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Prakxo
410 lines
17 KiB
C
410 lines
17 KiB
C
/*
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* lb_reki.c
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*
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* This source file contains a set of functions used to convert dates
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* between the Gregorian calendar (seiyo reki, 西洋暦) and the old Japanese
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* lunisolar calendar (kyuu reki, 旧暦). The functions also handle special
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* date calculations related to the Japanese calendar, such as Vernal Equinox Day,
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* Autumnal Equinox Day, and Harvest Moon Day.
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*
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* Functions in this file include:
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*
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* - lbRk_SeirekiDays: Calculate the number of days in a given month of a given year in the Gregorian calendar.
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* - lbRk_ToSeiyoMonthAndDay: Convert a kyuureki year and month to the corresponding Gregorian month and day.
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* - lbRk_KyuurekiLeapDays: Calculate the number of leap days in a given kyuureki year.
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* - lbRk_IsKyuurekiLeapYear: Check if a kyuureki year is a leap year.
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* - lbRk_IsLeapMonth: Check if a kyuureki month is a leap month.
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* - lbRk_IsLeapOnNextMonth: Check if a leap month occurs after the given kyuureki month.
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* - lbRk_KyuurekiDays: Calculate the number of days in a given kyuureki month of a given year.
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* - lbRk_ToSeiyouReki: Convert a kyuureki date to the corresponding Gregorian date.
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* - lbRk_ToKyuuReki: Convert a Gregorian date to the corresponding kyuureki date.
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* - lbRk_VernalEquinoxDay: Calculate the Vernal Equinox Day for a given year.
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* - lbRk_AutumnalEquinoxDay: Calculate the Autumnal Equinox Day for a given year.
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* - lbRk_HarvestMoonDay: Calculate the Harvest Moon Day for a given year.
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*/
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#include "lb_reki.h"
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#include "types.h"
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typedef struct lbRk_date_s {
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lbRTC_month_t month;
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lbRTC_day_t day;
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} lbRk_date_t;
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/**
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* @brief Gets the number of days in a given month of the Seiyo Reki (Gregorian calendar).
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*
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* @param year Year value.
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* @param month Month value.
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* @return The number of days in the specified month of the given year.
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*/
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static int lbRk_SeirekiDays(int year, int month) {
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// Table containing the number of days for each month in standard and leap years in the Seiyo Reki (Gregorian calendar)
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static lbRTC_day_t t_seiyo_days_tbl[][lbRTC_MONTHS_MAX + 1] = {
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{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}, /* Standard days for each month */
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{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} /* Days for each month during leap year */
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};
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int idx = 0;
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if ((year % 4) == 0) {
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idx = 1;
