fpc/rtl/objpas/dateutils.pp
2003-01-19 14:37:06 +00:00

1965 lines
54 KiB
ObjectPascal

{$mode objfpc}
{$h+}
{
$Id$
This file is part of the Free Pascal run time library.
Copyright (c) 1999-2000 by the Free Pascal development team
Delphi/Kylix compatibility unit, provides Date/Time handling routines.
See the file COPYING.FPC, included in this distribution,
for details about the copyright.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
**********************************************************************}
unit dateutils;
interface
uses
SysUtils, Math, Types;
{ ---------------------------------------------------------------------
Various constants
---------------------------------------------------------------------}
const
DaysPerWeek = 7;
WeeksPerFortnight = 2;
MonthsPerYear = 12;
YearsPerDecade = 10;
YearsPerCentury = 100;
YearsPerMillennium = 1000;
// ISO day numbers.
DayMonday = 1;
DayTuesday = 2;
DayWednesday = 3;
DayThursday = 4;
DayFriday = 5;
DaySaturday = 6;
DaySunday = 7;
// Fraction of a day
OneHour = 1/HoursPerDay;
OneMinute = 1/MinsPerDay;
OneSecond = 1/SecsPerDay;
OneMillisecond = 1/MSecsPerDay;
{ This is actual days per year but you need to know if it's a leap year}
DaysPerYear: array [Boolean] of Word = (365, 366);
{ Used in RecodeDate, RecodeTime and RecodeDateTime for those datetime }
{ fields you want to leave alone }
RecodeLeaveFieldAsIs = High(Word);
{ ---------------------------------------------------------------------
Global variables used in this unit
---------------------------------------------------------------------}
Const
{ Average over a 4 year span. Valid for next 100 years }
ApproxDaysPerMonth: Double = 30.4375;
ApproxDaysPerYear: Double = 365.25;
{ ---------------------------------------------------------------------
Simple trimming functions.
---------------------------------------------------------------------}
Function DateOf(const AValue: TDateTime): TDateTime;
Function TimeOf(const AValue: TDateTime): TDateTime;
{ ---------------------------------------------------------------------
Identification functions.
---------------------------------------------------------------------}
Function IsInLeapYear(const AValue: TDateTime): Boolean;
Function IsPM(const AValue: TDateTime): Boolean;
Function IsValidDate(const AYear, AMonth, ADay: Word): Boolean;
Function IsValidTime(const AHour, AMinute, ASecond, AMilliSecond: Word): Boolean;
Function IsValidDateTime(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word): Boolean;
Function IsValidDateDay(const AYear, ADayOfYear: Word): Boolean;
Function IsValidDateWeek(const AYear, AWeekOfYear, ADayOfWeek: Word): Boolean;
Function IsValidDateMonthWeek(const AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word): Boolean;
{ ---------------------------------------------------------------------
Enumeration functions.
---------------------------------------------------------------------}
Function WeeksInYear(const AValue: TDateTime): Word;
Function WeeksInAYear(const AYear: Word): Word;
Function DaysInYear(const AValue: TDateTime): Word;
Function DaysInAYear(const AYear: Word): Word;
Function DaysInMonth(const AValue: TDateTime): Word;
Function DaysInAMonth(const AYear, AMonth: Word): Word;
{ ---------------------------------------------------------------------
Variations on current date/time.
---------------------------------------------------------------------}
Function Today: TDateTime;
Function Yesterday: TDateTime;
Function Tomorrow: TDateTime;
Function IsToday(const AValue: TDateTime): Boolean;
Function IsSameDay(const AValue, ABasis: TDateTime): Boolean;
Function PreviousDayOfWeek (DayOfWeek : Word) : Word;
{ ---------------------------------------------------------------------
Extraction functions.
---------------------------------------------------------------------}
Function YearOf(const AValue: TDateTime): Word;
Function MonthOf(const AValue: TDateTime): Word;
Function WeekOf(const AValue: TDateTime): Word;
Function DayOf(const AValue: TDateTime): Word;
Function HourOf(const AValue: TDateTime): Word;
Function MinuteOf(const AValue: TDateTime): Word;
Function SecondOf(const AValue: TDateTime): Word;
Function MilliSecondOf(const AValue: TDateTime): Word;
{ ---------------------------------------------------------------------
Start/End of year functions.
---------------------------------------------------------------------}
Function StartOfTheYear(const AValue: TDateTime): TDateTime;
Function EndOfTheYear(const AValue: TDateTime): TDateTime;
Function StartOfAYear(const AYear: Word): TDateTime;
Function EndOfAYear(const AYear: Word): TDateTime;
{ ---------------------------------------------------------------------
Start/End of month functions.
---------------------------------------------------------------------}
Function StartOfTheMonth(const AValue: TDateTime): TDateTime;
Function EndOfTheMonth(const AValue: TDateTime): TDateTime;
Function StartOfAMonth(const AYear, AMonth: Word): TDateTime;
Function EndOfAMonth(const AYear, AMonth: Word): TDateTime;
{ ---------------------------------------------------------------------
Start/End of week functions.
---------------------------------------------------------------------}
Function StartOfTheWeek(const AValue: TDateTime): TDateTime;
Function EndOfTheWeek(const AValue: TDateTime): TDateTime;
Function StartOfAWeek(const AYear, AWeekOfYear: Word; const ADayOfWeek: Word): TDateTime;
Function StartOfAWeek(const AYear, AWeekOfYear: Word): TDateTime; // ADayOFWeek 1
Function EndOfAWeek(const AYear, AWeekOfYear: Word; const ADayOfWeek: Word): TDateTime;
Function EndOfAWeek(const AYear, AWeekOfYear: Word): TDateTime; // const ADayOfWeek: Word = 7
{ ---------------------------------------------------------------------
Start/End of day functions.
---------------------------------------------------------------------}
Function StartOfTheDay(const AValue: TDateTime): TDateTime;
Function EndOfTheDay(const AValue: TDateTime): TDateTime;
Function StartOfADay(const AYear, AMonth, ADay: Word): TDateTime; overload;
Function StartOfADay(const AYear, ADayOfYear: Word): TDateTime; overload;
Function EndOfADay(const AYear, AMonth, ADay: Word): TDateTime; overload;
Function EndOfADay(const AYear, ADayOfYear: Word): TDateTime; overload;
{ ---------------------------------------------------------------------
Part of year functions.
---------------------------------------------------------------------}
Function MonthOfTheYear(const AValue: TDateTime): Word;
Function WeekOfTheYear(const AValue: TDateTime): Word; overload;
Function WeekOfTheYear(const AValue: TDateTime; var AYear: Word): Word; overload;
Function DayOfTheYear(const AValue: TDateTime): Word;
Function HourOfTheYear(const AValue: TDateTime): Word;
Function MinuteOfTheYear(const AValue: TDateTime): LongWord;
Function SecondOfTheYear(const AValue: TDateTime): LongWord;
Function MilliSecondOfTheYear(const AValue: TDateTime): Int64;
{ ---------------------------------------------------------------------
Part of month functions.
---------------------------------------------------------------------}
Function WeekOfTheMonth(const AValue: TDateTime): Word; overload;
Function WeekOfTheMonth(const AValue: TDateTime; var AYear, AMonth: Word): Word; overload;
Function DayOfTheMonth(const AValue: TDateTime): Word;
Function HourOfTheMonth(const AValue: TDateTime): Word;
Function MinuteOfTheMonth(const AValue: TDateTime): Word;
Function SecondOfTheMonth(const AValue: TDateTime): LongWord;
Function MilliSecondOfTheMonth(const AValue: TDateTime): LongWord;
{ ---------------------------------------------------------------------
Part of week functions.
