summaryrefslogtreecommitdiff
path: root/Source/PopChunk.S
blob: ae0d00113980ee3de3954105600de1f8116a296a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
**
**	$Id: $
**	$Revision: $
**
**	$Filename: PopChunk.S $
**	$Author: Christian A. Weber $
**	$Release: 21.1 $
**	$Date: 92/05/14 22:26:34 $
**
**	iff.library/IFFL_PopChunk
**
**	COPYRIGHT (C) 1987-1992 BY CHRISTIAN A. WEBER, BRUGGERWEG 2,
**	CH-8037 ZUERICH, SWITZERLAND.  ALL RIGHTS RESERVED.  NO PART
**	OF THIS SOFTWARE MAY BE COPIED, REPRODUCED,  OR  TRANSMITTED
**	IN ANY FORM OR BY ANY MEANS,  WITHOUT THE PRIOR WRITTEN PER-
**	MISSION OF THE AUTHOR. USE AT YOUR OWN RISK.
**


		IDNT	IFFL_PopChunk
		SECTION	text,CODE

		INCLUDE	"IffLib.i"

		XREF	SetError,ClearError
		XDEF	PopChunkFunc


******* iff.library/IFFL_PopChunk *******************************************
*
*    NAME
*	IFFL_PopChunk -- Pop top context node off context stack.
*
*    SYNOPSIS
*	success = IFFL_PopChunk( iff )
*	D0                       A0
*
*	BOOL IFFL_PopChunk( IFFL_HANDLE )
*
*    FUNCTION
*	Pops top context chunk and updates the file accordingly.
*	The function is normally called only for writing files and signals
*	the end of a chunk.
*
*    INPUTS
*	iff - IFF handle
*
*    RESULTS
*	Non-zero  if successful or 0 if not successful (call IFFL_IFFError()
*	to get an IFFL_ERROR_... error code.
*
*    SEE ALSO
*	IFFL_PushChunk(), IFFL_WriteChunkBytes()
*
*****************************************************************************

PopChunkFunc:	movem.l	d2-d3/a2/a5-a6,-(SP)
		movea.l	a6,a5			; IFFBase für ClearError()
		movea.l	a0,a2			; A2 :  IFF-Handle
		movea.l	iffb_DOSBase(a5),a6	; A6 :  DOSBase

	*** Pad-Byte schreiben falls Chunk-Länge ungerade ist

		btst.b	#0,ifffh_ChunkSize+3(a2)
		beq.b	.NoOddChunkSize

		move.l	ifffh_File(a2),d1
		move.l	a2,d2			; Hier hat's ein 0 Byte
		moveq.l	#1,d3			; Länge: 1 Byte
		JSRLIB	Write
		cmp.l	d3,d0
		bne.b	.WriteError
		add.l	d3,ifffh_ChunkSize(a2)
.NoOddChunkSize:

	*** FORM-Grösse += Chunk-Grösse

		moveq.l	#8,d0			; Chunkheadersize
		add.l	ifffh_ChunkSize(a2),d0	; plus Chunksize
		add.l	d0,ifffh_FormSize(a2)	; zur Form-Size dazu

	*** An den Anfang des Chunks seeken

		move.l	ifffh_File(a2),d1
		moveq.l	#4,d2			; Grössen-Eintrag im Chunk-Header
		add.l	ifffh_ChunkFPos(a2),d2	; Plus Chunk-Anfang
		moveq.l	#OFFSET_BEGINNING,d3
		JSRLIB	Seek
		tst.l	d0
		bmi.b	.SeekError

	*** Richtige Chunk-Grösse eintragen

		move.l	ifffh_File(a2),d1
		lea	ifffh_ChunkSize(a2),a0
		move.l	a0,d2
		moveq.l	#4,d3			; 1 Langwort
		JSRLIB	Write			; schreiben
		cmp.l	d3,d0
		beq.b	.WriteError

	*** An das Ende des Chunks seeken

		move.l	ifffh_File(a2),d1
		moveq.l	#0,d2
		moveq.l	#OFFSET_END,d3
		JSRLIB	Seek
		tst.l	d0
		bmi.b	.SeekError

	*** Okay

		bsr	ClearError		; Setzt auch D0 auf TRUE
		bra.b	.End

	*** Schreibfehler oder Seekfehler

.SeekError:
.WriteError:	moveq.l	#IFFL_ERROR_WRITE,d0
		bsr	SetError		; Setzt auch D0 auf FALSE

	*** Routine beenden

.End:		movem.l	(SP)+,d2-d3/a2/a5-a6
		rts


		END