mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-13 02:34:54 +00:00
69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
/*
|
|
* bitstream.h
|
|
*
|
|
* Copyright (C) Aaron Holtzman - Dec 1999
|
|
*
|
|
* This file is part of ac3dec, a free AC-3 audio decoder
|
|
*
|
|
* ac3dec 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, or (at your option)
|
|
* any later version.
|
|
*
|
|
* ac3dec 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 GNU Make; see the file COPYING. If not, write to
|
|
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*
|
|
*/
|
|
|
|
//My new and improved vego-matic endian swapping routine
|
|
//(stolen from the kernel)
|
|
#ifdef WORDS_BIGENDIAN
|
|
|
|
# define swab32(x) (x)
|
|
|
|
#else
|
|
|
|
# if 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
|
|
|
|
extern uint32_t bits_left;
|
|
extern uint32_t current_word;
|
|
|
|
void bitstream_set_ptr (uint8_t * buf);
|
|
uint32_t bitstream_get_bh(uint32_t num_bits);
|
|
|
|
static inline uint32_t
|
|
bitstream_get(uint32_t num_bits)
|
|
{
|
|
uint32_t result;
|
|
|
|
if(num_bits < bits_left) {
|
|
result = (current_word << (32 - bits_left)) >> (32 - num_bits);
|
|
bits_left -= num_bits;
|
|
return result;
|
|
}
|
|
|
|
return bitstream_get_bh(num_bits);
|
|
}
|