---------------------------------------------------------------------}
Function DayOfTheWeek(const AValue: TDateTime): Word;
Function HourOfTheWeek(const AValue: TDateTime): Word;
Function MinuteOfTheWeek(const AValue: TDateTime): Word;
Function SecondOfTheWeek(const AValue: TDateTime): LongWord;
Function MilliSecondOfTheWeek(const AValue: TDateTime): LongWord;
{ ---------------------------------------------------------------------
Part of day functions.
---------------------------------------------------------------------}
Function HourOfTheDay(const AValue: TDateTime): Word;
Function MinuteOfTheDay(const AValue: TDateTime): Word;
Function SecondOfTheDay(const AValue: TDateTime): LongWord;
Function MilliSecondOfTheDay(const AValue: TDateTime): LongWord;
{ ---------------------------------------------------------------------
Part of hour functions.
---------------------------------------------------------------------}
Function MinuteOfTheHour(const AValue: TDateTime): Word;
Function SecondOfTheHour(const AValue: TDateTime): Word;
Function MilliSecondOfTheHour(const AValue: TDateTime): LongWord;
{ ---------------------------------------------------------------------
Part of minute functions.
---------------------------------------------------------------------}
Function SecondOfTheMinute(const AValue: TDateTime): Word;
Function MilliSecondOfTheMinute(const AValue: TDateTime): LongWord;
{ ---------------------------------------------------------------------
Part of second functions.
---------------------------------------------------------------------}
Function MilliSecondOfTheSecond(const AValue: TDateTime): Word;
{ ---------------------------------------------------------------------
Range checking functions.
---------------------------------------------------------------------}
Function WithinPastYears(const ANow, AThen: TDateTime; const AYears: Integer): Boolean;
Function WithinPastMonths(const ANow, AThen: TDateTime; const AMonths: Integer): Boolean;
Function WithinPastWeeks(const ANow, AThen: TDateTime; const AWeeks: Integer): Boolean;
Function WithinPastDays(const ANow, AThen: TDateTime; const ADays: Integer): Boolean;
Function WithinPastHours(const ANow, AThen: TDateTime; const AHours: Int64): Boolean;
Function WithinPastMinutes(const ANow, AThen: TDateTime; const AMinutes: Int64): Boolean;
Function WithinPastSeconds(const ANow, AThen: TDateTime; const ASeconds: Int64): Boolean;
Function WithinPastMilliSeconds(const ANow, AThen: TDateTime; const AMilliSeconds: Int64): Boolean;
{ ---------------------------------------------------------------------
Period functions.
---------------------------------------------------------------------}
Function YearsBetween(const ANow, AThen: TDateTime): Integer;
Function MonthsBetween(const ANow, AThen: TDateTime): Integer;
Function WeeksBetween(const ANow, AThen: TDateTime): Integer;
Function DaysBetween(const ANow, AThen: TDateTime): Integer;
Function HoursBetween(const ANow, AThen: TDateTime): Int64;
Function MinutesBetween(const ANow, AThen: TDateTime): Int64;
Function SecondsBetween(const ANow, AThen: TDateTime): Int64;
Function MilliSecondsBetween(const ANow, AThen: TDateTime): Int64;
{ ---------------------------------------------------------------------
Timespan in xxx functions.
---------------------------------------------------------------------}
{ YearSpan and MonthSpan are approximate values }
Function YearSpan(const ANow, AThen: TDateTime): Double;
Function MonthSpan(const ANow, AThen: TDateTime): Double;
Function WeekSpan(const ANow, AThen: TDateTime): Double;
Function DaySpan(const ANow, AThen: TDateTime): Double;
Function HourSpan(const ANow, AThen: TDateTime): Double;
Function MinuteSpan(const ANow, AThen: TDateTime): Double;
Function SecondSpan(const ANow, AThen: TDateTime): Double;
Function MilliSecondSpan(const ANow, AThen: TDateTime): Double;
{ ---------------------------------------------------------------------
Increment/decrement functions.
---------------------------------------------------------------------}
Function IncYear(const AValue: TDateTime; const ANumberOfYears: Integer ): TDateTime;
Function IncYear(const AValue: TDateTime): TDateTime; // ; const ANumberOfYears: Integer = 1)
// Function IncMonth is in SysUtils
Function IncWeek(const AValue: TDateTime; const ANumberOfWeeks: Integer): TDateTime;
Function IncWeek(const AValue: TDateTime): TDateTime; // ; const ANumberOfWeeks: Integer = 1)
Function IncDay(const AValue: TDateTime; const ANumberOfDays: Integer): TDateTime;
Function IncDay(const AValue: TDateTime): TDateTime; //; const ANumberOfDays: Integer = 1)
Function IncHour(const AValue: TDateTime; const ANumberOfHours: Int64): TDateTime;
Function IncHour(const AValue: TDateTime): TDateTime; //; const ANumberOfHours: Int64 = 1
Function IncMinute(const AValue: TDateTime; const ANumberOfMinutes: Int64): TDateTime;
Function IncMinute(const AValue: TDateTime): TDateTime; // ; const ANumberOfMinutes: Int64 = 1
Function IncSecond(const AValue: TDateTime; const ANumberOfSeconds: Int64): TDateTime;
Function IncSecond(const AValue: TDateTime): TDateTime; // ; const ANumberOfSeconds: Int64 = 1
Function IncMilliSecond(const AValue: TDateTime; const ANumberOfMilliSeconds: Int64): TDateTime;
Function IncMilliSecond(const AValue: TDateTime): TDateTime; // ; const ANumberOfMilliSeconds: Int64 = 1
{ ---------------------------------------------------------------------
Encode/Decode of complete timestamp
---------------------------------------------------------------------}
Function EncodeDateTime(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word): TDateTime;
Procedure DecodeDateTime(const AValue: TDateTime; var AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word);
Function TryEncodeDateTime(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word; var AValue: TDateTime): Boolean;
{ ---------------------------------------------------------------------
Encode/decode date, specifying week of year and day of week
---------------------------------------------------------------------}
Function EncodeDateWeek(const AYear, AWeekOfYear: Word; const ADayOfWeek: Word): TDateTime;
Function EncodeDateWeek(const AYear, AWeekOfYear: Word): TDateTime; //; const ADayOfWeek: Word = 1
Procedure DecodeDateWeek(const AValue: TDateTime; var AYear, AWeekOfYear, ADayOfWeek: Word);
Function TryEncodeDateWeek(const AYear, AWeekOfYear: Word; var AValue: TDateTime; const ADayOfWeek: Word): Boolean;
Function TryEncodeDateWeek(const AYear, AWeekOfYear: Word; var AValue: TDateTime): Boolean; //; const ADayOfWeek: Word = 1
{ ---------------------------------------------------------------------
Encode/decode date, specifying day of year
---------------------------------------------------------------------}
Function EncodeDateDay(const AYear, ADayOfYear: Word): TDateTime;
Procedure DecodeDateDay(const AValue: TDateTime; var AYear, ADayOfYear: Word);
Function TryEncodeDateDay(const AYear, ADayOfYear: Word; var AValue: TDateTime): Boolean;
{ ---------------------------------------------------------------------
Encode/decode date, specifying week of month
---------------------------------------------------------------------}
Function EncodeDateMonthWeek(const AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word): TDateTime;
Procedure DecodeDateMonthWeek(const AValue: TDateTime; var AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word);
Function TryEncodeDateMonthWeek(const AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word; var AValue: TDateTime): Boolean;
{ ---------------------------------------------------------------------
Replace given element with supplied value.
