/src/kdegraphics-mobipocket/lib/bitreader_p.h
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1 | | // SPDX-FileCopyrightText: 2008 by Jakub Stachowski <qbast@go2.pl> |
2 | | // Huffdic decompressor based on Python code by Igor Skochinsky |
3 | | // SPDX-License-Identifier: GPL-2.0-or-later |
4 | | |
5 | | #include <QByteArray> |
6 | | #include <QtEndian> |
7 | | |
8 | | namespace Mobipocket |
9 | | { |
10 | | class BitReader |
11 | | { |
12 | | public: |
13 | | BitReader(QByteArrayView d) |
14 | 391 | : len(d.size() * 8) |
15 | 391 | , data(d) |
16 | 391 | { |
17 | 391 | } |
18 | | |
19 | | quint32 read() |
20 | 341 | { |
21 | 369 | while (rEndPos - pos < 32) { |
22 | | // r does not hold sufficient data, fetch some more |
23 | 95 | qint64 bytePos = rEndPos / 8; |
24 | | |
25 | 95 | if (len - rEndPos >= 32) { |
26 | 67 | r <<= 32; |
27 | 67 | r |= qFromBigEndian<quint32>(data.constData() + bytePos); |
28 | 67 | rEndPos += 32; |
29 | 67 | break; |
30 | 67 | } else if (len - rEndPos > 0) { |
31 | 14 | r <<= 8; |
32 | 14 | quint8 d = data.at(bytePos); |
33 | 14 | r |= d; |
34 | 14 | rEndPos += 8; |
35 | 14 | } else { |
36 | 14 | r <<= 8; |
37 | 14 | rEndPos += 8; |
38 | 14 | } |
39 | 95 | } |
40 | | |
41 | 341 | quint64 t = r << (64 - (rEndPos - pos)); |
42 | 341 | return t >> 32; |
43 | 341 | } |
44 | | |
45 | | bool eat(int n) |
46 | 323 | { |
47 | 323 | pos += n; |
48 | 323 | return pos <= len; |
49 | 323 | } |
50 | | |
51 | | int left() |
52 | 693 | { |
53 | 693 | return len - pos; |
54 | 693 | } |
55 | | |
56 | | private: |
57 | | quint64 r = 0; |
58 | | int pos = 0; |
59 | | int len = 0; |
60 | | int rEndPos = 0; //< position past the LSB of r |
61 | | QByteArrayView data; |
62 | | }; |
63 | | } // namespace Mobipocket |