Adding ical support to the C version.

README.md

@@ -51,7 +51,7 @@ calendar, thunderbird + lightning插件, iphone/ipad, 安卓都支持。
 
 ### C 版本
 
-C版本速度更快，但暂时只在终端上输出农历，不能直接生成ical文件。
+C版本速度更快，但暂时只在终端上输出ical。用户必须使用`>`将stdout的结果导入到指定文件以生成ical文件。
 
 编译：
 
@@ -60,12 +60,11 @@ C版本速度更快，但暂时只在终端上输出农历，不能直接生成i
 
 运行:
 
-    生成某年农历
-    $ ./lunarcal 2015
-
-    生成数年农历
-    $ ./lunarcal 2015 2019
+    #生成某年农历
+    $ ./lunarcal 2016 > chinese_lunar_2016.ics
 
+    #生成数年农历
+    $ ./lunarcal 2016 2019 > chinese_lunar_2016_2019.ics
 
 ### 版权
 
@@ -148,11 +147,13 @@ The date must in ISO format.
 
 There is also a C version under directory "c". Run `make` to generate the
 executable `lunarcal`. Run `lunarcal` with year will print out the Chinese Lunar
-Calendar to terminal, for example:
+Calendar in ical format to the terminal. Use `>` to redirect the output to a file, for example:
 
-    $ ./lunarcal 2015
-        or
-    $ ./lunarcal 2015 2019
+    # Specific year
+    $ ./lunarcal 2016 > chinese_lunar_2016.ics
+
+    # or multiple years
+    $ ./lunarcal 2016 2019 > chinese_lunar_2016_2019.ics
 
 
 [Contact me](mailto: weichen302@gmail.com)

c/julian.c

@@ -196,7 +196,9 @@ size_t jdftime(char *isodt, double jd, char *fmt, double tz, int isut)
     M = ms / 60;
     S = ms % 60;
 
-    if (strcmp(fmt, "%y-%m-%d") == 0) {
+    if (strcmp(fmt, "%y%m%d") == 0) {
+        sprintf(isodt, "%04d%02d%02d", y, m, d);
+    } else if (strcmp(fmt, "%y-%m-%d") == 0) {
         sprintf(isodt, "%04d-%02d-%02d", y, m, d);
     } else if (strcmp(fmt, "%y-%m-%d %H:%M") == 0) {
         sprintf(isodt, "%04d-%02d-%02d %02d:%02d", y, m, d, H, M);

c/lunarcal.c

@@ -17,10 +17,19 @@ int main(int argc, char *argv[])
         exit(2);
     }
 
+    printf("BEGIN:VCALENDAR\n"
+           "PRODID:-//Chen Wei//Chinese Lunar Calendar//EN\n"
+           "VERSION:2.0\n"
+           "CALSCALE:GREGORIAN\n"
+           "METHOD:PUBLISH\n"
+           "X-WR-CALNAME:农历\n"
+           "X-WR-TIMEZONE:Asia/Shanghai\n"
+           "X-WR-CALDESC:中国农历%d-%d, 包括节气. 数据来自香港天文台\n", start, end);
     while (start <= end) {
         cn_lunarcal(start);
         start++;
     }
+    printf("END:VCALENDAR\n");
 
     return 0;
 }

c/lunarcalbase.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>
+#include <time.h>
 #include "astro.h"
 #include "lunarcalbase.h"
 
@@ -280,14 +281,30 @@ void print_lunarcal(struct lunarcal *p[], int len)
     int i;
     char isodate[30];
     char tmp[30];
+    char dtstart[30];
+    char dtend[30];
+    char utcstamp[30];
+    struct tm* utc_time;
+    time_t t = time(NULL);
+    utc_time = gmtime(&t);
+    sprintf (utcstamp, "%04d%02d%02dT%02d%02d%02dZ", 1900+utc_time->tm_year, utc_time->tm_mon, utc_time->tm_mday, utc_time->tm_hour, utc_time->tm_min, utc_time->tm_sec);
     for (i = 0; i < len; i++) {
         jdftime(isodate, p[i]->jd, "%y-%m-%d", 0, 0);
+        jdftime(dtstart, p[i]->jd, "%y%m%d", 0, 0);
+        jdftime(dtend, p[i]->jd, "%y%m%d", 24, 0);
         if (p[i]->day == 1)
             sprintf(tmp, "%s", CN_MON[p[i]->month]);
         else
             sprintf(tmp, "%s", CN_DAY[p[i]->day]);
         if (p[i]->solarterm > -1)
             sprintf(tmp, "%s %s", tmp, CN_SOLARTERM[p[i]->solarterm]);
-        printf("%s %s \n", isodate, tmp);
+        printf("BEGIN:VEVENT\n"
+               "DTSTAMP:%s\n"
+               "UID:%s-lc@infinet.github.io\n"
+               "DTSTART;VALUE=DATE:%s\n"
+               "DTEND;VALUE=DATE:%s\n"
+               "STATUS:CONFIRMED\n"
+               "SUMMARY:%s\n"
+               "END:VEVENT\n", utcstamp, isodate, dtstart, dtend, tmp);
      }
 }