mirror of
https://github.com/infinet/lunar-calendar.git
synced 2026-01-12 21:17:00 +08:00
402 lines
11 KiB
C
402 lines
11 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <time.h>
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#include "astro.h"
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#include "lunarcalbase.h"
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static char *CN_DAY[] = {
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"", "",
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"初二", "初三", "初四", "初五", "初六", "初七", "初八", "初九",
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"初十", "十一", "十二", "十三", "十四", "十五", "十六", "十七",
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"十八", "十九", "二十", "廿一", "廿二", "廿三", "廿四", "廿五",
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"廿六", "廿七", "廿八", "廿九", "三十"
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};
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static char *CN_MON[] = {
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"十二月",
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"正月", "二月", "三月", "四月", "五月", "六月",
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"七月", "八月", "九月", "十月", "十一月", "十二月", /* index = 12 */
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"", "", "", "", "", "", /* pad from index 13 to 18 */
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"閏十一月", "閏十二月", "閏正月", "閏二月", "閏三月", "閏四月",
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"閏五月", "閏六月", "閏七月", "閏八月", "閏九月", "閏十月",
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"閏十一月", "閏十二月"
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};
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/* solar term's angle + 120 / 15 */
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static char *CN_SOLARTERM[] = {
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"小雪", "大雪", "冬至", "小寒", "大寒", "立春", "雨水", "驚蟄",
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"春分", "清明", "穀雨", "立夏", "小滿", "芒種", "夏至", "小暑",
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"大暑", "立秋", "處暑", "白露", "秋分", "寒露", "霜降", "立冬",
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"小雪", "大雪", "冬至"
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};
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/* 干支记年 */
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static char *GAN[] = {
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"庚", "辛", "壬", "癸", "甲", "乙", "丙", "丁", "戊", "已"
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};
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static char *ZHI[] = {
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"申", "酉", "戌", "亥", "子", "丑", "寅", "卯", "辰", "巳", "午", "未"
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};
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static char *SX[] = {
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"猴", "鸡", "狗", "猪", "鼠", "牛", "虎", "兔", "龙", "蛇", "马", "羊"
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};
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static double newmoons[MAX_NEWMOONS];
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static double solarterms[MAX_SOLARTERMS];
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static int firstnm_offset;
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static struct lunarcal_cache *cached_lcs[CACHESIZE];
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static int cache_initialized = 0; /* flag for initialized cache */
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static int cachep = 0; /* next free location in cache */
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static int rewinded = 0; /* cache rewinded? free pointers */
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/* normalize Julian Day to midnight after adjust timezone and deltaT */
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double normjd(double jd, double tz)
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{
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double deltat, tmp, jd_i, jd_f;
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GregorianDate g;
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g = jd2g(jd);
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deltat = deltaT(g.year, g.month);
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tmp = jd + (tz * 3600.0 - deltat) / 86400.0;
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g = jd2g(tmp);
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jd_f = modf(tmp, &jd_i);
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if (jd_f >= 0.5)
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jd = jd_i + 0.5;
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else
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jd = jd_i - 0.5;
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return jd;
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}
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/* initialize cache storage */
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void init_cache(void)
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{
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if (cache_initialized)
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return;
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int i;
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struct lunarcal_cache *tmp;
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for (i = 0; i < CACHESIZE; i++) {
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tmp = (struct lunarcal_cache *) malloc(sizeof(struct lunarcal_cache));
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tmp->year = -1;
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tmp->len = -1;
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cached_lcs[i] = tmp;
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}
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cache_initialized = 1;
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}
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void cn_lunarcal(int year)
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{
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int i, k, len1, len2;
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double ystart, yend;
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struct lunarcal *thisyear[MAX_DAYS];
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struct lunarcal *nextyear[MAX_DAYS];
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struct lunarcal *output[MAX_DAYS];
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init_cache();
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len1 = get_cached_lc(thisyear, year);
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len2 = get_cached_lc(nextyear, year + 1);
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/* combine lunar calendars from this and next year. Leapmonth close to the
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* end of Gregorian year can only be found by compute Lunar calendar of the
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* next year */
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ystart = g2jd(year, 1, 1.0);
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yend = g2jd(year, 12, 31.0);
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k = 0;
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for (i = 0; i < len1; i++) {
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if (thisyear[i]->jd >= ystart)
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output[k++] = thisyear[i];
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}
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for (i = 0; i < len2; i++) {
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if (nextyear[i]->jd <= yend)
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output[k++] = nextyear[i];
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}
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print_lunarcal(output, k);
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}
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int get_cache_index(int year)
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{
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int i;
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for (i = 0; i < CACHESIZE; i++) {
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if (cached_lcs[i]->year == year)
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return i;
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}
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return -1;
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}
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int get_cached_lc(struct lunarcal *p[], int year)
