bitstream.h

来自「Sigma EM8300片（机顶盒上音视频编解码芯片）SDK」· C头文件 代码 · 共 47 行

/* 
 *  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. 
 *
 */


#include <inttypes.h>

extern uint32_t ac3bits_left;
extern uint64_t ac3current_word;

void bitstream_init(uint8_t *start);
inline 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 < ac3bits_left) {
		result = (ac3current_word << (64 - ac3bits_left)) >> (64 - num_bits);
		ac3bits_left -= num_bits;
		return result;
	}

	return bitstream_get_bh (num_bits);
}