1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/*
* bitstream.h
* Copyright (C) 2000-2002 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.
*
* Modified for use with MPlayer, changes contained in liba52_changes.diff.
* detailed changelog at http://svn.mplayerhq.hu/mplayer/trunk/
* $Id$
*
* 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
*/
/* code from ffmpeg/libavcodec */
#if defined(__sparc__) || defined(hpux)
/*
* the alt bitstream reader performs unaligned memory accesses; that doesn't work
* on sparc/hpux. For now, disable ALT_BITSTREAM_READER.
*/
#undef ALT_BITSTREAM_READER
#else
// alternative (faster) bitstram reader (reades upto 3 bytes over the end of the input)
#define ALT_BITSTREAM_READER
/* used to avoid misaligned exceptions on some archs (alpha, ...) */
#if ARCH_X86 || HAVE_ARMV6
# define unaligned32(a) (*(uint32_t*)(a))
#else
# ifdef __GNUC__
static inline uint32_t unaligned32(const void *v) {
struct Unaligned {
uint32_t i;
} __attribute__((packed));
return ((const struct Unaligned *) v)->i;
}
# elif defined(__DECC)
static inline uint32_t unaligned32(const void *v) {
return *(const __unaligned uint32_t *) v;
}
# else
static inline uint32_t unaligned32(const void *v) {
return *(const uint32_t *) v;
}
# endif
#endif //!ARCH_X86
#endif
/* (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) __generic_swab32(x)
static inline const uint32_t __generic_swab32(uint32_t x)
{
return ((((uint8_t*)&x)[0] << 24) | (((uint8_t*)&x)[1] << 16) |
(((uint8_t*)&x)[2] << 8) | (((uint8_t*)&x)[3]));
}
# endif
#endif
#ifdef ALT_BITSTREAM_READER
extern int indx;
#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)
{
#ifdef ALT_BITSTREAM_READER
uint32_t result= swab32( unaligned32(((uint8_t *)state->buffer_start)+(indx>>3)) );
result<<= (indx&0x07);
result>>= 32 - num_bits;
indx+= num_bits;
return result;
#else
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);
#endif
}
static inline void bitstream_skip(a52_state_t * state, int num_bits)
{
#ifdef ALT_BITSTREAM_READER
indx+= num_bits;
#else
bitstream_get(state, num_bits);
#endif
}
static inline int32_t bitstream_get_2 (a52_state_t * state, uint32_t num_bits)
{
#ifdef ALT_BITSTREAM_READER
int32_t result= swab32( unaligned32(((uint8_t *)state->buffer_start)+(indx>>3)) );
result<<= (indx&0x07);
result>>= 32 - num_bits;
indx+= num_bits;
return result;
#else
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);
#endif
}
|
