delphi时间日期函数

unit DateProcess;
interface

const
DayOfWeekStrings: array [1..7] of String = ('SUNDAY', 'MONDAY', 'TUESDAY',
'WEDNESDAY', 'THURSDAY', 'FRIDAY', 'SATURDAY');

//: English Calendar Months - used for Month2Int
const
MonthStrings: array [1..12] of String = ('JANUARY', 'FEBRUARY', 'MARCH',
'APRIL','MAY', 'JUNE', 'JULY', 'AUGUST', 'SEPTEMBER', 'OCTOBER',
'NOVEMBER', 'DECEMBER');
const
 //:中文显示星期─要用Week2CWeek()函数转换
    DayOfCWeekStrings: array [1..7] of String = ('星期日','星期一',
'星期二','星期三','星期四','星期五','星期六');
const
 //: 中文显示月份─要用Month2CMonth()函数转换
MonthCStrings: array [1..12] of String = ('一月', '二月', '三月','四月','五月',
                                              '六月', '七月', '八月', '九月', '十月','十一月', '十二月');
                                              
const
  OneDay         = 1.0;
  OneHour        = OneDay / 24.0;
  OneMinute      = OneHour / 60.0;
  OneSecond      = OneMinute / 60.0;
  OneMillisecond = OneSecond / 1000.0;

//--- 年度函数 ---

//检查日期值是否是润年
function IsLeapYear (Year: Word): Boolean;

//传回日期值年度的第一天
function GetFirstDayOfYear (const Year: Word): TDateTime;

//传回日期值年度的最后一天
function GetLastDayOfYear (const Year: Word): TDateTime;

//传回日期值年度的第一星期天的日期
function GetFirstSundayOfYear (const Year: Word): TDateTime;

//传回西洋日期的格式MM/DD/YY
function GetMDY (const DT: TDateTime): String;

//--- 日期型的转换 ---

//日期转成字符串
//如果是错误将传一空值
function Date2Str (const DT: TDateTime): String;

//传回日期值的日期
function GetDay (const DT: TDateTime): Word;

//:传回日期值的月份
function GetMonth (const DT: TDateTime): Word;

//: 传回日期值的年份
function GetYear (const DT: TDateTime): Word;

//:将日期的值取出时间的值
function Time2Hr (const DT: TDateTime): Word;

//:将日期的值取出分锺的值
function Time2Min (const DT: TDateTime): Word;

//:将日期的值取出秒数的值
function Time2Sec (const DT: TDateTime): Word;

//:将日期的值取出微秒的值
function Time2MSec (const DT: TDateTime): Word;

//传回目前的年度
function ThisYear: Word;

//传回目前的月份
function ThisMonth: Word;

//传回目前的日期
function ThisDay: Word;

//传回目前的时间
function ThisHr: Word;

//传回目前的分锺
function ThisMin: Word;

//传回目前的秒数
function ThisSec: Word;

//将英文的星期转成整数值
//例如EDOWToInt(''SUNDAY')=1
function EDOWToInt (const DOW: string): Integer;

//将英文的月份转成整数值的月
//例如EMonthToInt('JANUARY')=1
function EMonthToInt (const Month: string): Integer;

function GetCMonth(const DT: TDateTime): String;
//传回中文显示的月份

function GetC_Today: string;
//传回中国的日期
//例如： GetC_Today传回值为89/08/11

Function TransC_DateToE_Date(Const CDT :String) :TDateTime;
//将民国的年月日转换为公元的YYYY/MM/DD
//2001/02/02加入 例如：TransC_DateToE_Date('90年2月1日')传回值是2001/2/1

function GetCWeek(const DT: TDateTime): String;
//传回值为中文显示的星期  例如：GETCWeek(2000/08/31)=星期四

function GetLastDayForMonth(const DT: TDateTime):TDateTime;
//传回本月的最后一天

function GetFirstDayForMonth (const DT :TDateTime): TDateTime;
//取得月份的第一天

function GetLastDayForPeriorMonth(const DT: TDateTime):TDateTime;
//传回上个月的最后一天

function GetFirstDayForPeriorMonth (const DT :TDateTime): TDateTime;
//取得上个月份的第一天

function ROCDATE(DD:TDATETIME;P:integer):string;
{转换某日期为民国0YYMMDD 型式字符串，例如：ROCDATE(Now,0)='900304' }
{P=0 不加'年'+'月'+'日'}
{P=1 加'年'+'月'+'日'}

{------------------- 日期和时间的计算函数------------------}

//传回两个日期相减值的分锺数
function MinutesApart (const DT1, DT2: TDateTime): Word;

//调整年度的时间
//例如AdjustDateYear(Now,1998)传回值为'1998/02/25'
function AdjustDateYear (const D: TDateTime; const Year: Word): TDateTime;

//增加n个分钟的时间
function AddMins (const DT: TDateTime; const Mins: Extended): TDateTime;

