[374] | 1 | /* mbed Microcontroller Library
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| 2 | * Copyright (c) 2017-2017 ARM Limited
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| 3 | *
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| 4 | * Licensed under the Apache License, Version 2.0 (the "License");
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| 5 | * you may not use this file except in compliance with the License.
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| 6 | * You may obtain a copy of the License at
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| 7 | *
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| 8 | * http://www.apache.org/licenses/LICENSE-2.0
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| 9 | *
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| 10 | * Unless required by applicable law or agreed to in writing, software
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| 11 | * distributed under the License is distributed on an "AS IS" BASIS,
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| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 13 | * See the License for the specific language governing permissions and
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| 14 | * limitations under the License.
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| 15 | */
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| 16 |
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| 17 | #include "mbed_mktime.h"
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| 18 |
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| 19 | /* Time constants. */
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| 20 | #define SECONDS_BY_MINUTES 60
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| 21 | #define MINUTES_BY_HOUR 60
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| 22 | #define SECONDS_BY_HOUR (SECONDS_BY_MINUTES * MINUTES_BY_HOUR)
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| 23 | #define HOURS_BY_DAY 24
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| 24 | #define SECONDS_BY_DAY (SECONDS_BY_HOUR * HOURS_BY_DAY)
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| 25 | #define LAST_VALID_YEAR 206
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| 26 |
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| 27 | /* Macros which will be used to determine if we are within valid range. */
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| 28 | #define EDGE_TIMESTAMP_FULL_LEAP_YEAR_SUPPORT 3220095 // 7th of February 1970 at 06:28:15
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| 29 | #define EDGE_TIMESTAMP_4_YEAR_LEAP_YEAR_SUPPORT 3133695 // 6th of February 1970 at 06:28:15
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| 30 |
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| 31 | /*
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| 32 | * 2 dimensional array containing the number of seconds elapsed before a given
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| 33 | * month.
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| 34 | * The second index map to the month while the first map to the type of year:
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| 35 | * - 0: non leap year
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| 36 | * - 1: leap year
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| 37 | */
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| 38 | static const uint32_t seconds_before_month[2][12] = {
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| 39 | {
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| 40 | 0,
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| 41 | 31 * SECONDS_BY_DAY,
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| 42 | (31 + 28) *SECONDS_BY_DAY,
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| 43 | (31 + 28 + 31) *SECONDS_BY_DAY,
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| 44 | (31 + 28 + 31 + 30) *SECONDS_BY_DAY,
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| 45 | (31 + 28 + 31 + 30 + 31) *SECONDS_BY_DAY,
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| 46 | (31 + 28 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY,
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| 47 | (31 + 28 + 31 + 30 + 31 + 30 + 31) *SECONDS_BY_DAY,
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| 48 | (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31) *SECONDS_BY_DAY,
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| 49 | (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30) *SECONDS_BY_DAY,
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| 50 | (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) *SECONDS_BY_DAY,
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| 51 | (31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY,
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| 52 | },
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| 53 | {
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| 54 | 0,
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| 55 | 31 * SECONDS_BY_DAY,
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| 56 | (31 + 29) *SECONDS_BY_DAY,
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| 57 | (31 + 29 + 31) *SECONDS_BY_DAY,
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| 58 | (31 + 29 + 31 + 30) *SECONDS_BY_DAY,
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| 59 | (31 + 29 + 31 + 30 + 31) *SECONDS_BY_DAY,
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| 60 | (31 + 29 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY,
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| 61 | (31 + 29 + 31 + 30 + 31 + 30 + 31) *SECONDS_BY_DAY,
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| 62 | (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31) *SECONDS_BY_DAY,
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| 63 | (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30) *SECONDS_BY_DAY,
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| 64 | (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31) *SECONDS_BY_DAY,
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| 65 | (31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30) *SECONDS_BY_DAY,
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| 66 | }
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| 67 | };
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| 68 |
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| 69 | bool _rtc_is_leap_year(int year, rtc_leap_year_support_t leap_year_support)
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| 70 | {
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| 71 | /*
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| 72 | * since in practice, the value manipulated by this algorithm lie in the
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| 73 | * range: [70 : 206] the algorithm can be reduced to: year % 4 with exception for 200 (year 2100 is not leap year).
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| 74 | * The algorithm valid over the full range of value is:
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| 75 |
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| 76 | year = 1900 + year;
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| 77 | if (year % 4) {
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| 78 | return false;
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| 79 | } else if (year % 100) {
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| 80 | return true;
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| 81 | } else if (year % 400) {
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| 82 | return false;
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| 83 | }
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| 84 | return true;
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| 85 |
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| 86 | */
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| 87 | if (leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT && year == 200) {
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| 88 | return false; // 2100 is not a leap year
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| 89 | }
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| 90 |
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| 91 | return (year) % 4 ? false : true;
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| 92 | }
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| 93 |
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| 94 | bool _rtc_maketime(const struct tm *time, time_t *seconds, rtc_leap_year_support_t leap_year_support)
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| 95 | {
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| 96 | if (seconds == NULL || time == NULL) {
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| 97 | return false;
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| 98 | }
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| 99 |
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| 100 | /* Partial check for the upper bound of the range - check years only. Full check will be performed after the
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| 101 | * elapsed time since the beginning of the year is calculated.
