Aditya Mehrotra / mbed-dev

Biomimetics MBED Library w/ Added Support for CAN3

Dependents:   CAN_TEST SPIne_Plus_DYNO_SENSORS SPIne_Plus_v2 SPIne_Plus_Dyno_v2

platform/mbed_mktime.c@0:083111ae2a11, 2020-11-26 (annotated)

Committer:
saloutos
Date:
Thu Nov 26 04:08:56 2020 +0000
Revision:
0:083111ae2a11
first commit of leaned mbed dev lib

Who changed what in which revision?

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saloutos 0:083111ae2a11 1 /* mbed Microcontroller Library
saloutos 0:083111ae2a11 2 * Copyright (c) 2017-2017 ARM Limited
saloutos 0:083111ae2a11 3 *
saloutos 0:083111ae2a11 4 * Licensed under the Apache License, Version 2.0 (the "License");
saloutos 0:083111ae2a11 5 * you may not use this file except in compliance with the License.
saloutos 0:083111ae2a11 6 * You may obtain a copy of the License at
saloutos 0:083111ae2a11 7 *
saloutos 0:083111ae2a11 8 * http://www.apache.org/licenses/LICENSE-2.0
saloutos 0:083111ae2a11 9 *
saloutos 0:083111ae2a11 10 * Unless required by applicable law or agreed to in writing, software
saloutos 0:083111ae2a11 11 * distributed under the License is distributed on an "AS IS" BASIS,
saloutos 0:083111ae2a11 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
saloutos 0:083111ae2a11 13 * See the License for the specific language governing permissions and
saloutos 0:083111ae2a11 14 * limitations under the License.
saloutos 0:083111ae2a11 15 */
saloutos 0:083111ae2a11 16
saloutos 0:083111ae2a11 17 #include "mbed_mktime.h"
saloutos 0:083111ae2a11 18
saloutos 0:083111ae2a11 19 /*
saloutos 0:083111ae2a11 20 * time constants
saloutos 0:083111ae2a11 21 */
saloutos 0:083111ae2a11 22 #define SECONDS_BY_MINUTES 60
saloutos 0:083111ae2a11 23 #define MINUTES_BY_HOUR 60
saloutos 0:083111ae2a11 24 #define SECONDS_BY_HOUR (SECONDS_BY_MINUTES * MINUTES_BY_HOUR)
saloutos 0:083111ae2a11 25 #define HOURS_BY_DAY 24
saloutos 0:083111ae2a11 26 #define SECONDS_BY_DAY (SECONDS_BY_HOUR * HOURS_BY_DAY)
saloutos 0:083111ae2a11 27
saloutos 0:083111ae2a11 28 /*
saloutos 0:083111ae2a11 29 * 2 dimensional array containing the number of seconds elapsed before a given
saloutos 0:083111ae2a11 30 * month.
saloutos 0:083111ae2a11 31 * The second index map to the month while the first map to the type of year:
saloutos 0:083111ae2a11 32 * - 0: non leap year
saloutos 0:083111ae2a11 33 * - 1: leap year
saloutos 0:083111ae2a11 34 */
saloutos 0:083111ae2a11 35 static const uint32_t seconds_before_month[2][12] = {
saloutos 0:083111ae2a11 36 {
saloutos 0:083111ae2a11 37 0,
saloutos 0:083111ae2a11 38 31 * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 39 (31 + 28) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 40 (31 + 28 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 41 (31 + 28 + 31 + 30) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 42 (31 + 28 + 31 + 30 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 43 (31 + 28 + 31 + 30 + 31 + 30) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 44 (31 + 28 + 31 + 30 + 31 + 30 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 45 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 46 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 47 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 48 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 49 },
