upstream/opnsense-src
1
0
Fork 0
mirror of https://github.com/opnsense/src.git synced 2026-06-11 01:30:30 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Use a slightly better documented way of calculating easter and

Browse source 
include a reference to the Calendar FAQ. Also make argument parsing
a little more robust.

PR:		23881
This commit is contained in:
David Malone 2001-01-02 11:35:57 +00:00
parent 925c0d6804
commit db3626fb72
2 changed files with 35 additions and 58 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

36
usr.bin/calendar/day.c
View file

@ -165,17 +165,13 @@ settime(now)
time_t Mktime (dp)
char *dp;
{
char *date;
time_t t;
int len;
int d, m, y;
struct tm tm;
if ((date = strdup(dp)) == NULL)
errx(1, "strdup failed in Mktime");
(void)time(&t);
tp = localtime(&t);
len = strlen(date);
tm.tm_sec = 0;
tm.tm_min = 0;
tm.tm_hour = 0;
@ -184,31 +180,23 @@ time_t Mktime (dp)
tm.tm_mon = tp->tm_mon;
tm.tm_year = tp->tm_year;
/* day */
*(date+2) = '\0';
tm.tm_mday = atoi(date);
/* month */
if (len >= 4) {
*(date+5) = '\0';
tm.tm_mon = atoi(date+3) - 1;
}
/* Year */
if (len >= 7) {
tm.tm_year = atoi(date+6);
/* tm_year up 1900 ... */
if (tm.tm_year > 1900)
tm.tm_year -= 1900;
switch (sscanf(dp, "%d.%d.%d", &d, &m, &y)) {
case 3:
if (y > 1900)
y -= 1900;
tm.tm_year = y;
/* FALLTHROUGH */
case 2:
tm.tm_mon = m - 1;
/* FALLTHROUGH */
case 1:
tm.tm_mday = d;
}
#ifdef DEBUG
fprintf(stderr, "Mktime: %d %d %d %s\n", (int)mktime(&tm), (int)t, len,
asctime(&tm));
#endif
free(date);
return(mktime(&tm));
}

57
usr.bin/calendar/ostern.c
View file

@ -35,46 +35,35 @@
/* return year day for Easter */
/*
* This code is based on the Calendar FAQ's code for how to calculate
* easter is. This is the Gregorian calendar version. They refer to
* the Algorithm of Oudin in the "Explanatory Supplement to the
* Astronomical Almanac".
*/
int easter (year)
int year; /* 0 ... abcd, NOT since 1900 */
{
int G, /* Golden number - 1 */
C, /* Century */
H, /* 23 - epact % 30 */
I, /* days from 21 March to Paschal full moon */
J, /* weekday of full moon */
L; /* days from 21 March to Sunday on of before full moon */
int e_a, e_b, e_c, e_d, e_e,e_f, e_g, e_h, e_i, e_k,
e_l, e_m, e_n, e_p, e_q;
G = year % 19;
C = year / 100;
H = (C - C/4 - (8*C+13)/25 + 19*G + 15) % 30;
I = H - (H/28)*(1 - (H/28)*(29/(H + 1))*((21 - G)/11));
J = (year + year/4 + I + 2 - C + C/4) % 7;
/* silly, but it works */
e_a = year % 19;
e_b = year / 100;
e_c = year % 100;
L = I - J;
e_d = e_b / 4;
e_e = e_b % 4;
e_f = (e_b + 8) / 25;
e_g = (e_b + 1 - e_f) / 3;
e_h = ((19 * e_a) + 15 + e_b - (e_d + e_g)) % 30;
e_i = e_c / 4;
e_k = e_c % 4;
e_l = (32 + 2 * e_e + 2 * e_i - (e_h + e_k)) % 7;
e_m = (e_a + 11 * e_h + 22 * e_l) / 451;
e_n = (e_h + e_l + 114 - (7 * e_m)) / 31;
e_p = (e_h + e_l + 114 - (7 * e_m)) % 31;
e_p = e_p + 1;
e_q = 31 + 28;
if (e_k == 0 && e_c != 0)
e_q += 1;
if (e_n == 4)
e_q += 31;
e_q += e_p;
#if DEBUG
printf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d\n", e_a , e_b , e_c , e_d , e_e , e_f , e_g , e_h , e_i , e_k , e_l , e_m , e_n , e_p , e_q);
#endif
return (e_q);
if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
return 31 + 29 + 21 + L + 7;
else
return 31 + 28 + 21 + L + 7;
}
/* return year day for Easter or easter depending days