apps/codecs/libffmpegFLAC/bitstream.c

   1 /*
   2  * Common bit i/o utils
   3  * Copyright (c) 2000, 2001 Fabrice Bellard.
   4  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
  21  */
  22
  23 /**
  24  * @file bitstream.c
  25  * bitstream api.
  26  */
  27
  28 #include <stdio.h>
  29 #include "bitstream.h"
  30
  31 /* bit input functions */
  32
  33 /**
  34  * reads 0-32 bits.
  35  */
  36 unsigned int get_bits_long(GetBitContext *s, int n){
  37     if(n<=17) return get_bits(s, n);
  38     else{
  39         int ret= get_bits(s, 16) << (n-16);
  40         return ret | get_bits(s, n-16);
  41     }
  42 }
  43
  44 /**
  45  * shows 0-32 bits.
  46  */
  47 unsigned int show_bits_long(GetBitContext *s, int n){
  48     if(n<=17) return show_bits(s, n);
  49     else{
  50         GetBitContext gb= *s;
  51         int ret= get_bits_long(s, n);
  52         *s= gb;
  53         return ret;
  54     }
  55 }
  56
  57 void align_get_bits(GetBitContext *s)
  58 {
  59     int n= (-get_bits_count(s)) & 7;
  60     if(n) skip_bits(s, n);
  61 }
  62