saloutos 0:083111ae2a11 50 {
saloutos 0:083111ae2a11 51 0,
saloutos 0:083111ae2a11 52 31 * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 53 (31 + 29) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 54 (31 + 29 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 55 (31 + 29 + 31 + 30) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 56 (31 + 29 + 31 + 30 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 57 (31 + 29 + 31 + 30 + 31 + 30) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 58 (31 + 29 + 31 + 30 + 31 + 30 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 59 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 60 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 61 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 62 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) * SECONDS_BY_DAY,
saloutos 0:083111ae2a11 63 }
saloutos 0:083111ae2a11 64 };
saloutos 0:083111ae2a11 65
saloutos 0:083111ae2a11 66 bool _rtc_is_leap_year(int year) {
saloutos 0:083111ae2a11 67 /*
saloutos 0:083111ae2a11 68 * since in practice, the value manipulated by this algorithm lie in the
saloutos 0:083111ae2a11 69 * range [70 : 138], the algorith can be reduced to: year % 4.
saloutos 0:083111ae2a11 70 * The algorithm valid over the full range of value is:
saloutos 0:083111ae2a11 71
saloutos 0:083111ae2a11 72 year = 1900 + year;
saloutos 0:083111ae2a11 73 if (year % 4) {
saloutos 0:083111ae2a11 74 return false;
saloutos 0:083111ae2a11 75 } else if (year % 100) {
saloutos 0:083111ae2a11 76 return true;
saloutos 0:083111ae2a11 77 } else if (year % 400) {
saloutos 0:083111ae2a11 78 return false;
saloutos 0:083111ae2a11 79 }
saloutos 0:083111ae2a11 80 return true;
saloutos 0:083111ae2a11 81
saloutos 0:083111ae2a11 82 */
saloutos 0:083111ae2a11 83 return (year) % 4 ? false : true;
saloutos 0:083111ae2a11 84 }
saloutos 0:083111ae2a11 85
saloutos 0:083111ae2a11 86 time_t _rtc_mktime(const struct tm* time) {
saloutos 0:083111ae2a11 87 // partial check for the upper bound of the range
saloutos 0:083111ae2a11 88 // normalization might happen at the end of the function
saloutos 0:083111ae2a11 89 // this solution is faster than checking if the input is after the 19th of
saloutos 0:083111ae2a11 90 // january 2038 at 03:14:07.
saloutos 0:083111ae2a11 91 if ((time->tm_year < 70) || (time->tm_year > 138)) {
saloutos 0:083111ae2a11 92 return ((time_t) -1);
saloutos 0:083111ae2a11 93 }
saloutos 0:083111ae2a11 94
saloutos 0:083111ae2a11 95 uint32_t result = time->tm_sec;
saloutos 0:083111ae2a11 96 result += time->tm_min * SECONDS_BY_MINUTES;
saloutos 0:083111ae2a11 97 result += time->tm_hour * SECONDS_BY_HOUR;
saloutos 0:083111ae2a11 98 result += (time->tm_mday - 1) * SECONDS_BY_DAY;
saloutos 0:083111ae2a11 99 result += seconds_before_month[_rtc_is_leap_year(time->tm_year)][time->tm_mon];
saloutos 0:083111ae2a11 100
saloutos 0:083111ae2a11 101 if (time->tm_year > 70) {
saloutos 0:083111ae2a11 102 // valid in the range [70:138]
saloutos 0:083111ae2a11 103 uint32_t count_of_leap_days = ((time->tm_year - 1) / 4) - (70 / 4);
saloutos 0:083111ae2a11 104 result += (((time->tm_year - 70) * 365) + count_of_leap_days) * SECONDS_BY_DAY;
