 */
-	xtime.sec = hms % 60;
-	d1 = hms / 60;
-	xtime.min = d1 % 60;
-	d1 /= 60;
-	xtime.hour = d1;
-
-	/*
-	 * day is the day number.
-	 * generate day of the week.
-	 * The addend is 4 mod 7 (1/1/1970 was Thursday)
-	 */
-
-	xtime.wday = (day + 7340036L) % 7;
-
-	/*
-	 * year number
-	 */
-	if(day >= 0)
-		for(d1 = 1970; day >= dysize(d1); d1++)
-			day -= dysize(d1);
-	else
-		for (d1 = 1970; day < 0; d1--)
-			day += dysize(d1-1);
-	xtime.year = d1-1900;
-	xtime.yday = d0 = day;
-
-	/*
-	 * generate month
-	 */
-
-	if(dysize(d1) == 366)
-		dmsize[1] = 29;
-	for(d1 = 0; d0 >= dmsize[d1]; d1++)
-		d0 -= dmsize[d1];
-	dmsize[1] = 28;
-	xtime.mday = d0 + 1;
-	xtime.mon = d1;
-	strcpy(xtime.zone, "GMT");
-	return &xtime;
+	static Tm tm;
+	return tmtime(&tm, abs, nil);
 }
 
 char*
-asctime(Tm *t)
+ctime(long abs)
 {
-	char *ncp;
-	static char cbuf[30];
+	Tzone *tz;
+	Tm tm;
 
-	strcpy(cbuf, "Thu Jan 01 00:00:00 GMT 1970\n");
-	ncp = &"SunMonTueWedThuFriSat"[t->wday*3];
-	cbuf[0] = *ncp++;
-	cbuf[1] = *ncp++;
-	cbuf[2] = *ncp;
-	ncp = &"JanFebMarAprMayJunJulAugSepOctNovDec"[t->mon*3];
-	cbuf[4] = *ncp++;
-	cbuf[5] = *ncp++;
-	cbuf[6] = *ncp;
-	ct_numb(cbuf+8, t->mday);
-	ct_numb(cbuf+11, t->hour+100);
-	ct_numb(cbuf+14, t->min+100);
-	ct_numb(cbuf+17, t->sec+100);
-	ncp = t->zone;
-	cbuf[20] = *ncp++;
-	cbuf[21] = *ncp++;
-	cbuf[22] = *ncp;
-	ct_numb(cbuf+24, (t->year+1900) / 100 + 100);
-	ct_numb(cbuf+26, t->year+100);
-	return cbuf;
-}
-
-static
-dysize(int y)
-{
-
-	if(y%4 == 0 && (y%100 != 0 || y%400 == 0))
-		return 366;
-	return 365;
-}
-
-static
-void
-ct_numb(char *cp, int n)
-{
-
-	cp[0] = ' ';
-	if(n >= 10)
-		cp[0] = (n/10)%10 + '0';
-	cp[1] = n%10 + '0';
-}
-
-static
-void
-readtimezone(void)
-{
-	char buf[TZSIZE*11+30], *p;
-	int i;
-
-	memset(buf, 0, sizeof(buf));
-	i = open("/env/timezone", 0);
-	if(i < 0)
-		goto error;
-	if(read(i, buf, sizeof(buf)) >= sizeof(buf)){
-		close(i);
-		goto error;
-	}
-	close(i);
-	p = buf;
-	if(rd_name(&p, timezone.stname))
-		goto error;
-	if(rd_long(&p, &timezone.stdiff))
-		goto error;
-	if(rd_name(&p, timezone.dlname))
-		goto error;
-	if(rd_long(&p, &timezone.dldiff))
-		goto error;
-	for(i=0; i<TZSIZE; i++) {
-		if(rd_long(&p, &timezone.dlpairs[i]))
-			goto error;
-		if(timezone.dlpairs[i] == 0)
-			return;
-	}
-
-error:
-	timezone.stdiff = 0;
-	strcpy(timezone.stname, "GMT");
-	timezone.dlpairs[0] = 0;
-}
-
-static
-rd_name(char **f, char *p)
-{
-	int c, i;
-
-	for(;;) {
-		c = *(*f)++;
-		if(c != ' ' && c != '\n')
-			break;
-	}
-	for(i=0; i<3; i++) {
-		if(c == ' ' || c == '\n')
-			return 1;
-		*p++ = c;
-		c = *(*f)++;
-	}
-	if(c != ' ' && c != '\n')
-		return 1;
-	*p = 0;
-	return 0;
-}
-
-static
-rd_long(char **f, long *p)
-{
-	int c, s;
-	long l;
-
-	s = 0;
-	for(;;) {
-		c = *(*f)++;
-		if(c == '-') {
-			s++;
-			continue;
-		}
-		if(c != ' ' && c != '\n')
-			break;
-	}
-	if(c == 0) {
-		*p = 0;
-		return 0;
-	}
-	l = 0;
-	for(;;) {
-		if(c == ' ' || c == '\n')
-			break;
-		if(c < '0' || c > '9')
-			return 1;
-		l = l*10 + c-'0';
-		c = *(*f)++;
-	}
-	if(s)
-		l = -l;
-	*p = l;
-	return 0;
+	/*
+	 * We have no way to report errors,
+	 * so we just ignore them here.
