www.pudn.com > mediator15src.zip > bitstream.h

/* 
 * bitstream.h 
 * Copyright (C) 2000-2002 Michel Lespinasse  
 * Copyright (C) 1999-2000 Aaron Holtzman  
 * 
 * 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 
 
extern uint32_t a52_bits_left; 
extern uint32_t a52_current_word; 
 
void a52_bitstream_set_ptr (uint8_t * buf); 
uint32_t a52_bitstream_get_bh(uint32_t num_bits); 
int32_t a52_bitstream_get_bh_2(uint32_t num_bits); 
 
__inline static uint32_t  
bitstream_get(uint32_t num_bits) 
{ 
    uint32_t result; 
	 
    if(num_bits < a52_bits_left) { 
	result = (a52_current_word << (32 - a52_bits_left)) >> (32 - num_bits); 
	a52_bits_left -= num_bits; 
	return result; 
    } 
 
    return a52_bitstream_get_bh(num_bits); 
} 
 
__inline static int32_t  
bitstream_get_2(uint32_t num_bits) 
{ 
    int32_t result; 
	 
    if(num_bits < a52_bits_left) { 
	result = (((int32_t)a52_current_word) << (32 - a52_bits_left)) >> (32 - num_bits); 
	a52_bits_left -= num_bits; 
	return result; 
    } 
 
    return a52_bitstream_get_bh_2(num_bits); 
}