esbdates.pas

好用的日期转换函数 Date/Time Routines to enhance your 32-bit Delphi Programming.

	ISO-8601 Week No Routines.
	@param Year 4-digit year such as 1999.
	@cat DTMath
	@cat WeekMath
	@cat YearMath
}
function GetFirstMondayOfYear (const Year: Word): TDateTime;

{: Returns the Start of the week containing given Date/Time, assumes that
	the Start of the Week is Monday according to ISO-8601
	- Time portion preserved.
	@param DT Date to process.
	@cat DTMath
	@cat WeekMath
}
function StartOfISOWeek (const DT: TDateTime): TDateTime;

{: Returns the End of the week containing given Date/Time, assumes that
	the End of the Week is Sunday according to ISO-8601
	- Time portion preserved.
	@param DT Date to process.
	@cat DTMath
	@cat WeekMath
}
function EndOfISOWeek (const DT: TDateTime): TDateTime;

{: Converts Dates into a Week No and Year according to ISO-8601. Weeks are
	assumed to start with Monday. The week that Jan 4 occurs in is the 1st week of
	the year. Note that this does mean that there can be 53 weeks in a year!
	@param DT Date to process.
	@param WeekNo Returns the ISO-8601 Week Number in specified Year
	@param Year Returns 4 digit year to which the Week Number applies, not
		necessarily the same year as DT.
	@cat DTMath
	@cat WeekMath
}
procedure Date2ISOWeekNo (const DT: TDateTime; var WeekNo: Byte;
	var Year: Word);

{: Returns Date as a Basic Format for ISO Calendar Week/Day: YYYYWwwD where
	YYYY is year, 'W' is literal, ww is weekno and D is the ISO Day of Week -
	Monday is First Day.
	@param DT Date to take year from.
	@cat WeekMath
	@cat DTConv
}
function Date2ISOWeekStr (const DT: TDateTime): string;

{: Returns Date as a Enhanced Format for ISO Calendar Week/Day: YYYY-Www-D where
	YYYY is year, 'W' is literal, ww is weekno and D is the ISO Day of Week -
	Monday is First Day.
	@param DT Date to process.
	@cat WeekMath
	@cat DTConv
}
function Date2ISOWeekEnhStr (const DT: TDateTime): string;

{: Returns Date as a Basic Format for ISO Calendar Week: YYYYWww where
	YYYY is year, 'W' is literal, ww is weekno.
	@param DT Date to process.
	@cat WeekMath
	@cat DTConv
}
function Date2ISOWeekOnlyStr (const DT: TDateTime): string;

{: Returns Date as a Enhanced Format for ISO Calendar Week: YYYY-Www where
	YYYY is year, 'W' is literal, ww is weekno.
	@param DT Date to process.
	@cat WeekMath
	@cat DTConv
}
function Date2ISOWeekOnlyEnhStr (const DT: TDateTime): string;

{: Returns Date as a Basic Format for ISO Dates: YYYYMMDD where
	YYYY is year, MM is the Month, DD is Day of Month. Zero Padded.
	@param DT Date to process.
	@cat DTConv
}
function Date2ISOStr (const DT: TDateTime): string;

{: Returns Date as a Basic Format for ISO Dates: YYYY-MM-DD where
	YYYY is year, MM is the Month, DD is Day of Month. Zero Padded.
	@param DT Date to process.
	@cat DTConv
}
function Date2ISOEnhStr (const DT: TDateTime): string;

{: Returns Date as a Basic Format for ISO Dates: YYYYMMDD where
	YYYY is year, MM is the Month, DD is Day of Month. Zero Padded.
	@param DT Date to process.
	@cat DTConv
}
function Date2ISOInt (const DT: TDateTime): Cardinal;

{Returns true if the two Dates are in the same ISO-8601 WeekNo.
	@param DT1 First Date to process.
	@param DT2 Second Date to process.
	@cat DTMath
	@cat WeekMath
	@cat DTComparison
}
function DatesInSameISOWeekNo (const DT1, DT2: TDateTime): Boolean;

