"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libbasic' }"

Magnitude subclass:#Date

	instanceVariableNames:'dateEncoding'

	classVariableNames:'DayNames MonthNames DayAbbrevs MonthAbbrevs DefaultFormats

		ShortFormats LongFormats EnvironmentChange'

	poolDictionaries:''

	category:'Magnitude-Time'

!

!Date class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    Instances of Date represent dates as year, month and day encoded in the 

    (private & hidden) instance dateEncoding. The value found there is 

    year*100*100 + month*100 + day (which makes magnitude-like comparison of 

    dates easy, but is not guaranteed for future versions).

    Do not depend on the internal representation.

    The old representation used days since 1st Jan. 1901 internally - 

    with the new implementation, it is possible to reasonably represent almost 

    any Date.  (which insurance companies will like, since they can now 

    represent even very old peoples birthday :-)

    Notice: 

        no correction for pre-Gregorian dates (< 1583) is done.

        For dates before 1582 (when calendars were changed from Julian to Grgorian),

        the so called 'proleptic gregorian calendar' is used. This assumes leap years to continue in

        the past as if a gregorian calendar was used. Thus, 0000 is considered a leap year.

    The printed representation of dates is controlled by resource definitions -

    thus national variants are already supported (see file 'resources/Date.rs').

    Compatibility notice:

        due to some historic reasons, there are some methods found twice

        with different names in this class. The old ST/X methods will vanish in

        one of the next releases, and kept for a while to support existing

        applications (the info on how these methods should be named came 

        somewhat late from the testers ..).

        Please do not use methods marked as obsolete in their comment.

    Most useful methods:

        Date today

        (Date today) addDays:

        (Date today) subtractDays:

    [author:]

        Claus Gittinger

    [see also:]

        Time AbstractTime

        Filename

        OperatingSystem

"

! !

!Date class methodsFor:'initialization'!

initDefaultNames

    "read the language specific names."

    |enDayNames enDayAbbrevs enMonthNames enMonthAbbrevs

     enDefaultFormat enLongFormat enShortFormat |

    DayNames := Dictionary new.

    DayAbbrevs := Dictionary new.

    MonthNames := Dictionary new.

    MonthAbbrevs := Dictionary new.

    DefaultFormats := Dictionary new.

    LongFormats := Dictionary new.

    ShortFormats := Dictionary new.

    enDayNames := #('monday'

                    'tuesday'

                    'wednesday'

                    'thursday'

                    'friday'

                    'saturday'

                    'sunday').

    enDayAbbrevs := #('mon' 

                      'tue' 

                      'wed'

                      'thu' 

                      'fri' 

                      'sat' 

                      'sun').

    enMonthNames := #('january'

                      'february'

                      'march'

                      'april'

                      'may'

                      'june'

                      'july'

                      'august'

                      'september'

                      'october'

                      'november'

                      'december').

    enMonthAbbrevs := #('jan'

                        'feb'

                        'mar'

                        'apr'

                        'may'

                        'jun'

                        'jul'

                        'aug'

                        'sep'

                        'oct'

                        'nov'

                        'dec').

    DayNames at:#'en' put:enDayNames.

    DayAbbrevs at:#'en' put:enDayAbbrevs.

    MonthNames at:#'en' put:enMonthNames.

    MonthAbbrevs at:#'en' put:enMonthAbbrevs.

    DefaultFormats at:#'en' put:(enDefaultFormat := '%d-%m-%y').

    ShortFormats at:#'en' put:(enShortFormat := '%d-%m-%y').

    LongFormats at:#'en' put:(enLongFormat := '%(dayName), %d-%m-%y').

    "/ take the "master" language here, for the caching

    EnvironmentChange := (Smalltalk language asSymbol ~~ #'en').

    "

     Date initDefaultNames

    "

!

initNames

    "read the language specific names."

    |lang|

    DayNames isNil ifTrue:[

        self initDefaultNames.

    ].

    lang := Smalltalk language asSymbol.

    lang ~~ #'en' ifTrue:[

        self initNamesForLanguage: lang.

    ].

    EnvironmentChange := false

    "

     Date initNames

    "

!

initNamesForLanguage:language

    "read the language specific names."

    |resources lang 

     enDayNames enDayAbbrevs enMonthNames enMonthAbbrevs monthAbbrevKeys

     enDefaultFormat enLongFormat enShortFormat may|

    DayNames isNil ifTrue:[

        self initDefaultNames.

    ].

    lang := language asSymbol.

    lang ~~ #'en' ifTrue:[

	ResourcePack notNil ifTrue:[ "/ guard for tinytalk (no libview)

            resources := ResourcePack forPackage:'stx:libbasic' resourceFileName:(language,'.rs') cached:false.

