mbed-os/platform/mbed_mktime.h

132 lines
4.9 KiB
C

/** \addtogroup platform */
/** @{*/
/* mbed Microcontroller Library
* Copyright (c) 2017-2017 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MBED_MKTIME_H
#define MBED_MKTIME_H
#include <time.h>
#include <stdbool.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* \defgroup platform_mktime mktime functions
* @{
*/
/* Time range across the whole 32-bit range should be supported which means that years in range 1970 - 2106 can be
* encoded. We have two types of RTC devices:
* a) RTCs which handles all leap years in the mentioned year range correctly. Leap year is determined by checking if
* the year counter value is divisible by 400, 100, and 4. No problem here.
* b) RTCs which handles leap years correctly up to 2100. The RTC does a simple bit comparison to see if the two
* lowest order bits of the year counter are zero. In this case 2100 year will be considered
* incorrectly as a leap year, so the last valid point in time will be 28.02.2100 23:59:59 and next day will be
* 29.02.2100 (invalid). So after 28.02.2100 the day counter will be off by a day.
*/
typedef enum {
RTC_FULL_LEAP_YEAR_SUPPORT,
RTC_4_YEAR_LEAP_YEAR_SUPPORT
} rtc_leap_year_support_t;
/** Compute if a year is a leap year or not.
*
* @param year The year to test it shall be in the range [70:206]. Year 0 is
* translated into year 1900 CE.
* @param leap_year_support use RTC_FULL_LEAP_YEAR_SUPPORT if RTC device is able
* to correctly detect all leap years in range [70:206] otherwise use RTC_4_YEAR_LEAP_YEAR_SUPPORT.
*
* @return true if the year in input is a leap year and false otherwise.
*
* @note For use by the HAL only
* @note Year 2100 is treated differently for devices with full leap year support and devices with
* partial leap year support. Devices with partial leap year support treats 2100 as a leap year.
*/
bool _rtc_is_leap_year(int year, rtc_leap_year_support_t leap_year_support);
/* Convert a calendar time into time since UNIX epoch as a time_t.
*
* This function is a thread safe (partial) replacement for mktime. It is
* tailored around RTC peripherals needs and is not by any mean a complete
* replacement of mktime.
*
* @param time The calendar time to convert into a time_t since epoch.
* The fields from tm used for the computation are:
* - tm_sec
* - tm_min
* - tm_hour
* - tm_mday
* - tm_mon
* - tm_year
* Other fields are ignored and won't be renormalized by a call to this function.
* A valid calendar time is comprised between:
* the 1st of January 1970 at 00:00:00 to the 7th of February 2106 at 06:28:15.
* @param leap_year_support use RTC_FULL_LEAP_YEAR_SUPPORT if RTC device is able
* to correctly detect all leap years in range [70:206] otherwise use RTC_4_YEAR_LEAP_YEAR_SUPPORT.
* @param seconds holder for the result - calendar time as seconds since UNIX epoch.
*
* @return true on success, false if conversion error occurred.
*
* @note Leap seconds are not supported.
* @note Values in output range from 0 to UINT_MAX.
* @note Full and partial leap years support.
* @note For use by the HAL only
*/
bool _rtc_maketime(const struct tm* time, time_t * seconds, rtc_leap_year_support_t leap_year_support);
/* Convert a given time in seconds since epoch into calendar time.
*
* This function is a thread safe (partial) replacement for localtime. It is
* tailored around RTC peripherals specification and is not by any means a
* complete of localtime.
*
* @param timestamp The time (in seconds) to convert into calendar time. Valid
* input are in the range [0 : UINT32_MAX].
* @param calendar_time Pointer to the object which will contain the result of
* the conversion. The tm fields filled by this function are:
* - tm_sec
* - tm_min
* - tm_hour
* - tm_mday
* - tm_mon
* - tm_year
* - tm_wday
* - tm_yday
* The object remains untouched if the time in input is invalid.
* @param leap_year_support use RTC_FULL_LEAP_YEAR_SUPPORT if RTC device is able
* to correctly detect all leap years in range [70:206] otherwise use RTC_4_YEAR_LEAP_YEAR_SUPPORT.
* @return true if the conversion was successful, false otherwise.
*
* @note For use by the HAL only.
* @note Full and partial leap years support.
*/
bool _rtc_localtime(time_t timestamp, struct tm* time_info, rtc_leap_year_support_t leap_year_support);
/** @}*/
#ifdef __cplusplus
}
#endif
#endif /* MBED_MKTIME_H */
/** @}*/