//增加n个小时的时间
function AddHrs (const DT: TDateTime; const Hrs: Extended): TDateTime;

//可将日期加上欲增加的天数为得到的值   例如：AddDays(2000/08/31,10)=2000/09/10
function AddDays (const DT: TDateTime; const Days: Extended): TDateTime;

//增加n周的时间
//例如：AddWeeks(2001/01/21,2)传回值为'2001/02/4'
function AddWeeks (const DT: TDateTime; const Weeks: Extended): TDateTime;

//增加n个月的时间
function AddMonths (const DT: TDateTime; const Months: Extended): TDateTime;

//增加n个年的时间
function AddYrs (const DT: TDateTime; const Yrs: Extended): TDateTime;

//传回向前算的N个分锺
function SubtractMins (const DT: TDateTime; const Mins: Extended): TDateTime;

//传回向前算的N个小时
function SubtractHrs (const DT: TDateTime; const Hrs: Extended): TDateTime;

//传回向前算的N个天
function SubtractDays (const DT: TDateTime; const Days: Extended): TDateTime;

//传回向前算的N个周
function SubtractWeeks (const DT: TDateTime; const Weeks: Extended): TDateTime;

//传回向前算的N个月，例如：SubtractMonths('2000/11/21',3)传回'2000/08/22'
function SubtractMonths (const DT: TDateTime; const Months: Extended): TDateTime;

//传回日期值的本月份的最后一天
function GetLastDayOfMonth (const DT: TDateTime): TDateTime;

//传回日期值的本月份的第一天
function GetFirstDayOfMonth (const DT: TDateTime): TDateTime;

//传回年度第一周的第一个星期天的日期
function StartOfWeek (const DT: TDateTime): TDateTime;

//传回年度最后一周的最后一个星期天的日期
function EndOfWeek (const DT: TDateTime): TDateTime;

//将秒数转换为时分秒
function Hrs_Min_Sec (Secs: Extended): string;

//: 比较两的日期值是否是同月如果是为真
function DatesInSameMonth (const DT1, DT2: TDateTime): Boolean;

//: 比较两的日期值是否是同年如果是为真
function DatesInSameYear (const DT1, DT2: TDateTime): Boolean;

//: 比较两的日期值是否是同年和同月如果是为真
function DatesInSameMonthYear (const DT1, DT2: TDateTime): Boolean;

//:传回两个日期相减值的天数
//例如：DaysApart是DT2减DT1
function DaysApart (const DT1, DT2: TDateTime): LongInt;

//传回两个日期相减值的周数
//例如：ExactWeeksApart是DT2减DT1
function ExactWeeksApart (const DT1, DT2: TDateTime): Extended;

//传回两个日期相减值的周数
//例如：ExactWeeksApart是DT2减DT1
function WeeksApart (const DT1, DT2: TDateTime): LongInt;

//: 如果是真表示日期为润年
function DateIsLeapYear (const DT: TDateTime): Boolean;

//: 传回日期值本月份的天数
// DaysThisMonth(Now)= 31，三月有31天
function DaysThisMonth (const DT: TDateTime): Byte;

//: 传回日期值的本年度的月份中的日数，还有几天
//DaysLeftInMonth('2001/04/28')传回值2
function DaysLeftInMonth (const DT: TDateTime): Byte;

//: 传回日期值的本年度的月份中的日数，还有几天
function DaysInMonth (const DT: TDateTime): Byte;
//: 传回日期值的本年度的天数，如果是润年有366天；不是就有365天
function DaysInYear (const DT: TDateTime): Word;

//: 传回日期值中本年度已过了几天
//例如：DayOfYear(now)=119
function DayOfYear (const DT: TDateTime): Word;

//: 传回今天的日期在本年度过了几天
//例如: ThisDayOfYear=119
function ThisDayOfYear: Word;

//:传回今年度还有几天
function DaysLeftInYear (const DT: TDateTime): Word;

//传回日期值的季别
//例如：WhichQuarter(now)=2
function WhichQuarter (const DT: TDateTime): Byte;

//传回年龄，依现在其日期减出生的日期
function AgeAtDate (const DOB, DT: TDateTime): Integer;

//传回年龄，依现在其日期减出生的日期
function AgeNow (const DOB: TDateTime): Integer;

//传回年龄，依现在其日期减出生的日期
function AgeAtDateInMonths (const DOB, DT: TDateTime): Integer;

//传回年龄，依现在其日期减出生的日期
function AgeNowInMonths (const DOB: TDateTime): Integer;

//传回日期值已存活的周数
//例如 AgeAtDateInWeeks('1963/06/24',Now)=1975
function AgeAtDateInWeeks (const DOB, DT: TDateTime): Integer;

//传回日期值已存活的周数，不同的是此函数不用第二个参数是用上一个函数完成的
//例如 AgeNowInWeeks('1963/06/24')=1975
function AgeNowInWeeks (const DOB: TDateTime): Integer;

