calendar.c

UNIX/Linux下用C开发的公历农历转换程序

	if((constellation = getConstellation(cal)) < 0 ) return NULL;
	return ConstellationName[constellation];
}

//计算公历当天对应的节气 0-23，-1表示不是节气
int l_GetLunarHolDay(CALENDAR_STRU *cal)
{
	unsigned	char	Flag;
	int		Day, iYear, iMonth, iDay;

	iYear = cal->y;
	
	if(iYear < START_YEAR || iYear > END_YEAR) return -1;		//超出计算范围
	iMonth = cal->m;
	iDay = cal->d;
	
	Flag = gLunarHolDay[(iYear - START_YEAR) * 12 + iMonth - 1];
	if (iDay < 15) 
		Day = 15 - ((Flag >> 4) & 0x0f);
	else
		Day = (Flag & 0x0f) + 15;
	if (iDay == Day) {
		if (iDay > 15)
			return (iMonth - 1) * 2 + 1;
		else
			return (iMonth - 1) * 2;
	}
	else  return -1;
}

//返回中文形式的月份名
char *formatMonth(int iMonth)
{
	char	strText[] = "正二三四五六七八九十";
	static	char	strMonth[10];
	int		i;

  	memset(strMonth, '\0', sizeof(strMonth));

	if (iMonth <= 10) {
		strncpy(strMonth, &strText[(iMonth - 1) * 2], 2);
		strcat(strMonth, "月");
		return strMonth;
	}

  	i = iMonth % 10;
  	strncpy(strMonth, "十", 2);
	strncpy(&strMonth[2], &strText[(iMonth - 1) * 2], 2);
	strcat(strMonth, "月");
	return strMonth;
}

//返回中文形式的农历日期
char *formatLunarDay(int iDay)
{
	char	strText1[] = "初十廿三";
	char	strText2[] = "一二三四五六七八九十";
	static	char	strDay[14];
	int		i;

	if(iDay < 1 || iDay > 31) return NULL;
	memset(strDay, '\0', sizeof(strDay));

	if ((iDay != 20) && (iDay != 30)) {
		memcpy(strDay, &strText1[(iDay - 1)/10], 2);
		memcpy(&strDay[2], &strText2[(iDay - 1) % 10], 2);
		return strDay;
	}

	memcpy(strDay,  &strText1[(iDay/10)* 2], 2);
	strcat(strDay, "十");
	return strDay;
}

char *getLunarHolDay(CALENDAR_STRU *cal)
{
	int		i, iYear, iMonth, iDay;

	iYear = cal->y;
	if (iYear < START_YEAR || iYear > END_YEAR) return NULL;

	i = l_GetLunarHolDay(cal);
	if ((i >= 0) && (i <= 23)) return LunarHolDayName[i];
}

//返回阴历iLunarYear年的闰月月份，如没有返回0 1901年1月---2050年12月
int GetLeapMonth(int iLunarYear)
{
	unsigned char	Flag;

	if ((iLunarYear < START_YEAR) || (iLunarYear > END_YEAR)) return 0;
	Flag = gLunarMonth[(iLunarYear - START_YEAR) / 2];
	if ((iLunarYear - START_YEAR) % 2 == 0) return Flag >> 4;
	return Flag & 0x0F;
}

//返回阴历iLunarYer年阴历iLunarMonth月的天数，如果iLunarMonth为闰月，
//高字为第二个iLunarMonth月的天数，否则高字为0 1901年1月---2050年12月
int LunarMonthDays(int iLunarYear, int iLunarMonth)
{
	int		Height, Low, iBit;

	if ((iLunarYear < START_YEAR) || (iLunarYear > END_YEAR)) return 30;
	Height = 0;
	Low = 29;
	iBit = 16 - iLunarMonth;
	if ((iLunarMonth > GetLeapMonth(iLunarYear)) && (GetLeapMonth(iLunarYear) > 0))
		iBit--;
	if ((gLunarMonthDay[iLunarYear - START_YEAR] & (1 << iBit)) > 0)
		Low++;
	if (iLunarMonth == GetLeapMonth(iLunarYear)) {
		if ((gLunarMonthDay[iLunarYear - START_YEAR] & (1 << (iBit-1)))>0)
			Height = 30;
		else
			Height = 29;
	}

