FUNCTION getBIAScols, fitsHdr, COMPLEMENT=complement, COUNT=count

;;-----------------------------------------------------------------------------
;; PURPOSE:
;;	Determines which cols contain Bias values
;;
;; CALLING SEQUENCE:
;;	RETURN = getBIAScols(fitsHdr, COMPLEMENT=complement, COUNT=cnt)
;;
;; REQUIRED INPUTS:
;;	fitsHdr - The FITS header for the image that could contain BIAS cols
;;
;; OUTPUTS:
;;	RETURN - An array of all the cols that contain Bias values. If there
;;		are none, returns -1.
;;
;; OPTIONAL INPUT KEYWORDS:
;;	COMPLEMENT - Returns the first and last cols that aren't BIAS cols
;;		, ie. image cols
;;	COUNT - the number of Bias cols found. 
;;
;; EXAMPLE:
;;      IDL> cols = getBIAScols(fitsHdr)
;;
;; PROCEDURES USED (i.e. called directly!):
;;    SXPAR - Gets a parameter from a FITS header
;;
;; MODIFICATION HISTORY:
;;   2004-07-14  M. Desnoyer    Created
;;
;;-----------------------------------------------------------------------------

;ON_ERROR, 2

;; Default the return values
COUNT = 0
COMPLEMENT = -1

;; Get the FITS Parameters
mode = SXPAR(fitsHdr, 'IMGH030', COUNT=cnt1)
ncol = SXPAR(fitsHdr, 'NAXIS1', COUNT=cnt2)
dtctr = SXPAR(fitsHdr, 'IMGH021', COUNT=cnt3)

;; Check that the header was valid
IF NOT( (cnt1 EQ 1) AND (cnt2 EQ 1) AND (cnt3 EQ 1)) THEN $
	message, 'Invalid FITS header', /NONAME

;; Find the number of cols on the right and left that are BIAS rows
IF dtctr EQ 1 THEN BEGIN ;;IR images
	SWITCH mode OF
	1:
	2:
	3:
	5: BEGIN
		biasCnt = 2
		BREAK
	END
	4:
	6: BEGIN
		biasCnt = 5
		BREAK
	END
	ELSE: biasCnt = 0
	ENDSWITCH

ENDIF ELSE BEGIN	;; VIS images
	SWITCH mode OF
	9:
	1: BEGIN
		biasCnt = 8
	   	BREAK
	   END
	2:
	3:
	4: BEGIN
		biasCnt = 4
	   	BREAK
	   END
	5:
	6: BEGIN
		biasCnt = 2
	   	BREAK
	   END
	ELSE: biasCnt = 0
	ENDSWITCH
ENDELSE

;; Determine the Bias cols
IF biasCnt GT 0 THEN BEGIN
	bcols = indgen(biasCnt*2)
	bcols[biasCnt:*] = bcols[biasCnt:*]+ncol-2*biasCnt
ENDIF ELSE bcols = -1
	

;; Determine the other ouptuts
COUNT = biasCnt*2
COMPLEMENT = [biasCnt,ncol-biasCnt-1]
RETURN, bcols
END