Import sources from 2011-03-30 iso image

1 files changed, 304 insertions, 0 deletions

diff --git a/sys/src/libc/9sys/ctime.c b/sys/src/libc/9sys/ctime.c
new file mode 100755
index 000000000..d841b64e9
--- /dev/null
+++ b/sys/src/libc/9sys/ctime.c
@@ -0,0 +1,304 @@
+/*
+ * 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;
+
+	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;
+}
+
+Tm*
+gmtime(long tim)
+{
+	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;
+}
+
+char*
+asctime(Tm *t)
+{
+	char *ncp;
+	static char cbuf[30];
+
+	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;
+	if(t->year >= 100) {
+		cbuf[24] = '2';
+		cbuf[25] = '0';
+	}
+	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;
+}