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RIOT/sys/include/rtc_utils.h
2022-06-12 15:49:01 +02:00

101 lines
2.6 KiB
C

/*
* Copyright (C) 2019 ML!PA Consulting GmbH
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @defgroup sys_rtc_utils RTC helpers
* @ingroup sys
* @brief Common RTC helper functions
* @{
* @file
*
* @author Benjamin Valentin <benjamin.valentin@ml-pa.com>
*/
#ifndef RTC_UTILS_H
#define RTC_UTILS_H
#include <stdbool.h>
#include <stdint.h>
#include <time.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Normalize the time struct
*
* @note The function modifies the fields of the tm structure as follows:
* If structure members are outside their valid interval,
* they will be normalized.
* So that, for example, 40 October is changed into 9 November.
*
* If RTC_NORMALIZE_COMPAT is 1 `tm_wday` and `tm_yday` are set
* to values determined from the contents of the other fields.
*
* @param time Pointer to the struct to normalize.
*/
void rtc_tm_normalize(struct tm *time);
/**
* @brief Compare two time structs.
*
* @pre The time structs @p a and @p b are assumed to be normalized.
* Use @ref rtc_tm_normalize to normalize a struct tm that has been
* manually edited.
*
* @param[in] a The first time struct.
* @param[in] b The second time struct.
*
* @return an integer < 0 if a is earlier than b
* @return an integer > 0 if a is later than b
* @return 0 if a and b are equal
*/
int rtc_tm_compare(const struct tm *a, const struct tm *b);
/**
* @brief Convert time struct into timestamp.
*
* @pre The time struct t is assumed to be normalized.
* Use @ref rtc_tm_normalize to normalize a struct tm that has been
* manually edited.
*
* @param[in] t The time struct to convert
*
* @return elapsed seconds since `RIOT_EPOCH`
*/
uint32_t rtc_mktime(struct tm *t);
/**
* @brief Converts an RTC timestamp into a time struct.
*
* @param[in] time elapsed seconds since `RIOT_EPOCH`
* @param[out] t the corresponding timestamp
*/
void rtc_localtime(uint32_t time, struct tm *t);
/**
* @brief Verify that a time struct @p t contains valid data.
*
* @note This function checks whether the fields of the
* struct @p t are positive and within the bounds set
* by @ref rtc_tm_normalize.
*
* @param[in] t The struct to be checked.
*
* @return true when valid, false if not
*/
bool rtc_tm_valid(const struct tm *t);
#ifdef __cplusplus
}
#endif
#endif /* RTC_UTILS_H */
/** @} */