//可传回几岁几月几周的详细年龄
function AgeNowDescr (const DOB: TDateTime): String;

function CheckDate(const sCheckedDateString: string): boolean;
//检查是否是中华民国的日期格式
//例如：CheckDate(DatetoStr(Now))=89/08/29，传回值是Boolean

{----------------- 周数处理用函数 --------------------}

//将日期值转换成周数
function DateToWeekNo (const DT: TDateTime): Integer;

//比较两个日期值是否相同
function DatesInSameWeekNo (const DT1, DT2: TDateTime): Boolean;

//将两个日期相减后转成周数
function WeekNosApart (const DT1, DT2: TDateTime): Integer;

//传回目前日期的周数
function ThisWeekNo: Integer;

//传回在X的年度的第n周的时间
//例如：GetWeekNoToDate(28,2001)='2001/07/08'，取得值是从星期天开始
function GetWeekNoToDate_Sun (const WeekNo, Year: Word): TDateTime;

//传回在X的年度的第n周的时间
//例如：GetWeekNoToDate(28,2001)='2001/07/08'，取得值是从星期一开始
function GetWeekNoToDate_Mon (const WeekNo, Year: Word): TDateTime;

//传回在X的年度的第n周的时间
//例如：DWYToDate(3,28,2001)='2001/07/10'，取得值是强制从星期天开始的
function DWYToDate (const DOW, WeekNo, Year: Word): TDateTime;

//将周数转换成月日格式
//例如：WeekNoToDate(35)传回08/26
function WeekNoToDate(Const Weekno : Word):TDateTime;

{--- 检查确定日期函数 ---}
//: 如果传回值是真表示目前是一月
function IsJanuary (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是二月
function IsFebruary (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是三月
function IsMarch (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是四月
function IsApril (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是五月
function IsMay (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是六月
function IsJune (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是七月
function IsJuly (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是八月
function IsAugust (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是九月
function IsSeptember (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是十月
function IsOctober (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是十一月
function IsNovember (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是十二月
function IsDecember (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是上午
function IsAM (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是下午
function IsPM (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是中午
function IsNoon (const DT: TDateTime): Boolean;

//:如果传回值是真表示目前是夜晚
function IsMidnight (const DT: TDateTime): Boolean;

//: 如果传回值是真表示目前是星期天
function IsSunday (const DT: TDateTime): Boolean;

//: 如果日期值是星期一即为真
function IsMonday (const DT: TDateTime): Boolean;

//: 如果日期值是星期二即为真
function IsTuesday (const DT: TDateTime): Boolean;

//: 如果日期值是星期三即为真
function IsWednesday (const DT: TDateTime): Boolean;

//: 如果日期值是星期四即为真
function IsThursday (const DT: TDateTime): Boolean;

//: 如果日期值是星期五即为真
function IsFriday (const DT: TDateTime): Boolean;

//: 如果日期值是星期六即为真
function IsSaturday (const DT: TDateTime): Boolean;

//:如果日期值是星期六或日即为真
function IsWeekend (const DT: TDateTime): Boolean;

//: 如果日期值是星期一至五即为真
function IsWorkDays (const DT: TDateTime): Boolean;

function CheckLastDayOfMonth(DT : TDateTime) : Boolean;
//检查是否是本月的最后一天

implementation

uses

Windows, SysUtils, StrProcess;

function LInt2EStr (const L: LongInt): String;
begin
try
Result := IntToStr (L);
except
Result := '';
end;
end;

function LeftStr (const S : string; const N : Integer): string;
begin
Result := Copy (S, 1, N);
end;

function RightAfterStr (const S : String; const N : Integer): String;
begin
Result := Copy (S, N + 1, Length (S) - N );
end;

function FillStr (const Ch : Char; const N : Integer): string;
begin
SetLength (Result, N);
FillChar (Result [1], N, Ch);
end;

function PadChLeftStr (const S : string; const Ch : Char;
const Len : Integer): string;
var
N: Integer;
begin
N := Length (S);
if N < Len then
Result := FillStr (Ch, Len - N) + S
else
Result := S;
end;

function LInt2ZStr (const L: LongInt; const Len: Byte): String;
begin
Result := LInt2EStr (L);
Result := PadChLeftStr (LeftStr (Result, Len), '0', Len);
end;

function ReplaceChStr (const S : string;
const OldCh, NewCh : Char): string;
var
I: Integer;
begin
Result := S;
if OldCh = NewCh then
Exit;
for I := 1 to Length (S) do
if S [I] = OldCh then
Result [I] := NewCh;
end;

function Str2Ext (const S: String): Extended;
begin
try
Result := StrToFloat (S);
except
Result := 0;
end;
end;

function Str2Lint (const S: String): LongInt;
begin
try
Result := StrToInt (S);
except
Result := 0;
end;
end;

