--- bitstream.h	2002/11/26 23:44:10	1.15
+++ 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 1.15 2002/11/26 23:44:10 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"
@@ -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;
 }
 
 
@@ -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;
 }