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
|
/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program 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.
*
* This program 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#ifndef GLK_ALAN2_DECODE
#define GLK_ALAN2_DECODE
#include "glk/alan2/alan2.h"
#include "glk/alan2/acode.h"
#include "common/file.h"
namespace Glk {
namespace Alan2 {
// Structure for saved decode info
struct DecodeInfo {
long fpos;
int buffer;
int bits;
CodeValue value;
CodeValue high;
CodeValue low;
};
class Decode {
public:
Decode(Common::File *txtFile, Aword *freq): _txtFile(txtFile), _freq(freq) {}
void startDecoding();
int decodeChar();
/**
* Save so much about the decoding process, so it is possible to restore
* and continue later.
*/
DecodeInfo *pushDecode();
/**
* Restore enough info about the decoding process, so it is possible to
* continue after having decoded something else.
*/
void popDecode(DecodeInfo *info);
int inputBit();
private:
// Bit output
int _decodeBuffer; // Bits to be input
int _bitsToGo; // Bits still in buffer
int _garbageBits; // Bits past EOF
Aword *_freq;
Common::File *_txtFile;
// Current state of decoding
CodeValue _value; // Currently seen code value
CodeValue _low, _high; // Current code region
};
} // End of namespace Alan2
} // End of namespace Glk
#endif
|
