mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-21 06:50:44 +00:00
78 lines
2.2 KiB
C
78 lines
2.2 KiB
C
/*
|
|
* bitstream.h
|
|
* Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
|
|
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
|
|
*
|
|
* This file is part of a52dec, a free ATSC A-52 stream decoder.
|
|
* See http://liba52.sourceforge.net/ for updates.
|
|
*
|
|
* a52dec is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* a52dec is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
/* (stolen from the kernel) */
|
|
#ifdef WORDS_BIGENDIAN
|
|
|
|
# define swab32(x) (x)
|
|
|
|
#else
|
|
|
|
# if 0 && defined (__i386__)
|
|
|
|
# define swab32(x) __i386_swab32(x)
|
|
static inline const uint32_t __i386_swab32(uint32_t x)
|
|
{
|
|
__asm__("bswap %0" : "=r" (x) : "0" (x));
|
|
return x;
|
|
}
|
|
|
|
# else
|
|
|
|
# define swab32(x)\
|
|
((((uint8_t*)&x)[0] << 24) | (((uint8_t*)&x)[1] << 16) | \
|
|
(((uint8_t*)&x)[2] << 8) | (((uint8_t*)&x)[3]))
|
|
|
|
# endif
|
|
#endif
|
|
|
|
void a52_bitstream_set_ptr (a52_state_t * state, uint8_t * buf);
|
|
uint32_t a52_bitstream_get_bh (a52_state_t * state, uint32_t num_bits);
|
|
int32_t a52_bitstream_get_bh_2 (a52_state_t * state, uint32_t num_bits);
|
|
|
|
static inline uint32_t bitstream_get (a52_state_t * state, uint32_t num_bits)
|
|
{
|
|
uint32_t result;
|
|
|
|
if (num_bits < state->bits_left) {
|
|
result = (state->current_word << (32 - state->bits_left)) >> (32 - num_bits);
|
|
state->bits_left -= num_bits;
|
|
return result;
|
|
}
|
|
|
|
return a52_bitstream_get_bh (state, num_bits);
|
|
}
|
|
|
|
static inline int32_t bitstream_get_2 (a52_state_t * state, uint32_t num_bits)
|
|
{
|
|
int32_t result;
|
|
|
|
if (num_bits < state->bits_left) {
|
|
result = (((int32_t)state->current_word) << (32 - state->bits_left)) >> (32 - num_bits);
|
|
state->bits_left -= num_bits;
|
|
return result;
|
|
}
|
|
|
|
return a52_bitstream_get_bh_2 (state, num_bits);
|
|
}
|