+	 */
+	tz = tzload("local");
+	tmtime(&tm, abs, tz);
+	return asctime(&tm);
 }
--- a/sys/src/libc/9sys/tm2sec.c
+++ b/sys/src/libc/9sys/tm2sec.c
@@ -1,202 +1,11 @@
 #include <u.h>
 #include <libc.h>
 
-#define	TZSIZE	150
-static	void	readtimezone(void);
-static	int	rd_name(char**, char*);
-static	int	rd_long(char**, long*);
-static
-struct
-{
-	char	stname[4];
-	char	dlname[4];
-	long	stdiff;
-	long	dldiff;
-	long	dlpairs[TZSIZE];
-} timezone;
-
-#define SEC2MIN 60L
-#define SEC2HOUR (60L*SEC2MIN)
-#define SEC2DAY (24L*SEC2HOUR)
-
-/*
- *  days per month plus days/year
- */
-static	int	dmsize[] =
-{
-	365, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
-};
-static	int	ldmsize[] =
-{
-	366, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
-};
-
-/*
- *  return the days/month for the given year
- */
-static int *
-yrsize(int y)
-{
-	if((y%4) == 0 && ((y%100) != 0 || (y%400) == 0))
-		return ldmsize;
-	else
-		return dmsize;
-}
-
-/*
- * compute seconds since Jan 1 1970 GMT
- * and convert to our timezone.
- */
 long
 tm2sec(Tm *tm)
 {
-	long secs, *p;
-	int i, yday, year, *d2m;
+	Tm tt;
 
-	if(strcmp(tm->zone, "GMT") != 0 && timezone.stname[0] == 0)
-		readtimezone();
-	secs = 0;
-
-	/*
-	 *  seconds per year
-	 */
-	year = tm->year + 1900;
-	for(i = 1970; i < year; i++){
-		d2m = yrsize(i);
-		secs += d2m[0] * SEC2DAY;
-	}
-
-	/*
-	 *  if mday is set, use mon and mday to compute yday
-	 */
-	if(tm->mday){
-		yday = 0;
-		d2m = yrsize(year);
-		for(i=0; i<tm->mon; i++)
-			yday += d2m[i+1];
-		yday += tm->mday-1;
-	}else{
-		yday = tm->yday;
-	}
-	secs += yday * SEC2DAY;
-
-	/*
-	 * hours, minutes, seconds
-	 */
-	secs += tm->hour * SEC2HOUR;
-	secs += tm->min * SEC2MIN;
-	secs += tm->sec;
-
-	/*
-	 * Only handles zones mentioned in /env/timezone,
-	 * but things get too ambiguous otherwise.
-	 */
-	if(strcmp(tm->zone, timezone.stname) == 0)
-		secs -= timezone.stdiff;
-	else if(strcmp(tm->zone, timezone.dlname) == 0)
-		secs -= timezone.dldiff;
-	else if(tm->zone[0] == 0){
-		secs -= timezone.dldiff;
-		for(p = timezone.dlpairs; *p; p += 2)
-			if(secs >= p[0] && secs < p[1])
-				break;
-		if(*p == 0){
-			secs += timezone.dldiff;
-			secs -= timezone.stdiff;
-		}
-	}
-	return secs;
-}
-
-static
-void
-readtimezone(void)
-{
-	char buf[TZSIZE*11+30], *p;
-	int i;
-
-	memset(buf, 0, sizeof(buf));
-	i = open("/env/timezone", 0);
-	if(i < 0)
-		goto error;
-	if(read(i, buf, sizeof(buf)) >= sizeof(buf))
-		goto error;
-	close(i);
-	p = buf;
-	if(rd_name(&p, timezone.stname))
-		goto error;
-	if(rd_long(&p, &timezone.stdiff))
-		goto error;
-	if(rd_name(&p, timezone.dlname))
-		goto error;
-	if(rd_long(&p, &timezone.dldiff))
-		goto error;
-	for(i=0; i<TZSIZE; i++) {
-		if(rd_long(&p, &timezone.dlpairs[i]))
-			goto error;
-		if(timezone.dlpairs[i] == 0)
-			return;
-	}
-
-error:
-	timezone.stdiff = 0;
-	strcpy(timezone.stname, "GMT");
-	timezone.dlpairs[0] = 0;
-}
-
-static int
-rd_name(char **f, char *p)
-{
-	int c, i;
-
-	for(;;) {
-		c = *(*f)++;
-		if(c != ' ' && c != '\n')
-			break;
-	}
-	for(i=0; i<3; i++) {
-		if(c == ' ' || c == '\n')
-			return 1;
-		*p++ = c;
-		c = *(*f)++;
-	}
-	if(c != ' ' && c != '\n')
-		return 1;
-	*p = 0;
-	return 0;
-}
-
-static int
