Marco Zecchini / Mbed OS Example_RTOS

Rtos API example

mbed-os/platform/mbed_mktime.c@0:9fca2b23d0ba, 2019-02-23 (annotated)

Committer:
marcozecchini
Date:
Sat Feb 23 12:13:36 2019 +0000
Revision:
0:9fca2b23d0ba
final commit

Who changed what in which revision?

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marcozecchini 0:9fca2b23d0ba 1 /* mbed Microcontroller Library
marcozecchini 0:9fca2b23d0ba 2 * Copyright (c) 2017-2017 ARM Limited
marcozecchini 0:9fca2b23d0ba 3 *
marcozecchini 0:9fca2b23d0ba 4 * Licensed under the Apache License, Version 2.0 (the "License");
marcozecchini 0:9fca2b23d0ba 5 * you may not use this file except in compliance with the License.
marcozecchini 0:9fca2b23d0ba 6 * You may obtain a copy of the License at
marcozecchini 0:9fca2b23d0ba 7 *
marcozecchini 0:9fca2b23d0ba 8 * http://www.apache.org/licenses/LICENSE-2.0
marcozecchini 0:9fca2b23d0ba 9 *
marcozecchini 0:9fca2b23d0ba 10 * Unless required by applicable law or agreed to in writing, software
marcozecchini 0:9fca2b23d0ba 11 * distributed under the License is distributed on an "AS IS" BASIS,
marcozecchini 0:9fca2b23d0ba 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
marcozecchini 0:9fca2b23d0ba 13 * See the License for the specific language governing permissions and
marcozecchini 0:9fca2b23d0ba 14 * limitations under the License.
marcozecchini 0:9fca2b23d0ba 15 */
marcozecchini 0:9fca2b23d0ba 16
marcozecchini 0:9fca2b23d0ba 17 #include "mbed_mktime.h"
marcozecchini 0:9fca2b23d0ba 18
marcozecchini 0:9fca2b23d0ba 19 /*
marcozecchini 0:9fca2b23d0ba 20 * time constants
marcozecchini 0:9fca2b23d0ba 21 */
marcozecchini 0:9fca2b23d0ba 22 #define SECONDS_BY_MINUTES 60
marcozecchini 0:9fca2b23d0ba 23 #define MINUTES_BY_HOUR 60
marcozecchini 0:9fca2b23d0ba 24 #define SECONDS_BY_HOUR (SECONDS_BY_MINUTES * MINUTES_BY_HOUR)
marcozecchini 0:9fca2b23d0ba 25 #define HOURS_BY_DAY 24
marcozecchini 0:9fca2b23d0ba 26 #define SECONDS_BY_DAY (SECONDS_BY_HOUR * HOURS_BY_DAY)
marcozecchini 0:9fca2b23d0ba 27
marcozecchini 0:9fca2b23d0ba 28 /*
marcozecchini 0:9fca2b23d0ba 29 * 2 dimensional array containing the number of seconds elapsed before a given
marcozecchini 0:9fca2b23d0ba 30 * month.
marcozecchini 0:9fca2b23d0ba 31 * The second index map to the month while the first map to the type of year:
marcozecchini 0:9fca2b23d0ba 32 * - 0: non leap year
marcozecchini 0:9fca2b23d0ba 33 * - 1: leap year
marcozecchini 0:9fca2b23d0ba 34 */
marcozecchini 0:9fca2b23d0ba 35 static const uint32_t seconds_before_month[2][12] = {
marcozecchini 0:9fca2b23d0ba 36 {
marcozecchini 0:9fca2b23d0ba 37 0,
marcozecchini 0:9fca2b23d0ba 38 31 * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 39 (31 + 28) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 40 (31 + 28 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 41 (31 + 28 + 31 + 30) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 42 (31 + 28 + 31 + 30 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 43 (31 + 28 + 31 + 30 + 31 + 30) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 44 (31 + 28 + 31 + 30 + 31 + 30 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 45 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 46 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 47 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 48 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 49 },
marcozecchini 0:9fca2b23d0ba 50 {
marcozecchini 0:9fca2b23d0ba 51 0,