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| 102 | */
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| 103 | if ((time->tm_year < 70) || (time->tm_year > LAST_VALID_YEAR)) {
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| 104 | return false;
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| 105 | }
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| 106 |
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| 107 | uint32_t result = time->tm_sec;
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| 108 | result += time->tm_min * SECONDS_BY_MINUTES;
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| 109 | result += time->tm_hour * SECONDS_BY_HOUR;
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| 110 | result += (time->tm_mday - 1) * SECONDS_BY_DAY;
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| 111 | result += seconds_before_month[_rtc_is_leap_year(time->tm_year, leap_year_support)][time->tm_mon];
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| 112 |
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| 113 | /* Check if we are within valid range. */
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| 114 | if (time->tm_year == LAST_VALID_YEAR) {
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| 115 | if ((leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT && result > EDGE_TIMESTAMP_FULL_LEAP_YEAR_SUPPORT) ||
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| 116 | (leap_year_support == RTC_4_YEAR_LEAP_YEAR_SUPPORT && result > EDGE_TIMESTAMP_4_YEAR_LEAP_YEAR_SUPPORT)) {
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| 117 | return false;
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| 118 | }
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| 119 | }
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| 120 |
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| 121 | if (time->tm_year > 70) {
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| 122 | /* Valid in the range [70:206]. */
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| 123 | uint32_t count_of_leap_days = ((time->tm_year - 1) / 4) - (70 / 4);
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| 124 | if (leap_year_support == RTC_FULL_LEAP_YEAR_SUPPORT) {
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| 125 | if (time->tm_year > 200) {
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| 126 | count_of_leap_days--; // 2100 is not a leap year
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| 127 | }
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| 128 | }
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| 129 |
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| 130 | result += (((time->tm_year - 70) * 365) + count_of_leap_days) * SECONDS_BY_DAY;
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| 131 | }
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| 132 |
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| 133 | *seconds = result;
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| 134 |
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| 135 | return true;
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| 136 | }
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| 137 |
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| 138 | bool _rtc_localtime(time_t timestamp, struct tm *time_info, rtc_leap_year_support_t leap_year_support)
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| 139 | {
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| 140 | if (time_info == NULL) {
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| 141 | return false;
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| 142 | }
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| 143 |
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| 144 | uint32_t seconds = (uint32_t)timestamp;
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| 145 |
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| 146 | time_info->tm_sec = seconds % 60;
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| 147 | seconds = seconds / 60; // timestamp in minutes
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| 148 | time_info->tm_min = seconds % 60;
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| 149 | seconds = seconds / 60; // timestamp in hours
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| 150 | time_info->tm_hour = seconds % 24;
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| 151 | seconds = seconds / 24; // timestamp in days;
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| 152 |
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| 153 | /* Compute the weekday.
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| 154 | * The 1st of January 1970 was a Thursday which is equal to 4 in the weekday representation ranging from [0:6].
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| 155 | */
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| 156 | time_info->tm_wday = (seconds + 4) % 7;
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| 157 |
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| 158 | /* Years start at 70. */
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| 159 | time_info->tm_year = 70;
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| 160 | while (true) {
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| 161 | if (_rtc_is_leap_year(time_info->tm_year, leap_year_support) && seconds >= 366) {
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| 162 | ++time_info->tm_year;
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| 163 | seconds -= 366;
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| 164 | } else if (!_rtc_is_leap_year(time_info->tm_year, leap_year_support) && seconds >= 365) {
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| 165 | ++time_info->tm_year;
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| 166 | seconds -= 365;
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| 167 | } else {
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| 168 | /* The remaining days are less than a years. */
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| 169 | break;
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| 170 | }
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| 171 | }
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| 172 |
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| 173 | time_info->tm_yday = seconds;
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| 174 |
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| 175 | /* Convert days into seconds and find the current month. */
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| 176 | seconds *= SECONDS_BY_DAY;
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| 177 | time_info->tm_mon = 11;
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| 178 | bool leap = _rtc_is_leap_year(time_info->tm_year, leap_year_support);
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| 179 | for (uint32_t i = 0; i < 12; ++i) {
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| 180 | if ((uint32_t) seconds < seconds_before_month[leap][i]) {
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| 181 | time_info->tm_mon = i - 1;
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| 182 | break;
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| 183 | }
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| 184 | }
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| 185 |
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| 186 | /* Remove month from timestamp and compute the number of days.
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| 187 | * Note: unlike other fields, days are not 0 indexed.
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| 188 | */
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| 189 | seconds -= seconds_before_month[leap][time_info->tm_mon];
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| 190 | time_info->tm_mday = (seconds / SECONDS_BY_DAY) + 1;
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| 191 |
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| 192 | return true;
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| 193 | }
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