---------------------------------------------------------------------}
Function RecodeYear(const AValue: TDateTime; const AYear: Word): TDateTime;
Function RecodeMonth(const AValue: TDateTime; const AMonth: Word): TDateTime;
Function RecodeDay(const AValue: TDateTime; const ADay: Word): TDateTime;
Function RecodeHour(const AValue: TDateTime; const AHour: Word): TDateTime;
Function RecodeMinute(const AValue: TDateTime; const AMinute: Word): TDateTime;
Function RecodeSecond(const AValue: TDateTime; const ASecond: Word): TDateTime;
Function RecodeMilliSecond(const AValue: TDateTime; const AMilliSecond: Word): TDateTime;
Function RecodeDate(const AValue: TDateTime; const AYear, AMonth, ADay: Word): TDateTime;
Function RecodeTime(const AValue: TDateTime; const AHour, AMinute, ASecond, AMilliSecond: Word): TDateTime;
Function RecodeDateTime(const AValue: TDateTime; const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word): TDateTime;
Function TryRecodeDateTime(const AValue: TDateTime; const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word; var AResult: TDateTime): Boolean;
{ ---------------------------------------------------------------------
Comparision of date/time
---------------------------------------------------------------------}
Function CompareDateTime(const A, B: TDateTime): TValueRelationship;
Function CompareDate(const A, B: TDateTime): TValueRelationship;
Function CompareTime(const A, B: TDateTime): TValueRelationship;
Function SameDateTime(const A, B: TDateTime): Boolean;
Function SameDate(const A, B: TDateTime): Boolean;
Function SameTime(const A, B: TDateTime): Boolean;
{ For a given date these Functions tell you the which day of the week of the
month (or year). If its a Thursday, they will tell you if its the first,
second, etc Thursday of the month (or year). Remember, even though its
the first Thursday of the year it doesn't mean its the first week of the
year. See ISO 8601 above for more information. }
Function NthDayOfWeek(const AValue: TDateTime): Word;
Procedure DecodeDayOfWeekInMonth(const AValue: TDateTime; var AYear, AMonth, ANthDayOfWeek, ADayOfWeek: Word);
Function EncodeDayOfWeekInMonth(const AYear, AMonth, ANthDayOfWeek, ADayOfWeek: Word): TDateTime;
Function TryEncodeDayOfWeekInMonth(const AYear, AMonth, ANthDayOfWeek, ADayOfWeek: Word; var AValue: TDateTime): Boolean;
{ ---------------------------------------------------------------------
Exception throwing routines
---------------------------------------------------------------------}
Procedure InvalidDateTimeError(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word; const ABaseDate: TDateTime);
Procedure InvalidDateTimeError(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word); // const ABaseDate: TDateTime = 0
Procedure InvalidDateWeekError(const AYear, AWeekOfYear, ADayOfWeek: Word);
Procedure InvalidDateDayError(const AYear, ADayOfYear: Word);
Procedure InvalidDateMonthWeekError(const AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word);
Procedure InvalidDayOfWeekInMonthError(const AYear, AMonth, ANthDayOfWeek, ADayOfWeek: Word);
{ ---------------------------------------------------------------------
Julian and Modified Julian Date conversion support
---------------------------------------------------------------------}
Function DateTimeToJulianDate(const AValue: TDateTime): Double;
Function JulianDateToDateTime(const AValue: Double): TDateTime;
Function TryJulianDateToDateTime(const AValue: Double; var ADateTime: TDateTime): Boolean;
Function DateTimeToModifiedJulianDate(const AValue: TDateTime): Double;
Function ModifiedJulianDateToDateTime(const AValue: Double): TDateTime;
Function TryModifiedJulianDateToDateTime(const AValue: Double; var ADateTime: TDateTime): Boolean;
{ ---------------------------------------------------------------------
Unix timestamp support.
---------------------------------------------------------------------}
Function DateTimeToUnix(const AValue: TDateTime): Int64;
Function UnixToDateTime(const AValue: Int64): TDateTime;
implementation
Resourcestring
SErrInvalidTimeStamp = 'Invalid date/timestamp : "%s"';
SErrInvalidDateWeek = '%d %d %d is not a valid dateweek';
SErrInvalidDayOfYear = 'Year %d does not have a day number %d';
SErrInvalidDateMonthWeek = 'Year %d, month %d, Week %d and day %d is not a valid date.';
SErrInvalidDayOfWeekInMonth = 'Year %d Month %d NDow %d DOW %d is not a valid date';
SErrInvalidDayOfWeek = '%d is not a valid day of the week';
{ ---------------------------------------------------------------------
Auxiliary routines
---------------------------------------------------------------------}
Procedure NotYetImplemented (FN : String);
begin
Raise Exception.CreateFmt('Function "%s" (dateutils) is not yet implemented',[FN]);
end;
{ ---------------------------------------------------------------------
Simple trimming functions.
---------------------------------------------------------------------}
Function DateOf(const AValue: TDateTime): TDateTime;
begin
Result:=Trunc(DateOf);
end;
Function TimeOf(const AValue: TDateTime): TDateTime;
begin
Result:=Frac(Avalue);
end;
{ ---------------------------------------------------------------------
Identification functions.
---------------------------------------------------------------------}
Function IsInLeapYear(const AValue: TDateTime): Boolean;
Var
D,Y,M : Word;
begin
DecodeDate(AValue,Y,M,D);
Result:=IsLeapYear(Y);
end;
Function IsPM(const AValue: TDateTime): Boolean;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=(H>=12);
end;
Function IsValidDate(const AYear, AMonth, ADay: Word): Boolean;
begin
Result:=(AYear<>0) and (AYear<10000)
and (AMonth in [1..12])
and (ADay<>0) and (ADay<=MonthDays[IsleapYear(AYear),AMonth]);
end;
Function IsValidTime(const AHour, AMinute, ASecond, AMilliSecond: Word): Boolean;
begin
Result:=(AHour=HoursPerDay) and (AMinute=0) and (ASecond=0) and (AMillisecond=0);
Result:=Result or
((AHour<HoursPerDay) and (AMinute<MinsPerHour) and (ASecond<SecsPerMin) and
(AMillisecond<MSecsPerSec));
end;
Function IsValidDateTime(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word): Boolean;
begin
Result:=IsValidDate(AYear,AMonth,ADay) and
IsValidTime(AHour,AMinute,ASecond,AMillisecond)
end;
Function IsValidDateDay(const AYear, ADayOfYear: Word): Boolean;
begin
Result:=(AYear<>0) and (ADayOfYear<>0) and (AYear<10000) and
(ADayOfYear<=DaysPerYear[IsLeapYear(AYear)]);
end;
Function IsValidDateWeek(const AYear, AWeekOfYear, ADayOfWeek: Word): Boolean;
begin
Result:=(AYear<>0) and (AYear<10000)
and (ADayOfWeek in [1..7])
and (AWeekOfYear<>0)
and (AWeekOfYear<=WeeksInaYear(AYear));
{ should we not also check whether the day of the week is not
larger than the last day of the last week in the year 9999 ?? }
end;
Function IsValidDateMonthWeek(const AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word): Boolean;
begin
Result:=(AYear<>0) and (AYear<10000)
and (AMonth in [1..12])
and (AWeekOfMonth in [1..5])
and (ADayOfWeek in [1..7]);
end;
{ ---------------------------------------------------------------------
Enumeration functions.