-rd_long(char **f, long *p)
-{
-	int c, s;
-	long l;
-
-	s = 0;
-	for(;;) {
-		c = *(*f)++;
-		if(c == '-') {
-			s++;
-			continue;
-		}
-		if(c != ' ' && c != '\n')
-			break;
-	}
-	if(c == 0) {
-		*p = 0;
-		return 0;
-	}
-	l = 0;
-	for(;;) {
-		if(c == ' ' || c == '\n')
-			break;
-		if(c < '0' || c > '9')
-			return 1;
-		l = l*10 + c-'0';
-		c = *(*f)++;
-	}
-	if(s)
-		l = -l;
-	*p = l;
-	return 0;
+	tt = *tm;
+	return tmnorm(&tt);
 }
--- /dev/null
+++ b/sys/src/libc/port/date.c
@@ -1,0 +1,996 @@
+#include <u.h>
+#include <libc.h>
+
+typedef struct Tzabbrev Tzabbrev;
+typedef struct Tzoffpair Tzoffpair;
+
+#define Ctimefmt	"WW MMM _D hh:mm:ss ZZZ YYYY"
+#define P(pad, w)	((pad) < (w) ? 0 : pad - w)
+
+enum {
+	Tzsize		= 150,
+	Nsec		= 1000*1000*1000,
+	Usec		= 1000*1000,
+	Msec		= 1000,
+	Daysec		= (vlong)24*3600,
+	Days400y	= 365*400 + 4*25 - 3,
+	Days4y		= 365*4 + 1,
+};
+
+enum {
+	Cend,
+	Cspace,
+	Cnum,
+	Cletter,
+	Cpunct,
+};
+	
+struct Tzone {
+	char	tzname[32];
+	char	stname[16];
+	char	dlname[16];
+	long	stdiff;
+	long	dldiff;
+	long	dlpairs[150];
+};
+
+static QLock zlock;
+static int nzones;
+static Tzone **zones;
+static int mdays[] = {
+	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+static char *wday[] = {
+	"Sunday","Monday","Tuesday",
+	"Wednesday","Thursday","Friday",
+	"Saturday", nil,
+};
+static char *month[] = {
+	"January", "February", "March",
+	"April", "May", "June", "July",
+	"August", "September", "October",
+	"November", "December", nil
+};
+
+struct Tzabbrev {
+	char *abbr;
+	char *name;
+};
+
+struct Tzoffpair {
+	char *abbr;
+	int off;
+};
+
+#define isalpha(c)\
+	(((c)|0x60) >= 'a' && ((c)|0x60) <= 'z')
+
+/* Obsolete time zone names. Hardcoded to match RFC5322 */
+static Tzabbrev tzabbrev[] = {
+	{"UT", "GMT"}, {"GMT", "GMT"}, {"UTC", "GMT"},
+	{"EST",	"US_Eastern"}, {"EDT", "US_Eastern"},
+	{"CST", "US_Central"}, {"CDT", "US_Central"},
+	{"MST", "US_Mountain"}, {"MDT", "US_Mountain"},
+	{"PST", "US_Pacific"}, {"PDT", "US_Pacific"},
+	{nil},
+};
+
+/* Military timezone names */
+static Tzoffpair milabbrev[] = {
+	{"A", -1*3600},   {"B", -2*3600},   {"C", -3*3600},
+	{"D", -4*3600},   {"E", -5*3600},   {"F", -6*3600},
+	{"G", -7*3600},   {"H", -8*3600},   {"I", -9*3600},
+	{"K", -10*3600},  {"L", -11*3600},  {"M", -12*3600},
+	{"N", +1*3600},   {"O", +2*3600},   {"P", +3*3600},
+	{"Q", +4*3600},   {"R", +5*3600},   {"S", +6*3600},
+	{"T", +7*3600},   {"U", +8*3600},   {"V", +9*3600},
+	{"W", +10*3600},  {"X", +11*3600}, {"Y", +12*3600},
+	{"Z",	0}, {nil, 0}
+};
+
+static vlong
+mod(vlong a, vlong b)
+{
+	vlong r;
+
+	r = a % b;
+	if(r < 0)
+		r += b;
+	return r;
+}
+
+static int
+isleap(int y)
+{
+	return y % 4 == 0 && (y % 100 != 0 || y % 400 == 0);
+}
+
+static int
+rdname(char **f, char *p, int n)
+{
+	char *s, *e;
+
+	for(s = *f; *s; s++)
+		if(*s != ' ' && *s != '\t'  && *s != '\n')
+			break;
+	e = s + n;
+	for(; *s && s != e; s++) {
+		if(*s == ' ' || *s == '\t' || *s == '\n')
+			break;
+		*p++ = *s;
+	}
+	*p = 0;
+	if(n - (e - s) < 3 || *s != ' ' && *s != '\t' && *s != '\n'){
+		werrstr("truncated name");
+		return -1;
+	}
+	*f = s;
+	return 0;
+}
+
+static int
+rdlong(char **f, long *p)
+{
+	int c, s;
+	long l;
+
+	s = 0;
+	while((c = *(*f)++) != 0){
