www.pudn.com > mpeg4_DECORE.rar > GETBITS.C

/************************************************************************ 
 * 
 *  getbits.c, bit level routines for tmndecode (H.263 decoder) 
 *  Copyright (C) 1995, 1996  Telenor R&D, Norway 
 * 
 *  Contacts: 
 *  Robert Danielsen                   
 * 
 *  Telenor Research and Development  http://www.nta.no/brukere/DVC/ 
 *  P.O.Box 83                        tel.:   +47 63 84 84 00 
 *  N-2007 Kjeller, Norway            fax.:   +47 63 81 00 76 
 * 
 *  Copyright (C) 1997  University of BC, Canada 
 *  Modified by: Michael Gallant  
 *               Guy Cote  
 *               Berna Erol  
 * 
 *  Contacts: 
 *  Michael Gallant                    
 * 
 *  UBC Image Processing Laboratory   http://www.ee.ubc.ca/image 
 *  2356 Main Mall                    tel.: +1 604 822 4051 
 *  Vancouver BC Canada V6T1Z4        fax.: +1 604 822 5949 
 * 
 ************************************************************************/ 
 
/* Disclaimer of Warranty 
 *  
 * These software programs are available to the user without any license fee 
 * or royalty on an "as is" basis. The University of British Columbia 
 * disclaims any and all warranties, whether express, implied, or 
 * statuary, including any implied warranties or merchantability or of 
 * fitness for a particular purpose.  In no event shall the 
 * copyright-holder be liable for any incidental, punitive, or 
 * consequential damages of any kind whatsoever arising from the use of 
 * these programs. 
 *  
 * This disclaimer of warranty extends to the user of these programs and 
 * user's customers, employees, agents, transferees, successors, and 
 * assigns. 
 *  
 * The University of British Columbia does not represent or warrant that the 
 * programs furnished hereunder are free of infringement of any 
 * third-party patents. 
 *  
 * Commercial implementations of H.263, including shareware, are subject to 
 * royalty fees to patent holders.  Many of these patents are general 
 * enough such that they are unavoidable regardless of implementation 
 * design. 
 *  
 */ 
 
 
/* based on mpeg2decode, (C) 1994, MPEG Software Simulation Group and 
 * mpeg2play, (C) 1994 Stefan Eckart  
 *  
 */ 
 
/** 
*  Copyright (C) 2001 - Project Mayo 
 * 
 * adapted by Andrea Graziani (Ag) 
 * 
 * DivX Advanced Research Center  
* 
**/ 
 
#include  
 
#include "mp4_vars.h" 
 
#include "getbits.h" 
 
#define SE_CODE 31 
 
 
/* initialize buffer, call once before first getbits or showbits */ 
 
void initbits (unsigned char * stream, int length) 
{ 
  ld->incnt = 0; 
  ld->bitcnt = 0; 
  ld->rdptr = ld->rdbfr + 2048; 
 
#ifdef _DECORE 
  ld->rdptr = stream; 
	ld->length = length; 
#endif 
} 
 
/* return next bit (could be made faster than getbits(1)) */ 
 
unsigned int getbits1 () 
{ 
  return getbits (1); 
} 
 
/* return next n bits (right adjusted) */