marcozecchini 0:9fca2b23d0ba 52 31 * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 53 (31 + 29) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 54 (31 + 29 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 55 (31 + 29 + 31 + 30) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 56 (31 + 29 + 31 + 30 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 57 (31 + 29 + 31 + 30 + 31 + 30) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 58 (31 + 29 + 31 + 30 + 31 + 30 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 59 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 60 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 61 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 62 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) * SECONDS_BY_DAY,
marcozecchini 0:9fca2b23d0ba 63 }
marcozecchini 0:9fca2b23d0ba 64 };
marcozecchini 0:9fca2b23d0ba 65
marcozecchini 0:9fca2b23d0ba 66 bool _rtc_is_leap_year(int year) {
marcozecchini 0:9fca2b23d0ba 67 /*
marcozecchini 0:9fca2b23d0ba 68 * since in practice, the value manipulated by this algorithm lie in the
marcozecchini 0:9fca2b23d0ba 69 * range [70 : 138], the algorith can be reduced to: year % 4.
marcozecchini 0:9fca2b23d0ba 70 * The algorithm valid over the full range of value is:
marcozecchini 0:9fca2b23d0ba 71
marcozecchini 0:9fca2b23d0ba 72 year = 1900 + year;
marcozecchini 0:9fca2b23d0ba 73 if (year % 4) {
marcozecchini 0:9fca2b23d0ba 74 return false;
marcozecchini 0:9fca2b23d0ba 75 } else if (year % 100) {
marcozecchini 0:9fca2b23d0ba 76 return true;
marcozecchini 0:9fca2b23d0ba 77 } else if (year % 400) {
marcozecchini 0:9fca2b23d0ba 78 return false;
marcozecchini 0:9fca2b23d0ba 79 }
marcozecchini 0:9fca2b23d0ba 80 return true;
marcozecchini 0:9fca2b23d0ba 81
marcozecchini 0:9fca2b23d0ba 82 */
marcozecchini 0:9fca2b23d0ba 83 return (year) % 4 ? false : true;
marcozecchini 0:9fca2b23d0ba 84 }
marcozecchini 0:9fca2b23d0ba 85
marcozecchini 0:9fca2b23d0ba 86 time_t _rtc_mktime(const struct tm* time) {
marcozecchini 0:9fca2b23d0ba 87 // partial check for the upper bound of the range
marcozecchini 0:9fca2b23d0ba 88 // normalization might happen at the end of the function
marcozecchini 0:9fca2b23d0ba 89 // this solution is faster than checking if the input is after the 19th of
marcozecchini 0:9fca2b23d0ba 90 // january 2038 at 03:14:07.
marcozecchini 0:9fca2b23d0ba 91 if ((time->tm_year < 70) || (time->tm_year > 138)) {
marcozecchini 0:9fca2b23d0ba 92 return ((time_t) -1);
marcozecchini 0:9fca2b23d0ba 93 }
marcozecchini 0:9fca2b23d0ba 94
marcozecchini 0:9fca2b23d0ba 95 uint32_t result = time->tm_sec;
marcozecchini 0:9fca2b23d0ba 96 result += time->tm_min * SECONDS_BY_MINUTES;
marcozecchini 0:9fca2b23d0ba 97 result += time->tm_hour * SECONDS_BY_HOUR;
marcozecchini 0:9fca2b23d0ba 98 result += (time->tm_mday - 1) * SECONDS_BY_DAY;
marcozecchini 0:9fca2b23d0ba 99 result += seconds_before_month[_rtc_is_leap_year(time->tm_year)][time->tm_mon];
marcozecchini 0:9fca2b23d0ba 100
marcozecchini 0:9fca2b23d0ba 101 if (time->tm_year > 70) {
marcozecchini 0:9fca2b23d0ba 102 // valid in the range [70:138]
marcozecchini 0:9fca2b23d0ba 103 uint32_t count_of_leap_days = ((time->tm_year - 1) / 4) - (70 / 4);
marcozecchini 0:9fca2b23d0ba 104 result += (((time->tm_year - 70) * 365) + count_of_leap_days) * SECONDS_BY_DAY;
marcozecchini 0:9fca2b23d0ba 105 }
marcozecchini 0:9fca2b23d0ba 106
marcozecchini 0:9fca2b23d0ba 107 if (result > INT32_MAX) {