{Returns true No of Weeks, based on ISOWeekNo, that the two dates are
	apart. A Negative result implies DT2 occurs before D1.
	@param DT1 First Date to process.
	@param DT2 Second Date to process.
	@cat DTMath
	@cat WeekMath
}
function ISOWeekNosApart (DT1, DT2: TDateTime): Integer;

{: Returns the ISO-8601 WeekNo of the current Date (System Date).
	@param WeekNo Returns the ISO-8601 Week Number in specified Year
	@param Year Returns 4 digit year to which the Week Number applies.
	@cat DTMath
	@cat WeekMath
}
procedure ThisISOWeekNo (var WeekNo: Byte; var Year: Word);

{: Returns the Start of the Week for the given ISO-8601 WeekNo in the given
	year. Note that the Start of the Week is Monday in ISO-8601.
	@param WeekNo Returns the ISO-8601 Week Number in specified Year
	@param Year Returns 4 digit year to which the Week Number applies.
	@cat DTMath
	@cat WeekMath
}
function StartOfISOWeekNo (const WeekNo, Year: Word): TDateTime;

{: Returns the End of the Week for the given ISO-8601 WeekNo in the given
	year. Note that the End of the Week is Sunday in ISO-8601.
	@param WeekNo Returns the ISO-8601 Week Number in specified Year.
	@param Year Returns 4 digit year to which the Week Number applies.
	@cat DTMath
	@cat WeekMath
}
function EndOfISOWeekNo (const WeekNo, Year: Word): TDateTime;

{: Returns the Date for a given Day of Week, a given WeekNo, and the given Year,
	as defined in ISO-8601. Note that the Start of the Week is Monday, and
	that DOW uses 1 for Monday.
	@param Year 4 digit year to which the Week Number applies.
	@param WeekNo the ISO-8601 Week Number in specified Year.
	@param DOW Day of Week, 1 for Monday through 7 for Sunday.
	@cat DTMath
	@cat WeekMath
}
function ISOYWD2Date (const Year: Word; const WeekNo, DOW: Byte): TDateTime;

//--- Boolean Identification ---

{: Returns True if they are both the same Date ignoring the Time portion.
	@param DT1 First Date to process.
	@param DT2 Second Date to process.
	@cat DTComparison
}
function SameDate (const DT1, DT2: TDateTime): Boolean;

{: Returns True if they are both the same Time ignoring the Date portion.
	Times are considered the same if they are less then 1 millisecond apart.
	@param DT1 First Time to process.
	@param DT2 Second Time to process.
	@cat DTComparison
}
function SameTime (const DT1, DT2: TDateTime): Boolean;

{: Returns True if they are both the same Date/Time. Date/Times are considered
	the same if they are less then 1 millisecond apart.
	@param DT1 First Date/Time to process.
	@param DT2 Second Date/Time to process.
	@cat DTComparison
}
function SameDateTime (const DT1, DT2: TDateTime): Boolean;

{: Returns True if the given Date's Month is January.
	@param DT Date to process.
	@cat DTComparison
}
function IsJanuary (const DT: TDateTime): Boolean;

{: Returns True if today's Month is January.
	@cat DTComparison
}
function IsJanuaryNow: Boolean;

{: Returns True if the given Date's Month is February.
	@param DT Date to process.
	@cat DTComparison
}
function IsFebruary (const DT: TDateTime): Boolean;

{: Returns True if today's Month is February.
	@cat DTComparison
}
function IsFebruaryNow: Boolean;

{: Returns True if the given Date's Month is March.
	@param DT Date to process.
	@cat DTComparison
}
function IsMarch (const DT: TDateTime): Boolean;

{: Returns True if today's Month is March.
	@cat DTComparison
}
function IsMarchNow: Boolean;

{: Returns True if the given Date's Month is April.
	@param DT Date to process.
	@cat DTComparison
}
function IsApril (const DT: TDateTime): Boolean;

{: Returns True if today's Month is April.
	@cat DTComparison
}
function IsAprilNow: Boolean;

{: Returns True if the given Date's Month is May.
	@param DT Date to process.
	@cat DTComparison
}
function IsMay (const DT: TDateTime): Boolean;

{: Returns True if today's Month is May.
	@cat DTComparison
}
function IsMayNow: Boolean;

{: Returns True if the given Date's Month is June.
	@param DT Date to process.
	@cat DTComparison
}
function IsJune (const DT: TDateTime): Boolean;