saloutos 0:083111ae2a11 105 }
saloutos 0:083111ae2a11 106
saloutos 0:083111ae2a11 107 if (result > INT32_MAX) {
saloutos 0:083111ae2a11 108 return (time_t) -1;
saloutos 0:083111ae2a11 109 }
saloutos 0:083111ae2a11 110
saloutos 0:083111ae2a11 111 return result;
saloutos 0:083111ae2a11 112 }
saloutos 0:083111ae2a11 113
saloutos 0:083111ae2a11 114 bool _rtc_localtime(time_t timestamp, struct tm* time_info) {
saloutos 0:083111ae2a11 115 if (((int32_t) timestamp) < 0) {
saloutos 0:083111ae2a11 116 return false;
saloutos 0:083111ae2a11 117 }
saloutos 0:083111ae2a11 118
saloutos 0:083111ae2a11 119 time_info->tm_sec = timestamp % 60;
saloutos 0:083111ae2a11 120 timestamp = timestamp / 60; // timestamp in minutes
saloutos 0:083111ae2a11 121 time_info->tm_min = timestamp % 60;
saloutos 0:083111ae2a11 122 timestamp = timestamp / 60; // timestamp in hours
saloutos 0:083111ae2a11 123 time_info->tm_hour = timestamp % 24;
saloutos 0:083111ae2a11 124 timestamp = timestamp / 24; // timestamp in days;
saloutos 0:083111ae2a11 125
saloutos 0:083111ae2a11 126 // compute the weekday
saloutos 0:083111ae2a11 127 // The 1st of January 1970 was a Thursday which is equal to 4 in the weekday
saloutos 0:083111ae2a11 128 // representation ranging from [0:6]
saloutos 0:083111ae2a11 129 time_info->tm_wday = (timestamp + 4) % 7;
saloutos 0:083111ae2a11 130
saloutos 0:083111ae2a11 131 // years start at 70
saloutos 0:083111ae2a11 132 time_info->tm_year = 70;
saloutos 0:083111ae2a11 133 while (true) {
saloutos 0:083111ae2a11 134 if (_rtc_is_leap_year(time_info->tm_year) && timestamp >= 366) {
saloutos 0:083111ae2a11 135 ++time_info->tm_year;
saloutos 0:083111ae2a11 136 timestamp -= 366;
saloutos 0:083111ae2a11 137 } else if (!_rtc_is_leap_year(time_info->tm_year) && timestamp >= 365) {
saloutos 0:083111ae2a11 138 ++time_info->tm_year;
saloutos 0:083111ae2a11 139 timestamp -= 365;
saloutos 0:083111ae2a11 140 } else {
saloutos 0:083111ae2a11 141 // the remaining days are less than a years
saloutos 0:083111ae2a11 142 break;
saloutos 0:083111ae2a11 143 }
saloutos 0:083111ae2a11 144 }
saloutos 0:083111ae2a11 145
saloutos 0:083111ae2a11 146 time_info->tm_yday = timestamp;
saloutos 0:083111ae2a11 147
saloutos 0:083111ae2a11 148 // convert days into seconds and find the current month
saloutos 0:083111ae2a11 149 timestamp *= SECONDS_BY_DAY;
saloutos 0:083111ae2a11 150 time_info->tm_mon = 11;
saloutos 0:083111ae2a11 151 bool leap = _rtc_is_leap_year(time_info->tm_year);
saloutos 0:083111ae2a11 152 for (uint32_t i = 0; i < 12; ++i) {
saloutos 0:083111ae2a11 153 if ((uint32_t) timestamp < seconds_before_month[leap][i]) {
saloutos 0:083111ae2a11 154 time_info->tm_mon = i - 1;
saloutos 0:083111ae2a11 155 break;
saloutos 0:083111ae2a11 156 }
saloutos 0:083111ae2a11 157 }
saloutos 0:083111ae2a11 158
saloutos 0:083111ae2a11 159 // remove month from timestamp and compute the number of days.
saloutos 0:083111ae2a11 160 // note: unlike other fields, days are not 0 indexed.
saloutos 0:083111ae2a11 161 timestamp -= seconds_before_month[leap][time_info->tm_mon];
saloutos 0:083111ae2a11 162 time_info->tm_mday = (timestamp / SECONDS_BY_DAY) + 1;
saloutos 0:083111ae2a11 163
saloutos 0:083111ae2a11 164 return true;
saloutos 0:083111ae2a11 165 }