function IsLeapYear (Year: Word): Boolean;
begin
Result := ((Year and 3) = 0) and ((Year mod 100 > 0) or (Year mod 400 = 0))
end;

function Date2Str (const DT: TDateTime): String;
begin
try
if abs (DT) < 0.000001 then
Result := ''
else
Result := DateToStr (DT);
except
Result := '';
end;
end;

function GetYear (const DT: TDateTime): Word;
var
D, M: Word;
begin
DecodeDate (DT, Result, M, D);
end;

function GetMonth (const DT: TDateTime): Word;
var
D, Y : Word;
begin
DecodeDate (DT, Y, Result, D);
end;

function GetDay (const DT: TDateTime): Word;
var
M, Y : Word;
begin
DecodeDate (DT, Y, M, Result);
end;

function Time2Hr (const DT: TDateTime): Word;
var
Min, Sec, MSec: Word;
begin
DecodeTime (DT, Result, Min, Sec, MSec);
end;

function Time2Min (const DT: TDateTime): Word;
var
Hr, Sec, MSec: Word;
begin
DecodeTime (DT, Hr, Result, Sec, MSec);
end;

function Time2Sec (const DT: TDateTime): Word;
var
Hr, Min, MSec: Word;
begin
DecodeTime (DT, Hr, Min, Result, MSec);
end;

function Time2MSec (const DT: TDateTime): Word;
var
Hr, Min, Sec: Word;
begin
DecodeTime (DT, Hr, Min, Sec, Result);
end;

function MinutesApart (const DT1, DT2: TDateTime): Word;
var
Hr1, Min1, Sec1, MSec1: Word;
Hr2, Min2, Sec2, MSec2: Word;
begin
DecodeTime (DT1, Hr1, Min1, Sec1, MSec1);
DecodeTime (DT2, Hr2, Min2, Sec2, MSec2);
if Min2 < Min1 then
begin
Min2 := Min2 + 60;
Dec (Hr2);
end;
if Hr1 > Hr2 then
Hr2 := Hr2 + 24;
Result := (Hr2 - Hr1) * 60 + (Min2 - Min1);
end;

function AdjustDateYear (const D: TDateTime; const Year: Word): TDateTime;
var
Day, Month, OldYear: Word;
begin
DecodeDate (D, OldYear, Month, Day);
if Year = OldYear then
begin
Result := Int (D);
Exit;
end;
if not IsLeapYear (Year) and (Month = 2) and (Day = 29) then
begin
Month := 3;
Day := 1;
end;
Result := EncodeDate (Year, Month, Day);
end;

function AddMins (const DT: TDateTime; const Mins: Extended): TDateTime;
begin
Result := DT + Mins / (60 * 24)
end;

function AddHrs (const DT: TDateTime; const Hrs: Extended): TDateTime;
begin
Result := DT + Hrs / 24.0
end;

function AddWeeks (const DT: TDateTime; const Weeks: Extended): TDateTime;
begin
Result := DT + Weeks * 7;
end;

function AddMonths (const DT: TDateTime; const Months: Extended): TDateTime;
var
Day, Month, Year: Word;
IMonth: Integer;
begin
DecodeDate (DT, Year, Month, Day);
IMonth := Month + Trunc (Months);

if IMonth > 12 then
begin
Year := Year + (IMonth - 1) div 12;
IMonth := IMonth mod 12;
if IMonth = 0 then
IMonth := 12;
end
else if IMonth < 1 then
begin
Year := Year + (IMonth div 12) - 1; // sub years;
IMonth := 12 - abs (IMonth) mod 12;
end;
     Month := IMonth;

// Ensure Day of Month is valid
if Month = 2 then
begin
if IsLeapYear (Year) and (Day > 29) then
Day := 29
else if not IsLeapYear (Year) and (Day > 28) then
Day := 28;
end
else if (Month in [9, 4, 6, 11]) and (Day = 31) then
Day := 30;

Result := EncodeDate (Year, Month, Day) + Frac (Months) * 30 +
Frac (DT);
end;

function AddYrs (const DT: TDateTime; const Yrs: Extended): TDateTime;
var
Day, Month, Year: Word;
begin
DecodeDate (DT, Year, Month, Day);
Year := Year + Trunc (Yrs);
if not IsLeapYear (Year) and (Month = 2) and (Day = 29) then
Day := 28;
Result := EncodeDate (Year, Month, Day) + Frac (Yrs) * 365.25
+ Frac (DT);
end;

function GetLastDayofMonth (const DT: TDateTime): TDateTime;
var
D, M, Y: Word;
begin
DecodeDate (DT, Y, M, D);
case M of
2:
begin
if IsLeapYear (Y) then
D := 29
else
D := 28;
end;
4, 6, 9, 11: D := 30
else
D := 31;
end;
Result := EncodeDate (Y, M, D) + Frac (DT);
end;

function GetFirstDayofMonth (const DT: TDateTime): TDateTime;
var
D, M, Y: Word;
begin
DecodeDate (DT, Y, M, D);
Result := EncodeDate (Y, M, 1) + Frac (DT);
end;