	return Height << 8 | Low;
}

//返回阴历iLunarYear年的总天数 1901年1月---2050年12月
int LunarYearDays(int iLunarYear)
{
	int		Days;
	int		tmp, i;
	
	if ((iLunarYear < START_YEAR) || (iLunarYear > END_YEAR)) return 0;
	Days = 0;
	
	for (i=1; i <= 12; i++) {
		tmp = LunarMonthDays(iLunarYear, i);
		Days += (tmp & 0xff) + ((tmp>>8) & 0xff);
	}
	return Days;
}

//计算公历时间天数
century_days(int y, int m, int d)
{       
	return 365*y + (m-1)*30 + d + y/4 + (m>8? (m+1)/2 : m/2) -
		(m>2? 2 : y%4==0);
}

//日期形式转换
int convLunDate(CALENDAR_STRU *cal, int mode)
{
	int		i, y, m, d, h,  iDay;

	//按起始年1901年计算，阳历1901年2月19日为阴历1901年正月初一，阳历1901年1月1日到2月19日共有49天
	
	y = cal->y;
	m = cal->m;
	d = cal->d;

	iDay = century_days(y,m,d) - century_days(START_YEAR, 1, 1);
	if(iDay < 0) return -1;
	if(iDay < 49) {
		cal->ly = 36;
		if(iDay < 19) {
			cal->lm = 10;
			cal->ld = 11 + iDay;
		}
		else {
			cal->lm = 11;
			cal->ld = iDay - 18;
		}
		return 0;
	}

	//下面从阴历1901年正月初一即1901.2.19算起
	iDay = iDay - 49;
	cal->ly = 37;
	cal->lm = 0;
	cal->ld = 0;

	y = START_YEAR;
	m = 1;
	d = 1;
	//计算年
	i = LunarYearDays(y++);
	while(iDay >= i) {
		iDay -= i;
		cal->ly +=1;
		cal->ly = cal->ly%60;
		i = LunarYearDays(y++);
	}
	//计算月
	i = LunarMonthDays(y, m++); //取低位
	d = i & 0xff;
	while (iDay >= d) {
		iDay -= d;
		if( (i >> 8) & 0xff ) {			//本月闰月
			d = (i >>8)& 0xff; //取高位
			if (iDay < d) break;
			iDay -= d;
		}
		cal->lm +=1;
		i = LunarMonthDays(y, m++); //取低位
		d = i & 0xff;
	}

	//计算日
	cal->ld =iDay;
	cal->ly +=cal->lm/12;
	cal->lm = cal->lm % 12;
	cal->ly = cal->ly % 60;
}

//把iYear年格式化成天干记年法表示的字符串
char *formatLunarYear(CALENDAR_STRU *cal)
 {
	char	Text1[] = "甲乙丙丁戊己庚辛壬癸";
	char	Text2[] = "子丑寅卯辰巳午未申酉戌亥";
	char	Text3[] = "鼠牛虎免龙蛇马羊猴鸡狗猪";
	static	char	strYear[10];
	int		ly;
	
	ly = ((unsigned char)cal->ly) % 60;
	memset(strYear, '\0', sizeof(strYear));

	strncpy(strYear, &Text1[(ly % 10)*2], 2);
	strncpy(&strYear[2], &Text2[(ly % 12)*2], 2);
	return strYear;
 }

//for test
main(int argc, char **argv)
{
	int		rc, i, y, m, d;
	CALENDAR_STRU	cal;
	extern	int		optind;
	extern	char	*optarg;
	
	memset(&cal, '\0', sizeof(CALENDAR_STRU));
	
	while((rc = getopt(argc, argv, "d:"))!=EOF) {
		switch(rc) {
			case 'd':
				sscanf(optarg,"%04d%02d%02d", &y, &m, &d);
				cal.y = y;
				cal.m = m;
				cal.d = d;
				break;
			default:
				return 0;
			}
		}
	
	convLunDate(&cal, 0);
	fprintf(stderr, "%s %d %d %d\n",formatLunarYear(&cal), cal.ly, cal.lm, cal.ld);
	return 0;	
}