marcozecchini 0:9fca2b23d0ba 108 return (time_t) -1;
marcozecchini 0:9fca2b23d0ba 109 }
marcozecchini 0:9fca2b23d0ba 110
marcozecchini 0:9fca2b23d0ba 111 return result;
marcozecchini 0:9fca2b23d0ba 112 }
marcozecchini 0:9fca2b23d0ba 113
marcozecchini 0:9fca2b23d0ba 114 bool _rtc_localtime(time_t timestamp, struct tm* time_info) {
marcozecchini 0:9fca2b23d0ba 115 if (((int32_t) timestamp) < 0) {
marcozecchini 0:9fca2b23d0ba 116 return false;
marcozecchini 0:9fca2b23d0ba 117 }
marcozecchini 0:9fca2b23d0ba 118
marcozecchini 0:9fca2b23d0ba 119 time_info->tm_sec = timestamp % 60;
marcozecchini 0:9fca2b23d0ba 120 timestamp = timestamp / 60; // timestamp in minutes
marcozecchini 0:9fca2b23d0ba 121 time_info->tm_min = timestamp % 60;
marcozecchini 0:9fca2b23d0ba 122 timestamp = timestamp / 60; // timestamp in hours
marcozecchini 0:9fca2b23d0ba 123 time_info->tm_hour = timestamp % 24;
marcozecchini 0:9fca2b23d0ba 124 timestamp = timestamp / 24; // timestamp in days;
marcozecchini 0:9fca2b23d0ba 125
marcozecchini 0:9fca2b23d0ba 126 // compute the weekday
marcozecchini 0:9fca2b23d0ba 127 // The 1st of January 1970 was a Thursday which is equal to 4 in the weekday
marcozecchini 0:9fca2b23d0ba 128 // representation ranging from [0:6]
marcozecchini 0:9fca2b23d0ba 129 time_info->tm_wday = (timestamp + 4) % 7;
marcozecchini 0:9fca2b23d0ba 130
marcozecchini 0:9fca2b23d0ba 131 // years start at 70
marcozecchini 0:9fca2b23d0ba 132 time_info->tm_year = 70;
marcozecchini 0:9fca2b23d0ba 133 while (true) {
marcozecchini 0:9fca2b23d0ba 134 if (_rtc_is_leap_year(time_info->tm_year) && timestamp >= 366) {
marcozecchini 0:9fca2b23d0ba 135 ++time_info->tm_year;
marcozecchini 0:9fca2b23d0ba 136 timestamp -= 366;
marcozecchini 0:9fca2b23d0ba 137 } else if (!_rtc_is_leap_year(time_info->tm_year) && timestamp >= 365) {
marcozecchini 0:9fca2b23d0ba 138 ++time_info->tm_year;
marcozecchini 0:9fca2b23d0ba 139 timestamp -= 365;
marcozecchini 0:9fca2b23d0ba 140 } else {
marcozecchini 0:9fca2b23d0ba 141 // the remaining days are less than a years
marcozecchini 0:9fca2b23d0ba 142 break;
marcozecchini 0:9fca2b23d0ba 143 }
marcozecchini 0:9fca2b23d0ba 144 }
marcozecchini 0:9fca2b23d0ba 145
marcozecchini 0:9fca2b23d0ba 146 time_info->tm_yday = timestamp;
marcozecchini 0:9fca2b23d0ba 147
marcozecchini 0:9fca2b23d0ba 148 // convert days into seconds and find the current month
marcozecchini 0:9fca2b23d0ba 149 timestamp *= SECONDS_BY_DAY;
marcozecchini 0:9fca2b23d0ba 150 time_info->tm_mon = 11;
marcozecchini 0:9fca2b23d0ba 151 bool leap = _rtc_is_leap_year(time_info->tm_year);
marcozecchini 0:9fca2b23d0ba 152 for (uint32_t i = 0; i < 12; ++i) {
marcozecchini 0:9fca2b23d0ba 153 if ((uint32_t) timestamp < seconds_before_month[leap][i]) {
marcozecchini 0:9fca2b23d0ba 154 time_info->tm_mon = i - 1;
marcozecchini 0:9fca2b23d0ba 155 break;
marcozecchini 0:9fca2b23d0ba 156 }
marcozecchini 0:9fca2b23d0ba 157 }
marcozecchini 0:9fca2b23d0ba 158
marcozecchini 0:9fca2b23d0ba 159 // remove month from timestamp and compute the number of days.
marcozecchini 0:9fca2b23d0ba 160 // note: unlike other fields, days are not 0 indexed.
marcozecchini 0:9fca2b23d0ba 161 timestamp -= seconds_before_month[leap][time_info->tm_mon];
marcozecchini 0:9fca2b23d0ba 162 time_info->tm_mday = (timestamp / SECONDS_BY_DAY) + 1;
marcozecchini 0:9fca2b23d0ba 163
marcozecchini 0:9fca2b23d0ba 164 return true;
marcozecchini 0:9fca2b23d0ba 165 }