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
|
// Copyright (C) 2020 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Marc Mutz <marc.mutz@kdab.com>
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QDUPLICATETRACKER_P_H
#define QDUPLICATETRACKER_P_H
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
#include <private/qglobal_p.h>
#if __has_include(<memory_resource>)
# include <unordered_set>
# include <memory_resource>
# include <qhash.h> // for the hashing helpers
#else
# include <qset.h>
#endif
QT_BEGIN_NAMESPACE
template <typename T, size_t Prealloc = 32>
class QDuplicateTracker {
#ifdef __cpp_lib_memory_resource
template <typename HT>
struct QHasher {
size_t storedSeed = QHashSeed::globalSeed();
size_t operator()(const HT &t) const {
return QHashPrivate::calculateHash(t, storedSeed);
}
};
struct node_guesstimate { void *next; size_t hash; T value; };
static constexpr size_t bufferSize(size_t N) {
return N * sizeof(void*) // bucket list
+ N * sizeof(node_guesstimate); // nodes
}
char buffer[bufferSize(Prealloc)];
std::pmr::monotonic_buffer_resource res{buffer, sizeof buffer};
std::pmr::unordered_set<T, QHasher<T>> set{Prealloc, &res};
#else
class Set : public QSet<T> {
qsizetype setSize = 0;
public:
explicit Set(qsizetype n) : QSet<T>{}
{ this->reserve(n); }
auto insert(const T &e) {
auto it = QSet<T>::insert(e);
const auto n = this->size();
return std::pair{it, qExchange(setSize, n) != n};
}
auto insert(T &&e) {
auto it = QSet<T>::insert(std::move(e));
const auto n = this->size();
return std::pair{it, qExchange(setSize, n) != n};
}
};
Set set{Prealloc};
#endif
Q_DISABLE_COPY_MOVE(QDuplicateTracker);
public:
static constexpr inline bool uses_pmr =
#ifdef __cpp_lib_memory_resource
true
#else
false
#endif
;
QDuplicateTracker() = default;
explicit QDuplicateTracker(qsizetype n)
#ifdef __cpp_lib_memory_resource
: set{size_t(n), &res}
#else
: set{n}
#endif
{}
Q_DECL_DEPRECATED_X("Pass the capacity to reserve() to the ctor instead.")
void reserve(qsizetype n) { set.reserve(n); }
[[nodiscard]] bool hasSeen(const T &s)
{
return !set.insert(s).second;
}
[[nodiscard]] bool hasSeen(T &&s)
{
return !set.insert(std::move(s)).second;
}
template <typename C>
void appendTo(C &c) const &
{
for (const auto &e : set)
c.push_back(e);
}
template <typename C>
void appendTo(C &c) &&
{
if constexpr (uses_pmr) {
while (!set.empty())
c.push_back(std::move(set.extract(set.begin()).value()));
} else {
return appendTo(c); // lvalue version
}
}
void clear()
{
set.clear();
}
};
QT_END_NAMESPACE
#endif /* QDUPLICATETRACKER_P_H */
|