function GMTStr2Value(const GMTStr: string): Extended;
var
P: Integer;
begin
P := Pos (GMTStr, '+');
if P > 0 then
begin
Result := Str2Ext (Trim (Copy (GMTStr, P + 1, Length (GMTStr) - P)));
end
else
begin
P := Pos (GMTStr, '-');
if P > 0 then
begin
Result := -1 * Str2Ext (Trim (Copy (GMTStr, P + 1, Length (GMTStr) - P)));
end
else
Result := 0;
end;
end;

function ConvertGMTStrTimes (const FromGMTStr: string; const FromDT: TDateTime;
const ToGMTStr: string): TDateTime;
var
GMT1, GMT2: Extended;
begin
GMT1 := GMTStr2Value (FromGMTStr);
GMT2 := GMTStr2Value (ToGMTStr);
Result := FromDT + GMT2 - GMT1;
end;

function GetRFC822Difference: string;
var
TZ : TTimeZoneInformation;
begin
GetTimeZoneInformation (TZ);
if TZ.Bias <= 0 then
begin
TZ.Bias := Abs (TZ.Bias);
Result := '+' + LInt2ZStr (TZ.Bias div 60, 2)
+ LInt2ZStr (TZ.Bias mod 60, 2)
end
else
Result := '-' + LInt2ZStr (TZ.Bias div 60, 2)
+ LInt2ZStr (TZ.Bias mod 60, 2)
end;

function StartOfWeek (const DT: TDateTime): TDateTime;
begin
Result := DT - DayOfWeek (DT) + 1;
end;

function EndOfWeek (const DT: TDateTime): TDateTime;
begin
Result := DT - DayOfWeek (DT) + 7;
end;

function ThisYear: Word;
var
D, M: Word;
begin
DeCodeDate(Now,Result,M,D) ;
end;

function ThisMonth: Word;
var
D,  Y: Word;
begin
DeCodeDate(Now,Y,Result,D);
end;

function ThisDay: Word;
var
M, Y: Word;
begin
DeCodeDate(Now,Y,M,Result);
end;

function ThisHr: Word;
begin
Result := Time2Hr (Time);
end;

function ThisMin: Word;
begin
Result := Time2Min (Time);
end;

function ThisSec: Word;
begin
Result := Time2Sec (Time);
end;

function IsJanuary (const DT: TDateTime): Boolean;
begin
Result := GetMonth(DT) = 1;
end;

function IsFebruary (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 2;
end;

function IsMarch (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 3;
end;

function IsApril (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 4;
end;

function IsMay (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 5;
end;

function IsJune (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 6;
end;

function IsJuly (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 7;
end;

function IsAugust (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 8;
end;

function IsSeptember (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 9;
end;

function IsOctober (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 10;
end;

function IsNovember (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 11;
end;

function IsDecember (const DT: TDateTime): Boolean;
begin
Result := GetMonth (DT) = 12;
end;

function Hrs_Min_Sec (Secs: Extended): string;
const
OneSecond = 1/24/3600;
var
Total: Extended;
begin
Total := Secs * OneSecond;
Result := Format( '%1.0f 天%s', [Int (Total),
FormatDateTime ('hh:nn:ss', Frac (total))]);
end;

function DatesInSameMonth (const DT1, DT2: TDateTime): Boolean;
begin
Result := GetMonth (DT1) = GetMonth (DT2);
end;

function DatesInSameYear (const DT1, DT2: TDateTime): Boolean;
begin
Result := GetYear (DT1) = GetYear (DT2);
end;

function DatesInSameMonthYear (const DT1, DT2: TDateTime): Boolean;
begin
Result := DatesInSameMonth (DT1, DT2) and DatesInSameYear (DT1, DT2);
end;

function AddDays (const DT: TDateTime; const Days: Extended): TDateTime;
begin
Result := DT + Days;
end;

function IsAM (const DT: TDateTime): Boolean;
begin
Result := Frac (DT) < 0.5
end;

function IsPM (const DT: TDateTime): Boolean;
begin
Result := not IsAM (DT);
end;

function IsNoon (const DT: TDateTime): Boolean;
begin
Result := Frac (DT) = 0.5;
end;

function IsMidnight (const DT: TDateTime): Boolean;
begin
Result := Frac (DT) = 0.0;
end;

function IsSunday (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) = 1;
end;

function IsMonday (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) = 2;
end;

function IsTuesday (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) = 3;
end;

function IsWednesday (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) = 4;
end;

function IsThursday (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) = 5;
end;

function IsFriday (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) = 6;
end;

function IsSaturday (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) = 7;
end;

function IsWeekend (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) in [1, 7];
end;

function IsWorkDays (const DT: TDateTime): Boolean;
begin
Result := DayOfWeek (DT) in [2..6];
end;