	].

        resources notNil ifTrue:[

            enDayNames := DayNames at:#'en'.

            enDayAbbrevs := DayAbbrevs at:#'en'.

            enMonthNames := MonthNames at:#'en'.

            enMonthAbbrevs := MonthAbbrevs at:#'en'.

            monthAbbrevKeys := enMonthAbbrevs copy.

            monthAbbrevKeys at:5 put:'MAY_ABBREV'.

            enDefaultFormat := DefaultFormats at:#'en'.

            enShortFormat := ShortFormats at:#'en'.

            enLongFormat := LongFormats at:#'en'.

            DefaultFormats at:lang put:(resources at:'DATEFORMAT' default:enDefaultFormat).

            ShortFormats at:lang put:(resources at:'SHORTDATEFORMAT' default:enShortFormat).

            LongFormats at:lang put:(resources at:'LONGDATEFORMAT' default:enLongFormat).

            DayNames at:lang put:(resources array:enDayNames).

            DayAbbrevs at:lang put:(resources array:enDayAbbrevs).

            MonthNames at:lang put:(resources array:enMonthNames).

            MonthAbbrevs at:lang put:(resources array:monthAbbrevKeys).

            "/ may needs special care (same key for long and short name)

            may := resources string:'MAY_ABBREV' default:nil.

            may isNil ifTrue:[

                may := resources string:'may'.

            ].

            (MonthAbbrevs at:lang) at:5 put:may.

        ].

    ].

    "

     Date initNamesForLanguage:#de.

     Date initNamesForLanguage:#fr.

     Date initNamesForLanguage:#es.

    "

    "Modified (format): / 28-09-2011 / 15:56:41 / cg"

!

initialize

    DayNames isNil ifTrue:[

        self initDefaultNames.

    ].

    Smalltalk addDependent:self.

    Language ~= 'en' ifTrue:[

        EnvironmentChange := true

    ]

! !

!Date class methodsFor:'instance creation'!

fromDays:dayCount

    "return a new Date, given the day-number starting with 0 at 1.Jan 1901;

     (i.e. 'Date fromDays:0' returns 1st Jan. 1901).

     Date asDays is the reverse operation.

     Notice, that this is not able to represent dates before 1901!!.

     Added for GNU/ST-80 compatibility"

    |year rest d yearIncrement|

    "approx. year"

    year := (dayCount // 366) + 1901.

    dayCount < 0 ifTrue:[

        rest := dayCount negated - (self yearAsDays:year) + 1. "+1 for ST-80 compatibility"

        yearIncrement := -1.

    ] ifFalse:[

        rest := dayCount - (self yearAsDays:year) + 1. "+1 for ST-80 compatibility"

        yearIncrement := 1.

    ].

    rest > 365 ifTrue:[

        [d := self daysInYear:year. rest > d] whileTrue:[

            "adjust"

            year := year + yearIncrement.

            rest := rest - d.

        ].

    ].

    ^ self newDay:rest year:year

    "

     Date fromDays:0     -> 1 jan 1901

     Date fromDays:365   -> 1 jan 1902

     Date fromDays:730   -> 1 jan 1903

     Date fromDays:1095  -> 1 jan 1904

     Date fromDays:1460  ->31 dec 1904 since 1904 was a leap year

    "

    "Modified: 1.7.1996 / 14:24:25 / cg"

!

fromDaysFrom0:dayCount

    "return a new Date, given the day-number starting with 0 at 1.Jan 0;

     (i.e. 'Date fromDaysSince0:0' returns 1st Jan. 0).

     Date asDaysSince0 is the reverse operation.

     Notice, that this is a private interface"

    |year rest d yearIncrement|

    "approx. year"

    year := (dayCount // 366).

    dayCount < 0 ifTrue:[

        rest := dayCount negated - (self yearAsDaysFrom0:year) + 1. "+1 for ST-80 compatibility"

        yearIncrement := -1.

    ] ifFalse:[

        rest := dayCount - (self yearAsDaysFrom0:year) + 1. "+1 for ST-80 compatibility"

        yearIncrement := 1.

    ].

    rest > 365 ifTrue:[

        [d := self daysInYear:year. rest > d] whileTrue:[

            "adjust"

            year := year + yearIncrement.

            rest := rest - d.

        ].

    ].

    ^ self newDay:rest year:year

    "

     Date fromDaysSince0:0     -> 1 jan 0

     Date fromDaysSince0:366   -> 1 jan 1

    "

!

newDay:day month:month year:year

    "return a new Date, given the day, month and year.

     For your convenience, month may be either an integer 

     or the month's name as a string. 

     WARNING: semantics changed: 0..99 is no longer treated as 1900..1999,

              but as 0..99 now.

              Any such adjustments must be made by the caller of this method now

              (see those, for example readFrom:onError:)"

    |monthIndex ok|

    (year < 100 and:[year > 0]) ifTrue:[

        'Date [warning]: year in [0..99] no longer converted to [1900..1999]' infoPrintCR.

    ].

    year class ~= SmallInteger ifTrue:[

        "we support a lot of future, but LargeInteger years fail in #isLeapYear"

        self conversionErrorSignal raiseErrorString:' - invalid year (way too large)'.

