valid_year.pro (Kronos IDL library)

;+
; Contains the valid_year function
;
; :Author:
;    Gaëlle Boisnard
;
; :History:
;    2004/03/29: Created
;
;    2004/03/29: Last Edit
;-
;
;+
; Transforms the string year in a long integer, if possible
;
; :Returns:
;    <return desc here>
;
; :Params:
;    year: in, required, type=string
;       A string
;-
FUNCTION valid_year, year
tab0_9=['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
year=strtrim(year, 2)
length=strlen(year)
case length of
    2: begin
        for i=0, length-1 do begin
            ind=where(strmid(year, i, 1) eq tab0_9, count)
            if (count eq 0) then begin
                return, 0
            endif
        endfor
        year=long(year)
        if (year lt 80) then begin
            year=2000+year
        endif else begin
            if (year gt 79) then begin
                year=1900+year
            endif
        endelse
    end
    4: begin
        for i=0, length-1 do begin
            ind=where(strmid(year, i, 1) eq tab0_9, count)
            if (count eq 0) then begin
                return, 0
            endif
        endfor
        year=long(year)
    end
    else: begin
        return, 0
    end
endcase

return, year
end