+		if(c == '-')
+			s++;
+		else if(c != ' ' && c != '\n')
+			break;
+	}
+	if(c == 0) {
+		*p = 0;
+		return 0;
+	}
+	l = 0;
+	for(;;) {
+		if(c == ' ' || c == '\n')
+			break;
+		if(c < '0' || c > '9'){
+			werrstr("non-number %c in name", c);
+			return -1;
+		}
+		l = l*10 + c-'0';
+		c = *(*f)++;
+	}
+	if(s)
+		l = -l;
+	*p = l;
+	return 0;
+}
+
+static int
+loadzone(Tzone *tz, char *name)
+{
+	char buf[Tzsize*11+30], path[128], *p;
+	int i, f, r;
+
+	memset(tz, 0, sizeof(Tzone));
+	if(strcmp(name, "local") == 0)
+		snprint(path, sizeof(path), "/env/timezone");
+	else
+		snprint(path, sizeof(path), "/adm/timezone/%s", name);
+	memset(buf, 0, sizeof(buf));
+	if((f = open(path, 0)) == -1)
+		return -1;
+	r = read(f, buf, sizeof(buf));
+	close(f);
+	if(r == sizeof(buf) || r == -1)
+		return -1;
+	buf[r] = 0;
+	p = buf;
+	if(rdname(&p, tz->stname, sizeof(tz->stname)) == -1)
+		return -1;
+	if(rdlong(&p, &tz->stdiff) == -1)
+		return -1;
+	if(rdname(&p, tz->dlname, sizeof(tz->dlname)) == -1)
+		return -1;
+	if(rdlong(&p, &tz->dldiff) == -1)
+		return -1;
+	for(i=0; i < Tzsize; i++) {
+		if(rdlong(&p, &tz->dlpairs[i]) == -1){
+			werrstr("invalid transition time");
+			return -1;
+		}
+		if(tz->dlpairs[i] == 0)
+			return 0;
+	}
+	werrstr("invalid timezone %s", name);
+	return -1;
+}
+
+Tzone*
+tzload(char *tzname)
+{
+	Tzone *tz, **newzones;
+	int i;
+
+	if(tzname == nil)
+		tzname = "GMT";
+	qlock(&zlock);
+	for(i = 0; i < nzones; i++){
+		tz = zones[i];
+		if(strcmp(tz->stname, tzname) == 0)
+			goto found;
+		if(strcmp(tz->dlname, tzname) == 0)
+			goto found;
+		if(strcmp(tz->tzname, tzname) == 0)
+			goto found;
+	}
+
+	tz = malloc(sizeof(Tzone));
+	if(tz == nil)
+		goto error;
+	newzones = realloc(zones, (nzones + 1) * sizeof(Tzone*));
+	if(newzones == nil)
+		goto error;
+	if(loadzone(tz, tzname) != 0)
+		goto error;
+	if(snprint(tz->tzname, sizeof(tz->tzname), tzname) >= sizeof(tz->tzname)){
+		werrstr("timezone name too long");
+		return nil;
+	}
+	zones = newzones;
+	zones[nzones] = tz;
+	nzones++;
+found:
+	qunlock(&zlock);
+	return tz;
+error:
+	free(tz);
+	qunlock(&zlock);
+	return nil;
+}
+
+static void
+tzoffset(Tzone *tz, vlong abs, Tm *tm)
+{
+	long dl, *p;
+	dl = 0;
+	if(tz == nil){
+		snprint(tm->zone, sizeof(tm->zone), "GMT");
+		tm->tzoff = 0;
+		return;
+	}
+	for(p = tz->dlpairs; *p; p += 2)
+		if(abs > p[0] && abs <= p[1]){
+			dl = 1;
+			break;
+		}
+	if(dl){
+		snprint(tm->zone, sizeof(tm->zone), tz->dlname);
+		tm->tzoff = tz->dldiff;
+	}else{
+		snprint(tm->zone, sizeof(tm->zone), tz->stname);
+		tm->tzoff = tz->stdiff;
+	}
+}
+
+static Tm*
+tmfill(Tm *tm, vlong abs, vlong nsec)
+{
+	vlong zrel, j, y, m, d, t, e;
+	int i;
+
+	zrel = abs + tm->tzoff;
+	t = zrel % Daysec;
+	e = zrel / Daysec;
+	if(t < 0){
+		t += Daysec;
+		e -= 1;
+	}
+
+	t += nsec/Nsec;
+	tm->sec = mod(t, 60);
+	t /= 60;
+	tm->min = mod(t, 60);
+	t /= 60;
+	tm->hour = mod(t, 24);
+	tm->wday = mod((e + 4), 7);
+
+	/*
+	 * Split up year, month, day.
+	 * 
+	 * Implemented according to "Algorithm 199,
+	 * conversions between calendar  date and
+	 * Julian day number", Robert G. Tantzen,
+	 * Air Force Missile Development
+	 * Center, Holloman AFB, New Mex.
+	 * 
+	 * Lots of magic.