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}
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return t_seiyo_days_tbl[idx][month];
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}
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/* Convesion table which gets the beginning of a Kyuu Reki (Japanese lunisolar)
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date in Seiyo Reki (Gregoran calendar) date. */
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static lbRk_date_t l_lbRk_ConvertTable[lbRk_YEAR_NUM][lbRk_KYUU_LEAP_MONTH] = {
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/* 2000 */ {{2, 5}, {3, 6}, {4, 5}, {5, 4}, {6, 2}, {7, 2}, {7, 31}, {8, 29}, { 9, 28}, {10, 27}, {11, 26}, {12, 26}, { 0, 0}},
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/* 2001 */ {{1, 24}, {2, 23}, {3, 25}, {4, 24}, {6, 21}, {7, 21}, {8, 19}, {9, 17}, {10, 17}, {11, 15}, {12, 15}, { 1, 13}, { 5, 23}},
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/* 2002 */ {{2, 12}, {3, 14}, {4, 13}, {5, 12}, {6, 11}, {7, 10}, {8, 9}, {9, 7}, {10, 6}, {11, 5}, {12, 4}, { 1, 3}, { 0, 0}},
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/* 2003 */ {{2, 1}, {3, 3}, {4, 2}, {5, 1}, {5, 31}, {6, 30}, {7, 29}, {8, 28}, { 9, 26}, {10, 25}, {11, 24}, {12, 23}, { 0, 0}},
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/* 2004 */ {{1, 22}, {2, 20}, {4, 19}, {5, 19}, {6, 18}, {7, 17}, {8, 16}, {9, 14}, {10, 14}, {11, 12}, {12, 12}, { 1, 10}, { 3, 21}},
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/* 2005 */ {{2, 9}, {3, 10}, {4, 9}, {5, 8}, {6, 7}, {7, 6}, {8, 5}, {9, 4}, {10, 3}, {11, 2}, {12, 2}, {12, 31}, { 0, 0}},
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/* 2006 */ {{1, 29}, {2, 28}, {3, 29}, {4, 28}, {5, 27}, {6, 26}, {7, 25}, {9, 22}, {10, 22}, {11, 21}, {12, 20}, { 1, 19}, { 8, 24}},
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/* 2007 */ {{2, 18}, {3, 19}, {4, 17}, {5, 17}, {6, 15}, {7, 14}, {8, 13}, {9, 11}, {10, 11}, {11, 10}, {12, 10}, { 1, 8}, { 0, 0}},
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/* 2008 */ {{2, 7}, {3, 8}, {4, 6}, {5, 5}, {6, 4}, {7, 3}, {8, 1}, {8, 31}, { 9, 29}, {10, 29}, {11, 28}, {12, 27}, { 0, 0}},
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/* 2009 */ {{1, 26}, {2, 25}, {3, 27}, {4, 25}, {5, 24}, {7, 22}, {8, 20}, {9, 19}, {10, 18}, {11, 17}, {12, 16}, { 1, 15}, { 6, 23}},
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/* 2010 */ {{2, 14}, {3, 16}, {4, 14}, {5, 14}, {6, 12}, {7, 12}, {8, 10}, {9, 8}, {10, 8}, {11, 6}, {12, 6}, { 1, 4}, { 0, 0}},
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/* 2011 */ {{2, 3}, {3, 5}, {4, 3}, {5, 3}, {6, 2}, {7, 1}, {7, 31}, {8, 29}, { 9, 27}, {10, 27}, {11, 25}, {12, 25}, { 0, 0}},
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/* 2012 */ {{1, 23}, {2, 22}, {3, 22}, {5, 21}, {6, 20}, {7, 19}, {8, 18}, {9, 16}, {10, 15}, {11, 14}, {12, 13}, { 1, 12}, { 4, 21}},
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/* 2013 */ {{2, 10}, {3, 12}, {4, 10}, {5, 10}, {6, 9}, {7, 8}, {8, 7}, {9, 5}, {10, 5}, {11, 3}, {12, 3}, { 1, 1}, { 0, 0}},
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/* 2014 */ {{1, 31}, {3, 1}, {3, 31}, {4, 29}, {5, 29}, {6, 27}, {7, 27}, {8, 25}, { 9, 24}, {11, 22}, {12, 22}, { 1, 20}, {10, 24}},
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/* 2015 */ {{2, 19}, {3, 20}, {4, 19}, {5, 18}, {6, 16}, {7, 16}, {8, 14}, {9, 13}, {10, 13}, {11, 12}, {12, 11}, { 1, 10}, { 0, 0}},
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/* 2016 */ {{2, 8}, {3, 9}, {4, 7}, {5, 7}, {6, 5}, {7, 4}, {8, 3}, {9, 1}, {10, 1}, {10, 31}, {11, 29}, {12, 29}, { 0, 0}},
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/* 2017 */ {{1, 28}, {2, 26}, {3, 28}, {4, 26}, {5, 26}, {7, 23}, {8, 22}, {9, 20}, {10, 20}, {11, 18}, {12, 18}, { 1, 17}, { 6, 24}},
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/* 2018 */ {{2, 16}, {3, 17}, {4, 16}, {5, 15}, {6, 14}, {7, 13}, {8, 11}, {9, 10}, {10, 9}, {11, 8}, {12, 27}, { 1, 6}, { 0, 0}},
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/* 2019 */ {{2, 5}, {3, 7}, {4, 5}, {5, 5}, {6, 3}, {7, 3}, {8, 1}, {8, 30}, { 9, 29}, {10, 28}, {11, 27}, {12, 26}, { 0, 0}},
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/* 2020 */ {{1, 25}, {2, 24}, {3, 24}, {4, 23}, {6, 21}, {7, 21}, {8, 19}, {9, 17}, {10, 17}, {11, 15}, {12, 15}, { 1, 13}, { 5, 23}},
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/* 2021 */ {{2, 12}, {3, 13}, {4, 12}, {5, 12}, {6, 10}, {7, 10}, {8, 8}, {9, 7}, {10, 6}, {11, 5}, {12, 4}, { 1, 3}, { 0, 0}},
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/* 2022 */ {{2, 1}, {3, 3}, {4, 1}, {5, 1}, {5, 30}, {6, 29}, {7, 29}, {8, 27}, { 9, 26}, {10, 25}, {11, 24}, {12, 23}, { 0, 0}},
