Baloo

coding.cpp
1/*
2 This file is part of the KDE Baloo project.
3 SPDX-FileCopyrightText: 2015 Vishesh Handa <vhanda@kde.org>
4 SPDX-FileCopyrightText: 2011 The LevelDB Authors. All rights reserved.
5
6 SPDX-License-Identifier: LGPL-2.1-or-later AND BSD-3-Clause
7*/
8
9#include "coding.h"
10
11namespace Baloo {
12
13static inline int encodeVarint32Internal(char* dst, quint32 v) {
14 // Operate on characters as unsigneds
15 unsigned char* ptr = reinterpret_cast<unsigned char*>(dst);
16 static const int B = 128;
17 if (v < (1<<7)) {
18 ptr[0] = v;
19 return 1;
20 }
21 if (v < (1<<14)) {
22 ptr[0] = v | B;
23 ptr[1] = v>>7;
24 return 2;
25 }
26 if (v < (1<<21)) {
27 ptr[0] = v | B;
28 ptr[1] = (v>>7) | B;
29 ptr[2] = v>>14;
30 return 3;
31 }
32 if (v < (1<<28)) {
33 ptr[0] = v | B;
34 ptr[1] = (v>>7) | B;
35 ptr[2] = (v>>14) | B;
36 ptr[3] = v>>21;
37 return 4;
38 }
39
40 ptr[0] = v | B;
41 ptr[1] = (v>>7) | B;
42 ptr[2] = (v>>14) | B;
43 ptr[3] = (v>>21) | B;
44 ptr[4] = v>>28;
45 return 5;
46}
47
48static inline void putVarint32Internal(char* dst, quint32 v, int &pos)
49{
50 pos += encodeVarint32Internal(&dst[pos], v);
51}
52
53void putDifferentialVarInt32(QByteArray &temporaryStorage, QByteArray* dst, const QVector<quint32>& values)
54{
55 temporaryStorage.resize((values.size() + 1) * 5); // max size, correct size will be held in pos
56 int pos = 0;
57 putVarint32Internal(temporaryStorage.data(), values.size(), pos);
58
59 quint32 v = 0;
60 const auto itEnd = values.cend();
61 for (auto it = values.cbegin(); it != itEnd; ++it) {
62 const quint32 n = *it;
63 putVarint32Internal(temporaryStorage.data(), n - v, pos);
64 v = n;
65 }
66 dst->append(temporaryStorage.constData(), pos);
67}
68
69char* getDifferentialVarInt32(char* p, char* limit, QVector<quint32>* values)
70{
71 quint32 size = 0;
72 p = getVarint32Ptr(p, limit, &size);
73 values->resize(size);
74
75 auto it = values->begin();
76 auto end = values->end();
77
78 quint32 v = 0;
79 while (p && it != end) {
80 quint32 n = 0;
81 p = getVarint32Ptr(p, limit, &n);
82
83 *it = (n + v);
84 v += n;
85 ++it;
86 }
87 values->erase(it, end);
88
89 return p;
90}
91
92char* getVarint32PtrFallback(char* p, char* limit, quint32* value)
93{
94 quint32 result = 0;
95 for (quint32 shift = 0; shift <= 28 && p < limit; shift += 7) {
96 quint32 byte = *(reinterpret_cast<const unsigned char*>(p));
97 p++;
98 if (byte & 128) {
99 // More bytes are present
100 result |= ((byte & 127) << shift);
101 } else {
102 result |= (byte << shift);
103 *value = result;
104 return p;
105 }
106 }
107 return nullptr;
108}
109
110}
Implements storage for docIds without any associated data Instantiated for:
Definition coding.cpp:11
const char * constData() const const
char * data()
void resize(qsizetype newSize, char c)
iterator begin()
const_iterator cbegin() const const
const_iterator cend() const const
iterator end()
iterator erase(const_iterator begin, const_iterator end)
void resize(qsizetype size)
qsizetype size() const const
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