+	 */
+	j = (zrel + 2440588 * Daysec) / (Daysec) - 1721119;
+	y = (4 * j - 1) / Days400y;
+	j = 4 * j - 1 - Days400y * y;
+	d = j / 4;
+	j = (4 * d + 3) / Days4y;
+	d = 4 * d + 3 - Days4y * j;
+	d = (d + 4) / 4 ;
+	m = (5 * d - 3) / 153;
+	d = 5 * d - 3 - 153 * m;
+	d = (d + 5) / 5;
+	y = 100 * y + j;
+
+	if(m < 10)
+		m += 3;
+	else{
+		m -= 9;
+		y++;
+	}
+
+	/* there's no year 0 */
+	if(y <= 0)
+		y--;
+	/* and if j negative, the day and month are also negative */
+	if(m < 0)
+		m += 12;
+	if(d < 0)
+		d += mdays[m - 1];
+
+	tm->yday = d;
+	for(i = 0; i < m - 1; i++)
+		tm->yday += mdays[i];
+	if(m > 1 && isleap(y))
+		tm->yday++;
+	tm->year = y - 1900;
+	tm->mon = m - 1;
+	tm->mday = d;
+	tm->nsec = mod(nsec, Nsec);
+	return tm;
+}	
+
+
+Tm*
+tmtime(Tm *tm, vlong abs, Tzone *tz)
+{
+	return tmtimens(tm, abs, 0, tz);
+}
+
+Tm*
+tmtimens(Tm *tm, vlong abs, int ns, Tzone *tz)
+{
+	tm->tz = tz;
+	tzoffset(tz, abs, tm);
+	return tmfill(tm, abs, ns);
+}
+
+Tm*
+tmnow(Tm *tm, Tzone *tz)
+{
+	vlong ns;
+
+	ns = nsec();
+	return tmtimens(tm, nsec()/Nsec, mod(ns, Nsec), tz);
+}
+
+vlong
+tmnorm(Tm *tm)
+{
+	vlong c, yadj, j, abs, y, m, d;
+
+	if(tm->mon > 1){
+		m = tm->mon - 2;
+		y = tm->year + 1900;
+	}else{
+		m = tm->mon + 10;
+		y = tm->year + 1899;
+	}
+	d = tm->mday;
+	c = y / 100;
+	yadj = y - 100 * c;
+	j = (c * Days400y / 4 + 
+		Days4y * yadj / 4 +
+		(153 * m + 2)/5 + d -
+		719469);
+	abs = j * Daysec;
+	abs += tm->hour * 3600;
+	abs += tm->min * 60;
+	abs += tm->sec;
+	if(tm->tz){
+		tzoffset(tm->tz, abs - tm->tzoff, tm);
+		tzoffset(tm->tz, abs - tm->tzoff, tm);
+	}
+	abs -= tm->tzoff;
+	tmfill(tm, abs, tm->nsec);
+	return abs;
+}
+
+static int
+τconv(Fmt *f)
+{
+	int depth, n, v, w, h, m, c0, sgn, pad, off;
+	char *p, *am;
+	Tmfmt tf;
+	Tm *tm;
+
+	n = 0;
+	tf = va_arg(f->args, Tmfmt);
+	tm = tf.tm;
+	p = tf.fmt;
+	if(p == nil)
+		p = Ctimefmt;
+	while(*p){
+		w = 1;
+		pad = 0;
+		while(*p == '_'){
+			pad++;
+			p++;
+		}
+		c0 = *p++;
+		while(c0 && *p == c0){
+			w++;
+			p++;
+		}
+		pad += w;
+		switch(c0){
+		case 0:
+			break;
+		case 'Y':
+			switch(w){
+			case 1:	n += fmtprint(f, "%*d", pad, tm->year + 1900);		break;
+			case 2: n += fmtprint(f, "%*d", pad, tm->year % 100);		break;
+			case 4:	n += fmtprint(f, "%*d", pad, tm->year + 1900);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 'M':
+			switch(w){
+			case 1: n += fmtprint(f, "%*d", pad, tm->mon + 1);		break;
+			case 2:	n += fmtprint(f, "%*s%02d", pad-2, "", tm->mon + 1);	break;
+			case 3:	n += fmtprint(f, "%*.3s", pad, month[tm->mon]);		break;
+			case 4:	n += fmtprint(f, "%*s", pad, month[tm->mon]);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 'D':
+			switch(w){
+			case 1: n += fmtprint(f, "%*d", pad, tm->mday);			break;
+			case 2:	n += fmtprint(f, "%*s%02d", pad-2, "", tm->mday);	break;
+			default: goto badfmt;
+			}
+			break;
+		case 'W':
+			switch(w){
+			case 1:	n += fmtprint(f, "%*d", pad, tm->wday + 1);		break;
+			case 2:	n += fmtprint(f, "%*.3s", pad, wday[tm->wday]);		break;
+			case 3:	n += fmtprint(f, "%*s", pad, wday[tm->wday]);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 'H':
+			switch(w){
+			case 1: n += fmtprint(f, "%*d", pad, tm->hour % 12);		break;
+			case 2:	n += fmtprint(f, "%*s%02d", pad-2, "", tm->hour % 12);	break;
+			default: goto badfmt;
+			}
+			break;
+		case 'h':
+			switch(w){
+			case 1: n += fmtprint(f, "%*d", pad, tm->hour);			break;
+			case 2:	n += fmtprint(f, "%*s%02d", pad-2, "", tm->hour);	break;
+			default: goto badfmt;
+			}
+			break;
+		case 'm':
+			switch(w){
+			case 1: n += fmtprint(f, "%*d", pad, tm->min);			break;
+			case 2:	n += fmtprint(f, "%*s%02d", pad-2, "", tm->min);	break;
+			default: goto badfmt;
+			}
+			break;
+		case 's':
+			switch(w){
+			case 1: n += fmtprint(f, "%*d", pad, tm->sec);			break;
