INTEGER FUNCTION GFN(OUTSTR,OUTLEN,INSTR,INPTR,INLEN)
CC
C	GFN - GET FILE NAME FROM STRING.
C
C	ENTRY -
C		-INSTR- = STRING HOLDING FILE NAME(S)
C		-INPTR- = POINTER TO FIRST CHAR IN INPUT BUFFER-1
C		-INLEN- = MAX INDEX OF INPUT STRING
C
C	EXIT -
C		-OUTSTR- = FILE NAME (ZERO FILLED)
C	-INPTR- ADVANCED TO POINT AT EITHER TERMINATING COMMA, OR END OF
C	LINE.
C
	IMPLICIT INTEGER(A-Z)
	LOGICAL*1   INSTR(1), OUTSTR(1), CH
C
	GFN = -1			!   FLAG FILE NAME ENTERED
	NBRAK = 0			!   INIT BRACKET LEVEL
	FPTR = 1			!   OUTPUT FILE NAME POINTER
10	INPTR = INPTR+1			!   BUMP INPUT POINTER
	IF (INPTR.GT.INLEN)   GOTO 30	!   IF END OF INPUT LINE
	CH = INSTR(INPTR)		!   GET NEXT CHAR
	IF (CH.EQ.1H )   GOTO 10	!   IGNORE BLANKS
	GFN = -1			!   FLAG FILE NAME SPECIFIED
	IF (CH.EQ.1H[)   NBRAK = NBRAK+1
	IF (CH.EQ.1H])   NBRAK = NBRAK-1
	IF (CH.EQ.1H:)   GFN = 0	!   FLAG ONLY DEVICE SPEC
	IF (CH.NE.1H,)   GOTO 20	!   IF NOT END OF FILE NAME
	IF (NBRAK.EQ.0)   GOTO 30	!   IF FOUND END OF FILE NAME
20	OUTSTR(FPTR) = CH		!   COPY TO FILE NAME
	FPTR = FPTR+1
	IF (FPTR.LT.OUTLEN)   GOTO 10	!   IF STILL HAVE ROOM
30	DO 32 I=FPTR,OUTLEN
32	OUTSTR(I) = 0			!   CLEAN REMAINDER OF FILE NAME
40	IF (GFN.LT.0)   RETURN		!   IF FILENAME SPECIFIED
CC
C	CONVERT THE UNIT TO A NUMERIC AND PUT INTO THIRD CHAR OF -OUTSTR-
C
	IF (FPTR.GT.4)   GOTO 800	!   IF UNIT IS NON-NULL
	OUTSTR(3) = 0			!   FORCE UNIT 00
	RETURN
800	OUTSTR(3) = OUTSTR(3)-"60	!   CONVERT FIRST DIGIT
	IF (FPTR.EQ.6)   OUTSTR(3) = OUTSTR(3)*8+OUTSTR(4)-"60
	RETURN
	END