diff options
Diffstat (limited to 'watch-library/watch')
| -rw-r--r-- | watch-library/watch/watch_utility.c | 35 | ||||
| -rw-r--r-- | watch-library/watch/watch_utility.h | 21 |
2 files changed, 56 insertions, 0 deletions
diff --git a/watch-library/watch/watch_utility.c b/watch-library/watch/watch_utility.c index bfa3073a..df808404 100644 --- a/watch-library/watch/watch_utility.c +++ b/watch-library/watch/watch_utility.c @@ -35,6 +35,41 @@ const char * watch_utility_get_weekday(watch_date_time date_time) { return weekdays[(date_time.unit.day + 13 * (date_time.unit.month + 1) / 5 + date_time.unit.year + date_time.unit.year / 4 + 525) % 7]; } +uint32_t watch_utility_convert_to_unix_time(uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second, uint32_t utc_offset) { + uint16_t DAYS_SO_FAR[] = { + 0, // Jan + 31, // Feb + 59, // March + 90, // April + 120, // May + 151, // June + 181, // July + 212, // August + 243, // September + 273, // October + 304, // November + 334 // December + }; + + + uint32_t year_adj = year + 4800; + uint32_t febs = year_adj - (month <= 2 ? 1 : 0); /* Februaries since base. */ + uint32_t leap_days = 1 + (febs / 4) - (febs / 100) + (febs / 400); + uint32_t days = 365 * year_adj + leap_days + DAYS_SO_FAR[month - 1] + day - 1; + days -= 2472692; /* Adjust to Unix epoch. */ + + uint32_t timestamp = days * 86400; + timestamp += (hour + utc_offset) * 3600; + timestamp += minute * 60; + timestamp += second; + + return timestamp; +} + +uint32_t watch_utility_date_time_to_unix_time(watch_date_time date_time, uint32_t utc_offset) { + return watch_utility_convert_to_unix_time(date_time.unit.year + WATCH_RTC_REFERENCE_YEAR, date_time.unit.month, date_time.unit.day, date_time.unit.hour, date_time.unit.minute, date_time.unit.second, utc_offset); +} + float watch_utility_thermistor_temperature(uint16_t value, bool highside, float b_coefficient, float nominal_temperature, float nominal_resistance, float series_resistance) { float reading = (float)value; diff --git a/watch-library/watch/watch_utility.h b/watch-library/watch/watch_utility.h index aada783f..a6035dc3 100644 --- a/watch-library/watch/watch_utility.h +++ b/watch-library/watch/watch_utility.h @@ -38,6 +38,27 @@ */ const char * watch_utility_get_weekday(watch_date_time date_time); +/** @brief Returns the UNIX time (seconds since 1970) for a given date/time in UTC. + * @param date_time The watch_date_time that you wish to convert. + * @param year The year of the date you wish to convert. + * @param month The month of the date you wish to convert. + * @param day The day of the date you wish to convert. + * @param hour The hour of the date you wish to convert. + * @param minute The minute of the date you wish to convert. + * @param second The second of the date you wish to convert. + * @return A UNIX timestamp for the given date/time and UTC offset. + * @note Implemented by Wesley Ellis (tahnok) and based on BSD-licensed code by Josh Haberman: + * https://blog.reverberate.org/2020/05/12/optimizing-date-algorithms.html + */ +uint32_t watch_utility_convert_to_unix_time(uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second, uint32_t utc_offset); + +/** @brief Returns the UNIX time (seconds since 1970) for a given watch_date_time struct. + * @param date_time The watch_date_time that you wish to convert. + * @param utc_offset The number of seconds that date_time is offset from UTC, or 0 if the time is UTC. + * @return A UNIX timestamp for the given watch_date_time and UTC offset. + */ +uint32_t watch_utility_date_time_to_unix_time(watch_date_time date_time, uint32_t utc_offset); + /** @brief Returns a temperature in degrees Celsius for a given thermistor voltage divider circuit. * @param value The raw analog reading from the thermistor pin (0-65535) * @param highside True if the thermistor is connected to VCC and the series resistor is connected |