freebsd-dev/usr.bin/calendar/dates.c
Conrad Meyer fd1efedc79 Add extremely useful calendar(1) application to FreeBSD
It does extremely useful things like execute sendmail and spew dubiously
accurate factoids.

From the feedback, it seems like it is an essential utility in a modern unix
and not at all a useless bikeshed.  How do those Linux people live without it?
Reverts r358561.
2020-03-03 00:20:08 +00:00

454 lines
9.3 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1992-2009 Edwin Groothuis <edwin@FreeBSD.org>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdio.h>
#include <stdlib.h>
#include <err.h>
#include <time.h>
#include "calendar.h"
struct cal_year {
int year; /* 19xx, 20xx, 21xx */
int easter; /* Julian day */
int paskha; /* Julian day */
int cny; /* Julian day */
int firstdayofweek; /* 0 .. 6 */
struct cal_month *months;
struct cal_year *nextyear;
};
struct cal_month {
int month; /* 01 .. 12 */
int firstdayjulian; /* 000 .. 366 */
int firstdayofweek; /* 0 .. 6 */
struct cal_year *year; /* points back */
struct cal_day *days;
struct cal_month *nextmonth;
};
struct cal_day {
int dayofmonth; /* 01 .. 31 */
int julianday; /* 000 .. 366 */
int dayofweek; /* 0 .. 6 */
struct cal_day *nextday;
struct cal_month *month; /* points back */
struct cal_year *year; /* points back */
struct event *events;
};
int debug_remember = 0;
static struct cal_year *hyear = NULL;
/* 1-based month, 0-based days, cumulative */
int cumdaytab[][14] = {
{0, -1, 30, 58, 89, 119, 150, 180, 211, 242, 272, 303, 333, 364},
{0, -1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
};
/* 1-based month, individual */
static int *monthdays;
int monthdaytab[][14] = {
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 30},
{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 30},
};
static struct cal_day * find_day(int yy, int mm, int dd);
static void
createdate(int y, int m, int d)
{
struct cal_year *py, *pyp;
struct cal_month *pm, *pmp;
struct cal_day *pd, *pdp;
int *cumday;
pyp = NULL;
py = hyear;
while (py != NULL) {
if (py->year == y + 1900)
break;
pyp = py;
py = py->nextyear;
}
if (py == NULL) {
struct tm td;
time_t t;
py = (struct cal_year *)calloc(1, sizeof(struct cal_year));
py->year = y + 1900;
py->easter = easter(y);
py->paskha = paskha(y);
td = tm0;
td.tm_year = y;
td.tm_mday = 1;
t = mktime(&td);
localtime_r(&t, &td);
py->firstdayofweek = td.tm_wday;
if (pyp != NULL)
pyp->nextyear = py;
}
if (pyp == NULL) {
/* The very very very first one */
hyear = py;
}
pmp = NULL;
pm = py->months;
while (pm != NULL) {
if (pm->month == m)
break;
pmp = pm;
pm = pm->nextmonth;
}
if (pm == NULL) {
pm = (struct cal_month *)calloc(1, sizeof(struct cal_month));
pm->year = py;
pm->month = m;
cumday = cumdaytab[isleap(y)];
pm->firstdayjulian = cumday[m] + 2;
pm->firstdayofweek =
(py->firstdayofweek + pm->firstdayjulian -1) % 7;
if (pmp != NULL)
pmp->nextmonth = pm;
}
if (pmp == NULL)
py->months = pm;
pdp = NULL;
pd = pm->days;
while (pd != NULL) {
pdp = pd;
pd = pd->nextday;
}
if (pd == NULL) { /* Always true */
pd = (struct cal_day *)calloc(1, sizeof(struct cal_day));
pd->month = pm;
pd->year = py;
pd->dayofmonth = d;
pd->julianday = pm->firstdayjulian + d - 1;
pd->dayofweek = (pm->firstdayofweek + d - 1) % 7;
if (pdp != NULL)
pdp->nextday = pd;
}
if (pdp == NULL)
pm->days = pd;
}
void
generatedates(struct tm *tp1, struct tm *tp2)
{
int y1, m1, d1;
int y2, m2, d2;
int y, m, d;
y1 = tp1->tm_year;
m1 = tp1->tm_mon + 1;
d1 = tp1->tm_mday;
y2 = tp2->tm_year;
m2 = tp2->tm_mon + 1;
d2 = tp2->tm_mday;
if (y1 == y2) {
if (m1 == m2) {
/* Same year, same month. Easy! */
for (d = d1; d <= d2; d++)
createdate(y1, m1, d);
return;
}
/*
* Same year, different month.
* - Take the leftover days from m1
* - Take all days from <m1 .. m2>
* - Take the first days from m2
*/
monthdays = monthdaytab[isleap(y1)];
for (d = d1; d <= monthdays[m1]; d++)
createdate(y1, m1, d);
for (m = m1 + 1; m < m2; m++)
for (d = 1; d <= monthdays[m]; d++)
createdate(y1, m, d);
for (d = 1; d <= d2; d++)
createdate(y1, m2, d);
return;
}
/*
* Different year, different month.
