From 36c824864c02f0a3f62c8a1d365d1670835c8c96 Mon Sep 17 00:00:00 2001
From: "Christian A. Weber" <chris@gna.ch>
Date: Tue, 12 May 1992 22:26:12 +0000
Subject: Initial revision

---
 Source/FindChunk.S | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 Source/FindChunk.S

(limited to 'Source/FindChunk.S')

diff --git a/Source/FindChunk.S b/Source/FindChunk.S
new file mode 100644
index 0000000..2ddea63
--- /dev/null
+++ b/Source/FindChunk.S
@@ -0,0 +1,83 @@
+**
+**	$Id: $
+**	$Revision: $
+**
+**	$Filename: FindChunk.S $
+**	$Author: Christian A. Weber $
+**	$Release: 19.1 $
+**	$Date: 92/05/11 21:11:27 $
+**
+**	iff.library/IFFLib_FindChunk
+**
+**	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	IFFLib_FindChunk
+		SECTION	text,CODE
+
+		INCLUDE	"IffLib.i"
+
+		XDEF	FindChunkFunc
+
+
+******* iff.library/IFFLib_FindChunk ****************************************
+*
+*   NAME
+*	IFFLib_FindChunk -- find an IFF-chunk
+*
+*   SYNOPSIS
+*	chunk = IFFLib_FindChunk( ifffile, chunkname )
+*	 D0                       A1       D0
+*
+*	APTR IFFLib_FindChunk( IFFFILE, ULONG )
+*
+*   FUNCTION
+*	Find a specific chunk in an IFF file
+*
+*   INPUTS
+*	ifffile - pointer to a FORM, normally the result of OpenIFF()
+*	chunkname - 4 characters packed ASCII ('BODY', 'VHDR' ...)
+*	            if chunkname is 0, FindChunk() returns a pointer to the
+*	            first byte after the end of the current FORM. This can
+*	            be used byANIM readers for jumping from FORM to FORM.
+*
+*   RESULTS
+*	Pointer to the beginning of the chunk (that means to the chunk
+*	name itself, followed by the chunk size); zero if chunk not found
+*
+*   BUGS
+*	none known
+*
+*   SEE ALSO
+*	IFFLib_GetBMHD(), IFFLib_GetColorTab()
+*
+*****************************************************************************
+
+FindChunkFunc:	movea.l	4(a1),a0	; FORM-Länge
+		addq.l	#8,a1		; FORM.... überspringen
+		adda.l	a1,a0		; A0 zeigt jetzt ans Ende
+		addq.l	#4,a1		; FORM-Typ überspringen
+		tst.l	d0		; Chunk-ID == 0 ?
+		bne.s	1$		; nein --->
+		movea.l	a0,a1		; Sonst Ende des FORMs
+		bra.s	99$		; zurückgeben
+
+1$:		cmp.l	(a1),d0		; Chunk gefunden ?
+		beq.s	99$		; ja!
+		move.l	4(a1),d1	; Länge dieses Chunks
+		addq.l	#1,d1		; auf WORD ...
+		bclr	#0,d1		; ... aufrunden
+		lea	8(a1,d1.l),a1	; Name & Länge dazu und zu A1 dazu
+		cmpa.l	a0,a1		; FORM-Ende erreicht ?
+		bcs.s	1$		; noch nicht --->
+		suba.l	a1,a1		; Code für "nicht gefunden"
+99$:
+		move.l	a1,d0		; Resultat nach D0, set/reset Z-Flag
+		rts
+
+		END
-- 
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