; ==========================================================================
; ####################### ARTS IDL INTERFACE PROCEDURE #####################
; ==========================================================================
;
function aii_file_exists, filename
;+
;NAME:
;      aii_file_exists
; checks whether the file filename exists and returns 1 for yes and 0
; for no
;-

YES = 1
NO  = 0

get_lun,unit
openr,unit,filename,error=err
free_lun,unit

if (err ne 0) then return,NO   $
else return,YES
end



;; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



PRO aii_readfile,filename,output
;+
;NAME:
;      aii_readfile
;PURPOSE: 
;      checks whether the is file present by using aii_file_exists,
;      compressed, or gzipped, and reads it if possible by using
;      read_datafile into output variable
;USAGE: 
;      aii_readfile, filename, output
;-

;; do we have to uncompress?
com=-1

;; uncompressed
if aii_file_exists(filename) then begin
    filename = filename
    com = 0
endif 

;; compressed
if aii_file_exists(filename+'.Z') then begin
    filename = filename+'.Z'
    com = 1
endif 

;; gzipped
if aii_file_exists(filename+'.gz') then begin
    filename = filename+'.gz'
    com = 1
endif 

;; file not found
if com eq -1 then begin
    print,'Error: File not found: '+filename
    stop
endif

; read the file
if ( com ) then begin
	dummyname = './'+filename+'.arts.dummy.this.should.not.be.here'	
	print,'  decompressing...'
	spawn,'zcat '+filename+' > '+dummyname

	; read in from dummyname
        output=read_datafile(dummyname, /check)

	;remove the dummy matrix file
	spawn,'rm '+dummyname
endif else begin
	; read in from filename
        output=read_datafile(filename, /check)
endelse

end


;; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%