function DaysApart (const DT1, DT2: TDateTime): LongInt;
begin
Result := Trunc (DT2) - Trunc (DT1);
end;

function DateIsLeapYear (const DT: TDateTime): Boolean;
begin
Result := IsLeapYear (GetYear (DT));
end;

function DaysThisMonth (const DT: TDateTime): Byte;
begin
case GetMonth (DT) of
2: if DateIsLeapYear (DT) then
Result := 29
  else
Result := 28;
4, 6, 9, 11: Result := 30;
else
Result := 31;
end;
end;

function DaysInMonth (const DT: TDateTime): Byte;
begin    case GetMonth (DT) of       2: if DateIsLeapYear (DT) then          Result := 29          else          Result := 28;       4, 6, 9, 11: Result := 30;       else          Result := 31;    end; End;

function DaysLeftInMonth (const DT: TDateTime): Byte;
begin
Result := DaysInMonth (DT) - GetDay (DT);
end;

function DaysInYear (const DT: TDateTime): Word;
begin
if DateIsLeapYear (DT) then
Result := 366
else
Result := 365;
end;

function DayOfYear (const DT: TDateTime): Word;
begin
Result := Trunc (DT) - Trunc (EncodeDate (GetYear (DT), 1, 1)) + 1;
end;

function DaysLeftInYear (const DT: TDateTime): Word;
begin
Result := DaysInYear (DT) - DayOfYear (DT);
end;

function ThisDayOfYear: Word;
begin
Result := DayOfYear (Date);
end;

function WhichQuarter (const DT: TDateTime): Byte;
begin
Result := (GetMonth (DT) - 1) div 3 + 1;
end;

function GetFirstDayOfYear (const Year: Word): TDateTime;
begin
Result := EncodeDate (Year, 1, 1);
end;

function GetLastDayOfYear (const Year: Word): TDateTime;
begin
Result := EncodeDate (Year, 12, 31);
end;

function SubtractMins (const DT: TDateTime; const Mins: Extended): TDateTime;
begin
Result := AddMins (DT, -1 * Mins);
end;

function SubtractHrs (const DT: TDateTime; const Hrs: Extended): TDateTime;
begin
Result := AddHrs (DT, -1 * Hrs);
end;

function SubtractWeeks (const DT: TDateTime; const Weeks: Extended): TDateTime;
begin
Result := AddWeeks (DT, -1 * Weeks);
end;

function SubtractMonths (const DT: TDateTime; const Months: Extended): TDateTime;
begin
Result := AddMonths (DT, -1 * Months);
end;

function SubtractDays (const DT: TDateTime; const Days: Extended): TDateTime;
begin
Result := DT - Days;
end;

function AgeAtDate (const DOB, DT: TDateTime): Integer;
var
D1, M1, Y1, D2, M2, Y2: Word;
begin
if DT < DOB then
Result := -1
else
begin
DecodeDate (DOB, Y1, M1, D1);
DecodeDate (DT, Y2, M2, D2);
Result := Y2 - Y1;
if (M2 < M1) or ((M2 = M1) and (D2 < D1)) then
Dec (Result);
end;
end;

function AgeNow (const DOB: TDateTime): Integer;
begin
Result := AgeAtDate (DOB, Date);
end;

function EDOWToInt (const DOW: string): Integer;
var
UCDOW: string;
I,N: Integer;
begin
Result := 0;
UCDOW := UpperCase (DOW);
N := Length (DOW);
for I := 1 to 7 do
begin
if LeftStr (DayOfWeekStrings [I], N) = UCDOW then
begin
Result := I;
Break;
end;
end;
end;

function EMonthToInt (const Month: string): Integer;
var
UCMonth: string;
I,N: Integer;
begin
Result := 0;
UCMonth := UpperCase (Month);
N := Length (Month);
for I := 1 to 12 do
begin
if LeftStr (MonthStrings [I], N) = UCMonth then
begin
Result := I;
Break;
end;
end;
end;

function GetCMonth(const DT: TDateTime): String;
begin
Result :=MonthCStrings[GetMonth(DT)];
end;

function GetC_Today: string;
var
wYear, wMonth, wDay: Word;
sYear, sMonth, sDay: string[2];
begin
DecodeDate(Now, wYear, wMonth, wDay);
wYear  := wYear - 1911;
sYear  := Copy(IntToStr(wYear + 1000), 3, 2);
sMonth := Copy(IntToStr(wMonth + 100), 2, 2);
sDay   := Copy(IntToStr(wDay + 100), 2, 2);
Result := sYear + DateSeparator + sMonth + DateSeparator + sDay;
end;

