apps/codecs/liba52/bitstream.h

   1 /*
   2  * bitstream.h
   3  * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
   4  * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
   5  *
   6  * This file is part of a52dec, a free ATSC A-52 stream decoder.
   7  * See http://liba52.sourceforge.net/ for updates.
   8  *
   9  * a52dec is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * a52dec is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  */
  23
  24 #define swab32(x) (betoh32(x))
  25
  26 void a52_bitstream_set_ptr (a52_state_t * state, uint8_t * buf);
  27 uint32_t a52_bitstream_get_bh (a52_state_t * state, uint32_t num_bits);
  28 int32_t a52_bitstream_get_bh_2 (a52_state_t * state, uint32_t num_bits);
  29
  30 static inline uint32_t bitstream_get (a52_state_t * state, uint32_t num_bits)
  31 {
  32     uint32_t result;
  33
  34     if (num_bits < state->bits_left) {
  35         result = (state->current_word << (32 - state->bits_left)) >> (32 - num_bits);
  36         state->bits_left -= num_bits;
  37         return result;
  38     }
  39
  40     return a52_bitstream_get_bh (state, num_bits);
  41 }
  42
  43 static inline int32_t bitstream_get_2 (a52_state_t * state, uint32_t num_bits)
  44 {
  45     int32_t result;
  46
  47     if (num_bits < state->bits_left) {
  48         result = (((int32_t)state->current_word) << (32 - state->bits_left)) >> (32 - num_bits);
  49         state->bits_left -= num_bits;
  50         return result;
  51     }
  52
  53     return a52_bitstream_get_bh_2 (state, num_bits);
  54 }