modules/demux/mp4/minibox.h

   1 /*****************************************************************************
   2  * minibox.h: minimal mp4 box iterator
   3  *****************************************************************************
   4  * Copyright (C) 2017 VideoLabs, VLC authors and VideoLAN
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program 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
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 typedef struct
  22 {
  23     const uint8_t *p_buffer;
  24     size_t i_buffer;
  25     const uint8_t *p_payload;
  26     size_t i_payload;
  27     vlc_fourcc_t i_type;
  28 } mp4_box_iterator_t;
  29
  30 static void mp4_box_iterator_Init( mp4_box_iterator_t *p_it,
  31                                    const uint8_t *p_data, size_t i_data )
  32 {
  33     p_it->p_buffer = p_data;
  34     p_it->i_buffer = i_data;
  35 }
  36
  37 static bool mp4_box_iterator_Next( mp4_box_iterator_t *p_it )
  38 {
  39     while( p_it->i_buffer > 8 )
  40     {
  41         const uint8_t *p = p_it->p_buffer;
  42         const size_t i_size = GetDWBE( p );
  43         p_it->i_type = VLC_FOURCC(p[4], p[5], p[6], p[7]);
  44         if( i_size >= 8 && i_size <= p_it->i_buffer )
  45         {
  46             p_it->p_payload = &p_it->p_buffer[8];
  47             p_it->i_payload = i_size - 8;
  48             /* update for next run */
  49             p_it->p_buffer += i_size;
  50             p_it->i_buffer -= i_size;
  51             return true;
  52         }
  53         else break;
  54     }
  55     return false;
  56 }