{: Returns True if today's Month is June.
	@cat DTComparison
}
function IsJuneNow: Boolean;

{: Returns True if the given Date's Month is July.
	@param DT Date to process.
	@cat DTComparison
}
function IsJuly (const DT: TDateTime): Boolean;

{: Returns True if today's Month is July.
	@cat DTComparison
}
function IsJulyNow: Boolean;

{: Returns True if the given Date's Month is August.
	@param DT Date to process.
	@cat DTComparison
}
function IsAugust (const DT: TDateTime): Boolean;

{: Returns True if today's Month is August.
	@cat DTComparison
}
function IsAugustNow: Boolean;

{: Returns True if the given Date's Month is September.
	@param DT Date to process.
	@cat DTComparison
}
function IsSeptember (const DT: TDateTime): Boolean;

{: Returns True if today's Month is September.
	@cat DTComparison
}
function IsSeptemberNow: Boolean;

{: Returns True if the given Date's Month is October.
	@param DT Date to process.
	@cat DTComparison
}
function IsOctober (const DT: TDateTime): Boolean;

{: Returns True if today's Month is October.
	@cat DTComparison
}
function IsOctoberNow: Boolean;

{: Returns True if the given Date's Month is November.
	@param DT Date to process.
	@cat DTComparison
}
function IsNovember (const DT: TDateTime): Boolean;

{: Returns True if today's Month is November.
	@cat DTComparison
}
function IsNovemberNow: Boolean;

{: Returns True if the given Date's Month is December.
	@param DT Date to process.
	@cat DTComparison
}
function IsDecember (const DT: TDateTime): Boolean;

{: Returns True if todays Month is December.
	@cat DTComparison
}
function IsDecemberNow: Boolean;

{: Returns True if the Time portion is a AM value.
	@param DT Time to process.
	@cat DTComparison
}
function IsAM (const DT: TDateTime): Boolean;

{: Returns True if the currnet Time is a AM value.
	@cat DTComparison
}
function IsAMNow: Boolean;

{: Returns True if the Time portion is a PM value.
	@param DT Time to process.
	@cat DTComparison
}
function IsPM (const DT: TDateTime): Boolean;

{: Returns True if the current Time is a PM value.
	@cat DTComparison
}
function IsPMNow: Boolean;

{: Returns True if the Time portion represents Noon, 12:00pm.
	@param DT Time to process.
	@cat DTComparison
}
function IsNoon (const DT: TDateTime): Boolean;

{: Returns True if the current Time represents Noon, 12:00pm.
	@cat DTComparison
}
function IsNoonNow: Boolean;

{: Returns True if the Time portion represents Midnight, 12:00am.
	@param DT Time to process.
	@cat DTComparison
}
function IsMidnight (const DT: TDateTime): Boolean;

{: Returns True if the current Time represents Midnight, 12:00am.
	@cat DTComparison
}
function IsMidnightNow: Boolean;

{: Returns True if the Date represents a Sunday.
	@param DT Time to process.
	@cat DTComparison
}
function IsSunday (const DT: TDateTime): Boolean;

{: Returns True if today is a Sunday.
	@cat DTComparison
}
function IsSundayNow: Boolean;

{: Returns True if the Date represents a Monday.
	@param DT Date to process.
	@cat DTComparison
}
function IsMonday (const DT: TDateTime): Boolean;

{: Returns True if today is a Monday.
	@cat DTComparison
}
function IsMondayNow: Boolean;

{: Returns True if the Date represents a Tuesday.
	@param DT Date to process.
	@cat DTComparison
}
function IsTuesday (const DT: TDateTime): Boolean;

{: Returns True if today is a Tuesday.
	@cat DTComparison
}
function IsTuesdayNow: Boolean;

{: Returns True if the Date represents a Wednesday.
	@param DT Date to process.
	@cat DTComparison
}
function IsWednesday (const DT: TDateTime): Boolean;

{: Returns True if today is a Wednesday.
	@cat DTComparison
}
function IsWednesdayNow: Boolean;

{: Returns True if the Date represents a Thursday.
	@param DT Date to process.
	@cat DTComparison
}
function IsThursday (const DT: