mbed_mktime.h

00001 
00002 /** \addtogroup platform */
00003 /** @{*/
00004 /* mbed Microcontroller Library
00005  * Copyright (c) 2017-2017 ARM Limited
00006  * SPDX-License-Identifier: Apache-2.0
00007  *
00008  * Licensed under the Apache License, Version 2.0 (the "License");
00009  * you may not use this file except in compliance with the License.
00010  * You may obtain a copy of the License at
00011  *
00012  *     http://www.apache.org/licenses/LICENSE-2.0
00013  *
00014  * Unless required by applicable law or agreed to in writing, software
00015  * distributed under the License is distributed on an "AS IS" BASIS,
00016  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00017  * See the License for the specific language governing permissions and
00018  * limitations under the License.
00019  */
00020 
00021 #ifndef MBED_MKTIME_H
00022 #define MBED_MKTIME_H
00023 
00024 #include <time.h>
00025 #include <stdbool.h>
00026 #include <stdint.h>
00027 
00028 #ifdef __cplusplus
00029 extern "C" {
00030 #endif
00031 
00032 /**
00033  * \defgroup platform_mktime mktime functions
00034  * @{
00035  */
00036 
00037 /* Time range across the whole 32-bit range should be supported which means that years in range 1970 - 2106 can be
00038  * encoded. We have two types of RTC devices:
00039  * a) RTCs which handles all leap years in the mentioned year range correctly. Leap year is determined by checking if
00040  *    the year counter value is divisible by 400, 100, and 4. No problem here.
00041  * b) RTCs which handles leap years correctly up to 2100. The RTC does a simple bit comparison to see if the two
00042  *    lowest order bits of the year counter are zero. In this case 2100 year will be considered
00043  *    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
00044  *    29.02.2100 (invalid). So after 28.02.2100 the day counter will be off by a day.
00045  */
00046 typedef enum {
00047     RTC_FULL_LEAP_YEAR_SUPPORT,
00048     RTC_4_YEAR_LEAP_YEAR_SUPPORT
00049 } rtc_leap_year_support_t;
00050 
00051 /** Compute if a year is a leap year or not.
00052  *
00053  * @param year The year to test it shall be in the range [70:206]. Year 0 is
00054  * translated into year 1900 CE.
00055  * @param leap_year_support use RTC_FULL_LEAP_YEAR_SUPPORT if RTC device is able
00056  * to correctly detect all leap years in range [70:206] otherwise use RTC_4_YEAR_LEAP_YEAR_SUPPORT.
00057  *
00058  * @return true if the year in input is a leap year and false otherwise.
00059  *
00060  * @note For use by the HAL only
00061  * @note Year 2100 is treated differently for devices with full leap year support and devices with
00062  * partial leap year support. Devices with partial leap year support treats 2100 as a leap year.
00063  */
00064 bool _rtc_is_leap_year(int year, rtc_leap_year_support_t leap_year_support);
00065 
00066 /* Convert a calendar time into time since UNIX epoch as a time_t.
00067  *
00068  * This function is a thread safe (partial) replacement for mktime. It is
00069  * tailored around RTC peripherals needs and is not by any mean a complete
00070  * replacement of mktime.
00071  *
00072  * @param time The calendar time to convert into a time_t since epoch.
00073  * The fields from tm used for the computation are:
00074  *   - tm_sec
00075  *   - tm_min
00076  *   - tm_hour
00077  *   - tm_mday
00078  *   - tm_mon
00079  *   - tm_year
00080  * Other fields are ignored and won't be renormalized by a call to this function.
00081  * A valid calendar time is comprised between:
00082  * the 1st of January 1970 at 00:00:00 to the 7th of February 2106 at 06:28:15.
00083  * @param leap_year_support use RTC_FULL_LEAP_YEAR_SUPPORT if RTC device is able
00084  * to correctly detect all leap years in range [70:206] otherwise use RTC_4_YEAR_LEAP_YEAR_SUPPORT.
00085  * @param seconds holder for the result - calendar time as seconds since UNIX epoch.
00086  *
00087  * @return true on success, false if conversion error occurred.
00088  *
00089  * @note Leap seconds are not supported.
00090  * @note Values in output range from 0 to UINT_MAX.
00091  * @note Full and partial leap years support.
00092  * @note For use by the HAL only
00093  */
00094 bool _rtc_maketime(const struct tm *time, time_t *seconds, rtc_leap_year_support_t leap_year_support);
00095 
00096 /* Convert a given time in seconds since epoch into calendar time.
00097  *
00098  * This function is a thread safe (partial) replacement for localtime. It is
00099  * tailored around RTC peripherals specification and is not by any means a
00100  * complete of localtime.
00101  *
00102  * @param timestamp The time (in seconds) to convert into calendar time. Valid
00103  * input are in the range [0 : UINT32_MAX].
00104  * @param calendar_time Pointer to the object which will contain the result of
00105  * the conversion. The tm fields filled by this function are:
00106  *   - tm_sec
00107  *   - tm_min
00108  *   - tm_hour
00109  *   - tm_mday
00110  *   - tm_mon
00111  *   - tm_year
00112  *   - tm_wday
00113  *   - tm_yday
00114  * The object remains untouched if the time in input is invalid.
00115  * @param leap_year_support use RTC_FULL_LEAP_YEAR_SUPPORT if RTC device is able
00116  * to correctly detect all leap years in range [70:206] otherwise use RTC_4_YEAR_LEAP_YEAR_SUPPORT.
00117  * @return true if the conversion was successful, false otherwise.
00118  *
00119  * @note For use by the HAL only.
00120  * @note Full and partial leap years support.
00121  */
00122 bool _rtc_localtime(time_t timestamp, struct tm *time_info, rtc_leap_year_support_t leap_year_support);
00123 
00124 /** @}*/
00125 
00126 #ifdef __cplusplus
00127 }
00128 #endif
00129 
00130 #endif /* MBED_MKTIME_H */
00131 
00132 /** @}*/