libc, seconds: new time and date apis (try 2)

Redo date handling in libc almost entirely. This allows
handling dates and times from outside your timezones,
fixes timezone loading in multithreaded applications,
and allows parsing and formatting using custom format
strings.

As a test of the APIs, we replace the formatting code in
seconds(1), shrinking it massively.

The last commit missed a few removals, and made it
unnecessarily hard to do an update.

1 files changed, 2 insertions, 195 deletions

diff --git a/sys/src/libc/9sys/tm2sec.c b/sys/src/libc/9sys/tm2sec.c
index 20bebd0c8..96d4c3d61 100644
--- a/sys/src/libc/9sys/tm2sec.c
+++ b/sys/src/libc/9sys/tm2sec.c
@@ -1,202 +1,9 @@
 #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;
-
-	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;
+	tmnorm(tm);
+	return tm->abs;
 }