* - Take the leftover days from y1-m1
* - Take all days from y1-<m1 .. 12]
* - Take all days from <y1 .. y2>
* - Take all days from y2-[1 .. m2>
* - Take the first days of y2-m2
*/
monthdays = monthdaytab[isleap(y1)];
for (d = d1; d <= monthdays[m1]; d++)
createdate(y1, m1, d);
for (m = m1 + 1; m <= 12; m++)
for (d = 1; d <= monthdays[m]; d++)
createdate(y1, m, d);
for (y = y1 + 1; y < y2; y++) {
monthdays = monthdaytab[isleap(y)];
for (m = 1; m <= 12; m++)
for (d = 1; d <= monthdays[m]; d++)
createdate(y, m, d);
}
monthdays = monthdaytab[isleap(y2)];
for (m = 1; m < m2; m++)
for (d = 1; d <= monthdays[m]; d++)
createdate(y2, m, d);
for (d = 1; d <= d2; d++)
createdate(y2, m2, d);
}
void
dumpdates(void)
{
struct cal_year *y;
struct cal_month *m;
struct cal_day *d;
y = hyear;
while (y != NULL) {
printf("%-5d (wday:%d)\n", y->year, y->firstdayofweek);
m = y->months;
while (m != NULL) {
printf("-- %-5d (julian:%d, dow:%d)\n", m->month,
m->firstdayjulian, m->firstdayofweek);
d = m->days;
while (d != NULL) {
printf(" -- %-5d (julian:%d, dow:%d)\n",
d->dayofmonth, d->julianday, d->dayofweek);
d = d->nextday;
}
m = m->nextmonth;
}
y = y->nextyear;
}
}
int
remember_ymd(int yy, int mm, int dd)
{
struct cal_year *y;
struct cal_month *m;
struct cal_day *d;
if (debug_remember)
printf("remember_ymd: %d - %d - %d\n", yy, mm, dd);
y = hyear;
while (y != NULL) {
if (y->year != yy) {
y = y->nextyear;
continue;
}
m = y->months;
while (m != NULL) {
if (m->month != mm) {
m = m->nextmonth;
continue;
}
d = m->days;
while (d != NULL) {
if (d->dayofmonth == dd)
return (1);
d = d->nextday;
continue;
}
return (0);
}
return (0);
}
return (0);
}
int
remember_yd(int yy, int dd, int *rm, int *rd)
{
struct cal_year *y;
struct cal_month *m;
struct cal_day *d;
if (debug_remember)
printf("remember_yd: %d - %d\n", yy, dd);
y = hyear;
while (y != NULL) {
if (y->year != yy) {
y = y->nextyear;
continue;
}
m = y->months;
while (m != NULL) {
d = m->days;
while (d != NULL) {
if (d->julianday == dd) {
*rm = m->month;
*rd = d->dayofmonth;
return (1);
}
d = d->nextday;
}
m = m->nextmonth;
}
return (0);
}
return (0);
}
int
first_dayofweek_of_year(int yy)
{
struct cal_year *y;
y = hyear;
while (y != NULL) {
if (y->year == yy)
return (y->firstdayofweek);
y = y->nextyear;
}
/* Should not happen */
return (-1);
}
int
first_dayofweek_of_month(int yy, int mm)
{
struct cal_year *y;
struct cal_month *m;
y = hyear;
while (y != NULL) {
if (y->year != yy) {
y = y->nextyear;
continue;
}
m = y->months;
while (m != NULL) {
if (m->month == mm)
return (m->firstdayofweek);
m = m->nextmonth;
}
/* No data for this month */
return (-1);
}
/* No data for this year. Error? */
return (-1);
}
int
walkthrough_dates(struct event **e)
{
static struct cal_year *y = NULL;
static struct cal_month *m = NULL;
static struct cal_day *d = NULL;
if (y == NULL) {
y = hyear;
m = y->months;
d = m->days;
*e = d->events;
return (1);
}
if (d->nextday != NULL) {
d = d->nextday;
*e = d->events;
return (1);
}
if (m->nextmonth != NULL) {
m = m->nextmonth;
d = m->days;
*e = d->events;
return (1);
}
if (y->nextyear != NULL) {
y = y->nextyear;
m = y->months;
d = m->days;
*e = d->events;
return (1);
}
return (0);
}
static struct cal_day *
find_day(int yy, int mm, int dd)
{
struct cal_year *y;
struct cal_month *m;
struct cal_day *d;
if (debug_remember)
printf("remember_ymd: %d - %d - %d\n", yy, mm, dd);
y = hyear;
while (y != NULL) {
if (y->year != yy) {
y = y->nextyear;
continue;
}
m = y->months;
while (m != NULL) {
if (m->month != mm) {
m = m->nextmonth;
continue;
}
d = m->days;
while (d != NULL) {
if (d->dayofmonth == dd)
return (d);
d = d->nextday;
continue;
}
return (NULL);
}
return (NULL);
}
return (NULL);
}
void
addtodate(struct event *e, int year, int month, int day)
{
struct cal_day *d;
d = find_day(year, month, day);
e->next = d->events;
d->events = e;
}