.TITLE	FILE-NAME MATCHING ROUTINE
	.IDENT	-5.0-		; 19-NOV-79

; 	ON ENTRY:
; 		R1 POINTS TO THE ACTUAL FILE-NAME
; 		R2 POINTS TO THE MATCH TEMPLATE
; 	NB:
; 		BOTH THE FILE-NAME AND THE TEMPLATE MUST TERMINATE
; 		IN A SEMICOLON (; ).
;
; 	RETURNS SUCCESS OR FAILURE INDICATOR IN THE 'C'-BIT
;
MATCH::	MOV	R1,-(SP)	; SAVE THE REGISTERS THAT WE WILL USE
	MOV	R2,-(SP)	; (GOOD CODING PRACTICE, IF RATHER TOO
	MOV	R3,-(SP)	; MUCH LIKE HARD WORK FOR THE AVERAGE
	MOV	R4,-(SP)	; [WHERE AVERAGE=MEAN] PROGRAMMER).
	CALL	MATCH0		; GO DO THE COMPLEX WORK
	MOV	(SP)+,R4	; > N.B.  A COMPLEX PROBLEM IS ONE WHICH
	MOV	(SP)+,R3	; >>	CONTAINS BOTH REAL AND IMAGINARY
	MOV	(SP)+,R2	; >>>	DIFFICULTIES...
	MOV	(SP)+,R1	; >>>>
	RETURN			; ---> ALL DONE - GO HOME TO MOTHER.
;
MATCH0:	MOVB	(R2)+,R4	; GET CHARACTER FROM MATCH TEMPLATE
	CMPB	R4,#'*		; IS IT A '*' ? ( WILD STRING CHARACTER )
	BEQ	MWILD		; BR IF YES
MATCH1:	CALL	NEXTCH		; GET NEXT CHARACTER FROM FILE-NAME
	BNE	10$		; BR IF THEY DON'T MATCH
	CMPB	R3,#'; 		; BOTH AT END OF THEIR RESPECTIVE STRINGS ?
	BNE	MATCH0		; NO, TRY MATCH REST OF FILE-NAME
	RETURN			; YES, FILE-NAME MATCHES TEMPLATE SO QUIT.

10$:	CMPB	R4,#'%		; IS TEMPLATE CHARACTER A % ( JOKER CHARACTER ) ?
	BEQ	15$		; YES, ACCEPT IT.
	CMPB	R4,#'?		; IS IT THE OTHER JOKER?
	BNE	20$		; NOPE. DOESN'T MATCH
15$:	CMPB	R3,#'; 		; YEP, ALLOW MATCH FOR ALL BUT '; '
	BNE	MATCH0		; IT WAS ALLOWABLE SO MATCH IT.
20$:	SEC			; FILE-NAME DOESN'T MATCH.
	RETURN			; TELL CALLER THE BAD NEWS & EXIT.
;
MWILD:	MOVB	(R2)+,R4	; GET NEXT CHARACTER FROM TEMPLATE
	CMPB	R4,#'*		; ANOTHER WILD CARD ??
	BEQ	MWILD		; YES, DON'T BE B....Y SILLY !
	MOV	R2,-(SP)	; SAVE CONTEXT FOR LATER
	MOV	R1,-(SP)	; ..
1$:	CALL	MATCH1		; TRY TO MATCH REMAINDER OF TEMPLATE.
	BCC	3$		; WE MANAGED IT.
	CMPB	@(SP)+,#'; 	; IT DIDN'T. WAS IT BECAUSE FILE-NAME RAN OUT ?
	BEQ	2$		; YES, TOTAL FAILURE. GO UNWIND & QUIT.
	MOV	(SP),R2		; RECOVER ORIGINAL POSITION IN FILE-NAME
	MOVB	-1(R2),R4	; GET TEMPLATE CHARACTER AGAIN
	INC	-(SP)		; SKIP A CHARACTER IN FILE-NAME THAT WAS WRONG
	MOV	(SP),R1		; GET POINTER BACK TO R1
	BR	1$		; TRY TO MATCH FURTHER DOWN THE FILE-NAME.

2$:	TST	(SP)+		; TIDY UP STACK
	SEC			; SAY IT WAS BAD
	RETURN			; GO HOME WITH TAIL BETWEEN LEGS

3$:	CMP	(SP)+,(SP)+	; TIDY STACK ON SUCESS
	CLC			; CHUFFED TO BITS
	RETURN			;
;
NEXTCH:	MOVB	(R1)+,R3	; GET NEXT CHARACTER FROM FILE-NAME
	CMPB	R3,#040		; IS IT A SPACE ?
	BEQ	NEXTCH		; YES - IGNORE IT
	CMPB	R3,R4		; NO - SET CONDITION CODES FOR LATER
	RETURN			; AND RETURN
;
	.END