From cc9174ba4176775e80cb366cd5025ea537d3b17c Mon Sep 17 00:00:00 2001
From: Piotr Fusik <fox@scene.pl>
Date: Wed, 1 Apr 1998 11:35:16 +0200
Subject: [PATCH] MS-DOS COM-format program compressor.

---
 compack.asm | 274 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 274 insertions(+)
 create mode 100644 compack.asm

diff --git a/compack.asm b/compack.asm
new file mode 100644
index 0000000..b2d4163
--- /dev/null
+++ b/compack.asm
@@ -0,0 +1,274 @@
+; COMpack
+; b. Fox
+
+	IDEAL
+	P386
+	MODEL	TINY
+	CODESEG
+	ORG	100h
+	include	'fox.mak'
+start:
+;	db	1024 dup(0)	;4 self-packing
+
+inplen	=	24000
+outlen	=	27000
+
+	print	hello
+	mov	di, 81h
+	movzx	cx, [di-1]
+	jcxz	usg
+	mov	al, ' '
+	repe	scasb
+	je	usg
+	push	cx di
+	dec	di
+	inc	cx
+	mov	al, '?'
+	repne	scasb
+	pop	di cx
+	jne	nousg
+
+usg:	print	usgtxt
+	int	20h
+
+getfil:	lea	si, [di-1]
+	mov	al, ' '
+	repne	scasb
+	jne	noout1
+	dec	di
+noout1:	mov	cx, di
+	sub	cx, si
+	mov	di, offset fname
+	rep	movsb
+	mov	bx, di
+srchex:	dec	bx
+	cmp	[byte bx], '\'
+	je	addext
+	cmp	[byte bx], '.'
+	je	extexs
+	cmp	bx, offset fname
+	ja	srchex
+addext:	mov	ax, 'c.'
+	stosw
+	mov	ax, 'mo'
+	stosw
+extexs:	mov	[word di], 0a0dh
+	mov	[byte di+2], '$'
+	print	namtxt
+	print	fname
+	mov	[byte di], 0
+rts:	ret
+
+	smartdisk
+
+nousg:	print	srctxt
+	call	getfil
+	push	si
+
+	fopen
+	mov	cx, inplen
+	fread	inpbuf
+	mov	dx, offset lontxt
+	cmp	ax, inplen
+	je	panic
+	push	ax
+	add	[filend], ax
+	fclose
+	pop	cx
+
+	mov	dx, offset emptxt
+	jcxz	panic
+	mov	di, offset inpbuf
+	xor	al, al
+	repe	scasb
+	jne	spox
+panic:	print
+	int	20h
+
+spox:	dec	di
+	push	di
+	mov	[filbgn], di
+	sub	di, offset inpbuf
+	add	[destad], di
+	add	[reljad], di
+	lda	cx
+	inc	ax
+	call	prilen
+
+	pop	bx
+	mov	si, offset firflg
+	mov	di, offset outbuf
+
+pack1:	push	si di
+	mov	ax, 1
+	mov	bp, [filend]
+	lea	si, [bx-0ffh]
+	cmp	si, [filbgn]
+	jnb	pack2
+	mov	si, [filbgn]
+	cmp	si, bx
+	je	packn
+
+pack2:	mov	di, bx
+	mov	cx, bp
+	sub	cx, bx
+	push	si
+	repe	cmpsb
+	pop	si
+	je	pack3
+	dec	di
+pack3:	mov	cx, di
+	sub	cx, bx
+	cmp	cx, ax
+	jbe	pack4
+	lda	cx
+	mov	dx, si
+pack4:	inc	si
+	cmp	si, bx
+	jb	pack2
+
+packn:	pop	di si
+	mov	bp, ax
+	sta	cx
+	mov	ax, 1
+
+putfl1:	cmp	cx, 2
+	rcl	[byte si], 1
+	jnc	putfl2
+	mov	si, di
+	stosb
+putfl2:	loop	putfl1
+
+	cmp	bp, ax
+	mov	al, [bx]
+	je	putbyt
+	mov	al, dl
+	sub	al, bl
