modules/mux/mpeg/bits.h

   1 /*****************************************************************************
   2  * bits.h
   3  *****************************************************************************
   4  * Copyright (C) 2001, 2002 VLC authors and VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
   8  *          Eric Petit <titer@videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 typedef struct bits_buffer_s
  26 {
  27     int     i_size;
  28
  29     int     i_data;
  30     uint8_t i_mask;
  31     uint8_t *p_data;
  32
  33 } bits_buffer_t;
  34
  35 static inline int bits_initwrite( bits_buffer_t *p_buffer,
  36                                   int i_size, void *p_data )
  37 {
  38     p_buffer->i_size = i_size;
  39     p_buffer->i_data = 0;
  40     p_buffer->i_mask = 0x80;
  41     p_buffer->p_data = p_data;
  42     if( !p_buffer->p_data )
  43     {
  44         if( !( p_buffer->p_data = malloc( i_size ) ) )
  45             return -1;
  46     }
  47     p_buffer->p_data[0] = 0;
  48     return 0;
  49 }
  50
  51 static inline void bits_align( bits_buffer_t *p_buffer )
  52 {
  53     if( p_buffer->i_mask != 0x80 && p_buffer->i_data < p_buffer->i_size )
  54     {
  55         p_buffer->i_mask = 0x80;
  56         p_buffer->i_data++;
  57         p_buffer->p_data[p_buffer->i_data] = 0x00;
  58     }
  59 }
  60
  61 static inline void bits_write( bits_buffer_t *p_buffer,
  62                                int i_count, uint64_t i_bits )
  63 {
  64     while( i_count > 0 )
  65     {
  66         i_count--;
  67
  68         if( ( i_bits >> i_count )&0x01 )
  69         {
  70             p_buffer->p_data[p_buffer->i_data] |= p_buffer->i_mask;
  71         }
  72         else
  73         {
  74             p_buffer->p_data[p_buffer->i_data] &= ~p_buffer->i_mask;
  75         }
  76         p_buffer->i_mask >>= 1;
  77         if( p_buffer->i_mask == 0 )
  78         {
  79             p_buffer->i_data++;
  80             p_buffer->i_mask = 0x80;
  81         }
  82     }
  83 }
  84
  85