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/*
* The MIT License (MIT)
*
* Copyright (c) 2015 Derick Rethans
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "timelib.h"
static int m_table_common[13] = { -1, 0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; /* 1 = jan */
static int m_table_leap[13] = { -1, 6, 2, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; /* 1 = jan */
static timelib_sll positive_mod(timelib_sll x, timelib_sll y)
{
timelib_sll tmp;
tmp = x % y;
if (tmp < 0) {
tmp += y;
}
return tmp;
}
static timelib_sll century_value(timelib_sll j)
{
return 6 - positive_mod(j, 4) * 2;
}
static timelib_sll timelib_day_of_week_ex(timelib_sll y, timelib_sll m, timelib_sll d, int iso)
{
timelib_sll c1, y1, m1, dow;
/* Only valid for Gregorian calendar, commented out as we don't handle
* Julian calendar. We just return the 'wrong' day of week to be
* consistent. */
c1 = century_value(y / 100);
y1 = positive_mod(y, 100);
m1 = timelib_is_leap(y) ? m_table_leap[m] : m_table_common[m];
dow = positive_mod((c1 + y1 + m1 + (y1 / 4) + d), 7);
if (iso) {
if (dow == 0) {
dow = 7;
}
}
return dow;
}
timelib_sll timelib_day_of_week(timelib_sll y, timelib_sll m, timelib_sll d)
{
return timelib_day_of_week_ex(y, m, d, 0);
}
timelib_sll timelib_iso_day_of_week(timelib_sll y, timelib_sll m, timelib_sll d)
{
return timelib_day_of_week_ex(y, m, d, 1);
}
/* jan feb mar apr may jun jul aug sep oct nov dec */
static int d_table_common[13] = { 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
static int d_table_leap[13] = { 0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 };
static int ml_table_common[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
static int ml_table_leap[13] = { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
timelib_sll timelib_day_of_year(timelib_sll y, timelib_sll m, timelib_sll d)
{
return (timelib_is_leap(y) ? d_table_leap[m] : d_table_common[m]) + d - 1;
}
timelib_sll timelib_days_in_month(timelib_sll y, timelib_sll m)
{
return timelib_is_leap(y) ? ml_table_leap[m] : ml_table_common[m];
}
void timelib_isoweek_from_date(timelib_sll y, timelib_sll m, timelib_sll d, timelib_sll *iw, timelib_sll *iy)
{
int y_leap, prev_y_leap, doy, jan1weekday, weekday;
y_leap = timelib_is_leap(y);
prev_y_leap = timelib_is_leap(y-1);
doy = timelib_day_of_year(y, m, d) + 1;
if (y_leap && m > 2) {
doy++;
}
jan1weekday = timelib_day_of_week(y, 1, 1);
weekday = timelib_day_of_week(y, m, d);
if (weekday == 0) weekday = 7;
if (jan1weekday == 0) jan1weekday = 7;
/* Find if Y M D falls in YearNumber Y-1, WeekNumber 52 or 53 */
if (doy <= (8 - jan1weekday) && jan1weekday > 4) {
*iy = y - 1;
if (jan1weekday == 5 || (jan1weekday == 6 && prev_y_leap)) {
*iw = 53;
} else {
*iw = 52;
}
} else {
*iy = y;
}
/* 8. Find if Y M D falls in YearNumber Y+1, WeekNumber 1 */
if (*iy == y) {
int i;
i = y_leap ? 366 : 365;
if ((i - (doy - y_leap)) < (4 - weekday)) {
*iy = y + 1;
*iw = 1;
return;
}
}
/* 9. Find if Y M D falls in YearNumber Y, WeekNumber 1 through 53 */
if (*iy == y) {
int j;
j = doy + (7 - weekday) + (jan1weekday - 1);
*iw = j / 7;
if (jan1weekday > 4) {
*iw -= 1;
}
}
}
timelib_sll timelib_daynr_from_weeknr(timelib_sll y, timelib_sll w, timelib_sll d)
{
timelib_sll dow, day;
/* Figure out the dayofweek for y-1-1 */
dow = timelib_day_of_week(y, 1, 1);
/* then use that to figure out the offset for day 1 of week 1 */
day = 0 - (dow > 4 ? dow - 7 : dow);
/* Add weeks and days */
return day + ((w - 1) * 7) + d;
}
int timelib_valid_time(timelib_sll h, timelib_sll i, timelib_sll s)
{
if (h < 0 || h > 23 || i < 0 || i > 59 || s < 0 || s > 59) {
return 0;
}
return 1;
}
int timelib_valid_date(timelib_sll y, timelib_sll m, timelib_sll d)
{
if (m < 1 || m > 12 || d < 1 || d > timelib_days_in_month(y, m)) {
return 0;
}
return 1;
}
#if 0
int main(void)
{
printf("dow = %d\n", timelib_day_of_week(1978, 12, 22)); /* 5 */
printf("dow = %d\n", timelib_day_of_week(2005, 2, 19)); /* 6 */
}
#endif
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