主题：请教:谁能给一个公历和农历的对照算法.举个例子: -- 步战将军

interface

uses sysutils;

type TCNDate = Cardinal;

function DecodeGregToCNDate(dtGreg:TDateTime):TCNDate;

function GetGregDateFromCN(cnYear,cnMonth,cnDay:word;bLeap:Boolean=False):

TDateTime;

function GregDateToCNStr(dtGreg:TDateTime):String;

function isCNLeap(cnDate:TCNDate):boolean;

implementation

const cstDateOrg:Integer=32900; //公历1990-01-27的TDateTime表示 对应农历19

90-01-01

const cstCNYearOrg=1990;

const cstCNTable:array[cstCNYearOrg..cstCNYearOrg + 60] of WORD=( //

unsigned 16-bit

24402, 3730, 3366, 13614, 2647, 35542, 858, 1749, //1997

23401, 1865, 1683, 19099, 1323, 2651, 10926, 1386, //2005

32213, 2980, 2889, 23891, 2709, 1325, 17757, 2741, //2013

39850, 1490, 3493, 61098, 3402, 3221, 19102, 1366, //2021

2773, 10970, 1746, 26469, 1829, 1611, 22103, 3243, //2029

1370, 13678, 2902, 48978, 2898, 2853, 60715, 2635, //2037

1195, 21179, 1453, 2922, 11690, 3474, 32421, 3365, //2045

2645, 55901, 1206, 1461, 14038);

//2050

//建表方法：

// 0101 111101010010 高四位是闰月位置,后12位表示大小月,大月30天,小月29

天,

//闰月一般算小月,但是有三个特例2017/06,2036/06,2047/05

//对于特例则高四位的闰月位置表示法中的最高为设置为1 特殊处理用wLeapNormal变

量

// //2017/06 28330->61098 2036/06 27947->60715 2047/05 23133->55901

//如果希望用汇编,这里有一条信息:农历不会滞后公历2个月.

//将公历转换为农历

//返回:12位年份+4位月份+5位日期

function DecodeGregToCNDate(dtGreg:TDateTime):TCNDate;

var

iDayLeave:Integer;

wYear,wMonth,wDay:WORD;

i,j:integer;

wBigSmallDist,wLeap,wCount,wLeapShift:WORD;

label OK;

begin

result := 0;

iDayLeave := Trunc(dtGreg) - cstDateOrg;

DecodeDate(IncMonth(dtGreg,-1),wYear,wMonth,wDay);

if (iDayLeave < 0) or (iDayLeave > 22295 )then Exit;

//Raise Exception.Create('目前只能算1990-01-27以后的');

//Raise Exception.Create('目前只能算2051-02-11以前的');

for i:=Low(cstCNTable) to High(cstCNTable) do begin

wBigSmallDist := cstCNTable[i];

wLeap := wBigSmallDist shr 12;

if wLeap > 12 then begin

wLeap := wLeap and 7;

wLeapShift := 1;

end else

wLeapShift := 0;

for j:=1 to 12 do begin

wCount:=(wBigSmallDist and 1) + 29;

if j=wLeap then wCount := wCount - wLeapShift;

if iDayLeave < wCount then begin

Result := (i shl 9) + (j shl 5) + iDayLeave + 1;

Exit;

end;

iDayLeave := iDayLeave - wCount;

if j=wLeap then begin

wCount:=29 + wLeapShift;

if iDayLeave < wCount then begin

Result := (i shl 9) + (j shl 5) + iDayLeave + 1 + (1 shl

21);

Exit;

end;

iDayLeave := iDayLeave - wCount;

end;

wBigSmallDist := wBigSmallDist shr 1;

end;

end;

//返回值:

// 1位闰月标志 + 12位年份+4位月份+5位日期 (共22位)

end;

function isCNLeap(cnDate:TCNDate):boolean;

begin

result := (cnDate and $200000) <> 0;

end;

function GetGregDateFromCN(cnYear,cnMonth,cnDay:word;bLeap:Boolean=False):

TDateTime;

var

i,j:integer;

DayCount:integer;

wBigSmallDist,wLeap,wLeapShift:WORD;

begin

// 0101 010010101111 高四位是闰月位置,后12位表示大小月,大月30天,小月

29天,

DayCount := 0;

if (cnYear < 1990) or (cnYear >2050) then begin

Result := 0;

Exit;

end;

for i:= cstCNYearOrg to cnYear-1 do begin

wBigSmallDist := cstCNTable[i];

if (wBIgSmallDist and $F000) <> 0 then DayCount := DayCount + 29;

DayCount := DayCount + 12 * 29;

for j:= 1 to 12 do begin

DayCount := DayCount + wBigSmallDist and 1;

wBigSmallDist := wBigSmallDist shr 1;

end;

end;

wBigSmallDist := cstCNTable[cnYear];

wLeap := wBigSmallDist shr 12;

if wLeap > 12 then begin

wLeap := wLeap and 7;

wLeapShift := 1; //大月在闰月.

end else

wLeapShift := 0;

for j:= 1 to cnMonth-1 do begin

DayCount:=DayCount + (wBigSmallDist and 1) + 29;

if j=wLeap then DayCount := DayCount + 29;

wBigSmallDist := wBigSmallDist shr 1;

end;

if bLeap and (cnMonth = wLeap) then //是要闰月的吗?

DayCount := DayCount + 30 - wLeapShift;

result := cstDateOrg + DayCount + cnDay - 1;

end;

//将日期显示成农历字符串.

function GregDateToCNStr(dtGreg:TDateTime):String;

const hzNumber:array[0..10] of string=('零','一','二','三','四','五','六',

'七','八','九','十');

function ConvertYMD(Number:Word;YMD:Word):string;

var

wTmp:word;

begin

result := '';

if YMD = 1 then begin //年份

while Number > 0 do begin

result := hzNumber[Number Mod 10] + result;

Number := Number DIV 10;

end;

Exit;

end;

if Number<=10 then begin //可只用1位

if YMD = 2 then //月份

result := hzNumber[Number]

else //天

result := '初' + hzNumber[Number];

Exit;

end;

wTmp := Number Mod 10; //个位

if wTmp <> 0 then result := hzNumber[wTmp];

wTmp := Number Div 10; //十位

result:='十'+result;

if wTmp > 1 then result := hzNumber[wTmp] + result;

end;

var

cnYear,cnMonth,cnDay:word;

cnDate:TCNDate;

strLeap:string;

begin

cnDate:= DecodeGregToCNDate(dtGreg);

if cnDate = 0 then begin

result := '输入越界';

Exit;

end;

cnDay := cnDate and $1F;

cnMonth := (cnDate shr 5) and $F;

cnYear := (cnDate shr 9) and $FFF;

//测试第22位,为1表示闰月

if isCNLeap(cnDate) then strLeap:='(闰)' else strLeap := '';

result := '农历' + ConvertYMD(cnYear,1) + '年' + ConvertYMD(cnMonth,2) +

'月'

+ strLeap + ConvertYMD(cnDay,3) ;

end;

end.