---------------------------------------------------------------------}
Function WeeksInYear(const AValue: TDateTime): Word;
Var
Y,M,D : Word;
begin
DecodeDate(AValue,Y,M,D);
Result:=WeeksInAYear(Y);
end;
Function WeeksInAYear(const AYear: Word): Word;
Var
DOW : Word;
begin
Result:=52;
DOW:=DayOfTheWeek(StartOfAYear(AYear));
If (DOW=4) or ((DOW=3) and IsLeapYear(AYear)) then
Inc(Result);
end;
Function DaysInYear(const AValue: TDateTime): Word;
Var
Y,M,D : Word;
begin
DecodeDate(AValue,Y,M,D);
Result:=DaysPerYear[IsLeapYear(Y)];
end;
Function DaysInAYear(const AYear: Word): Word;
begin
Result:=DaysPerYear[Isleapyear(AYear)];
end;
Function DaysInMonth(const AValue: TDateTime): Word;
Var
Y,M,D : Word;
begin
Decodedate(AValue,Y,M,D);
Result:=MonthDays[IsLeapYear(Y),M];
end;
Function DaysInAMonth(const AYear, AMonth: Word): Word;
begin
Result:=MonthDays[IsLeapYear(AYear),AMonth];
end;
{ ---------------------------------------------------------------------
Variations on current date/time.
---------------------------------------------------------------------}
Function Today: TDateTime;
begin
Result:=Date;
end;
Function Yesterday: TDateTime;
begin
Result:=Date-1;
end;
Function Tomorrow: TDateTime;
begin
Result:=Date+1;
end;
Function IsToday(const AValue: TDateTime): Boolean;
begin
Result:=IsSameDay(AValue,Date);
end;
Function IsSameDay(const AValue, ABasis: TDateTime): Boolean;
Var
D : TDateTime;
begin
D:=AValue-Trunc(ABasis);
Result:=(D>=0) and (D<1);
end;
const
DOWMap: array [1..7] of Word = (7, 1, 2, 3, 4, 5, 6);
Function PreviousDayOfWeek (DayOfWeek : Word) : Word;
begin
If Not (DayOfWeek in [1..7]) then
Raise EConvertError.CreateFmt(SErrInvalidDayOfWeek,[DayOfWeek]);
Result:=DOWMap[DayOfWeek];
end;
{ ---------------------------------------------------------------------
Extraction functions.
---------------------------------------------------------------------}
Function YearOf(const AValue: TDateTime): Word;
Var
D,M : Word;
begin
DecodeDate(AValue,Result,D,M);
end;
Function MonthOf(const AValue: TDateTime): Word;
Var
Y,D : Word;
begin
DecodeDate(AValue,Y,Result,D);
end;
Function WeekOf(const AValue: TDateTime): Word;
begin
Result:=WeekOfTheYear(AValue);
end;
Function DayOf(const AValue: TDateTime): Word;
Var
Y,M : Word;
begin
DecodeDate(AValue,Y,M,Result);
end;
Function HourOf(const AValue: TDateTime): Word;
Var
N,S,MS : Word;
begin
DecodeTime(AValue,Result,N,S,MS);
end;
Function MinuteOf(const AValue: TDateTime): Word;
Var
H,S,MS : Word;
begin
DecodeTime(AValue,H,Result,S,MS);
end;
Function SecondOf(const AValue: TDateTime): Word;
Var
H,N,MS : Word;
begin
DecodeTime(AVAlue,H,N,Result,MS);
end;
Function MilliSecondOf(const AValue: TDateTime): Word;
Var
H,N,S : Word;
begin
DecodeTime(AValue,H,N,S,Result);
end;
{ ---------------------------------------------------------------------
Start/End of year functions.
---------------------------------------------------------------------}
Function StartOfTheYear(const AValue: TDateTime): TDateTime;
Var
Y,M,D : Word;
begin
DecodeDate(AValue,Y,M,D);
Result:=EncodeDate(Y,1,1);
end;
Function EndOfTheYear(const AValue: TDateTime): TDateTime;
Var
Y,M,D : Word;
begin
DecodeDate(AValue,Y,M,D);
Result:=EncodeDateTime(Y,12,31,23,59,59,999);
end;
Function StartOfAYear(const AYear: Word): TDateTime;
begin
Result:=EncodeDate(AYear,1,1);
end;
Function EndOfAYear(const AYear: Word): TDateTime;
begin
Result:=(EncodeDateTime(AYear,12,31,23,59,59,999));
end;
{ ---------------------------------------------------------------------
Start/End of month functions.
---------------------------------------------------------------------}
Function StartOfTheMonth(const AValue: TDateTime): TDateTime;
Var
Y,M,D : Word;
begin
DecodeDate(AValue,Y,M,D);
Result:=EncodeDate(Y,M,1);
// MonthDays[IsLeapYear(Y),M])
end;
Function EndOfTheMonth(const AValue: TDateTime): TDateTime;
Var
Y,M,D : Word;
begin
DecodeDate(AValue,Y,M,D);
Result:=EncodeDateTime(Y,M,MonthDays[IsLeapYear(Y),M],23,59,59,999);
end;
Function StartOfAMonth(const AYear, AMonth: Word): TDateTime;
begin
Result:=EncodeDate(AYear,AMonth,1);
end;
Function EndOfAMonth(const AYear, AMonth: Word): TDateTime;
begin
Result:=EncodeDateTime(AYear,AMonth,MonthDays[IsLeapYear(AYear),AMonth],23,59,59,999);
end;
{ ---------------------------------------------------------------------
Start/End of week functions.
---------------------------------------------------------------------}
Function StartOfTheWeek(const AValue: TDateTime): TDateTime;
begin
Result:=Trunc(AValue)-DayOfTheWeek(AValue)+1;
end;
Function EndOfTheWeek(const AValue: TDateTime): TDateTime;
begin
Result:=EndOfTheDay(AValue-DayOfTheWeek(AValue)+7);
end;
Function StartOfAWeek(const AYear, AWeekOfYear: Word; const ADayOfWeek: Word): TDateTime;
begin
Result:=EncodeDateWeek(AYear,AWeekOfYear,ADayOfWeek);
end;
Function StartOfAWeek(const AYear, AWeekOfYear: Word): TDateTime; // ADayOFWeek 1
begin
Result:=StartOfAWeek(AYear,AWeekOfYear,1)
end;
Function EndOfAWeek(const AYear, AWeekOfYear: Word; const ADayOfWeek: Word): TDateTime;
begin
Result := EndOfTheDay(EncodeDateWeek(AYear, AWeekOfYear, ADayOfWeek));
end;
Function EndOfAWeek(const AYear, AWeekOfYear: Word): TDateTime; // const ADayOfWeek: Word = 7
begin
Result:=EndOfAWeek(AYear,AWeekOfYear,7);
end;
{ ---------------------------------------------------------------------
Start/End of day functions.
