www.pudn.com > jm50g.zip > golomb_dec.c

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* Copyright 2001, International Telecommunications Union, Geneva 
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/* 
 ************************************************************************************* 
 * \file 
 *    golomb_dec.c 
 * 
 * \brief 
 *    Description 
 * 
 * \author 
 *    Main contributors (see contributors.h for copyright, address and affiliation details) 
 *     -  Achim Dahlhoff       
 * 
 * \date 
 *    Fri Mar 8 2002 
 * 
 *  copyright : (C) 2002      Institut und Lehrstuhl für Nachrichtentechnik 
 *                            RWTH Aachen University 
 *                            52072 Aachen 
 *                            Germany 
 ************************************************************************************* 
 */ 
 
#include  
#include "golomb_dec.h" 
 
unsigned int decode_golomb_word(const unsigned char **buffer,unsigned int *bitoff,unsigned int grad0,unsigned int max_levels) 
{ 
  const unsigned char *rd; 
  unsigned int bit,byte,level,databits,t,testbit; 
  rd=*buffer; 
  bit=*bitoff; 
  byte=*rd; 
  level=0UL; 
  while( level+1UL>bit)&1UL) ; 
    bit = (bit-1UL) & 7UL ; 
    if(bit==7UL)byte=*(++rd); 
  } 
  *buffer=rd; 
  *bitoff=bit; 
  return (((1UL<bitstream; 
  frame_bitoffset = currStream->frame_bitoffset; 
  buf = (unsigned char*)currStream->streamBuffer; 
  BitstreamLengthInBytes = currStream->bitstream_length; 
 
  bit=7UL-(frame_bitoffset&7); 
  read=buf+(frame_bitoffset>>3); 
 
  if(!( se->golomb_maxlevels&~0xFF )) 
  { 
    se->value1=decode_golomb_word(&read,&bit,se->golomb_grad,se->golomb_maxlevels); 
  }else{ 
    for(i=0UL;i<4UL;i++) 
    { 
      grad[i]=(se->golomb_grad>>(i<<3))&0xFFUL; 
      max_lev[i]=(se->golomb_maxlevels>>(i<<3))&0xFFUL; 
    } 
    se->value1=decode_multilayer_golomb_word(&read,&bit,grad,max_lev); 
  } 
  se->len=(((read-buf)<<3)+(7-bit))-frame_bitoffset; 
 
  se->value2=0; 
 
  currStream->frame_bitoffset += se->len; 
 
  return 1; 
}