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
|
/*
* Copyright (c) 2002-2003, Antonin Descampe
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "raw.h"
unsigned char raw_c; /* temporary buffer where bits are coded or decoded */
unsigned int raw_ct; /* number of bits already read or free to write */
unsigned int raw_lenmax; /* maximum length to decode */
unsigned int raw_len; /* length decoded */
unsigned char *raw_bp; /* pointer to the current position in the buffer */
unsigned char *raw_start; /* pointer to the start of the buffer */
unsigned char *raw_end; /* pointer to the end of the buffer */
/*
* Return the number of bytes already encoded.
*/
int raw_numbytes()
{
return raw_bp - raw_start;
}
/*
* Initialize raw-decoder.
*
* bp : pointer to the start of the buffer from which the bytes will be read
* len : length of the input buffer
*/
void raw_init_dec(unsigned char *bp, int len)
{
raw_start = bp;
raw_lenmax = len;
raw_len = 0;
raw_c = 0;
raw_ct = 0;
}
/*
* Decode a symbol using raw-decoder. Cfr p.506 TAUBMAN
*/
int raw_decode()
{
int d;
if (raw_ct == 0) {
raw_ct = 8;
if (raw_len == raw_lenmax)
raw_c = 0xff;
else {
if (raw_c == 0xff)
raw_ct = 7;
raw_c = *(raw_start + raw_len);
raw_len++;
}
}
raw_ct--;
d = (raw_c >> raw_ct) & 0x01;
return d;
}
|