Function TransC_DateToE_Date(Const CDT :String) :TDateTime;
Var  iYear,iMonth,iDay:Word;
Begin
  if Length(CDT) <> 12 then Exit;
if Pos(' ',CDT ) <> 0 then Exit;
  (* 民国日期 -> 公元日期 *)
iYear := StrToInt(Copy(CDT, 1, 2)) + 1911;
iMonth := StrToInt(Copy(CDT, 5, 2));
iDay:= StrToInt(Copy(CDT, 9, 2));
  Result:=EncodeDate(iYear,iMonth,iDay);
End;

function GetCWeek(const DT: TDateTime): String;
begin
Result :=DayOfCWeekStrings[DayOfWeek(DT)];
end;

function GetLastDayForMonth(const DT: TDateTime):TDateTime;
Var Y,M,D :Word;
Begin
DecodeDate(DT,Y,M,D);
Case M of
2: Begin
If IsLeapYear(Y) then
D:=29
Else
D:=28;
End;
4,6,9,11:D:=30
Else
D:=31;
End;
Result:=EnCodeDate(Y,M,D);
End;

function GetFirstDayForMonth (const DT : TDateTime): TDateTime;
Var  Y,M,D:Word;
Begin
     DecodeDate(DT,Y,M,D);
//DecodeDate(DT,Y,M,1);
Result := EncodeDate (Y, M, 1);
End;

function GetLastDayForPeriorMonth(const DT: TDateTime):TDateTime;
Var  Y,M,D:Word;
Begin
DecodeDate(DT,Y,M,D);
   M:=M-1;
Case M of
2: Begin
If IsLeapYear(Y) then
D:=29
Else
D:=28;
End;
4,6,9,11:D:=30
Else
D:=31;
End;
Result:=EnCodeDate(Y,M,D);
End;

function GetFirstDayForPeriorMonth (const DT :TDateTime): TDateTime;
Var  Y,M,D:Word;
Begin
     DecodeDate(DT,Y,M,D);
M:=M-1;
Result := EncodeDate (Y, M, 1);
End;

function ROCDATE(DD:TDATETIME;P:integer):string; {转换某日期为民国0YYMMDD 型式字符串 }
var YEAR,MONTH,DAY : WORD;  {P=0 不加'年'+'月'+'日'}
Y,CY,M,D,LONGY : string;  {P=1 加'年'+'月'+'日'}
YY:integer;
begin
DECODEDATE(DD,YEAR,MONTH,DAY);

if (year=0) and (month=0) and (day=0) then
begin
Result:='';
exit;
end;

YY:=YEAR-1911;
if YY>0 then
begin
CY:=inttostr(YY);
if Length(CY)=1 then CY:='00'+CY;
if Length(CY)=2 then CY:='0'+CY;
end
else
begin
YY:=YEAR-1912;
CY:=inttostr(YY);
if Length(CY)=2 then CY:='-0'+RIGHT(CY,1);
end;

if strtoint(CY)>999 then
CY:='XXX';

if (CY<>'XXX') and (strtoint(CY)<-99) then
CY:='-XX';

M:=inttostr(MONTH);
if Length(M)=1 then M:='0'+M;
D:=inttostr(DAY);
   if Length(D)=1 then D:='0'+D;

if P=0 then
 Result:=CY+ DateSeparator+M+ DateSeparator+D
else
 Result:=CY+'年'+M+'月'+D+'日';

end;

function ExactWeeksApart (const DT1, DT2: TDateTime): Extended;
begin
Result := DaysApart (DT1, DT2) / 7;
end;

function WeeksApart (const DT1, DT2: TDateTime): Integer;
begin
Result := DaysApart (DT1, DT2) div 7;;
end;

function GetFirstSundayOfYear (const Year: Word): TDateTime;
var
StartYear: TDateTime;
begin
StartYear := GetFirstDayOfYear (Year);
if DayOfWeek (StartYear) = 1 then
Result := StartYear
else
Result := StartOfWeek (StartYear) + 7;
end;

function GetMDY (const DT: TDateTime): String;

Begin
   Result := FormatDateTime('MM/DD/YY',DT);
End;

function DateToWeekNo (const DT: TDateTime): Integer;
var
Year: Word;
FirstSunday, StartYear: TDateTime;
WeekOfs: Byte;
begin
Year := GetYear (DT);
StartYear := GetFirstDayOfYear (Year);
if DayOfWeek (StartYear) = 0 then
begin
FirstSunday := StartYear;
WeekOfs := 1;
end
else
begin
FirstSunday := StartOfWeek (StartYear) + 7;
WeekOfs := 2;
if DT < FirstSunday then
begin
Result := 1;
Exit;
end;
end;
Result := DaysApart (FirstSunday, StartofWeek (DT)) div 7 + WeekOfs;
end;

function DatesInSameWeekNo (const DT1, DT2: TDateTime): Boolean;
begin
if GetYear (DT1) <> GetYear (DT2) then
Result := False
else
Result := DateToWeekNo (DT1) = DateToWeekNo (DT2);
end;

function WeekNosApart (const DT1, DT2: TDateTime): Integer;
begin
if GetYear (DT1) <> GetYear (DT2) then
Result := -999
else
Result := DateToWeekNo (DT2) - DateToWeekNo (DT1);
end;