    ].    

    month isInteger ifTrue:[

        monthIndex := month

    ] ifFalse:[

        monthIndex := self indexOfMonth:month

    ].

    (monthIndex == 2 and:[day == 29]) ifTrue:[

        ok := self leapYear:year

    ] ifFalse:[

        ok := day <= (self daysInMonth:month forYear:year)

    ].

    ((day > 0) and:[ok]) ifTrue:[

        ^ self basicNew year:year month:monthIndex day:day.

    ].

    "this error is triggered if you try to create a date from an

     invalid year/month/day combination;

     Such as 29-feb-year, where year is no leap year

    "

    self conversionErrorSignal raiseErrorString:' - invalid date'.

    "

     Date newDay:8  month:'may' year:1993

     Date newDay:8  month:5     year:1994

     Date newDay:29 month:'feb' year:2004

     Date newDay:29 month:'feb' year:2003

     Date newDay:28 month:'feb' year:5   

     Date newDay:28 month:'feb' year:95  

    "

    "Modified: 19.4.1996 / 15:28:15 / cg"

!

newDay:dayInYear year:year

    "return a new Date, given the year and the day-in-year (starting at 1).

     See also: Date today / Time now / Timestamp now.

     ST-80 compatibility"

    |monthAndDay|

    (dayInYear between:1 and:365) ifFalse:[

        (dayInYear == 366 and:[self leapYear:year]) ifFalse:[

            "

             this error is triggered, when you try to create a

             day from an invalid day-in-year; 

             for example, 366 in a non-leap year.

             I don't know, if ST-80 wraps to the next year(s) in this case.

            "

            ^ self conversionErrorSignal raiseErrorString:' - invalid day in year'.

        ]

    ].

    monthAndDay := self monthAndDayFromDayInYear:dayInYear forYear:year.

    ^ self basicNew year:year month:(monthAndDay at:1) day:(monthAndDay at:2)  

    "

     Date newDay:150 year:1994

     Date newDay:1 year:1994

     Date newDay:1 year:1901

     Date newDay:1 year:1902

     Date newDay:365 year:1992

     Date newDay:366 year:1992

     Date newDay:365 year:1994

     Date newDay:366 year:1994

     Date newDay:0 year:1994

     Date newDay:271 year:2008

     Date newDay:270 year:2008

     Date newDay:271 year:2007

    "

    "Modified: 1.7.1996 / 14:22:24 / cg"

!

newDayInWeek:dayInWeek week:week year:yearArg

    "return a new Date, given the year, the week (1..) and the day in week (1..7).

     See http://en.wikipedia.org/wiki/ISO_week_date"

    |weekDayOfJan4 dayInYear year|

    year := yearArg.

    weekDayOfJan4 := (Date newDay:4 month:1 year:year) dayInWeek.

    dayInYear := (week * 7) + dayInWeek - (weekDayOfJan4 + 3).

    dayInYear < 1 ifTrue:[

        dayInYear := dayInYear + (Date daysInYear:year-1).

        year := year - 1.

    ].

    dayInYear > (Date daysInYear:year) ifTrue:[

        dayInYear := dayInYear - (Date daysInYear:year).

        year := year + 1.

    ].

    ^ Date newDay:dayInYear year:year.

    "

     Date newDayInWeek:6 week:39 year:2008     

     Date newDayInWeek:1 week:40 year:2014     

     Date newDayInWeek:1 week:44 year:2014     

    "

!

readFrom:aStringOrStream onError:exceptionBlock

    "return a new Date, reading a printed representation from aStream.

     Notice, that this is not the storeString format and 

     is different from the format expected by readFrom:.

     BUG:

       This method handles american format (i.e. month/day/year),

       common format with letter month in the middle (10 December 2007)

       and ISO format (yyyy-mm-dd) - as long as yyyy is > 12.

       It does not handle the german/french and other dd-mm-yyyy.

       use readFrom:printFormat:onError: for this."

    ^ [

        |str items first second month day year|

        str := aStringOrStream readStream.

        items := #(1 2 3) collect:[:idx|

            [str peek isLetterOrDigit] whileFalse:[str next].

            (str peek isDigit) ifTrue:[

                Integer readFrom:str

            ] ifFalse:[

                str nextAlphaNumericWord

            ].

        ].

        first := items at:1.

        second := items at:2.

        (first isInteger and:[second isInteger and:[first > 12]]) ifTrue:[

            "ISO Date: yyyy-mm-dd"

            year := first.

            month := second.

            day := items at:3.

        ] ifFalse:[

            second isInteger ifTrue:[

                "must be an american date mm/dd/yy"

                month := first.

                day := second.

            ] ifFalse:[

                "3 Dec 2007"

                day := first.

                month := second.

            ].

            year := items at:3.

        ].

        (year between:0 and:99) ifTrue:[

            year := UserPreferences current twoDigitDateHandler value:year.

        ].

        self newDay:day month:month year:year

    ] on:Error do:exceptionBlock.