3 * Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
4 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
6 * This file is part of a52dec, a free ATSC A-52 stream decoder.
7 * See http://liba52.sourceforge.net/ for updates.
9 * Modified for use with MPlayer, changes contained in liba52_changes.diff.
10 * detailed changelog at http://svn.mplayerhq.hu/mplayer/trunk/
13 * a52dec is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * a52dec is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 /* code from ffmpeg/libavcodec */
29 #if defined(__GNUC__) && (__GNUC__ > 3 || __GNUC_ == 3 && __GNUC_MINOR__ > 0)
30 # define always_inline __attribute__((always_inline)) inline
32 # define always_inline inline
35 #if defined(__sparc__) || defined(hpux)
37 * the alt bitstream reader performs unaligned memory accesses; that doesn't work
38 * on sparc/hpux. For now, disable ALT_BITSTREAM_READER.
40 #undef ALT_BITSTREAM_READER
42 // alternative (faster) bitstram reader (reades upto 3 bytes over the end of the input)
43 #define ALT_BITSTREAM_READER
45 /* used to avoid misaligned exceptions on some archs (alpha, ...) */
46 #if defined (ARCH_X86) || defined(ARCH_ARMV4L)
47 # define unaligned32(a) (*(uint32_t*)(a))
50 static always_inline
uint32_t unaligned32(const void *v
) {
53 } __attribute__((packed
));
55 return ((const struct Unaligned
*) v
)->i
;
57 # elif defined(__DECC)
58 static inline uint32_t unaligned32(const void *v
) {
59 return *(const __unaligned
uint32_t *) v
;
62 static inline uint32_t unaligned32(const void *v
) {
63 return *(const uint32_t *) v
;
70 /* (stolen from the kernel) */
71 #ifdef WORDS_BIGENDIAN
73 # define swab32(x) (x)
77 # if defined (__i386__)
79 # define swab32(x) __i386_swab32(x)
80 static inline const uint32_t __i386_swab32(uint32_t x
)
82 __asm__("bswap %0" : "=r" (x
) : "0" (x
));
88 # define swab32(x) __generic_swab32(x)
89 static always_inline
const uint32_t __generic_swab32(uint32_t x
)
91 return ((((uint8_t*)&x
)[0] << 24) | (((uint8_t*)&x
)[1] << 16) |
92 (((uint8_t*)&x
)[2] << 8) | (((uint8_t*)&x
)[3]));
97 #ifdef ALT_BITSTREAM_READER
101 void a52_bitstream_set_ptr (a52_state_t
* state
, uint8_t * buf
);
102 uint32_t a52_bitstream_get_bh (a52_state_t
* state
, uint32_t num_bits
);
103 int32_t a52_bitstream_get_bh_2 (a52_state_t
* state
, uint32_t num_bits
);
105 static inline uint32_t bitstream_get (a52_state_t
* state
, uint32_t num_bits
)
107 #ifdef ALT_BITSTREAM_READER
108 uint32_t result
= swab32( unaligned32(((uint8_t *)state
->buffer_start
)+(indx
>>3)) );
110 result
<<= (indx
&0x07);
111 result
>>= 32 - num_bits
;
118 if (num_bits
< state
->bits_left
) {
119 result
= (state
->current_word
<< (32 - state
->bits_left
)) >> (32 - num_bits
);
120 state
->bits_left
-= num_bits
;
124 return a52_bitstream_get_bh (state
, num_bits
);
128 static inline void bitstream_skip(a52_state_t
* state
, int num_bits
)
130 #ifdef ALT_BITSTREAM_READER
133 bitstream_get(state
, num_bits
);
137 static inline int32_t bitstream_get_2 (a52_state_t
* state
, uint32_t num_bits
)
139 #ifdef ALT_BITSTREAM_READER
140 int32_t result
= swab32( unaligned32(((uint8_t *)state
->buffer_start
)+(indx
>>3)) );
142 result
<<= (indx
&0x07);
143 result
>>= 32 - num_bits
;
150 if (num_bits
< state
->bits_left
) {
151 result
= (((int32_t)state
->current_word
) << (32 - state
->bits_left
)) >> (32 - num_bits
);
152 state
->bits_left
-= num_bits
;
156 return a52_bitstream_get_bh_2 (state
, num_bits
);