function ThisWeekNo: Integer;
begin
Result := DateToWeekNo (Date);
end;

function GetWeekNoToDate_Sun (const WeekNo, Year: Word): TDateTime;
var
FirstSunday: TDateTime;
begin
FirstSunday := GetFirstSundayOfYear (Year);
if GetDay (FirstSunday) = 1 then
Result := AddWeeks (FirstSunday, WeekNo - 1)
else
Result := AddWeeks (FirstSunday, WeekNo - 2)
end;

function GetWeekNoToDate_Mon (const WeekNo, Year: Word): TDateTime;
begin
Result := GetWeekNoToDate_Sun (WeekNo, Year) + 6;
end;

function DWYToDate (const DOW, WeekNo, Year: Word): TDateTime;
begin
Result := GetWeekNoToDate_Sun (WeekNo, Year) + DOW - 1;
end;

function AgeAtDateInMonths (const DOB, DT: TDateTime): Integer;
var
   D1, D2 : Word;
   M1, M2 : Word;
   Y1, Y2 : Word;
begin
if DT < DOB then
Result := -1
else
begin
DecodeDate (DOB, Y1, M1, D1);
DecodeDate (DT, Y2, M2, D2);
if Y1 = Y2 then // Same Year
Result := M2 - M1
else // 不同年份
begin
// 前12月的年龄
Result := 12 * AgeAtDate (DOB, DT);
if M1 > M2 then
Result := Result + (12 - M1) + M2
else if M1 < M2 then
Result := Result + M2 - M1
else if D1 > D2 then // Same Month
Result := Result + 12;
end;
if D1 > D2 then // we have counted one month too many
Dec (Result);
end;
end;

function WeekNoToDate(Const Weekno : Word):TDateTime;
Begin
   Result :=AddDays(GetWeekNoToDate_Sun(WeekNo,GetYear(Now)),1);
End;

function AgeAtDateInWeeks (const DOB, DT: TDateTime): Integer;
begin
if DT < DOB then
Result := -1
else
begin
Result := Trunc (DT - DOB) div 7;
end;
end;

function AgeNowInMonths (const DOB: TDateTime): Integer;
begin
Result := AgeAtDateInMonths (DOB, Date);
end;

function AgeNowInWeeks (const DOB: TDateTime): Integer;
begin
Result := AgeAtDateInWeeks (DOB, Date);
end;

function AgeNowDescr (const DOB: TDateTime): String;
var
Age : integer;
begin
Age := AgeNow (DOB);
if Age > 0 then
begin
if Age = 1 then
Result := LInt2EStr (Age) + ' 岁'
else
Result := LInt2EStr (Age) + ' 岁';
end
else
begin
Age := AgeNowInMonths (DOB);
if Age >= 2 then
Result := LInt2EStr(Age) + ' 月'
else
begin
Age := AgeNowInWeeks (DOB);
if Age = 1 then
Result := LInt2EStr(Age) + ' 周'
else
Result := LInt2EStr(Age) + ' 周';
end;
end;
end;

function CheckDate(const sCheckedDateString: string): boolean;
var
iYear, iMonth, iDay: word;
begin
Result := False;
(* 格式检查 *)
if Length(sCheckedDateString) <> 8 then Exit;
if Pos(' ', sCheckedDateString) <> 0 then Exit;
if (sCheckedDateString[3] <> DateSeparator) or
(sCheckedDateString[6] <> DateSeparator) then Exit;

(* 民国日期 -> 公元日期 *)
iYear := StrToInt(Copy(sCheckedDateString, 1, 2)) + 1911;
iMonth := StrToInt(Copy(sCheckedDateString, 4, 2));
iDay := StrToInt(Copy(sCheckedDateString, 7, 2));

(* 日之判断 *)
if iDay < 0 then Exit;
case iMonth of
1, 3, 5, 7, 8, 10, 12: Result := iDay <= 31; (* 大月 *)
4, 6, 9, 11: Result := iDay <= 30; (* 小月 *)
2:  (* 依闰年计算法判断 *)
if (iYear mod 400 = 0) or
( (iYear mod 4 = 0) and (iYear Mod 100 <> 0) ) then
(* 闰年 *)
Result := iDay <= 29
else
Result := iDay <= 28;
end;
end;

function CheckLastDayOfMonth(DT : TDateTime) : Boolean;
var
D, M, Y: Word; Begin DecodeDate (DT, Y, M, D);
If M in [4,6,9,11]  then begin
If D = 30 then
Result:= True
Else
Result:= False;
End;
If M in [1,3,5,7,8,10,12]  then Begin
If D = 31 then
Result:= True
Else
Result:= False;
End;
if M=2 then begin
if IsLeapYear (Y) and (D=29) or Not IsLeapYear (Y) and (D=28) then
Begin
Result:= True; end else Begin Result:= False; end; End;end;

end.