////////////////////////////////////////////////////
// 用法举例：
// var lunar = new Lunar(new Date());//某天：var lunar = new Lunar(new Date(1980,5,20));
// lunar.convert();
// var year = lunar.getYear();
// var animal = lunar.getAnimal();
// var month = lunar.getMonth();
// var day = lunar.getDay();
// var ganzhi = lunar.getCyclical();//天干地支
////////////////////////////////////////////////////
function Lunar(objDate)
{
	this.date = objDate;
	this.lunarInfo=new Array(
	0x04bd8,0x04ae0,0x0a570,0x054d5,0x0d260,0x0d950,0x16554,0x056a0,0x09ad0,0x055d2,
	0x04ae0,0x0a5b6,0x0a4d0,0x0d250,0x1d255,0x0b540,0x0d6a0,0x0ada2,0x095b0,0x14977,
	0x04970,0x0a4b0,0x0b4b5,0x06a50,0x06d40,0x1ab54,0x02b60,0x09570,0x052f2,0x04970,
	0x06566,0x0d4a0,0x0ea50,0x06e95,0x05ad0,0x02b60,0x186e3,0x092e0,0x1c8d7,0x0c950,
	0x0d4a0,0x1d8a6,0x0b550,0x056a0,0x1a5b4,0x025d0,0x092d0,0x0d2b2,0x0a950,0x0b557,
	0x06ca0,0x0b550,0x15355,0x04da0,0x0a5d0,0x14573,0x052d0,0x0a9a8,0x0e950,0x06aa0,
	0x0aea6,0x0ab50,0x04b60,0x0aae4,0x0a570,0x05260,0x0f263,0x0d950,0x05b57,0x056a0,
	0x096d0,0x04dd5,0x04ad0,0x0a4d0,0x0d4d4,0x0d250,0x0d558,0x0b540,0x0b5a0,0x195a6,
	0x095b0,0x049b0,0x0a974,0x0a4b0,0x0b27a,0x06a50,0x06d40,0x0af46,0x0ab60,0x09570,
	0x04af5,0x04970,0x064b0,0x074a3,0x0ea50,0x06b58,0x055c0,0x0ab60,0x096d5,0x092e0,
	0x0c960,0x0d954,0x0d4a0,0x0da50,0x07552,0x056a0,0x0abb7,0x025d0,0x092d0,0x0cab5,
	0x0a950,0x0b4a0,0x0baa4,0x0ad50,0x055d9,0x04ba0,0x0a5b0,0x15176,0x052b0,0x0a930,
	0x07954,0x06aa0,0x0ad50,0x05b52,0x04b60,0x0a6e6,0x0a4e0,0x0d260,0x0ea65,0x0d530,
	0x05aa0,0x076a3,0x096d0,0x04bd7,0x04ad0,0x0a4d0,0x1d0b6,0x0d250,0x0d520,0x0dd45,
	0x0b5a0,0x056d0,0x055b2,0x049b0,0x0a577,0x0a4b0,0x0aa50,0x1b255,0x06d20,0x0ada0);
	this.Animals=new Array("鼠","牛","虎","兔","龙","蛇","马","羊","猴","鸡","狗","猪");
	this.Gan=new Array("甲","乙","丙","丁","戊","己","庚","辛","壬","癸");
	this.Zhi=new Array("子","丑","寅","卯","辰","巳","午","未","申","酉","戌","亥");
	//==== 传入 offset 传回干支, 0=甲子
	this.cyclical = function(num)
	{
		return(this.Gan[num%10]+this.Zhi[num%12]);
	}
	//==== 传回农历 y年的总天数
	this.lYearDays = function(y)
	{
		var i, sum = 348;
		for(i=0x8000; i>0x8; i>>=1)
			sum += (this.lunarInfo[y-1900] & i)? 1: 0;
		return (sum+this.leapDays(y));
	}
	//==== 传回农历 y年闰月的天数
	this.leapDays = function(y)
	{
		if(this.leapMonth(y))
			return((this.lunarInfo[y-1900] & 0x10000)? 30: 29);
		else
			return(0);
	}
	//==== 传回农历 y年闰哪个月 1-12 , 没闰传回 0
	this.leapMonth = function(y)
	{
		return(this.lunarInfo[y-1900] & 0xf);
	}
	//====================================== 传回农历 y年m月的总天数
	this.monthDays = function(y,m)
	{
		return( (this.lunarInfo[y-1900] & (0x10000>>m))? 30: 29 );
	}
	//==== 算出农历, 传入日期物件, 传回农历日期物件
	//     该物件属性有 .year .month .day .isLeap .yearCyl .dayCyl .monCyl
	this.convert = function()
	{
		var i, leap=0, temp=0;
		var baseDate = new Date(1900,0,31);
		var offset   = parseInt((objDate - baseDate)/86400000);
		var dayCyl = offset + 40;
		var monCyl = 14;
		for(i=1900; i<2050 && offset>0; i++)
		{
			temp = this.lYearDays(i);
			offset -= temp;
			monCyl += 12;
		}
		if(offset<0) 
		{
			offset += temp;
			i--;
			monCyl -= 12;
		}
		var year = i;
		this.year = year;
		var yearCyl = i-1864;
		leap = this.leapMonth(i); //闰哪个月
		var isLeap = false;
		for(i=1; i<13 && offset>0; i++)
		{
			//闰月
			if(leap>0 && i==(leap+1) && isLeap==false)
			{
				--i;
				isLeap = true;
				temp = this.leapDays(year); 
			}
			else
			{
				temp = this.monthDays(year, i); 
			}
			//解除闰月
			if(this.isLeap==true && i==(leap+1))
				this.isLeap = false;
			offset -= temp;
			if(this.isLeap == false) 
				this.monCyl ++;
		}
		if(offset==0 && leap>0 && i==leap+1)
			if(this.isLeap)
			{
				this.isLeap = false;
			}
			else
			{ 
				this.isLeap = true;
				--i;
				--this.monCyl;
			}
		if(offset<0)
		{
			offset += temp; 
			--i;
			--this.monCyl;
		}
		this.month = i;
		this.day = offset + 1;
		var nstr = new Array('正月','二月','三月','四月','五月','六月','七月','八月','九月','十月','十一月','腊月');
		this.lunar_month = nstr[i-1];
		var Dn="初一;初二;初三;初四;初五;初六;初七;初八;初九;初十;十一;十二;十三;十四;十五;十六;十七;十八;十九;二十;廿一;廿二;廿三;廿四;廿五;廿六;廿七;廿八;廿九;三十"; 
		Dn=Dn.split(";");
		this.lunar_day = Dn[this.day-1];
		this.getAnimal = function()
		{
			return this.Animals[(this.year-4)%12]
		}
		this.getYear = function()
		{
			return this.year;
		}
		this.getMonth = function()
		{
			return this.lunar_month;
		}
		this.getDay = function()
		{
			return this.lunar_day;
		}
		this.getCyclical = function()
		{
			return this.cyclical(this.year-1900+36);
		}
	}
}