---------------------------------------------------------------------}
Function StartOfTheDay(const AValue: TDateTime): TDateTime;
begin
StartOfTheDay:=Trunc(Avalue);
end;
Function EndOfTheDay(const AValue: TDateTime): TDateTime;
Var
Y,M,D : Word;
begin
DecodeDate(AValue,Y,M,D);
Result:=EncodeDateTime(Y,M,D,23,59,59,999);
end;
Function StartOfADay(const AYear, AMonth, ADay: Word): TDateTime;
begin
Result:=EncodeDate(AYear,AMonth,ADay);
end;
Function StartOfADay(const AYear, ADayOfYear: Word): TDateTime;
begin
Result:=StartOfAYear(AYear)+ADayOfYear;
end;
Function EndOfADay(const AYear, AMonth, ADay: Word): TDateTime;
begin
Result:=EndOfTheDay(EncodeDate(AYear,AMonth,ADay));
end;
Function EndOfADay(const AYear, ADayOfYear: Word): TDateTime;
begin
Result:=StartOfAYear(AYear)+ADayOfYear+EncodeTime(23,59,59,999);
end;
{ ---------------------------------------------------------------------
Part of year functions.
---------------------------------------------------------------------}
Function MonthOfTheYear(const AValue: TDateTime): Word;
Var
Y,D : Word;
begin
DecodeDate(AValue,Y,Result,D);
end;
Function WeekOfTheYear(const AValue: TDateTime): Word;
Var
Y,DOW : Word;
begin
DecodeDateWeek(AValue,Y,Result,DOW)
end;
Function WeekOfTheYear(const AValue: TDateTime; var AYear: Word): Word;
Var
DOW : Word;
begin
DecodeDateWeek(AValue,AYear,Result,DOW);
end;
Function DayOfTheYear(const AValue: TDateTime): Word;
begin
Result:=Trunc(AValue-StartOfTheYear(AValue)+1);
end;
Function HourOfTheYear(const AValue: TDateTime): Word;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=H+((DayOfTheYear(AValue)-1)*24);
end;
Function MinuteOfTheYear(const AValue: TDateTime): LongWord;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=M+(H+((DayOfTheYear(AValue)-1)*24))*60;
end;
Function SecondOfTheYear(const AValue: TDateTime): LongWord;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=(M+(H+((DayOfTheYear(AValue)-1)*24))*60)*60+S;
end;
Function MilliSecondOfTheYear(const AValue: TDateTime): Int64;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=((M+(H+((DayOfTheYear(AValue)-1)*24))*60)*60+S)*1000+MS;
end;
{ ---------------------------------------------------------------------
Part of month functions.
---------------------------------------------------------------------}
Function WeekOfTheMonth(const AValue: TDateTime): Word;
var
Y,M,DOW : word;
begin
DecodeDateMonthWeek(AValue,Y,M,Result,DOW);
end;
Function WeekOfTheMonth(const AValue: TDateTime; var AYear, AMonth: Word): Word;
Var
DOW : Word;
begin
DecodeDateMonthWeek(AValue,AYear,AMonth,Result,DOW);
end;
Function DayOfTheMonth(const AValue: TDateTime): Word;
Var
Y,M : Word;
begin
DecodeDate(AValue,Y,M,Result);
end;
Function HourOfTheMonth(const AValue: TDateTime): Word;
Var
Y,M,D,H,N,S,MS : Word;
begin
DecodeDateTime(AValue,Y,M,D,H,N,S,MS);
Result:=(D-1)*24+H;
end;
Function MinuteOfTheMonth(const AValue: TDateTime): Word;
Var
Y,M,D,H,N,S,MS : Word;
begin
DecodeDateTime(AValue,Y,M,D,H,N,S,MS);
Result:=((D-1)*24+H)*60+N;
end;
Function SecondOfTheMonth(const AValue: TDateTime): LongWord;
Var
Y,M,D,H,N,S,MS : Word;
begin
DecodeDateTime(AValue,Y,M,D,H,N,S,MS);
Result:=(((D-1)*24+H)*60+N)*60+S;
end;
Function MilliSecondOfTheMonth(const AValue: TDateTime): LongWord;
Var
Y,M,D,H,N,S,MS : Word;
begin
DecodeDateTime(AValue,Y,M,D,H,N,S,MS);
Result:=((((D-1)*24+H)*60+N)*60+S)*1000+MS;
end;
{ ---------------------------------------------------------------------
Part of week functions.
---------------------------------------------------------------------}
Function DayOfTheWeek(const AValue: TDateTime): Word;
begin
Result:=DowMAP[DayOfWeek(AValue)];
end;
Function HourOfTheWeek(const AValue: TDateTime): Word;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=(DayOfTheWeek(AValue)-1)*24+H;
end;
Function MinuteOfTheWeek(const AValue: TDateTime): Word;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=((DayOfTheWeek(AValue)-1)*24+H)*60+M;
end;
Function SecondOfTheWeek(const AValue: TDateTime): LongWord;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=(((DayOfTheWeek(AValue)-1)*24+H)*60+M)*60+S;
end;
Function MilliSecondOfTheWeek(const AValue: TDateTime): LongWord;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=((((DayOfTheWeek(AValue)-1)*24+H)*60+M)*60+S)*1000+MS;
end;
{ ---------------------------------------------------------------------
Part of day functions.
---------------------------------------------------------------------}
Function HourOfTheDay(const AValue: TDateTime): Word;
Var
M,S,MS : Word;
begin
DecodeTime(AValue,Result,M,S,MS);
end;
Function MinuteOfTheDay(const AValue: TDateTime): Word;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=(H*60)+M;
end;
Function SecondOfTheDay(const AValue: TDateTime): LongWord;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=((H*60)+M)*60+S;
end;
Function MilliSecondOfTheDay(const AValue: TDateTime): LongWord;
Var
H,M,S,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=(((H*60)+M)*60+S)*1000+MS;
end;
{ ---------------------------------------------------------------------
Part of hour functions.
---------------------------------------------------------------------}
Function MinuteOfTheHour(const AValue: TDateTime): Word;
Var
H,S,MS : Word;
begin
DecodeTime(AValue,H,Result,S,MS);
end;
Function SecondOfTheHour(const AValue: TDateTime): Word;
Var
H,S,M,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=M*60+S;
end;
Function MilliSecondOfTheHour(const AValue: TDateTime): LongWord;
Var
H,S,M,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=(M*60+S)*1000+MS;
end;
{ ---------------------------------------------------------------------
Part of minute functions.
---------------------------------------------------------------------}
Function SecondOfTheMinute(const AValue: TDateTime): Word;
Var
H,M,MS : Word;
begin
DecodeTime(AValue,H,M,Result,MS);
end;
Function MilliSecondOfTheMinute(const AValue: TDateTime): LongWord;
Var
H,S,M,MS : Word;
begin
DecodeTime(AValue,H,M,S,MS);
Result:=S*1000+MS;
end;
{ ---------------------------------------------------------------------
Part of second functions.
---------------------------------------------------------------------}
Function MilliSecondOfTheSecond(const AValue: TDateTime): Word;
Var
H,M,S : Word;
begin
DecodeTime(AValue,H,M,S,Result);
end;
{ ---------------------------------------------------------------------
Range checking functions.