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/* 2023 */ {{1, 22}, {2, 20}, {3, 22}, {5, 20}, {6, 18}, {7, 18}, {8, 16}, {9, 15}, {10, 15}, {11, 13}, {12, 13}, { 1, 11}, { 4, 20}},
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/* 2024 */ {{2, 10}, {3, 10}, {4, 9}, {5, 8}, {6, 6}, {7, 6}, {8, 4}, {9, 3}, {10, 3}, {11, 1}, {12, 1}, {12, 31}, { 0, 0}},
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/* 2025 */ {{1, 29}, {2, 28}, {3, 29}, {4, 28}, {5, 27}, {6, 25}, {8, 23}, {9, 22}, {10, 21}, {11, 20}, {12, 20}, { 1, 19}, { 7, 25}},
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/* 2026 */ {{2, 17}, {3, 19}, {4, 17}, {5, 17}, {6, 15}, {7, 14}, {8, 13}, {9, 11}, {10, 11}, {11, 9}, {12, 9}, { 1, 8}, { 0, 0}},
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/* 2027 */ {{2, 7}, {3, 8}, {4, 7}, {5, 6}, {6, 5}, {7, 4}, {8, 2}, {9, 1}, { 9, 30}, {10, 29}, {11, 28}, {12, 28}, { 0, 0}},
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/* 2028 */ {{1, 27}, {2, 25}, {3, 26}, {4, 25}, {5, 24}, {7, 22}, {8, 20}, {9, 19}, {10, 18}, {11, 16}, {12, 16}, { 1, 15}, { 6, 23}},
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/* 2029 */ {{2, 13}, {3, 15}, {4, 14}, {5, 13}, {6, 12}, {7, 12}, {8, 10}, {9, 8}, {10, 8}, {11, 6}, {12, 5}, { 1, 4}, { 0, 0}},
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/* 2030 */ {{2, 3}, {3, 4}, {4, 3}, {5, 2}, {6, 1}, {7, 1}, {7, 30}, {8, 29}, { 9, 27}, {10, 27}, {11, 25}, {12, 25}, { 0, 0}},
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/* 2031 */ {{1, 23}, {2, 22}, {3, 23}, {4, 22}, {6, 20}, {7, 19}, {8, 18}, {9, 17}, {10, 16}, {11, 15}, {12, 14}, { 1, 13}, { 5, 21}},
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/* 2032 */ {{2, 11}, {3, 12}, {4, 10}, {5, 9}, {6, 8}, {7, 7}, {8, 6}, {9, 5}, {10, 4}, {11, 3}, {12, 3}, { 1, 1}, { 0, 0}},
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};
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// The number of Japanese lunisolar leap days for a given lunisolar year.
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static int l_lbRk_leapdays[lbRk_YEAR_NUM] = {
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0, 29, 0, 0,
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29, 0, 29, 0,
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0, 29, 0, 0,
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30, 0, 29, 0,
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0, 29, 0, 0,
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29, 0, 0, 30,
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0, 29, 0, 0,
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29, 0, 0, 30,
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0
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};
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/**
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* @brief Get a pointer to the lbRk_date_t structure for the Seiyo Reki (Gregorian calendar) month and day.
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*
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* @param year Year value.
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* @param month Month value.
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* @return Pointer to the lbRk_date_t structure representing the Seiyo Reki (Gregorian calendar) month and day.
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*/
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static lbRk_date_t* lbRk_ToSeiyoMonthAndDay(int year, int month) {
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return &l_lbRk_ConvertTable[year - lbRk_YEAR_MIN][month - 1];
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}
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/**
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* @brief Get the number of leap days for a given Kyuu Reki (Japanese lunisolar) year.
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*
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* @param year Year value.
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* @return The number of leap days for the specified Kyuu Reki (Japanese lunisolar) year.
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*/
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static int lbRk_KyuurekiLeapDays(int year) {
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return l_lbRk_leapdays[year - lbRk_YEAR_MIN];
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}
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/**
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* @brief Check if a given Kyuu Reki (Japanese lunisolar) year is a leap year.
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*
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* @param year Year value.
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* @return Non-zero (TRUE) if the given Kyuu Reki (Japanese lunisolar) year is a leap year, zero (FALSE) otherwise.
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*/
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static int lbRk_IsKyuurekiLeapYear(int year) {
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return l_lbRk_leapdays[year - lbRk_YEAR_MIN] != 0;
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}
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/**
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* @brief Check if a given month is a leap month in the Kyuu Reki (Japanese lunisolar) calendar.
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*
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* @param month Month value.
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* @return Non-zero (TRUE) if the given month is a leap month, zero (FALSE) otherwise.
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*/
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static int lbRk_IsLeapMonth(int month) {
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return month == lbRk_KYUU_LEAP_MONTH;
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}
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/**
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* @brief Check if the leap month occurs next month in the Kyuu Reki (Japanese lunisolar) calendar.
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*
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* @param year Year value.
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* @param month Month value.
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* @return Non-zero (TRUE) if the leap month occurs next month, zero (FALSE) otherwise.
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*/
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static int lbRk_IsLeapOnNextMonth(int year, int month) {
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lbRk_date_t* seiyo_monthday = lbRk_ToSeiyoMonthAndDay(year, month);
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lbRk_date_t* convert_monthday = &l_lbRk_ConvertTable[year - lbRk_YEAR_MIN][lbRTC_MONTHS_MAX];
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// Check if the leap month occurs next month by comparing the month values
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// in the Seiyo Reki (Gregorian calendar)
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return !(convert_monthday->month != seiyo_monthday->month + 1);
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}
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/**
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* Calculates the number of days in a given month of the Japanese lunisolar calendar (kyuureki)
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* for a given year and month.
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*
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* @param year The year in the kyuureki calendar.
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* @param month The month in the kyuureki calendar.
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* @return The number of days in the specified month of the Japanese lunisolar calendar.
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*/
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static int lbRk_KyuurekiDays(int year, int month) {
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int days;
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lbRk_date_t* next_seiyo_month_day;
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// Get the corresponding Seiyo (Gregorian) month and day for the given kyuureki year and month
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lbRk_date_t* seiyo_monthday = lbRk_ToSeiyoMonthAndDay(year, month);
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// If the month is a leap month, return the number of leap days for the year
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if (lbRk_IsLeapMonth(month) == TRUE) {
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return lbRk_KyuurekiLeapDays(year);
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}
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// Determine the Seiyo (Gregorian) month and day for the next month in the kyuureki calendar
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if (month != lbRTC_MONTHS_MAX) {
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if (lbRk_IsLeapOnNextMonth(year, month) == TRUE) {
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next_seiyo_month_day = lbRk_ToSeiyoMonthAndDay(year, lbRk_KYUU_LEAP_MONTH);
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} else {
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next_seiyo_month_day = lbRk_ToSeiyoMonthAndDay(year, month + 1);
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}
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} else {
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next_seiyo_month_day = lbRk_ToSeiyoMonthAndDay(year + 1, 1);
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}
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// Calculate the number of days in the Kyuu (Japanese lunisolar) month
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if (seiyo_monthday->month == next_seiyo_month_day->month) {
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days = next_seiyo_month_day->day - seiyo_monthday->day;
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} else {
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if (seiyo_monthday->month < month) {
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year += 1;
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}
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days = lbRk_SeirekiDays(year, seiyo_monthday->month) - seiyo_monthday->day;
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if ((next_seiyo_month_day->month - seiyo_monthday->month) >= 2) {
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days += lbRk_SeirekiDays(year, seiyo_monthday->month + 1);
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}
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days += next_seiyo_month_day->day;
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}
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return days;
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}
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/**
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* Converts a date from the Japanese lunisolar calendar (kyuureki) to the Gregorian calendar (seiyo reki).
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*
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* @param seiyo_ymd The output date in the Gregorian calendar.
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* @param kyuu_ymd The input date in the kyuureki calendar.
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* @return TRUE if the conversion is successful, FALSE if the input date is invalid.
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*/
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extern int lbRk_ToSeiyouReki(lbRTC_ymd_c* seiyo_ymd, const lbRTC_ymd_c* kyuu_ymd) {
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int seireki_days;
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int year;
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int month;
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int day;
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lbRk_date_t* seiyo_monthday;
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// Validate the input kyuureki date
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if ((kyuu_ymd->year < 1) || (kyuu_ymd->year > lbRk_YEAR_MAX)) {
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return FALSE;
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}
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if (kyuu_ymd->month > lbRk_KYUU_LEAP_MONTH) {
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return FALSE;
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}
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if (lbRk_IsKyuurekiLeapYear(kyuu_ymd->year) == FALSE && kyuu_ymd->month >= lbRk_KYUU_LEAP_MONTH) {
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return FALSE;
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}
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if (lbRk_KyuurekiDays(kyuu_ymd->year, kyuu_ymd->month) < kyuu_ymd->day) {
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return FALSE;
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}
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// Get the corresponding Seiyo (Gregorian) month and day for the given kyuureki year and month
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seiyo_monthday = lbRk_ToSeiyoMonthAndDay(kyuu_ymd->year, kyuu_ymd->month);
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month = seiyo_monthday->month;
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year = kyuu_ymd->year;
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day = seiyo_monthday->day + kyuu_ymd->day - 1;
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// Adjust the Gregorian date based on the number of days in the Seiyo (Gregorian) month
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seireki_days = lbRk_SeirekiDays(year, month);
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if (day > seireki_days) {
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month++;
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day -= seireki_days;
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if (month > lbRTC_MONTHS_MAX) {
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month = 1;
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}
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}
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// Adjust the Gregorian year if necessary
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if (month < kyuu_ymd->month && kyuu_ymd->month != lbRk_KYUU_LEAP_MONTH) {
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year++;
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}
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// Set the output Gregorian date
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seiyo_ymd->year = year;
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seiyo_ymd->month = month;
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seiyo_ymd->day = day;
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return TRUE;
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}
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/**
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* Converts a date from the Gregorian calendar (seiyo reki) to the Japanese lunisolar calendar (kyuureki).
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*
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* @param kyuu_ymd The output date in the kyuureki calendar.
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* @param seiyo_ymd The input date in the Gregorian calendar.
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* @return TRUE if the conversion is successful, FALSE if the input date is invalid.
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*/
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extern int lbRk_ToKyuuReki(lbRTC_ymd_c* kyuu_ymd, const lbRTC_ymd_c* seiyo_ymd) {
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lbRTC_ymd_c kyuu_date = (lbRTC_ymd_c){lbRk_YEAR_MIN, lbRk_KYUU_MONTH_START, lbRk_KYUU_DAY_START};
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lbRTC_ymd_c seyio_date;
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while (TRUE) {
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// Attempt to convert the current kyuureki date to Gregorian date
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if (lbRk_ToSeiyouReki(&seyio_date, &kyuu_date) == FALSE) {
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return FALSE;
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}
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// Check if the converted Gregorian date matches the input seiyo_ymd
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if (seyio_date.day == seiyo_ymd->day && seyio_date.month == seiyo_ymd->month && seyio_date.year == seiyo_ymd->year) {
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kyuu_ymd->day = kyuu_date.day;
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kyuu_ymd->month = kyuu_date.month;
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kyuu_ymd->year = kyuu_date.year;
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return TRUE;
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}
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// Increment the kyuureki day
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kyuu_date.day++;
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// If the kyuureki day exceeds the number of days in the current kyuureki month, reset the day and increment the month
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if (lbRk_KyuurekiDays(kyuu_date.year, kyuu_date.month) < kyuu_date.day) {
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kyuu_date.day = 1;
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kyuu_date.month++;
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// Handle leap years and month transitions
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if (lbRk_IsKyuurekiLeapYear(kyuu_date.year) == FALSE) {
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if (kyuu_date.month > lbRk_KYUU_MONTH_END) {
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kyuu_date.month = 1;
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kyuu_date.year++;
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if (kyuu_date.year > lbRk_YEAR_MAX) {
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return FALSE;
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}
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}
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} else if (kyuu_date.month > lbRk_KYUU_LEAP_MONTH) {
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kyuu_date.month = 1;
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kyuu_date.year++;
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if (kyuu_date.year > lbRk_YEAR_MAX) {
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return FALSE;
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}
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}
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}
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}
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|
}
|
|
|
|
/**
|
|
* Calculates the Vernal Equinox Day for the given year.
|
|
*
|
|
* @param year The input year.
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|
* @return The Vernal Equinox Day for the given year.
|
|
* @remarks This function calculates the Vernal Equinox Day from 1980 thru 2099.
|
|
* It was sourced from '新こよみ便利帳 天文現象・暦計算のすべて'
|
|
* by Kouseisha Kouseikaku (ISBN4-7699-0700-1).
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|
*/
|
|
extern int lbRk_VernalEquinoxDay(int year) {
|
|
year -= 1980;
|
|
return (int)(20.8431f + (0.242194f * (f32)year)) - (year / 4);
|
|
}
|
|
|
|
/**
|
|
* Calculates the Autumnal Equinox Day for the given year.
|
|
*
|
|
* @param year The input year.
|
|
* @return The Autumnal Equinox Day for the given year.
|
|
* @remarks This function calculates the Autmnal Equinox Day from 1980 thru 2099.
|
|
* It was sourced from '新こよみ便利帳 天文現象・暦計算のすべて'
|
|
* by Kouseisha Kouseikaku (ISBN4-7699-0700-1).
|
|
*/
|
|
extern int lbRk_AutumnalEquinoxDay(int year) {
|
|
year -= 1980;
|
|
return (int)(23.2488f + (0.242194f * (f32)year)) - (year / 4);
|
|
}
|
|
|
|
/**
|
|
* Calculates the Harvest Moon Day for the given year.
|
|
*
|
|
* @param harvest_moon_day The output Harvest Moon Day in the Gregorian calendar.
|
|
* @param year The input year.
|
|
*/
|
|
extern void lbRk_HarvestMoonDay(lbRTC_ymd_c* harvest_moon_day, int year) {
|
|
/* Array of precomputed Seiyo Reki (Gregorian calendar)
|
|
Havest Moon Day dates. */
|
|
static lbRk_date_t ev_day[lbRk_HARVEST_MOON_YEAR_NUM] = {
|
|
/* 2002 */ {9, 21},
|
|
/* 2003 */ {9, 10},
|
|
/* 2004 */ {9, 28},
|
|
/* 2005 */ {9, 18},
|
|
/* 2006 */ {10, 7},
|
|
/* 2007 */ {9, 26},
|
|
/* 2008 */ {9, 15},
|
|
/* 2009 */ {10, 4},
|
|
/* 2010 */ {9, 23},
|
|
/* 2011 */ {9, 12},
|
|
/* 2012 */ {9, 30},
|
|
/* 2013 */ {9, 19},
|
|
/* 2014 */ {9, 9},
|
|
/* 2015 */ {9, 28},
|
|
/* 2016 */ {9, 16},
|
|
/* 2017 */ {10, 5},
|
|
/* 2018 */ {9, 25},
|
|
/* 2019 */ {9, 14},
|
|
/* 2020 */ {10, 1},
|
|
/* 2021 */ {9, 20},
|
|
/* 2022 */ {9, 10},
|
|
/* 2023 */ {9, 29},
|
|
/* 2024 */ {9, 18},
|
|
/* 2025 */ {10, 7},
|
|
/* 2026 */ {9, 26},
|
|
/* 2027 */ {9, 15},
|
|
/* 2028 */ {10, 3},
|
|
/* 2029 */ {9, 22},
|
|
/* 2030 */ {9, 11}
|
|
};
|
|
|
|
lbRTC_ymd_c kyuu_ymd;
|
|
|
|
// If the year is within the pre-calculated range, use the stored values
|
|
if ((year >= lbRk_HARVEST_MOON_YEAR_MIN) && (year < lbRk_HARVEST_MOON_YEAR_MAX + 1)) {
|
|
year -= lbRk_HARVEST_MOON_YEAR_MIN;
|
|
harvest_moon_day->month = ev_day[year].month;
|
|
harvest_moon_day->day = ev_day[year].day;
|
|
return;
|
|
}
|
|
|
|
// If the year is outside the pre-calculated range, calculate the Harvest Moon Day
|
|
// using the Japanese lunisolar date of 8th month 15th day.
|
|
kyuu_ymd.year = year;
|
|
kyuu_ymd.month = 8;
|
|
kyuu_ymd.day = 15;
|
|
lbRk_ToSeiyouReki(harvest_moon_day, &kyuu_ymd);
|
|
}
|