+			case 2:	n += fmtprint(f, "%*s%02d", pad-2, "", tm->sec);	break;
+			default: goto badfmt;
+			}
+			break;
+		case 't':
+			v = tm->nsec / (1000*1000);
+			switch(w){
+			case 1:	n += fmtprint(f, "%*d", pad, v % 1000);			break;
+			case 2:
+			case 3:	n += fmtprint(f, "%*s%03d", P(pad, 3), "", v % 1000);	break;
+			default: goto badfmt;
+			}
+			break;
+		case 'u':
+			v = tm->nsec / 1000;
+			switch(w){
+			case 1:	n += fmtprint(f, "%*d", pad, v % 1000);			break;
+			case 2:	n += fmtprint(f, "%*s%03d", P(pad, 3), "", v % 1000);	break;
+			case 3:	n += fmtprint(f, "%*d", P(pad, 6), v);			break;
+			case 4:	n += fmtprint(f, "%*s%06d", P(pad, 6), "", v);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 'n':
+			v = tm->nsec;
+			switch(w){
+			case 1:	n += fmtprint(f, "%*d", pad, v%1000);			break;
+			case 2:	n += fmtprint(f, "%*s%03d", P(pad, 3), "", v % 1000);	break;
+			case 3:	n += fmtprint(f, "%*d", pad , v%(1000*1000));		break;
+			case 4: n += fmtprint(f, "%*s%06d", P(pad, 6), "", v%(1000000)); break;
+			case 5:	n += fmtprint(f, "%*d", pad, v);			break;
+			case 6:	n += fmtprint(f, "%*s%09d", P(pad, 9), "", v);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 'z':
+			if(w != 1)
+				goto badfmt;
+		case 'Z':
+			sgn = (tm->tzoff < 0) ? '-' : '+';
+			off = (tm->tzoff < 0) ? -tm->tzoff : tm->tzoff;
+			h = off/3600;
+			m = (off/60)%60;
+			if(w < 3 && pad < 5)
+				pad = 5;
+			switch(w){
+			case 1:	n += fmtprint(f, "%*s%c%02d%02d", pad-5, "", sgn, h, m); break;
+			case 2:	n += fmtprint(f, "%*s%c%02d:%02d", pad-5, "", sgn, h, m); break;
+			case 3:	n += fmtprint(f, "%*s", pad, tm->zone);			 break;
+			}
+			break;
+		case 'A':
+		case 'a':
+			if(w != 1)
+				goto badfmt;
+			if(c0 == 'a')
+				am = (tm->hour < 12) ? "am" : "pm";
+			else
+				am = (tm->hour < 12) ? "AM" : "PM";
+			n += fmtprint(f, "%*s", pad, am);
+			break;
+		case '[':
+			depth = 1;
+			while(*p){
+				if(*p == '[')
+					depth++;
+				if(*p == ']')
+					depth--;
+				if(*p == '\\')
+					p++;
+				if(depth == 0)
+					break;
+				fmtrune(f, *p++);
+			}
+			if(*p++ != ']')
+				goto badfmt;
+			break;
+		default:
+			while(w-- > 0)
+				n += fmtrune(f, c0);
+			break;
+		}
+	}
+	return n;
+badfmt:
+	werrstr("garbled format %s", tf.fmt);
+	return -1;			
+}
+
+static int
+getnum(char **ps, int maxw, int *ok)
+{
+	char *s, *e;
+	int n;
+
+	n = 0;
+	e = *ps + maxw;
+	for(s = *ps; s != e && *s >= '0' && *s <= '9'; s++){
+		n *= 10;
+		n += *s - '0';
+	}
+	*ok = s != *ps;
+	*ps = s;
+	return n;
+}
+
+static int
+lookup(char **s, char **tab, int len, int *ok)
+{
+	int nc, i;
+
+	*ok = 0;
+	for(i = 0; *tab; tab++){
+		nc = (len != -1) ? len : strlen(*tab);
+		if(cistrncmp(*s, *tab, nc) == 0){
+			*s += nc;
+			*ok = 1;
+			return i;
+		}
+		i++;
+	}
+	*ok = 0;
+	return -1;
+}
+
+Tm*
+tmparse(Tm *tm, char *fmt, char *str, Tzone *tz, char **ep)
+{
+	int depth, n, w, c0, zs, z0, z1, md, ampm, zoned, sloppy, tzo, ok;
+	vlong abs;
+	char *s, *p, *q;
+	Tzone *zparsed;
+	Tzabbrev *a;
+	Tzoffpair *m;
+
+	p = fmt;
+	s = str;
+	tzo = 0;
+	ampm = -1;
+	zoned = 0;
+	zparsed = nil;
+	sloppy = 0;
+	/* Default all fields */
+	tmtime(tm, 0, nil);
+	if(*p == '~'){
+		sloppy = 1;
+		p++;
+	}
+	while(*p){
+		w = 1;
+		c0 = *p++;
+		if(c0 == '?'){
+			w = -1;
+			c0 = *p++;
+		}
+		while(*p == c0){
+			if(w != -1) w++;
+			p++;
+		}
+		ok = 1;
+		switch(c0){
+		case 'Y':
+			switch(w){
+			case -1:
+				tm->year = getnum(&s, 4, &ok);
+				if(tm->year > 100) tm->year -= 1900;
+				break;
+			case 1:	tm->year = getnum(&s, 4, &ok) - 1900;	break;
+			case 2: tm->year = getnum(&s, 2, &ok);		break;
+			case 3:
+			case 4:	tm->year = getnum(&s, 4, &ok) - 1900;	break;
+			default: goto badfmt;
+			}
+			break;
+		case 'M':
+			switch(w){
+			case -1:
+				tm->mon = getnum(&s, 2, &ok) - 1;
