--- bitstream.h	2002/11/17 00:57:57	1.14
+++ bitstream.h	2003/04/04 22:12:07	1.16.2.1
@@ -50,13 +50,15 @@
  *  exception also makes it possible to release a modified version which
  *  carries forward this exception.
  *
- * $Id: bitstream.h,v 1.14 2002/11/17 00:57:57 edgomez Exp $
+ * $Id: bitstream.h,v 1.16.2.1 2003/04/04 22:12:07 edgomez Exp $
  *
  ****************************************************************************/
 
 #ifndef _BITSTREAM_H_
 #define _BITSTREAM_H_
 
+#include <stdio.h>
+
 #include "../portab.h"
 #include "../decoder.h"
 #include "../encoder.h"
@@ -66,7 +68,7 @@
  * Constants
  ****************************************************************************/
 
-// comment any #defs we dont use
+/* comment any #defs we dont use */
 
 #define VIDOBJ_START_CODE		0x00000100	/* ..0x0000011f  */
 #define VIDOBJLAY_START_CODE	0x00000120	/* ..0x0000012f */
@@ -74,30 +76,30 @@
 #define VISOBJSEQ_STOP_CODE		0x000001b1	/* ??? */
 #define USERDATA_START_CODE		0x000001b2
 #define GRPOFVOP_START_CODE		0x000001b3
-//#define VIDSESERR_ERROR_CODE  0x000001b4
+/*#define VIDSESERR_ERROR_CODE  0x000001b4 */
 #define VISOBJ_START_CODE		0x000001b5
-//#define SLICE_START_CODE      0x000001b7
-//#define EXT_START_CODE        0x000001b8
+/*#define SLICE_START_CODE      0x000001b7 */
+/*#define EXT_START_CODE        0x000001b8 */
 
 
 #define VISOBJ_TYPE_VIDEO				1
-//#define VISOBJ_TYPE_STILLTEXTURE      2
-//#define VISOBJ_TYPE_MESH              3
-//#define VISOBJ_TYPE_FBA               4
-//#define VISOBJ_TYPE_3DMESH            5
+/*#define VISOBJ_TYPE_STILLTEXTURE      2 */
+/*#define VISOBJ_TYPE_MESH              3 */
+/*#define VISOBJ_TYPE_FBA               4 */
+/*#define VISOBJ_TYPE_3DMESH            5 */
 
 
 #define VIDOBJLAY_TYPE_SIMPLE			1
-//#define VIDOBJLAY_TYPE_SIMPLE_SCALABLE    2
+/*#define VIDOBJLAY_TYPE_SIMPLE_SCALABLE    2 */
 #define VIDOBJLAY_TYPE_CORE				3
 #define VIDOBJLAY_TYPE_MAIN				4
 
 
-//#define VIDOBJLAY_AR_SQUARE           1
-//#define VIDOBJLAY_AR_625TYPE_43       2
-//#define VIDOBJLAY_AR_525TYPE_43       3
-//#define VIDOBJLAY_AR_625TYPE_169      8
-//#define VIDOBJLAY_AR_525TYPE_169      9
+/*#define VIDOBJLAY_AR_SQUARE           1 */
+/*#define VIDOBJLAY_AR_625TYPE_43       2 */
+/*#define VIDOBJLAY_AR_525TYPE_43       3 */
+/*#define VIDOBJLAY_AR_625TYPE_169      8 */
+/*#define VIDOBJLAY_AR_525TYPE_169      9 */
 #define VIDOBJLAY_AR_EXTPAR				15
 
 
@@ -113,15 +115,15 @@
 #define READ_MARKER()	BitstreamSkip(bs, 1)
 #define WRITE_MARKER()	BitstreamPutBit(bs, 1)
 
-// vop coding types 
-// intra, prediction, backward, sprite, not_coded
+/* vop coding types  */
+/* intra, prediction, backward, sprite, not_coded */
 #define I_VOP	0
 #define P_VOP	1
 #define B_VOP	2
 #define S_VOP	3
 #define N_VOP	4
 
-// resync-specific
+/* resync-specific */
 #define NUMBITS_VP_RESYNC_MARKER  17
 #define RESYNC_MARKER 1
 
@@ -134,7 +136,7 @@
 read_video_packet_header(Bitstream *bs, const int addbits, int * quant);
 
 
-// header stuff
+/* header stuff */
 int BitstreamReadHeaders(Bitstream * bs,
 						 DECODER * dec,
 						 uint32_t * rounding,
@@ -165,23 +167,31 @@
 			  uint32_t length)
 {
 	uint32_t tmp;
+	size_t bitpos;
+	ptr_t adjbitstream = (ptr_t)bitstream;
 
-	bs->start = bs->tail = (uint32_t *) bitstream;
+	/*
+	 * Start the stream on a uint32_t boundary, by rounding down to the
+	 * previous uint32_t and skipping the intervening bytes.
+	 */
+	bitpos = ((sizeof(uint32_t)-1) & (size_t)bitstream);
+	adjbitstream = adjbitstream - bitpos;
+	bs->start = bs->tail = (uint32_t *) adjbitstream;
 
-	tmp = *(uint32_t *) bitstream;
+	tmp = *bs->start;
 #ifndef ARCH_IS_BIG_ENDIAN
 	BSWAP(tmp);
 #endif
 	bs->bufa = tmp;
 
-	tmp = *((uint32_t *) bitstream + 1);
+	tmp = *(bs->start + 1);
 #ifndef ARCH_IS_BIG_ENDIAN
 	BSWAP(tmp);
 #endif
 	bs->bufb = tmp;
 
 	bs->buf = 0;
-	bs->pos = 0;
+	bs->pos = bs->initpos = bitpos*8;
 	bs->length = length;
 }
 
@@ -208,7 +218,7 @@
 	bs->bufb = tmp;
 
 	bs->buf = 0;
-	bs->pos = 0;
+	bs->pos = bs->initpos;
 }
 
 
@@ -253,7 +263,7 @@
 }
 
 
-// number of bits to next byte alignment
+/* number of bits to next byte alignment */
 static uint32_t __inline
 BitstreamNumBitsToByteAlign(Bitstream *bs)
 {
@@ -262,7 +272,7 @@
 }
 
 
-// show nbits from next byte alignment
+/* show nbits from next byte alignment */
 static uint32_t __inline
 BitstreamShowBitsFromByteAlign(Bitstream *bs, int bits)
 {
@@ -301,7 +311,7 @@
 static uint32_t __inline
 BitstreamPos(const Bitstream * const bs)
 {
-	return 8 * ((ptr_t)bs->tail - (ptr_t)bs->start) + bs->pos;
+	return((uint32_t)(8*((ptr_t)bs->tail - (ptr_t)bs->start) + bs->pos - bs->initpos));
 }
 
 
@@ -312,7 +322,7 @@
 static uint32_t __inline
 BitstreamLength(Bitstream * const bs)
 {
-	uint32_t len = (ptr_t) bs->tail - (ptr_t) bs->start;
+	uint32_t len = (uint32_t)((ptr_t)bs->tail - (ptr_t)bs->start);
 
 	if (bs->pos) {
 		uint32_t b = bs->buf;
@@ -325,6 +335,10 @@
 		len += (bs->pos + 7) / 8;
 	}
 
+	/* initpos is always on a byte boundary */
+	if (bs->initpos)
+		len -= bs->initpos/8;
+
 	return len;
 }