+putbyt:	stosb
+	mov	ah, 1
+	cmp	[si], ah
+	jne	swpflg
+	mov	[si], ax
+	inc	si
+swpflg:	add	bx, bp
+	cmp	bx, [filend]
+	jb	pack1
+
+	shl	[byte si], 1
+	jnc	corfl1
+	mov	al, 80h
+	stosb
+	jmp	corfl3
+corfl1:	stc
+corfl2:	rcl	[byte si], 1
+	jnc	corfl2
+corfl3:	rcl	[firflg], 1	;+
+	xor	al, al	
+	stosb
+
+	sub	di, offset depack
+	mov	[filend], di
+
+	print	pkdtxt
+	pop	di
+	mov	cx, 81h
+	add	cl, [80h]
+	sub	cx, di
+	jz	nowri
+	mov	al, ' '
+	repe	scasb
+	je	nowri
+	mov	ax, [filend]
+	inc	ah
+	cmp	ax, [destad]
+	ja	nospac
+
+	call	getfil
+	fcreate
+	mov	cx, [filend]
+	fwrite	depack
+	fclose
+
+nowri:	mov	ax, [filend]
+
+prilen:	mov	di, offset lenlst
+	mov	bx, 10
+outnm1:	xor	dx, dx
+	div	bx
+	add	dl, '0'
+outnm2:	mov	[di], dl
+	dec	di
+	test	ax, ax
+	jnz	outnm1
+	mov	dl, ' '
+	cmp	di, offset lennum
+	jnb	outnm2
+	print	lentxt
+	ret
+
+nospac:	mov	dx, offset zertxt
+	dos	9
+	jmp	nowri
+
+hello	db	'COMpack 1.0 by Fox/Taquart',eot
+usgtxt	db	'This is FREEWARE packer for .COM programs.',eol
+	db	'Syntax:',eol
+	db	'COMPACK inpfile [outfile]',eol
+	db	'"inpfile" specifies source path\filename',eol
+	db	'"outfile" specifies target path\filename',eol
+	db	'The ".COM" extension of filename is default and you don''t have to write it',eol
+	db	'If you don''t give "outfile" parameter, no file will be saved',eol
+	db	'and you can only watch the results of packing',eol
+zertxt	db	'If you want the file saved, you must compile some zero bytes at the beginning',eol
+	db	'of file to reserve the space for packed data. The code should immediately',eol
+	db	'follow the zeros.',eot
+
+srctxt	db	'Source file:',eot
+pkdtxt	db	'Packed file:',eot
+namtxt	db	'  Name: $'
+lentxt	db	'Length: '
+lennum	db	'    '
+lenlst	db	'  bytes',eot
+emptxt	db	'File is empty!',eot
+lontxt	db	'File is too long!',eot
+	smarterr
+
+filbgn	dw	inpbuf
+filend	dw	inpbuf
+
+depack:	mov	si, offset packed-depack+100h
+	mov	di, 100h
+destad	=	word $-2
+	mov	al, 1
+firflg	=	byte $-1
+	xor	cx, cx
+dep1:	movsb
+	dec	cx
+dep2:	inc	cx
+dep3:	add	al, al
+	jnz	dep4
+	lodsb
+	adc	al, al	;+
+dep4:	jnc	dep2
+	jcxz	dep1
+	sbb	bx, bx	;+
+	and	bl, [si]
+	db	0fh,84h		;jz near
+reljad	dw	depack-reljmp
+reljmp:	inc	si
+	inc	cx
+	push	si
+	lea	si, [di+bx]
+	rep	movsb
+	pop	si
+	jmp	dep3
+packed:
+
+outbuf	db	outlen dup(?)
+
+fname:
+
+inpbuf	db	inplen dup(?)
+
+	ENDS
+	END	start
\ No newline at end of file