You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
circuitpython/lib/timeutils/timeutils.c

215 lines
6.5 KiB

/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
* Copyright (c) 2015 Daniel Campora
*
* 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 "py/obj.h"
#include "lib/timeutils/timeutils.h"
// LEAPOCH corresponds to 2000-03-01, which is a mod-400 year, immediately
// after Feb 29. We calculate seconds as a signed integer relative to that.
//
// Our timebase is relative to 2000-01-01.
#define LEAPOCH ((31 + 29) * 86400)
#define DAYS_PER_400Y (365*400 + 97)
#define DAYS_PER_100Y (365*100 + 24)
#define DAYS_PER_4Y (365*4 + 1)
STATIC const uint16_t days_since_jan1[]= { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
bool timeutils_is_leap_year(mp_uint_t year) {
return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0;
}
// month is one based
mp_uint_t timeutils_days_in_month(mp_uint_t year, mp_uint_t month) {
mp_uint_t mdays = days_since_jan1[month] - days_since_jan1[month - 1];
if (month == 2 && timeutils_is_leap_year(year)) {
mdays++;
}
return mdays;
}
// compute the day of the year, between 1 and 366
// month should be between 1 and 12, date should start at 1
mp_uint_t timeutils_year_day(mp_uint_t year, mp_uint_t month, mp_uint_t date) {
mp_uint_t yday = days_since_jan1[month - 1] + date;
if (month >= 3 && timeutils_is_leap_year(year)) {
yday += 1;
}
return yday;
}
void timeutils_seconds_since_2000_to_struct_time(mp_uint_t t, timeutils_struct_time_t *tm) {
// The following algorithm was adapted from musl's __secs_to_tm and adapted
// for differences in Micro Python's timebase.
mp_int_t seconds = t - LEAPOCH;
mp_int_t days = seconds / 86400;
seconds %= 86400;
if (seconds < 0) {
seconds += 86400;
days -= 1;
}
tm->tm_hour = seconds / 3600;
tm->tm_min = seconds / 60 % 60;
tm->tm_sec = seconds % 60;
mp_int_t wday = (days + 2) % 7; // Mar 1, 2000 was a Wednesday (2)
if (wday < 0) {
wday += 7;
}
tm->tm_wday = wday;
mp_int_t qc_cycles = days / DAYS_PER_400Y;
days %= DAYS_PER_400Y;
if (days < 0) {
days += DAYS_PER_400Y;
qc_cycles--;
}
mp_int_t c_cycles = days / DAYS_PER_100Y;
if (c_cycles == 4) {
c_cycles--;
}
days -= (c_cycles * DAYS_PER_100Y);
mp_int_t q_cycles = days / DAYS_PER_4Y;
if (q_cycles == 25) {
q_cycles--;
}
days -= q_cycles * DAYS_PER_4Y;
mp_int_t years = days / 365;
if (years == 4) {
years--;
}
days -= (years * 365);
/* We will compute tm_yday at the very end
mp_int_t leap = !years && (q_cycles || !c_cycles);
tm->tm_yday = days + 31 + 28 + leap;
if (tm->tm_yday >= 365 + leap) {
tm->tm_yday -= 365 + leap;
}
tm->tm_yday++; // Make one based
*/
tm->tm_year = 2000 + years + 4 * q_cycles + 100 * c_cycles + 400 * qc_cycles;
// Note: days_in_month[0] corresponds to March
STATIC const int8_t days_in_month[] = {31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31, 29};
mp_int_t month;
for (month = 0; days_in_month[month] <= days; month++) {
days -= days_in_month[month];
}
tm->tm_mon = month + 2;
if (tm->tm_mon >= 12) {
tm->tm_mon -= 12;
tm->tm_year++;
}
tm->tm_mday = days + 1; // Make one based
tm->tm_mon++; // Make one based
tm->tm_yday = timeutils_year_day(tm->tm_year, tm->tm_mon, tm->tm_mday);
}
// returns the number of seconds, as an integer, since 2000-01-01
mp_uint_t timeutils_seconds_since_2000(mp_uint_t year, mp_uint_t month,
mp_uint_t date, mp_uint_t hour, mp_uint_t minute, mp_uint_t second) {
return
second
+ minute * 60
+ hour * 3600
+ (timeutils_year_day(year, month, date) - 1
+ ((year - 2000 + 3) / 4) // add a day each 4 years starting with 2001
- ((year - 2000 + 99) / 100) // subtract a day each 100 years starting with 2001
+ ((year - 2000 + 399) / 400) // add a day each 400 years starting with 2001
) * 86400
+ (year - 2000) * 31536000;
}
mp_uint_t timeutils_mktime(mp_uint_t year, mp_int_t month, mp_int_t mday,
mp_int_t hours, mp_int_t minutes, mp_int_t seconds) {
// Normalize the tuple. This allows things like:
//
// tm_tomorrow = list(time.localtime())
// tm_tomorrow[2] += 1 # Adds 1 to mday
// tomorrow = time.mktime(tm_tomorrow)
//
// And not have to worry about all the weird overflows.
//
// You can subtract dates/times this way as well.
minutes += seconds / 60;
if ((seconds = seconds % 60) < 0) {
seconds += 60;
minutes--;
}
hours += minutes / 60;
if ((minutes = minutes % 60) < 0) {
minutes += 60;
hours--;
}
mday += hours / 24;
if ((hours = hours % 24) < 0) {
hours += 24;
mday--;
}
month--; // make month zero based
year += month / 12;
if ((month = month % 12) < 0) {
month += 12;
year--;
}
month++; // back to one based
while (mday < 1) {
if (--month == 0) {
month = 12;
year--;
}
mday += timeutils_days_in_month(year, month);
}
while ((mp_uint_t)mday > timeutils_days_in_month(year, month)) {
mday -= timeutils_days_in_month(year, month);
if (++month == 13) {
month = 1;
year++;
}
}
return timeutils_seconds_since_2000(year, month, mday, hours, minutes, seconds);
}