---------------------------------------------------------------------}
Function WithinPastYears(const ANow, AThen: TDateTime; const AYears: Integer): Boolean;
begin
Result:=YearsBetween(ANow,AThen)<=AYears;
end;
Function WithinPastMonths(const ANow, AThen: TDateTime; const AMonths: Integer): Boolean;
begin
Result:=MonthsBetween(ANow,AThen)<=AMonths;
end;
Function WithinPastWeeks(const ANow, AThen: TDateTime; const AWeeks: Integer): Boolean;
begin
Result:=WeeksBetween(ANow,AThen)<=AWeeks;
end;
Function WithinPastDays(const ANow, AThen: TDateTime; const ADays: Integer): Boolean;
begin
Result:=DaysBetween(ANow,AThen)<=ADays;
end;
Function WithinPastHours(const ANow, AThen: TDateTime; const AHours: Int64): Boolean;
begin
Result:=HoursBetween(ANow,AThen)<=AHours;
end;
Function WithinPastMinutes(const ANow, AThen: TDateTime; const AMinutes: Int64): Boolean;
begin
Result:=MinutesBetween(ANow,AThen)<=AMinutes;
end;
Function WithinPastSeconds(const ANow, AThen: TDateTime; const ASeconds: Int64): Boolean;
begin
Result:=SecondsBetween(ANow,Athen)<=ASeconds;
end;
Function WithinPastMilliSeconds(const ANow, AThen: TDateTime; const AMilliSeconds: Int64): Boolean;
begin
Result:=MilliSecondsBetween(ANow,AThen)<=AMilliSeconds;
end;
{ ---------------------------------------------------------------------
Period functions.
---------------------------------------------------------------------}
{
These functions are declared as approximate by Borland.
A bit strange, since it can be calculated exactly ?
}
Function YearsBetween(const ANow, AThen: TDateTime): Integer;
begin
Result:=Trunc(Abs(ANow-AThen)/ApproxDaysPerYear);
end;
Function MonthsBetween(const ANow, AThen: TDateTime): Integer;
begin
Result:=Trunc(Abs(ANow-Athen)/ApproxDaysPerMonth);
end;
Function WeeksBetween(const ANow, AThen: TDateTime): Integer;
begin
Result:=Trunc(Abs(ANow-AThen)) div 7;
end;
Function DaysBetween(const ANow, AThen: TDateTime): Integer;
begin
Result:=Trunc(Abs(ANow-AThen));
end;
Function HoursBetween(const ANow, AThen: TDateTime): Int64;
begin
Result:=Trunc(Abs(ANow-AThen)*HoursPerDay);
end;
Function MinutesBetween(const ANow, AThen: TDateTime): Int64;
begin
Result:=Trunc(Abs(ANow-AThen)*MinsPerDay);
end;
Function SecondsBetween(const ANow, AThen: TDateTime): Int64;
begin
Result:=Trunc(Abs(ANow-AThen)*SecsPerDay);
end;
Function MilliSecondsBetween(const ANow, AThen: TDateTime): Int64;
begin
Result:=Trunc(Abs(ANow-AThen)*MSecsPerDay);
end;
{ ---------------------------------------------------------------------
Timespan in xxx functions.
---------------------------------------------------------------------}
Function YearSpan(const ANow, AThen: TDateTime): Double;
begin
Result:=Abs(Anow-Athen)/ApproxDaysPerYear;
end;
Function MonthSpan(const ANow, AThen: TDateTime): Double;
begin
Result:=Abs(ANow-AThen)/ApproxDaysPerMonth;
end;
Function WeekSpan(const ANow, AThen: TDateTime): Double;
begin
Result:=Abs(ANow-AThen) / 7
end;
Function DaySpan(const ANow, AThen: TDateTime): Double;
begin
Result:=Abs(ANow-AThen);
end;
Function HourSpan(const ANow, AThen: TDateTime): Double;
begin
Result:=Abs(ANow-AThen)*HoursPerDay;
end;
Function MinuteSpan(const ANow, AThen: TDateTime): Double;
begin
Result:=Abs(ANow-AThen)*MinsPerDay;
end;
Function SecondSpan(const ANow, AThen: TDateTime): Double;
begin
Result:=Abs(ANow-AThen)*SecsPerDay;
end;
Function MilliSecondSpan(const ANow, AThen: TDateTime): Double;
begin
Result:=Abs(ANow-AThen)*MSecsPerDay;
end;
{ ---------------------------------------------------------------------
Increment/decrement functions.
---------------------------------------------------------------------}
Function IncYear(const AValue: TDateTime; const ANumberOfYears: Integer ): TDateTime;
Var
Y,M,D,H,N,S,MS : Word;
begin
DecodeDateTime(AValue,Y,M,D,H,N,S,MS);
Y:=Y+ANumberOfYears;
If (M=2) and (D=29) And (Not IsLeapYear(Y)) then
D:=28;
Result:=EncodeDateTime(Y,M,D,H,N,S,MS);
end;
Function IncYear(const AValue: TDateTime): TDateTime; // ; const ANumberOfYears: Integer = 1)
begin
Result:=IncYear(Avalue,1);
end;
Function IncWeek(const AValue: TDateTime; const ANumberOfWeeks: Integer): TDateTime;
begin
Result:=AValue+ANumberOfWeeks*7;
end;
Function IncWeek(const AValue: TDateTime): TDateTime; // ; const ANumberOfWeeks: Integer = 1)
begin
Result:=IncWeek(Avalue,1);
end;
Function IncDay(const AValue: TDateTime; const ANumberOfDays: Integer): TDateTime;
begin
Result:=AValue+ANumberOfDays;
end;
Function IncDay(const AValue: TDateTime): TDateTime; //; const ANumberOfDays: Integer = 1)
begin
Result:=IncDay(Avalue,1);
end;
Function IncHour(const AValue: TDateTime; const ANumberOfHours: Int64): TDateTime;
begin
Result:=AValue+ANumberOfHours/HoursPerDay;
end;
Function IncHour(const AValue: TDateTime): TDateTime; //; const ANumberOfHours: Int64 = 1
begin
Result:=IncHour(AValue,1);
end;
Function IncMinute(const AValue: TDateTime; const ANumberOfMinutes: Int64): TDateTime;
begin
Result:=Result+ANumberOfMinutes / MinsPerDay;
end;
Function IncMinute(const AValue: TDateTime): TDateTime; // ; const ANumberOfMinutes: Int64 = 1
begin
Result:=IncMinute(AValue,1);
end;
Function IncSecond(const AValue: TDateTime; const ANumberOfSeconds: Int64): TDateTime;
begin
Result:=Result+ANumberOfSeconds / SecsPerDay;
end;
Function IncSecond(const AValue: TDateTime): TDateTime; // ; const ANumberOfSeconds: Int64 = 1
begin
Result:=IncSecond(Avalue,1);
end;
Function IncMilliSecond(const AValue: TDateTime; const ANumberOfMilliSeconds: Int64): TDateTime;
begin
Result:=Result+ANumberOfMilliSeconds/MSecsPerDay;
end;
Function IncMilliSecond(const AValue: TDateTime): TDateTime; // ; const ANumberOfMilliSeconds: Int64 = 1
begin
Result:=IncMilliSecond(AValue,1);
end;
{ ---------------------------------------------------------------------
Encode/Decode of complete timestamp
---------------------------------------------------------------------}
Function EncodeDateTime(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word): TDateTime;
begin
If Not TryEncodeDateTime(AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond,Result) then
InvalidDateTimeError(AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond)