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{
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int i, k, len;
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double angle;
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double jd_nm, est_nm;
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if ((k = get_cache_index(year)) > -1) {
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for (i = 0; i < cached_lcs[k]->len; i++) {
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p[i] = cached_lcs[k]->lcs[i];
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}
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return i;
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}
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for (i = 0; i < MAX_SOLARTERMS; i++) {
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angle = (double) (i * 15 - 120);
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solarterms[i] = normjd(solarterm(year, angle), TZ_CN);
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}
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/* search 15 newmoons start 30 days before last Winter Solstice */
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est_nm = solarterms[2] - 30;
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for (i = 0; i < MAX_NEWMOONS; i++) {
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jd_nm = newmoon(est_nm);
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newmoons[i] = normjd(jd_nm, TZ_CN);
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est_nm = jd_nm + SYNODIC_MONTH;
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}
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/* fill in and mark each day with its lunar calendar year, month, day */
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len = mark_month_day(p);
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/* add to cache */
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if (cachep >= CACHESIZE) {
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cachep = 0;
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rewinded = 1;
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}
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if (rewinded)
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for (i = 0; i < len; i++) {
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free(cached_lcs[cachep]->lcs[i]);
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}
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for (i = 0; i < len; i++) {
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cached_lcs[cachep]->lcs[i] = p[i];
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}
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cached_lcs[cachep]->year = year;
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cached_lcs[cachep]->len = len;
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cachep++;
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return len;
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}
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/* mark month and day number, solarterms */
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int mark_month_day(struct lunarcal *lcs[])
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{
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int i, k, len, idx_lc_newyear;
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int leapmonth, month;
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double lc_start, lc_end, jd, month_day1;
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struct lunarcal *lc;
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GregorianDate g;
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len = 0;
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month = 11;
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month_day1 = 0;
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idx_lc_newyear = -1;
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leapmonth = find_leap();
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lc_start = newmoons[firstnm_offset];
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lc_end = solarterms[MAX_SOLARTERMS -1];
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jd = lc_start;
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while (jd < lc_end) { /* fill in days into array lcs */
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/* scan for month jd belongs */
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for (i = firstnm_offset; i < MAX_NEWMOONS; i++) {
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if (jd < newmoons[i]) {
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month = 11 + i - 1 - firstnm_offset;
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month_day1 = newmoons[i - 1];
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break;
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}
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}
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/* adjust leapmonth */
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if (leapmonth > -1 && month == leapmonth) {
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month = (month - 1) % 12 + 20; /* add offset 20 to distinguish */
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} else if (leapmonth > -1 && month > leapmonth) {
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month = (month - 1) % 12;
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} else {
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month %= 12;
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}
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lc = lcalloc(jd);
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lc->month = month;
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lc->day = (int) (jd - month_day1 + 1);
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if (lc->month == 1 && lc->day == 1)
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idx_lc_newyear = len; /* found 正月初一 */
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lcs[len++] = lc;
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jd += 1.0;
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}
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/* mark lunar year */
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int lyear;
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g = jd2g(lcs[idx_lc_newyear]->jd); /* 正月初一 in Gregorian */
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for (i = 0; i < len; i++) {
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if (i < idx_lc_newyear)
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lyear = g.year - 1;
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else
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lyear = g.year;
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lcs[i]->lyear = lyear;
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}
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/* modify days with solar terms */
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for (i = 0; i < MAX_SOLARTERMS - 1; i++) {
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if (solarterms[i] >= lc_start) {
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k = (int) (solarterms[i] - lc_start);
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if (lcs[k])
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lcs[k]->solarterm = i;
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}
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}
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return len;
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}
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int find_leap(void)
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{
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/* count newmoons between two Winter Solstice */
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int nmcount, flag, leapmonth, i, n;
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nmcount = 0;
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for (i = 0; i < MAX_NEWMOONS; i++) {
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if (newmoons[i] > solarterms[2]
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&& newmoons[i] <= solarterms[MAX_SOLARTERMS - 1])
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nmcount += 1;
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}
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/* first new moon of new year */
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for (i = 0; i < MAX_NEWMOONS; i++) {
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if (newmoons[i] > solarterms[2]) {
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firstnm_offset = i - 1;
