Commit 1b8fa736 authored by Richard M. Stallman's avatar Richard M. Stallman

(Fencode_time): Rewrite by Naggum.

parent 61392e7b
......@@ -741,15 +741,15 @@ This is the reverse operation of `decode-time', which see. ZONE defaults\n\
to the current time zone and daylight savings time if not specified; if\n\
specified, it can be either a list (as from `current-time-zone') or an\n\
integer (as from `decode-time'), and is applied without consideration for\n\
daylight savings time. If YEAR is less than 100, values in the range 0 to\n\
37 are interpreted as in the 21st century, all other values are in the 20th\n\
century.")
daylight savings time.\n\
If YEAR is less than 100, values in the range 0 through 69 are treated\n\
as 2000 through 2069; values 70 through 99 are treated as 1970...1999.")
(sec, min, hour, day, month, year, zone)
Lisp_Object sec, min, hour, day, month, year, zone;
{
double universal;
int fullyear, mon;
static char days[11] = { 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31 };
time_t time;
int fullyear, mon, days, seconds, tz = 0;
static char days_per_month[11] = { 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31 };
CHECK_NATNUM (sec, 0);
CHECK_NATNUM (min, 1);
......@@ -761,62 +761,79 @@ century.")
fullyear = XINT (year);
if (fullyear < 100)
{
if (fullyear < 38) /* end of time: 2038-01-19 03:14:08 */
if (fullyear < 70) /* Epoch is 1970. */
fullyear += 2000;
else
fullyear += 1900;
}
if (NILP (zone))
zone = Fcurrent_time_zone (Qnil);
if (CONSP (zone))
zone = Fcar (zone);
CHECK_NUMBER (zone, 6);
/* all of these should evaluate to compile-time constants. */
#define MIN 60.0 /* 60 */
#define HOUR (60*MIN) /* 3600 */
#define DAY (24*HOUR) /* 86400 */
#define YEAR (365*DAY) /* 31536000 */
#define YEAR4 (4*YEAR+DAY) /* 126230400 */
#define YEAR100 (25*YEAR4-DAY) /* 3155673600 */
#define YEAR400 (4*YEAR100+DAY) /* 12622780800 */
#define YEAR1900 (4*YEAR400+3*YEAR100) /* 59958144000 */
#define YEAR1970 (YEAR1900+17*YEAR4+2*YEAR) /* 62167132800 */
#define LEAPBIAS (59*DAY) /* 5097600 */
mon = XINT (month) - 1;
fullyear--;
mon += 10;
fullyear += mon/12;
/* Adjust incoming datespec to epoch = March 1, year 0. */
mon = XINT (month) - 1 + 10;
fullyear += mon/12 - 1;
mon %= 12;
universal = XINT (sec) + XINT (min) * MIN + XINT (hour) * HOUR;
while (mon-- > 0)
universal += days[mon] * DAY;
universal += (XINT (day) - 1) * DAY;
universal += YEAR400 * (fullyear/400);
days = XINT (day) - 1; /* day of month */
while (mon-- > 0) /* day of year */
days += days_per_month[mon];
days += 146097 * (fullyear/400); /* 400 years = 146097 days */
fullyear %= 400;
universal += YEAR100 * (fullyear/100);
days += 36524 * (fullyear/100); /* 100 years = 36524 days */
fullyear %= 100;
universal += YEAR4 * (fullyear/4);
days += 1461 * (fullyear/4); /* 4 years = 1461 days */
fullyear %= 4;
universal += YEAR * fullyear;
universal -= YEAR1970 - LEAPBIAS;
return make_time ((int)(universal - XINT (zone)));
#undef MIN
#undef HOUR
#undef DAY
#undef YEAR
#undef YEAR4
#undef YEAR100
#undef YEAR400
#undef YEAR1900
#undef YEAR1970
#undef LEAPBIAS
days += 365 * fullyear; /* 1 year = 365 days */
/* Adjust computed datespec to epoch = January 1, 1970. */
days += 59; /* March 1 is 59th day. */
days -= 719527; /* 1970 years = 719527 days */
seconds = XINT (sec) + 60 * XINT (min) + 3600 * XINT (hour);
if (sizeof (time_t) == 4
&& ((days+(seconds/86400) > 24854) || (days+(seconds/86400) < -24854)))
error ("the specified time is outside the representable range");
time = days * 86400 + seconds;
/* We have the correct value for UTC. Adjust for timezones. */
if (NILP (zone))
{
struct tm gmt, *t;
time_t adjusted_time;
int adjusted_tz;
/* If the system does not use timezones, gmtime returns 0, and we
already have the correct value, by definition. */
if ((t = gmtime (&time)) != 0)
{
gmt = *t;
t = localtime (&time);
tz = difftm (t, &gmt);
/* The timezone returned is that at the specified Universal Time,
not the local time, which is what we want. Adjust, repeat. */
adjusted_time = time - tz;
gmt = *gmtime (&adjusted_time); /* this is safe now */
t = localtime (&adjusted_time);
adjusted_tz = difftm (t, &gmt);
/* In case of discrepancy, adjust again for extra accuracy. */
if (adjusted_tz != tz)
{
adjusted_time = time - adjusted_tz;
gmt = *gmtime (&adjusted_time);
t = localtime (&adjusted_time);
adjusted_tz = difftm (t, &gmt);
}
tz = adjusted_tz;
}
}
else
{
if (CONSP (zone))
zone = Fcar (zone);
CHECK_NUMBER (zone, 6);
tz = XINT (zone);
}
return make_time (time - tz);
}
DEFUN ("current-time-string", Fcurrent_time_string, Scurrent_time_string, 0, 1, 0,
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment