mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

Dependents:   Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more

platform/mbed_mktime.c@189:f392fc9709a3, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 22:31:08 2019 +0000
Revision:
189:f392fc9709a3
Parent:
187:0387e8f68319 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AnnaBridge 167:e84263d55307 1 /* mbed Microcontroller Library
AnnaBridge 167:e84263d55307 2 * Copyright (c) 2017-2017 ARM Limited
AnnaBridge 189:f392fc9709a3 3 * SPDX-License-Identifier: Apache-2.0
AnnaBridge 167:e84263d55307 4 *
AnnaBridge 167:e84263d55307 5 * Licensed under the Apache License, Version 2.0 (the "License");
AnnaBridge 167:e84263d55307 6 * you may not use this file except in compliance with the License.
AnnaBridge 167:e84263d55307 7 * You may obtain a copy of the License at
AnnaBridge 167:e84263d55307 8 *
AnnaBridge 167:e84263d55307 9 * http://www.apache.org/licenses/LICENSE-2.0
AnnaBridge 167:e84263d55307 10 *
AnnaBridge 167:e84263d55307 11 * Unless required by applicable law or agreed to in writing, software
AnnaBridge 167:e84263d55307 12 * distributed under the License is distributed on an "AS IS" BASIS,
AnnaBridge 167:e84263d55307 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
AnnaBridge 167:e84263d55307 14 * See the License for the specific language governing permissions and
AnnaBridge 167:e84263d55307 15 * limitations under the License.
AnnaBridge 167:e84263d55307 16 */
AnnaBridge 167:e84263d55307 17
AnnaBridge 167:e84263d55307 18 #include "mbed_mktime.h"
AnnaBridge 167:e84263d55307 19
AnnaBridge 184:08ed48f1de7f 20 /* Time constants. */
AnnaBridge 167:e84263d55307 21 #define SECONDS_BY_MINUTES 60
AnnaBridge 167:e84263d55307 22 #define MINUTES_BY_HOUR 60
AnnaBridge 167:e84263d55307 23 #define SECONDS_BY_HOUR (SECONDS_BY_MINUTES * MINUTES_BY_HOUR)
AnnaBridge 187:0387e8f68319 24 #define HOURS_BY_DAY 24
AnnaBridge 167:e84263d55307 25 #define SECONDS_BY_DAY (SECONDS_BY_HOUR * HOURS_BY_DAY)
AnnaBridge 184:08ed48f1de7f 26 #define LAST_VALID_YEAR 206
AnnaBridge 184:08ed48f1de7f 27
AnnaBridge 184:08ed48f1de7f 28 /* Macros which will be used to determine if we are within valid range. */
AnnaBridge 184:08ed48f1de7f 29 #define EDGE_TIMESTAMP_FULL_LEAP_YEAR_SUPPORT 3220095 // 7th of February 1970 at 06:28:15
AnnaBridge 184:08ed48f1de7f 30 #define EDGE_TIMESTAMP_4_YEAR_LEAP_YEAR_SUPPORT 3133695 // 6th of February 1970 at 06:28:15
AnnaBridge 167:e84263d55307 31
AnnaBridge 167:e84263d55307 32 /*
AnnaBridge 187:0387e8f68319 33 * 2 dimensional array containing the number of seconds elapsed before a given
AnnaBridge 167:e84263d55307 34 * month.
AnnaBridge 167:e84263d55307 35 * The second index map to the month while the first map to the type of year:
AnnaBridge 187:0387e8f68319 36 * - 0: non leap year
AnnaBridge 167:e84263d55307 37 * - 1: leap year
AnnaBridge 167:e84263d55307 38 */
AnnaBridge 167:e84263d55307 39 static const uint32_t seconds_before_month[2][12] = {
AnnaBridge 167:e84263d55307 40 {
AnnaBridge 167:e84263d55307 41 0,
AnnaBridge 167:e84263d55307 42 31 * SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 43 (31 + 28) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 44 (31 + 28 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 45 (31 + 28 + 31 + 30) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 46 (31 + 28 + 31 + 30 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 47 (31 + 28 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 48 (31 + 28 + 31 + 30 + 31 + 30 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 49 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 50 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 51 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 52 (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY,
AnnaBridge 167:e84263d55307 53 },
AnnaBridge 167:e84263d55307 54 {
AnnaBridge 167:e84263d55307 55 0,
AnnaBridge 167:e84263d55307 56 31 * SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 57 (31 + 29) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 58 (31 + 29 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 59 (31 + 29 + 31 + 30) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 60 (31 + 29 + 31 + 30 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 61 (31 + 29 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 62 (31 + 29 + 31 + 30 + 31 + 30 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 63 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 64 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 65 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) *SECONDS_BY_DAY,
AnnaBridge 187:0387e8f68319 66 (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY,
AnnaBridge 167:e84263d55307 67 }
AnnaBridge 167:e84263d55307 68 };
AnnaBridge 167:e84263d55307 69
AnnaBridge 187:0387e8f68319 70 bool _rtc_is_leap_year(int year, rtc_leap_year_support_t leap_year_support)
AnnaBridge 187:0387e8f68319 71 {
AnnaBridge 187:0387e8f68319 72 /*
AnnaBridge 187:0387e8f68319 73 * since in practice, the value manipulated by this algorithm lie in the
AnnaBridge 184:08ed48f1de7f 74 * range: [70 : 206] the algorithm can be reduced to: year % 4 with exception for 200 (year 2100 is not leap year).
AnnaBridge 187:0387e8f68319 75 * The algorithm valid over the full range of value is:
AnnaBridge 167:e84263d55307 76
AnnaBridge 167:e84263d55307 77 year = 1900 + year;
AnnaBridge 167:e84263d55307 78 if (year % 4) {
AnnaBridge 167:e84263d55307 79 return false;
AnnaBridge 167:e84263d55307 80 } else if (year % 100) {
AnnaBridge 167:e84263d55307 81 return true;
AnnaBridge 167:e84263d55307 82 } else if (year % 400) {
AnnaBridge 167:e84263d55307 83 return false;
AnnaBridge 167:e84263d55307 84 }
AnnaBridge 167:e84263d55307 85 return true;
AnnaBridge 167:e84263d55307 86
AnnaBridge 187:0387e8f68319 87 */
AnnaBridge 184:08ed48f1de7f 88 if (leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT && year == 200) {
AnnaBridge 184:08ed48f1de7f 89 return false; // 2100 is not a leap year
AnnaBridge 184:08ed48f1de7f 90 }
AnnaBridge 184:08ed48f1de7f 91
AnnaBridge 167:e84263d55307 92 return (year) % 4 ? false : true;
AnnaBridge 167:e84263d55307 93 }
AnnaBridge 167:e84263d55307 94
AnnaBridge 187:0387e8f68319 95 bool _rtc_maketime(const struct tm *time, time_t *seconds, rtc_leap_year_support_t leap_year_support)
AnnaBridge 187:0387e8f68319 96 {
AnnaBridge 184:08ed48f1de7f 97 if (seconds == NULL || time == NULL) {
AnnaBridge 184:08ed48f1de7f 98 return false;
AnnaBridge 184:08ed48f1de7f 99 }
AnnaBridge 184:08ed48f1de7f 100
AnnaBridge 184:08ed48f1de7f 101 /* Partial check for the upper bound of the range - check years only. Full check will be performed after the
AnnaBridge 184:08ed48f1de7f 102 * elapsed time since the beginning of the year is calculated.
AnnaBridge 184:08ed48f1de7f 103 */
AnnaBridge 184:08ed48f1de7f 104 if ((time->tm_year < 70) || (time->tm_year > LAST_VALID_YEAR)) {
AnnaBridge 184:08ed48f1de7f 105 return false;
AnnaBridge 167:e84263d55307 106 }
AnnaBridge 167:e84263d55307 107
AnnaBridge 167:e84263d55307 108 uint32_t result = time->tm_sec;
AnnaBridge 167:e84263d55307 109 result += time->tm_min * SECONDS_BY_MINUTES;
AnnaBridge 167:e84263d55307 110 result += time->tm_hour * SECONDS_BY_HOUR;
AnnaBridge 167:e84263d55307 111 result += (time->tm_mday - 1) * SECONDS_BY_DAY;
AnnaBridge 184:08ed48f1de7f 112 result += seconds_before_month[_rtc_is_leap_year(time->tm_year, leap_year_support)][time->tm_mon];
AnnaBridge 184:08ed48f1de7f 113
AnnaBridge 184:08ed48f1de7f 114 /* Check if we are within valid range. */
AnnaBridge 184:08ed48f1de7f 115 if (time->tm_year == LAST_VALID_YEAR) {
AnnaBridge 184:08ed48f1de7f 116 if ((leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT && result > EDGE_TIMESTAMP_FULL_LEAP_YEAR_SUPPORT) ||
AnnaBridge 187:0387e8f68319 117 (leap_year_support == RTC_4_YEAR_LEAP_YEAR_SUPPORT && result > EDGE_TIMESTAMP_4_YEAR_LEAP_YEAR_SUPPORT)) {
AnnaBridge 187:0387e8f68319 118 return false;
AnnaBridge 184:08ed48f1de7f 119 }
AnnaBridge 184:08ed48f1de7f 120 }
AnnaBridge 167:e84263d55307 121
AnnaBridge 187:0387e8f68319 122 if (time->tm_year > 70) {
AnnaBridge 184:08ed48f1de7f 123 /* Valid in the range [70:206]. */
AnnaBridge 167:e84263d55307 124 uint32_t count_of_leap_days = ((time->tm_year - 1) / 4) - (70 / 4);
AnnaBridge 184:08ed48f1de7f 125 if (leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT) {
AnnaBridge 184:08ed48f1de7f 126 if (time->tm_year > 200) {
AnnaBridge 184:08ed48f1de7f 127 count_of_leap_days--; // 2100 is not a leap year
AnnaBridge 184:08ed48f1de7f 128 }
AnnaBridge 184:08ed48f1de7f 129 }
AnnaBridge 184:08ed48f1de7f 130
AnnaBridge 167:e84263d55307 131 result += (((time->tm_year - 70) * 365) + count_of_leap_days) * SECONDS_BY_DAY;
AnnaBridge 167:e84263d55307 132 }
AnnaBridge 167:e84263d55307 133
AnnaBridge 184:08ed48f1de7f 134 *seconds = result;
AnnaBridge 167:e84263d55307 135
AnnaBridge 184:08ed48f1de7f 136 return true;
AnnaBridge 167:e84263d55307 137 }
AnnaBridge 167:e84263d55307 138
AnnaBridge 187:0387e8f68319 139 bool _rtc_localtime(time_t timestamp, struct tm *time_info, rtc_leap_year_support_t leap_year_support)
AnnaBridge 187:0387e8f68319 140 {
AnnaBridge 184:08ed48f1de7f 141 if (time_info == NULL) {
AnnaBridge 167:e84263d55307 142 return false;
AnnaBridge 184:08ed48f1de7f 143 }
AnnaBridge 184:08ed48f1de7f 144
AnnaBridge 184:08ed48f1de7f 145 uint32_t seconds = (uint32_t)timestamp;
AnnaBridge 167:e84263d55307 146
AnnaBridge 184:08ed48f1de7f 147 time_info->tm_sec = seconds % 60;
AnnaBridge 184:08ed48f1de7f 148 seconds = seconds / 60; // timestamp in minutes
AnnaBridge 184:08ed48f1de7f 149 time_info->tm_min = seconds % 60;
AnnaBridge 184:08ed48f1de7f 150 seconds = seconds / 60; // timestamp in hours
AnnaBridge 184:08ed48f1de7f 151 time_info->tm_hour = seconds % 24;
AnnaBridge 184:08ed48f1de7f 152 seconds = seconds / 24; // timestamp in days;
AnnaBridge 167:e84263d55307 153
AnnaBridge 184:08ed48f1de7f 154 /* Compute the weekday.
AnnaBridge 184:08ed48f1de7f 155 * The 1st of January 1970 was a Thursday which is equal to 4 in the weekday representation ranging from [0:6].
AnnaBridge 184:08ed48f1de7f 156 */
AnnaBridge 184:08ed48f1de7f 157 time_info->tm_wday = (seconds + 4) % 7;
AnnaBridge 167:e84263d55307 158
AnnaBridge 184:08ed48f1de7f 159 /* Years start at 70. */
AnnaBridge 167:e84263d55307 160 time_info->tm_year = 70;
AnnaBridge 187:0387e8f68319 161 while (true) {
AnnaBridge 184:08ed48f1de7f 162 if (_rtc_is_leap_year(time_info->tm_year, leap_year_support) && seconds >= 366) {
AnnaBridge 167:e84263d55307 163 ++time_info->tm_year;
AnnaBridge 184:08ed48f1de7f 164 seconds -= 366;
AnnaBridge 184:08ed48f1de7f 165 } else if (!_rtc_is_leap_year(time_info->tm_year, leap_year_support) && seconds >= 365) {
AnnaBridge 167:e84263d55307 166 ++time_info->tm_year;
AnnaBridge 184:08ed48f1de7f 167 seconds -= 365;
AnnaBridge 167:e84263d55307 168 } else {
AnnaBridge 184:08ed48f1de7f 169 /* The remaining days are less than a years. */
AnnaBridge 167:e84263d55307 170 break;
AnnaBridge 167:e84263d55307 171 }
AnnaBridge 167:e84263d55307 172 }
AnnaBridge 167:e84263d55307 173
AnnaBridge 184:08ed48f1de7f 174 time_info->tm_yday = seconds;
AnnaBridge 167:e84263d55307 175
AnnaBridge 184:08ed48f1de7f 176 /* Convert days into seconds and find the current month. */
AnnaBridge 184:08ed48f1de7f 177 seconds *= SECONDS_BY_DAY;
AnnaBridge 167:e84263d55307 178 time_info->tm_mon = 11;
AnnaBridge 184:08ed48f1de7f 179 bool leap = _rtc_is_leap_year(time_info->tm_year, leap_year_support);
AnnaBridge 167:e84263d55307 180 for (uint32_t i = 0; i < 12; ++i) {
AnnaBridge 184:08ed48f1de7f 181 if ((uint32_t) seconds < seconds_before_month[leap][i]) {
AnnaBridge 167:e84263d55307 182 time_info->tm_mon = i - 1;
AnnaBridge 167:e84263d55307 183 break;
AnnaBridge 167:e84263d55307 184 }
AnnaBridge 167:e84263d55307 185 }
AnnaBridge 167:e84263d55307 186
AnnaBridge 184:08ed48f1de7f 187 /* Remove month from timestamp and compute the number of days.
AnnaBridge 184:08ed48f1de7f 188 * Note: unlike other fields, days are not 0 indexed.
AnnaBridge 184:08ed48f1de7f 189 */
AnnaBridge 184:08ed48f1de7f 190 seconds -= seconds_before_month[leap][time_info->tm_mon];
AnnaBridge 184:08ed48f1de7f 191 time_info->tm_mday = (seconds / SECONDS_BY_DAY) + 1;
AnnaBridge 167:e84263d55307 192
AnnaBridge 167:e84263d55307 193 return true;
AnnaBridge 167:e84263d55307 194 }