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break;
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}
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}
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/* leap year has more than 12 newmoons between two Winter Solstice */
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if (nmcount > 12) {
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for (i = 1; i < MAX_NEWMOONS; i++) {
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flag = 0;
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for (n = 0; n < MAX_SOLARTERMS; n++) {
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/* the leap month is the first month which does NOT contain
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* solar terms that is multiple of 30 degrees */
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if (solarterms[n] >= newmoons[i - 1]
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&& solarterms[n] < newmoons[i]
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&& n % 2 == 0)
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flag = 1;
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}
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if (!flag) {
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leapmonth = 11 + i - 1 - firstnm_offset;
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return leapmonth;
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}
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}
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}
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return -1;
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}
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struct lunarcal *lcalloc(double jd)
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{
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struct lunarcal *p;
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p = (struct lunarcal *) malloc(sizeof(struct lunarcal));
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if (p) {
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p->jd = jd;
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p->solarterm = -1;
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p->lyear = -1;
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p->month = -1;
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p->day = -1;
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}
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return p;
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}
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/* generate 干支年份, e.g. 丙申[猴] */
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void ganzhi(char *buf, size_t buflen, int lyear)
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{
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int idx_gan, idx_zhi, idx_sx;
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idx_gan = lyear % 10;
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idx_zhi = lyear % 12;
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idx_sx = idx_zhi;
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snprintf(buf, buflen, "%s%s[%s]", GAN[idx_gan], ZHI[idx_zhi], SX[idx_sx]);
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}
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/* chinese traditional holiday */
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void holiday(char *buf, size_t buflen, int m, int d)
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{
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char cn_hol[30] = "";
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if (m == 12 && d == 8)
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sprintf(cn_hol, "腊八");
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if (m == 1 && d == 1)
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sprintf(cn_hol, "春节");
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if (m == 1 && d == 15)
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sprintf(cn_hol, "元宵");
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if (m == 5 && d == 5)
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sprintf(cn_hol, "端午");
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if (m == 7 && d == 7)
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sprintf(cn_hol, "七夕");
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if (m == 7 && d == 15)
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sprintf(cn_hol, "中元");
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if (m == 8 && d == 15)
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sprintf(cn_hol, "中秋");
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if (m == 9 && d == 9)
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sprintf(cn_hol, "重阳");
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if (m == 10 && d == 15)
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sprintf(cn_hol, "下元");
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snprintf(buf, buflen, cn_hol);
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}
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void print_lunarcal(struct lunarcal *p[], int len)
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{
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int i;
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char isodate[30], dtstart[30], dtend[30];
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char tmp[30];
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char gzyear[30];
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char cnholiday[30];
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char utcstamp[30];
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struct tm *utc_time;
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time_t t = time(NULL);
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utc_time = gmtime(&t);
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sprintf(utcstamp, "%04d%02d%02dT%02d%02d%02dZ",
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1900 + utc_time->tm_year, 1 + utc_time->tm_mon, utc_time->tm_mday,
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utc_time->tm_hour, utc_time->tm_min, utc_time->tm_sec);
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for (i = 0; i < len; i++) {
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jdftime(isodate, p[i]->jd, "%y-%m-%d", 0, 0);
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jdftime(dtstart, p[i]->jd, "%y%m%d", 0, 0);
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jdftime(dtend, p[i]->jd, "%y%m%d", 24, 0);
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if (p[i]->day == 1) {
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ganzhi(gzyear, 30, p[i]->lyear);
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sprintf(tmp, "%s%s", gzyear, CN_MON[p[i]->month]);
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} else {
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sprintf(tmp, "%s", CN_DAY[p[i]->day]);
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}
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if (p[i]->solarterm > -1)
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sprintf(tmp, "%s %s", tmp, CN_SOLARTERM[p[i]->solarterm]);
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holiday(cnholiday, 30, p[i]->month, p[i]->day);
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// temp fix for 除夕 and 寒食 (need to find a way to include them into the holiday function)
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if (p[i+1]->month == 1 && p[i+1]->day == 1)
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sprintf(cnholiday, "除夕");
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// solarterm 9 is 清明
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if (p[i+1]->solarterm == 9)
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sprintf(cnholiday, "寒食");
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sprintf(tmp, "%s %s", tmp, cnholiday);
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printf("BEGIN:VEVENT\n"
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"DTSTAMP:%s\n"
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"UID:%s-lc@infinet.github.io\n"
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"DTSTART;VALUE=DATE:%s\n"
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"DTEND;VALUE=DATE:%s\n"
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"STATUS:CONFIRMED\n"
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"SUMMARY:%s\n"
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"END:VEVENT\n", utcstamp, isodate, dtstart, dtend, tmp);
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}
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}
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