1// Copyright (C) 2024 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4#ifndef QGLIST_HELPER_P_H
5#define QGLIST_HELPER_P_H
6
7//
8// W A R N I N G
9// -------------
10//
11// This file is not part of the Qt API. It exists purely as an
12// implementation detail. This header file may change from version to
13// version without notice, or even be removed.
14//
15// We mean it.
16//
17
18#include <QtCore/qtconfigmacros.h>
19
20#include <glib.h>
21#include <iterator>
22
23QT_BEGIN_NAMESPACE
24
25namespace QGstUtils {
26
27template <typename ListType, bool IsConst>
28struct GListIterator
29{
30 using GListType = std::conditional_t<IsConst, const GList *, GList *>;
31
32 explicit GListIterator(GListType element = nullptr) : element(element) { }
33
34 const ListType &operator*() const noexcept { return *operator->(); }
35 const ListType *operator->() const noexcept
36 {
37 return reinterpret_cast<const ListType *>(&element->data);
38 }
39
40 GListIterator &operator++() noexcept
41 {
42 if (element)
43 element = element->next;
44
45 return *this;
46 }
47 GListIterator operator++(int n) noexcept
48 {
49 for (int i = 0; i != n; ++i)
50 operator++();
51
52 return *this;
53 }
54
55 bool operator==(const GListIterator &r) const noexcept { return element == r.element; }
56 bool operator!=(const GListIterator &r) const noexcept { return element != r.element; }
57
58 using difference_type = std::ptrdiff_t;
59 using value_type = ListType;
60 using pointer = value_type *;
61 using reference = value_type &;
62 using iterator_category = std::input_iterator_tag;
63
64 GListType element = nullptr;
65};
66
67template <typename ListType, bool IsConst>
68struct GListRangeAdaptorImpl
69{
70 static_assert(std::is_pointer_v<ListType>);
71
72 using GListType = std::conditional_t<IsConst, const GList *, GList *>;
73
74 explicit GListRangeAdaptorImpl(GListType list) : head(list) { }
75
76 auto begin() { return GListIterator<ListType, IsConst>(head); }
77 auto end() { return GListIterator<ListType, IsConst>(nullptr); }
78
79 GListType head;
80};
81
82template <typename ListType>
83using GListRangeAdaptor = GListRangeAdaptorImpl<ListType, false>;
84template <typename ListType>
85using GListConstRangeAdaptor = GListRangeAdaptorImpl<ListType, true>;
86
87} // namespace QGstUtils
88
89QT_END_NAMESPACE
90
91#endif
92

source code of qtmultimedia/src/plugins/multimedia/gstreamer/common/qglist_helper_p.h