end;
Procedure DecodeDateTime(const AValue: TDateTime; var AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word);
begin
DecodeDate(AValue,AYear,AMonth,ADay);
DecodeTime(AValue,AHour,AMinute,ASecond,AMilliSecond);
end;
Function TryEncodeDateTime(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word; var AValue: TDateTime): Boolean;
Var
tmp : TDateTime;
begin
Result:=TryEncodeDate(AYear,AMonth,ADay,AValue);
Result:=Result and TryEncodeTime(AHour,AMinute,ASecond,Amillisecond,Tmp);
If Result then
Avalue:=AValue+Tmp;
end;
{ ---------------------------------------------------------------------
Encode/decode date, specifying week of year and day of week
---------------------------------------------------------------------}
Function EncodeDateWeek(const AYear, AWeekOfYear: Word; const ADayOfWeek: Word): TDateTime;
begin
If Not TryEncodeDateWeek(AYear,AWeekOfYear,Result,ADayOfWeek) then
InvalidDateWeekError(AYear,AWeekOfYear,ADayOfWeek);
end;
Function EncodeDateWeek(const AYear, AWeekOfYear: Word): TDateTime; //; const ADayOfWeek: Word = 1
begin
EncodeDateWeek(AYear,AWeekOfYear,1);
end;
Procedure DecodeDateWeek(const AValue: TDateTime; var AYear, AWeekOfYear, ADayOfWeek: Word);
begin
NotYetImplemented('DecodeDateWeek');
end;
Function TryEncodeDateWeek(const AYear, AWeekOfYear: Word; var AValue: TDateTime; const ADayOfWeek: Word): Boolean;
Var
DOW : Word;
Rest : Integer;
begin
Result:=IsValidDateWeek(Ayear,AWeekOfYear,ADayOfWeek);
If Result then
begin
AValue:=EncodeDate(AYear,1,1)+(7*(AWeekOfYear-1));
DOW:=DayOfTheWeek(AValue);
Rest:=ADayOfWeek-DOW;
If (DOW>4) then
Inc(Rest,7);
AValue:=AValue+Rest;
end;
end;
Function TryEncodeDateWeek(const AYear, AWeekOfYear: Word; var AValue: TDateTime): Boolean; //; const ADayOfWeek: Word = 1
begin
Result:=TryEncodeDateWeek(AYear,AWeekOfYear,AValue,1);
end;
{ ---------------------------------------------------------------------
Encode/decode date, specifying day of year
---------------------------------------------------------------------}
Function EncodeDateDay(const AYear, ADayOfYear: Word): TDateTime;
begin
If Not TryEncodeDateDay(AYear,ADayOfYear,Result) then
InvalidDateDayError(AYear,ADayOfYear);
end;
Procedure DecodeDateDay(const AValue: TDateTime; var AYear, ADayOfYear: Word);
Var
M,D : Word;
begin
DecodeDate(AValue,AYear,M,D);
ADayOfyear:=Trunc(AValue-EncodeDate(AYear,1,1))+1;
end;
Function TryEncodeDateDay(const AYear, ADayOfYear: Word; var AValue: TDateTime): Boolean;
begin
Result:=(ADayOfYear<>0) and (ADayOfYear<=DaysPerYear [IsleapYear(AYear)]);
If Result then
AValue:=EncodeDate(AYear,1,1)+ADayOfYear-1;
end;
{ ---------------------------------------------------------------------
Encode/decode date, specifying week of month
---------------------------------------------------------------------}
Function EncodeDateMonthWeek(const AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word): TDateTime;
begin
If Not TryEncodeDateMonthWeek(Ayear,AMonth,AWeekOfMonth,ADayOfWeek,Result) then
InvalidDateMonthWeekError(AYear,AMonth,AWeekOfMonth,ADayOfWeek);
end;
Procedure DecodeDateMonthWeek(const AValue: TDateTime; var AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word);
Var
D,SDOM,EDOM : Word;
SOM,EOM : TdateTime;
DOM : Integer;
begin
DecodeDate(AValue,AYear,AMonth,D);
ADayOfWeek:=DayOfTheWeek(AValue);
SOM:=EncodeDate(Ayear,Amonth,1);
SDOM:=DayOfTheWeek(SOM);
DOM:=D-1+SDOM;
If SDOM>4 then
Dec(DOM,7);
// Too early in the month. First full week is next week, day is after thursday.
If DOM<=0 Then
DecodeDateMonthWeek(SOM-1,AYear,AMonth,AWeekOfMonth,D)
else
begin
AWeekOfMonth:=(DOM div 7)+Ord((DOM mod 7)<>0);
EDOM:=DayOfTheWeek(EndOfAMonth(Ayear,AMonth));
// In last days of last long week, so in next month...
If (EDOM<4) and ((DaysInAMonth(AYear,Amonth)-D)<EDOM) then
begin
AWeekOfMonth:=1;
Inc(AMonth);
If (AMonth=13) then
begin
AMonth:=1;
Inc(AYear);
end;
end;
end;
end;
Function TryEncodeDateMonthWeek(const AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word; var AValue: TDateTime): Boolean;
begin
NotYetImplemented('TryEncodeDateMonthWeek');
end;
{ ---------------------------------------------------------------------
Replace given element with supplied value.
---------------------------------------------------------------------}
Const
LFAI = RecodeLeaveFieldAsIS; // Less typing, readable code
{
Note: We have little choice but to implement it like Borland did:
If AValue contains some 'wrong' value, it will throw an error.
To simulate this we'd have to check in each function whether
both arguments are correct. To avoid it, all is routed through
the 'central' RecodeDateTime function as in Borland's implementation.
}
Function RecodeYear(const AValue: TDateTime; const AYear: Word): TDateTime;
begin
RecodeDateTime(AValue,AYear,LFAI,LFAI,LFAI,LFAI,LFAI,LFAI);
end;
Function RecodeMonth(const AValue: TDateTime; const AMonth: Word): TDateTime;
begin
RecodeDateTime(AValue,LFAI,AMonth,LFAI,LFAI,LFAI,LFAI,LFAI);
end;
Function RecodeDay(const AValue: TDateTime; const ADay: Word): TDateTime;
begin
RecodeDateTime(AValue,LFAI,LFAI,ADay,LFAI,LFAI,LFAI,LFAI);
end;
Function RecodeHour(const AValue: TDateTime; const AHour: Word): TDateTime;
begin
RecodeDateTime(AValue,LFAI,LFAI,LFAI,AHour,LFAI,LFAI,LFAI);
end;
Function RecodeMinute(const AValue: TDateTime; const AMinute: Word): TDateTime;
begin
RecodeDateTime(AValue,LFAI,LFAI,LFAI,LFAI,AMinute,LFAI,LFAI);
end;
Function RecodeSecond(const AValue: TDateTime; const ASecond: Word): TDateTime;
begin
RecodeDateTime(AValue,LFAI,LFAI,LFAI,LFAI,LFAI,ASecond,LFAI);
end;
Function RecodeMilliSecond(const AValue: TDateTime; const AMilliSecond: Word): TDateTime;
begin
RecodeDateTime(AValue,LFAI,LFAI,LFAI,LFAI,LFAI,LFAI,AMilliSecond);
end;
Function RecodeDate(const AValue: TDateTime; const AYear, AMonth, ADay: Word): TDateTime;
begin
RecodeDateTime(AValue,AYear,AMonth,ADay,LFAI,LFAI,LFAI,LFAI);
end;
Function RecodeTime(const AValue: TDateTime; const AHour, AMinute, ASecond, AMilliSecond: Word): TDateTime;
begin
RecodeDateTime(AValue,LFAI,LFAI,LFAI,AHour,AMinute,ASecond,AMilliSecond);
end;
