;External decruncher for xfdmaster.library
;It decrunches PCR4 packed files.
;31.8.1997
	INCLUDE	AINCLUDE:IncDirs.i
	INCLUDE	libraries/xfdmaster.i
	INCLUDe	lvo.i
;	include	"dh0:asm/newincl/values/xfdmaster.i"
;	include	"dh0:asm/newincl/offsets/libs.offsets"

;	opt	x-,o-,w-
	moveq	#-1,d0
	rts
	dc.l	XFDF_ID		;'XFDF' identifier
	dc.w	1		;XFDF version
	dc.w	$0000		;must be null
	dc.l	0		;private
	dc.l	0		;private
	dc.l	pcr4slave		;first slave
	dc.b	'$VER: External PCR4 decruncher for xfdmaster.library by TTL (31.08.97)'
	dc.b	10,0
	even
pcr4slave
	dc.l	0		;no next slave
	dc.w	2		;xfds version
	dc.w	36		;minimum xfdM version required
	dc.l	pcr4name	;name of packer
	dc.w	XFDPFF_DATA	;packer flags
				;=data file packer
	dc.w	0		;max. lenght of special info
	dc.l	pcr4test	;ptr to recognition buffer
	dc.l	unpack		;ptr to buffer decrunch code
	dc.l	0		;ptr to segment recognition code
	dc.l	0		;ptr to segment decrunch code
	dc.l	0
	dc.l	0
	dc.l	12

pcr4name	dc.b	'(PCR4) Data Cruncher',0
	even
pcr4test
;from xfdmaster	in:	a0=buffer
;			d0=length

	cmp.l	#'PCR4',(a0)
	bne.s	.err		;bad identifier
;these tests are from original PCR4 depack
	move.l	4(a0),d1	* fixed
	bmi.s	.err
	cmp.l	#$1800000,d1	* fixed
	bgt.s	.err
	tst.l	8(a0)
	ble.s	.err
.ok	moveq	#1,d0		;ok, I hope it is right packed data
	rts
.err	moveq	#0,d0		;error
	rts

;in: A0-adr of xfd buffer info
unpack		movem.l	d2-d7/a2-a6,-(sp)
	move.l	a0,a5
	move.l	xfdbi_SourceBuffer(a5),a2	;adr of PCR4 packed data
	move.l	4(a2),d0			;get decrunched lenght
	move.l	d0,xfdbi_TargetBufSaveLen(a5)
	move.l	d0,xfdbi_TargetBufLen(a5)
	move.l	xfdbi_TargetBufMemType(a5),d1	;get memf
	move.l	4.w,a6				;execbase
	jsr	_LVOAllocMem(a6)		;allocmem
	move.w	#XFDERR_NOMEMORY,xfdbi_Error(a5)
	move.l	d0,xfdbi_TargetBuffer(a5)
	beq.s	.err				;no memory
	move.w	#XFDERR_OK,xfdbi_Error(a5)	;memory ok
	move.l	d0,a1				;adr of decrunched data
	move.l	a2,a0				;adr of crunched data

	bsr.s	PCR4UNPACK
	beq.s	.ok
	move.w	#XFDERR_CORRUPTEDDATA,xfdbi_Error(a5)
	moveq	#0,d0		;unpack error
	bra.s	.err
.ok	moveq	#1,d0		;all ok
.err	movem.l	(sp)+,d2-d7/a2-a6
	rts

;PCR4 unpack from game onEscapee
;in: a0-source, a1-destination
PCR4UNPACK
		movem.l	d0-d7/a0-a2,-(a7)
		cmpi.l	#$50435234,(a0)+
		bne	l782832A4		;test it again
;		move.l	(a0),d6
;		bmi	l782832A4
;		cmp.l	#$1800000,d6
;		bgt	l782832A4
;		tst.l	4(a0)
;		ble	l782832A4
		move.l	a1,d6
		add.l	(a0)+,d6
		move.l	(a0)+,d7
l782831DC	moveq	#0,d2
l782831DE	moveq	#0,d0
		moveq	#0,d1
		subq.l	#1,d7
		bmi	l7828329A
		move.b	(a0)+,d0
		btst	#0,d0
		bne.s	l78283204
		tst.b	d0
		bpl.s	l78283242
		ror.l	#7,d0
		move.b	(a0)+,d0
		bpl.s	l7828323C
		ror.l	#7,d0
		move.b	(a0)+,d0
		swap	d0
		ror.l	#2,d0
		bra.s	l78283242
l78283204	move.b	(a0)+,d1
		lsr.b	#2,d0
		bcs.s	l78283222
		subq.w	#1,d0
		bmi.s	l78283214
l7828320E	move.b	(a0)+,(a1)+
		dbf	d0,l7828320E
l78283214	addq.w	#3,d1
		movea.l	a1,a2
		suba.w	d1,a2
		move.b	(a2)+,(a1)+
		move.b	(a2)+,(a1)+
		move.b	(a2),(a1)+
		bra.s	l782831DE
l78283222	subq.w	#1,d0
		bmi.s	l7828322C
l78283226	move.b	(a0)+,(a1)+
		dbf	d0,l78283226
l7828322C	addq.w	#4,d1
		movea.l	a1,a2
		suba.w	d1,a2
		move.b	(a2)+,(a1)+
		move.b	(a2)+,(a1)+
		move.b	(a2)+,(a1)+
		move.b	(a2),(a1)+
		bra.s	l782831DE
l7828323C	andi.b	#$7F,d0
		rol.l	#7,d0
l78283242	lsr.l	#1,d0
		move.b	(a0)+,d2
		beq.s	l78283282
		bpl.s	l78283250
		ror.w	#7,d2
		move.b	(a0)+,d2
		rol.w	#7,d2
l78283250	move.b	(a0)+,d1
		bpl.s	l7828325A
		ror.w	#7,d1
		move.b	(a0)+,d1
		rol.w	#7,d1
l7828325A	subq.l	#1,d0
		bmi.s	l7828326E
		bra.s	l78283262
l78283260	swap	d0
l78283262	move.b	(a0)+,(a1)+
		dbf	d0,l78283262
		swap	d0
		dbf	d0,l78283260
l7828326E	addq.w	#3,d2
		add.w	d2,d1
		addq.w	#1,d1
		movea.l	a1,a2
		suba.w	d1,a2
l78283278	move.b	(a2)+,(a1)+
		dbf	d2,l78283278
		bra	l782831DC
l78283282	subq.l	#1,d0
		bmi.s	l7828329A
		bra.s	l7828328A
l78283288	swap	d0
l7828328A	move.b	(a0)+,(a1)+
		dbf	d0,l7828328A
		swap	d0
		dbf	d0,l78283288
		bra	l782831DC
l7828329A	cmp.l	a1,d6
		moveq	#0,d0
pcr4end		tst.l	d0
		movem.l	(a7)+,d0-d7/a0-a2
		rts
l782832A4	moveq	#-1,d0
		bra.s	pcr4end