+				if(!ok) tm->mon = lookup(&s, month, -1, &ok);
+				if(!ok) tm->mon = lookup(&s, month, 3, &ok);
+				break;
+			case 1:
+			case 2: tm->mon = getnum(&s, 2, &ok) - 1;	break;
+			case 3:	tm->mon = lookup(&s, month, 3, &ok);	break;
+			case 4:	tm->mon = lookup(&s, month, -1, &ok);	break;
+			default: goto badfmt;
+			}
+			break;
+		case 'D':
+			switch(w){
+			case -1:
+			case 1:
+			case 2: tm->mday = getnum(&s, 2, &ok);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 'W':
+			switch(w){
+			case -1:
+				tm->wday = lookup(&s, wday, -1, &ok);
+				if(!ok) tm->wday = lookup(&s, wday, 3, &ok);
+				if(!ok) tm->wday = getnum(&s, 1, &ok) - 1;
+				break;
+			case 1: tm->wday = getnum(&s, 1, &ok) - 1;	break;
+			case 2:	tm->wday = lookup(&s, wday, 3, &ok);	break;
+			case 3:	tm->wday = lookup(&s, wday, -1, &ok);	break;
+			default: goto badfmt;
+			}
+			break;
+		case 'h':
+			switch(w){
+			case -1:
+			case 1:
+			case 2: tm->hour = getnum(&s, 2, &ok);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 'm':
+			switch(w){
+			case -1:
+			case 1:
+			case 2: tm->min = getnum(&s, 2, &ok);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 's':
+			switch(w){
+			case -1:
+			case 1:
+			case 2: tm->sec = getnum(&s, 2, &ok);		break;
+			default: goto badfmt;
+			}
+			break;
+		case 't':
+			switch(w){
+			case -1:
+			case 1:
+			case 2:
+			case 3:	tm->nsec += getnum(&s, 3, &ok)*1000000;	break;
+			}
+			break;
+		case 'u':
+			switch(w){
+			case -1:
+			case 1:
+			case 2:	tm->nsec += getnum(&s, 3, &ok)*1000;	break;
+			case 3:
+			case 4: tm->nsec += getnum(&s, 6, &ok)*1000;	break;
+			}
+			break;
+		case 'n':
+			switch(w){
+			case 1:
+			case 2:	tm->nsec += getnum(&s, 3, &ok);		break;
+			case 3:
+			case 4: tm->nsec += getnum(&s, 6, &ok);		break;
+			case -1:
+			case 5:
+			case 6: tm->nsec += getnum(&s, 9, &ok);		break;
+			}
+			break;
+		case 'z':
+			if(w != 1)
+				goto badfmt;
+		case 'Z':
+			zs = 0;
+			zoned = 1;
+			switch(*s++){
+			case '+': zs = 1; break;
+			case '-': zs = -1; break;
+			default: s--; break;
+			}
+			q = s;
+			switch(w){
+			case -1:
+			case 3:
+				for(a = tzabbrev; a->abbr; a++){
+					n = strlen(a->abbr);
+					if(cistrncmp(s, a->abbr, n) == 0 && !isalpha(s[n]))
+						break;
+				}
+				if(a->abbr != nil){
+					s += strlen(a->abbr);
+					zparsed = tzload(a->name);
+					if(zparsed == nil){
+						werrstr("unloadable zone %s (%s)", a->abbr, a->name);
+						if(w != -1)
+							return nil;
+					}
+					goto Zoneparsed;
+				}
+				for(m = milabbrev; m->abbr != nil; m++){
+					n = strlen(m->abbr);
+					if(cistrncmp(s, m->abbr, n) == 0 && !isalpha(s[n]))
+						break;
+				}
+				if(m->abbr != nil){
+					snprint(tm->zone, sizeof(tm->zone), "%s", m->abbr);
+					tzo = m->off;
+					goto Zoneparsed;
+				}
+				if(w != -1)
+					break;
+				/* fall through */
+			case 1:
+				/* offset: [+-]hhmm */
+				z0 = getnum(&s, 4, &ok);
+				if(s - q == 4){
+					z1 = z0 % 100;
+					if(z0/100 > 13 || z1 >= 60)
+						goto baddate;
+					tzo = zs*(3600*(z0/100) + 60*z1);
+					snprint(tm->zone, sizeof(tm->zone), "%c%02d%02d", zs<0?'-':'+', z0/100, z1);
+					goto Zoneparsed;
+				}
+				if(w != -1)
+					goto baddate;
+				/* fall through */
+			case 2:
+				s = q;
+				/* offset: [+-]hh:mm */
+				z0 = getnum(&s, 2, &ok);
+				if(*s++ != ':')
+					break;
+				z1 = getnum(&s, 2, &ok);
+				if(z1 > 60)
+					break;
+				tzo = zs*(3600*z0 + 60*z1);
+				snprint(tm->zone, sizeof(tm->zone), "%c%d02:%02d", zs<0?'-':'+', z0, z1);
+				goto Zoneparsed;
+			}
+			if(w != -1)
+				goto baddate;
+			/*
+			 * Final fuzzy fallback: If we have what looks like an
+			 * unknown timezone abbreviation, keep the zone name,
+			 * but give it a timezone offset of 0. This allows us
+			 * to avoid rejecting zones outside of RFC5322.
+			 */
+			for(s = q; *s; s++)
+				if(!isalpha(*s))
+					break;
+			if(s - q >= 3 && !isalpha(*s)){
+				strncpy(tm->zone, q, s - q);
+				tzo = 0;
+				ok = 1;
+				goto Zoneparsed;
+			}
+			goto baddate;
+Zoneparsed:
+			break;
+		case 'A':
+		case 'a':
+			if(cistrncmp(s, "am", 2) == 0)
+				ampm = 0;
+			else if(cistrncmp(s, "pm", 2) == 0)
+				ampm = 1;
+			else
+				goto baddate;
+			s += 2;
+			break;
+		case '[':
+			depth = 1;
+			while(*p){
+				if(*p == '[')
+					depth++;
+				if(*p == ']')
+					depth--;
+				if(*p == '\\')
+					p++;
+				if(depth == 0)
+					break;
+				if(*s == 0)
+					goto baddate;
+				if(*s++ != *p++)
+					goto baddate;
+			}
+			if(*p != ']')
+				goto badfmt;
+			p++;
+			break;
+		case '_':
+		case ',':
+		case ' ':
+
+			if(*s != ' ' && *s != '\t' && *s != ',' && *s != '\n' && *s != '\0')
+				goto baddate;
+			p += strspn(p, " ,_\t\n");
+			s += strspn(s, " ,\t\n");
+			break;
+		default:
+			if(*s == 0)
+				goto baddate;
+			if(*s++ != c0)
+				goto baddate;
+			break;
+		}
+		if(!ok)
+			goto baddate;
+	}
+	if(*p != '\0')
+		goto baddate;
+	if(ep != nil)
+		*ep = s;
+	if(!sloppy && ampm != -1 && (tm->hour < 1 || tm->hour > 12))
+		goto baddate;
+	if(ampm == 0 && tm->hour == 12)
+		tm->hour = 0;
+	else if(ampm == 1 && tm->hour < 12)
+		tm->hour += 12;
+	/*
+	 * If we're allowing sloppy date ranges,
+	 * we'll normalize out of range values.
+	 */
+	if(!sloppy){
+		if(tm->yday < 0 || tm->yday > 365 + isleap(tm->year + 1900))
+			goto baddate;
+		if(tm->wday < 0 || tm->wday > 6)
+			goto baddate;
+		if(tm->mon < 0 || tm->mon > 11)
+			goto baddate;
+		md = mdays[tm->mon];
+		if(tm->mon == 1 && isleap(tm->year + 1900))
+			md++;
+		if(tm->mday < 0 || tm->mday > md)
+			goto baddate;
+		if(tm->hour < 0 || tm->hour > 24)
+			goto baddate;
+		if(tm->min < 0 || tm->min > 59)
+			goto baddate;
+		if(tm->sec < 0 || tm->sec > 60)
+			goto baddate;
+		if(tm->nsec < 0 || tm->nsec > Nsec)
+			goto baddate;
+		if(tm->wday < 0 || tm->wday > 6)
+			goto baddate;
+	}
+
+	/*
+	 * Normalizing gives us the local time,
+	 * but because we havnen't applied the
+	 * timezone, we think we're GMT. So, we
+	 * need to shift backwards. Then, we move
+	 * the "GMT that was local" back to local
+	 * time.
+	 */
+	abs = tmnorm(tm);
+	tm->tzoff = tzo;
+	if(!zoned)
+		tzoffset(tz, abs, tm);
+	else if(zparsed != nil){
+		tzoffset(zparsed, abs, tm);
+		tzoffset(zparsed, abs + tm->tzoff, tm);
+	}
+	abs -= tm->tzoff;
+	if(tz != nil || !zoned)
+		tmtimens(tm, abs, tm->nsec, tz);
+	return tm;
+baddate:
+	werrstr("invalid date %s", str);
+	return nil;
+badfmt:
+	werrstr("garbled format %s near '%s'", fmt, p);
+	return nil;			
+}
+
+Tmfmt
+tmfmt(Tm *d, char *fmt)
+{
+	return (Tmfmt){fmt, d};
+}
+
+void
+tmfmtinstall(void)
+{
+	fmtinstall(L'τ', τconv);
+}
+
+/* These legacy functions need access to τconv */
+static char*
+dotmfmt(Fmt *f, ...)
+{
+	static char buf[30];
+	va_list ap;
+
+	va_start(ap, f);
+	f->runes = 0;
+	f->start = buf;
+	f->to = buf;
+	f->stop = buf + sizeof(buf) - 1;
+	f->flush = nil;
+	f->farg = nil;
+	f->nfmt = 0;
+	f->args = ap;
+	τconv(f);
+	va_end(ap);
+	buf[sizeof(buf) - 1] = 0;
+	return buf;
+}
+
+char*
+asctime(Tm* tm)
+{
+	Tmfmt tf;
+	Fmt f;
+
+	tf = tmfmt(tm, "WW MMM _D hh:mm:ss ZZZ YYYY\n");
+	return dotmfmt(&f, tf);
+}
+
--- a/sys/src/libc/port/mkfile
+++ b/sys/src/libc/port/mkfile
@@ -20,6 +20,7 @@
 	cleanname.c\
 	crypt.c\
 	ctype.c\
+	date.c\
 	encodefmt.c\
 	execl.c\
 	exits.c\