Function RecodeDateTime(const AValue: TDateTime; const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word): TDateTime;
begin
If Not TryRecodeDateTime(AValue,AYear,AMonth,ADay,AHour,AMinute,ASecond,AMilliSecond,Result) then
InvalidDateTimeError(AYear,AMonth,ADay,AHour,AMinute,ASecond,AMilliSecond,AValue);
end;
Function TryRecodeDateTime(const AValue: TDateTime; const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word; var AResult: TDateTime): Boolean;
Procedure FV (Var FV : Word; Arg : Word);
begin
If (Arg<>LFAI) then
FV:=Arg;
end;
Var
Y,M,D,H,N,S,MS : Word;
begin
DecodeDateTime(AValue,Y,M,D,H,N,S,MS);
FV(Y,AYear);
FV(M,AMonth);
FV(D,ADay);
FV(H,AHour);
FV(N,AMinute);
FV(S,ASecond);
FV(S,AMillisecond);
Result:=TryEncodeDateTime(Y,M,D,H,N,S,MS,AResult);
end;
{ ---------------------------------------------------------------------
Comparision of date/time
---------------------------------------------------------------------}
Function CompareDateTime(const A, B: TDateTime): TValueRelationship;
begin
If SameDateTime(A,B) then
Result:=EqualsValue
else If A>B then
Result:=GreaterThanValue
else
Result:=LessThanValue
end;
Function CompareDate(const A, B: TDateTime): TValueRelationship;
begin
If SameDate(A,B) then
Result:=EQualsValue
else if A<B then
Result:=LessThanValue
else
Result:=GreaterThanValue;
end;
Function CompareTime(const A, B: TDateTime): TValueRelationship;
begin
If SameTime(A,B) then
Result:=EQualsValue
else If Frac(A)<Frac(B) then
Result:=LessThanValue
else
Result:=GreaterThanValue;
end;
Function SameDateTime(const A, B: TDateTime): Boolean;
begin
Result:=Abs(A-B)<OneMilliSecond;
end;
Function SameDate(const A, B: TDateTime): Boolean;
begin
Result:=Trunc(A)=Trunc(B);
end;
Function SameTime(const A, B: TDateTime): Boolean;
begin
Result:=Frac(Abs(A-B))<OneMilliSecond;
end;
Function NthDayOfWeek(const AValue: TDateTime): Word;
begin
Result:=(DayOfTheMonth(AValue)-1) div 7 + 1;
end;
Procedure DecodeDayOfWeekInMonth(const AValue: TDateTime; var AYear, AMonth, ANthDayOfWeek, ADayOfWeek: Word);
begin
NotYetImplemented('DecodeDayOfWeekInMonth');
end;
Function EncodeDayOfWeekInMonth(const AYear, AMonth, ANthDayOfWeek, ADayOfWeek: Word): TDateTime;
begin
If Not TryEncodeDayOfWeekInMonth(AYear,AMonth,ANthDayOfWeek,ADayOfWeek,Result) then
InvalidDayOfWeekInMonthError(AYear,AMonth,ANthDayOfWeek,ADayOfWeek);
end;
Function TryEncodeDayOfWeekInMonth(const AYear, AMonth, ANthDayOfWeek, ADayOfWeek: Word; var AValue: TDateTime): Boolean;
Var
SOM,D : Word;
begin
SOM:=DayOfTheWeek(EncodeDate(Ayear,AMonth,1));
D:=1+ADayOfWeek-SOM+7*(ANthDayOfWeek-1);
If SOM>ADayOfWeek then
D:=D+7; // Clearer would have been Inc(ANthDayOfweek) but it's a const
Result:=TryEncodeDate(Ayear,AMonth,D,AValue);
end;
{ ---------------------------------------------------------------------
Exception throwing routines
---------------------------------------------------------------------}
Procedure InvalidDateTimeError(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word; const ABaseDate: TDateTime);
Function DoField(Arg,Def : Word; Unknown: String) : String;
begin
If (Arg<>LFAI) then
Result:=Format('%.*d',[Length(Unknown),Arg])
else if (ABaseDate=0) then
Result:=Unknown
else
Result:=Format('%.*d',[Length(Unknown),Arg]);
end;
Var
Y,M,D,H,N,S,MS : Word;
Msg : String;
begin
DecodeDateTime(ABasedate,Y,M,D,H,N,S,MS);
Msg:=DoField(AYear,Y,'????');
Msg:=Msg+DateSeparator+DoField(AMonth,M,'??');
Msg:=Msg+DateSeparator+DoField(ADay,D,'??');
Msg:=Msg+' '+DoField(AHour,H,'??');
Msg:=Msg+TimeSeparator+DoField(AMinute,N,'??');
Msg:=Msg+TimeSeparator+Dofield(ASecond,S,'??');
Msg:=Msg+DecimalSeparator+DoField(AMilliSecond,MS,'???');
Raise EConvertError.CreateFmt(SErrInvalidTimeStamp,[Msg]);
end;
Procedure InvalidDateTimeError(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word); // const ABaseDate: TDateTime = 0
begin
InvalidDateTimeError(AYear,AMonth,ADay,AHour,AMinute,ASecond,AMilliSecond,0);
end;
Procedure InvalidDateWeekError(const AYear, AWeekOfYear, ADayOfWeek: Word);
begin
Raise EConvertError.CreateFmt(SErrInvalidDateWeek,[AYear,AWeekOfYear,ADayOfWeek]);
end;
Procedure InvalidDateDayError(const AYear, ADayOfYear: Word);
begin
Raise EConvertError.CreateFmt(SErrInvalidDayOfYear,[AYear,ADayOfYear]);
end;
Procedure InvalidDateMonthWeekError(const AYear, AMonth, AWeekOfMonth, ADayOfWeek: Word);
begin
Raise EConvertError.CreateFmt(SErrInvalidDateMonthWeek,[Ayear,AMonth,AWeekOfMonth,ADayOfWeek]);
end;
Procedure InvalidDayOfWeekInMonthError(const AYear, AMonth, ANthDayOfWeek, ADayOfWeek: Word);
begin
Raise EConvertError.CreateFmt(SErrInvalidDayOfWeekInMonth,[AYear,AMonth,ANthDayOfWeek,ADayOfWeek]);
end;
{ ---------------------------------------------------------------------
Julian and Modified Julian Date conversion support
---------------------------------------------------------------------}
Function DateTimeToJulianDate(const AValue: TDateTime): Double;
begin
NotYetImplemented('DateTimeToJulianDate');
end;
Function JulianDateToDateTime(const AValue: Double): TDateTime;
begin
NotYetImplemented('JulianDateToDateTime');
end;
Function TryJulianDateToDateTime(const AValue: Double; var ADateTime: TDateTime): Boolean;
begin
NotYetImplemented('TryJulianDateToDateTime');
end;
Function DateTimeToModifiedJulianDate(const AValue: TDateTime): Double;
begin
NotYetImplemented('DateTimeToModifiedJulianDate');
end;
Function ModifiedJulianDateToDateTime(const AValue: Double): TDateTime;
begin
NotYetImplemented('ModifiedJulianDateToDateTime');
end;
Function TryModifiedJulianDateToDateTime(const AValue: Double; var ADateTime: TDateTime): Boolean;
begin
NotYetImplemented('TryModifiedJulianDateToDateTime');
end;
{ ---------------------------------------------------------------------
Unix timestamp support.
---------------------------------------------------------------------}
Function DateTimeToUnix(const AValue: TDateTime): Int64;
begin
NotYetImplemented('DateTimeToUnix');
end;
Function UnixToDateTime(const AValue: Int64): TDateTime;
begin
NotYetImplemented('UnixToDateTime');
end;
end.
{
$Log$
Revision 1.2 2003-01-19 14:37:06 michael
+ Much more functions implemented
}