lib9: rewrite date routines to use /usr/share/zoneinfo directly

1 files changed, 110 insertions, 0 deletions

diff --git a/src/lib9/tm2sec.c b/src/lib9/tm2sec.c
new file mode 100644
index 00000000..5edf439d
--- /dev/null
+++ b/src/lib9/tm2sec.c
@@ -0,0 +1,110 @@
+#include <u.h>
+#include <libc.h>
+
+#include "zoneinfo.h"
+
+#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)
+{
+	Tinfo ti0, ti1, *ti;
+	long secs;
+	int i, yday, year, *d2m;
+
+	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;
+
+	/*
+	 * Assume the local time zone if zone is not GMT
+	 */
+	if(strcmp(tm->zone, "GMT") != 0) {
+		i = zonelookuptinfo(&ti0, secs);
+		ti = &ti0;
+		if (i != -1)
+		if (ti->tzoff!=0) {
+			/*
+			 * to what local time period `secs' belongs?
+			 */
+			if (ti->tzoff>0) {
+				/*
+				 * east of GMT; check previous local time transition
+				 */
+				if (ti->t+ti->tzoff > secs)
+				if (zonetinfo(&ti1, i-1)!=-1)
+					ti = &ti1;
+			} else
+				/*
+				 * west of GMT; check next local time transition
+				 */
+				if (zonetinfo(&ti1, i+1))
+				if (ti1.t+ti->tzoff < secs)
+					ti = &ti1;
+//			fprint(2, "tt: %ld+%d %ld\n", (long)ti->t, ti->tzoff, (long)secs);
+			secs -= ti->tzoff;
+		}
+	}
+	
+	if(secs < 0)
+		secs = 0;
+	return secs;
+}