RTC auf true
Diff: platform/mbed_mktime.c
- Revision:
- 0:38ceb79fef03
diff -r 000000000000 -r 38ceb79fef03 platform/mbed_mktime.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/platform/mbed_mktime.c Wed Nov 28 15:10:15 2018 +0000 @@ -0,0 +1,193 @@ +/* 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. + */ + +#include "mbed_mktime.h" + +/* Time constants. */ +#define SECONDS_BY_MINUTES 60 +#define MINUTES_BY_HOUR 60 +#define SECONDS_BY_HOUR (SECONDS_BY_MINUTES * MINUTES_BY_HOUR) +#define HOURS_BY_DAY 24 +#define SECONDS_BY_DAY (SECONDS_BY_HOUR * HOURS_BY_DAY) +#define LAST_VALID_YEAR 206 + +/* Macros which will be used to determine if we are within valid range. */ +#define EDGE_TIMESTAMP_FULL_LEAP_YEAR_SUPPORT 3220095 // 7th of February 1970 at 06:28:15 +#define EDGE_TIMESTAMP_4_YEAR_LEAP_YEAR_SUPPORT 3133695 // 6th of February 1970 at 06:28:15 + +/* + * 2 dimensional array containing the number of seconds elapsed before a given + * month. + * The second index map to the month while the first map to the type of year: + * - 0: non leap year + * - 1: leap year + */ +static const uint32_t seconds_before_month[2][12] = { + { + 0, + 31 * SECONDS_BY_DAY, + (31 + 28) *SECONDS_BY_DAY, + (31 + 28 + 31) *SECONDS_BY_DAY, + (31 + 28 + 31 + 30) *SECONDS_BY_DAY, + (31 + 28 + 31 + 30 + 31) *SECONDS_BY_DAY, + (31 + 28 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY, + (31 + 28 + 31 + 30 + 31 + 30 + 31) *SECONDS_BY_DAY, + (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31) *SECONDS_BY_DAY, + (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30) *SECONDS_BY_DAY, + (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) *SECONDS_BY_DAY, + (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY, + }, + { + 0, + 31 * SECONDS_BY_DAY, + (31 + 29) *SECONDS_BY_DAY, + (31 + 29 + 31) *SECONDS_BY_DAY, + (31 + 29 + 31 + 30) *SECONDS_BY_DAY, + (31 + 29 + 31 + 30 + 31) *SECONDS_BY_DAY, + (31 + 29 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY, + (31 + 29 + 31 + 30 + 31 + 30 + 31) *SECONDS_BY_DAY, + (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31) *SECONDS_BY_DAY, + (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30) *SECONDS_BY_DAY, + (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) *SECONDS_BY_DAY, + (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY, + } +}; + +bool _rtc_is_leap_year(int year, rtc_leap_year_support_t leap_year_support) +{ + /* + * since in practice, the value manipulated by this algorithm lie in the + * range: [70 : 206] the algorithm can be reduced to: year % 4 with exception for 200 (year 2100 is not leap year). + * The algorithm valid over the full range of value is: + + year = 1900 + year; + if (year % 4) { + return false; + } else if (year % 100) { + return true; + } else if (year % 400) { + return false; + } + return true; + + */ + if (leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT && year == 200) { + return false; // 2100 is not a leap year + } + + return (year) % 4 ? false : true; +} + +bool _rtc_maketime(const struct tm *time, time_t *seconds, rtc_leap_year_support_t leap_year_support) +{ + if (seconds == NULL || time == NULL) { + return false; + } + + /* Partial check for the upper bound of the range - check years only. Full check will be performed after the + * elapsed time since the beginning of the year is calculated. + */ + if ((time->tm_year < 70) || (time->tm_year > LAST_VALID_YEAR)) { + return false; + } + + uint32_t result = time->tm_sec; + result += time->tm_min * SECONDS_BY_MINUTES; + result += time->tm_hour * SECONDS_BY_HOUR; + result += (time->tm_mday - 1) * SECONDS_BY_DAY; + result += seconds_before_month[_rtc_is_leap_year(time->tm_year, leap_year_support)][time->tm_mon]; + + /* Check if we are within valid range. */ + if (time->tm_year == LAST_VALID_YEAR) { + if ((leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT && result > EDGE_TIMESTAMP_FULL_LEAP_YEAR_SUPPORT) || + (leap_year_support == RTC_4_YEAR_LEAP_YEAR_SUPPORT && result > EDGE_TIMESTAMP_4_YEAR_LEAP_YEAR_SUPPORT)) { + return false; + } + } + + if (time->tm_year > 70) { + /* Valid in the range [70:206]. */ + uint32_t count_of_leap_days = ((time->tm_year - 1) / 4) - (70 / 4); + if (leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT) { + if (time->tm_year > 200) { + count_of_leap_days--; // 2100 is not a leap year + } + } + + result += (((time->tm_year - 70) * 365) + count_of_leap_days) * SECONDS_BY_DAY; + } + + *seconds = result; + + return true; +} + +bool _rtc_localtime(time_t timestamp, struct tm *time_info, rtc_leap_year_support_t leap_year_support) +{ + if (time_info == NULL) { + return false; + } + + uint32_t seconds = (uint32_t)timestamp; + + time_info->tm_sec = seconds % 60; + seconds = seconds / 60; // timestamp in minutes + time_info->tm_min = seconds % 60; + seconds = seconds / 60; // timestamp in hours + time_info->tm_hour = seconds % 24; + seconds = seconds / 24; // timestamp in days; + + /* Compute the weekday. + * The 1st of January 1970 was a Thursday which is equal to 4 in the weekday representation ranging from [0:6]. + */ + time_info->tm_wday = (seconds + 4) % 7; + + /* Years start at 70. */ + time_info->tm_year = 70; + while (true) { + if (_rtc_is_leap_year(time_info->tm_year, leap_year_support) && seconds >= 366) { + ++time_info->tm_year; + seconds -= 366; + } else if (!_rtc_is_leap_year(time_info->tm_year, leap_year_support) && seconds >= 365) { + ++time_info->tm_year; + seconds -= 365; + } else { + /* The remaining days are less than a years. */ + break; + } + } + + time_info->tm_yday = seconds; + + /* Convert days into seconds and find the current month. */ + seconds *= SECONDS_BY_DAY; + time_info->tm_mon = 11; + bool leap = _rtc_is_leap_year(time_info->tm_year, leap_year_support); + for (uint32_t i = 0; i < 12; ++i) { + if ((uint32_t) seconds < seconds_before_month[leap][i]) { + time_info->tm_mon = i - 1; + break; + } + } + + /* Remove month from timestamp and compute the number of days. + * Note: unlike other fields, days are not 0 indexed. + */ + seconds -= seconds_before_month[leap][time_info->tm_mon]; + time_info->tm_mday = (seconds / SECONDS_BY_DAY) + 1; + + return true; +}