valid_day.pro (Kronos IDL library)

;+
; Contains the valid_day function
;
; :Author:
;    Gaëlle Boisnard
;
; :History:
;    2004/03/29: Created
;
;    2004/03/29: Last Edit
;-
;
;+
; Transforms the string month in a long integer, if possible
;
; :Returns:
;    <return desc here>
;
; :Params:
;    day:   in, required, type=sometype
;       A parameter named day
;    month: in, required, type=sometype
;       A parameter named month
;    year:  in, required, type=sometype
;       A parameter named year
;-
FUNCTION valid_day, day, month, year

tab01_31=['1', '2', '3', '4', '5', '6', '7', '8', '9', '01', '02', '03', '04', '05', '06', '07', $
          '08', '09', '10', '11', '12', '13', '14', '15', '16', '17', '18', '19', '20', '21', $
          '22', '23', '24', '25', '26', '27', '28', '29', '30', '31']
day=strtrim(day, 2)
case 1 of
    (month eq 1) or (month eq 3) or (month eq 5) or (month eq 7) or (month eq 8) or (month eq 10) $
      or (month eq 12): begin
        ind=where(day eq tab01_31, count)
        if (count eq 0) then begin
            return, 0
        endif
    end
    (month eq 4) or (month eq 6) or (month eq 9) or (month eq 11): begin
        ind=where(day eq tab01_31(0:38), count)
        if (count eq 0) then begin
            return, 0
        endif
    end
    (month eq 2) and ( (year mod 4) eq 0): begin
        ind=where(day eq tab01_31(0:37), count)
        if (count eq 0) then begin
            return, 0
        endif
    end
    (month eq 2) and ( (year mod 4) ne 0): begin
        ind=where(day eq tab01_31(0:36), count)
        if (count eq 0) then begin
            return, 0
        endif
    end
endcase
return, long(day)
end