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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
/*
* bitstream.h: generic bitstream parsing
*
* See the main source file 'xineliboutput.c' for copyright information and
* how to reach the author.
*
* $Id: bitstream.h,v 1.2 2008-02-04 22:41:14 phintuka Exp $
*
*/
#ifndef _XINELIBOUTPUT_BITSTREAM_H_
#define _XINELIBOUTPUT_BITSTREAM_H_
#include <stdint.h>
# ifdef NOCACHE
typedef struct {
const uint8_t *data;
int count; /* in bits */
int index; /* in bits */
} br_state;
#define BR_INIT(data,bytes) { (data), 8*(bytes), 0 }
#define BR_EOF(br) ((br)->index >= (br)->count)
static inline void br_init(br_state *br, const uint8_t *data, int bytes)
{
br->data = data;
br->count = 8*bytes;
br->index = 0;
}
static inline int br_get_bit(br_state *br)
{
if(br->index >= br->count)
return 1; /* -> no infinite colomb's ... */
int r = (br->data[br->index>>3] >> (7 - (br->index&7))) & 1;
br->index++;
return r;
}
static inline uint32_t br_get_bits(br_state *br, uint32_t n)
{
uint32_t r = 0;
while(n--)
r = r | (br_get_bit(br) << n);
return r;
}
#define br_skip_bit(br) br_skip_bits(br,1)
static inline void br_skip_bits(br_state *br, int n)
{
br->index += n;
}
# else /* NOCACHE */
typedef struct {
uint8_t *data;
uint8_t *data_end;
uint32_t cache;
uint32_t cache_bits;
} br_state;
#define BR_INIT(data,bytes) { (data), (data)+(bytes), 0, 0 }
static inline void br_init(br_state *br, const uint8_t *data, int bytes)
{
br->data = data;
br->data_end = data + bytes;
br->cache = 0;
br->cache_bits = 0;
}
#define BR_GET_BYTE(br) \
(br->data < br->data_end ? *br->data++ : 0xff)
#define BR_EOF(br) ((br)->data >= (br)->data_end)
static inline uint32_t br_get_bits(br_state *br, uint32_t n)
{
if(n > 24)
return (br_get_bits(br, 16) << 16) | br_get_bits(br, n-16);
while (br->cache_bits < 24) {
br->cache = (br->cache<<8) | BR_GET_BYTE(br);
br->cache_bits += 8;
}
br->cache_bits -= n;
return (br->cache >> br->cache_bits) & ((1<<n) - 1);
}
static inline int br_get_bit(br_state *br)
{
if(!br->cache_bits) {
br->cache = BR_GET_BYTE(br);
br->cache_bits = 7;
} else {
br->cache_bits--;
}
return (br->cache >> br->cache_bits) & 1;
}
static inline void br_skip_bit(br_state *br)
{
if(!br->cache_bits) {
br->cache = BR_GET_BYTE(br);
br->cache_bits = 7;
} else {
br->cache_bits--;
}
}
static inline void br_skip_bits(br_state *br, int n)
{
if(br->cache_bits >= n) {
br->cache_bits -= n;
} else {
/* drop cached bits */
n -= br->cache_bits;
/* drop full bytes */
br->data += (n >> 3);
n &= 7;
/* update cache */
if(n) {
br->cache = BR_GET_BYTE(br);
br->cache_bits = 8 - n;
} else {
br->cache_bits = 0;
}
}
}
# endif /* NOCACHE */
#define br_get_u8(br) br_get_bits(br, 8)
#define br_get_u16(br) ((br_get_bits(br, 8)<<8) | br_get_bits(br, 8))
static inline uint32_t br_get_ue_golomb(br_state *br)
{
int n = 0;
while (!br_get_bit(br) && n < 32)
n++;
return n ? ((1<<n) - 1) + br_get_bits(br, n) : 0;
}
static inline int32_t br_get_se_golomb(br_state *br)
{
uint32_t r = br_get_ue_golomb(br) + 1;
return (r&1) ? -(r>>1) : (r>>1);
}
static inline void br_skip_golomb(br_state *br)
{
int n = 0;
while (!br_get_bit(br) && n < 32)
n++;
br_skip_bits(br, n);
}
#define br_skip_ue_golomb(br) br_skip_golomb(br)
#define br_skip_se_golomb(br) br_skip_golomb(br)
#endif /* _XINELIBOUTPUT_BITSTREAM_H_ */
|
