summaryrefslogtreecommitdiffstats
path: root/src/corelib/tools/qarraydata.h
blob: 0226fa4c925fe3f50b1fca5062f9195eaa975d43 (plain)
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
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Copyright (C) 2019 Intel Corporation.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QARRAYDATA_H
#define QARRAYDATA_H

#include <QtCore/qpair.h>
#include <QtCore/qatomic.h>
#include <string.h>

QT_BEGIN_NAMESPACE

template <class T> struct QTypedArrayData;

struct Q_CORE_EXPORT QArrayData
{
    enum ArrayOption {
        /// this option is used by the allocate() function
        DefaultAllocationFlags = 0,
        CapacityReserved     = 0x1,  //!< the capacity was reserved by the user, try to keep it
        GrowsForward         = 0x2,  //!< allocate with eyes towards growing through append()
        GrowsBackwards       = 0x4   //!< allocate with eyes towards growing through prepend()
    };
    Q_DECLARE_FLAGS(ArrayOptions, ArrayOption)

    QBasicAtomicInt ref_;
    uint flags;
    qsizetype alloc;

    inline qsizetype allocatedCapacity() noexcept
    {
        return alloc;
    }

    inline qsizetype constAllocatedCapacity() const noexcept
    {
        return alloc;
    }

    /// Returns true if sharing took place
    bool ref() noexcept
    {
        ref_.ref();
        return true;
    }

    /// Returns false if deallocation is necessary
    bool deref() noexcept
    {
        return ref_.deref();
    }

    bool isShared() const noexcept
    {
        return ref_.loadRelaxed() != 1;
    }

    // Returns true if a detach is necessary before modifying the data
    // This method is intentionally not const: if you want to know whether
    // detaching is necessary, you should be in a non-const function already
    bool needsDetach() const noexcept
    {
        return ref_.loadRelaxed() > 1;
    }

    qsizetype detachCapacity(qsizetype newSize) const noexcept
    {
        if (flags & CapacityReserved && newSize < constAllocatedCapacity())
            return constAllocatedCapacity();
        return newSize;
    }

    ArrayOptions detachFlags() const noexcept
    {
        ArrayOptions result = DefaultAllocationFlags;
        if (flags & CapacityReserved)
            result |= CapacityReserved;
        return result;
    }

    Q_REQUIRED_RESULT
#if defined(Q_CC_GNU)
    __attribute__((__malloc__))
#endif
    static void *allocate(QArrayData **pdata, qsizetype objectSize, qsizetype alignment,
            qsizetype capacity, ArrayOptions options = DefaultAllocationFlags) noexcept;
    Q_REQUIRED_RESULT static QPair<QArrayData *, void *> reallocateUnaligned(QArrayData *data, void *dataPointer,
            qsizetype objectSize, qsizetype newCapacity, ArrayOptions newOptions = DefaultAllocationFlags) noexcept;
    static void deallocate(QArrayData *data, qsizetype objectSize,
            qsizetype alignment) noexcept;
};

Q_DECLARE_OPERATORS_FOR_FLAGS(QArrayData::ArrayOptions)

template <class T>
struct QTypedArrayData
    : QArrayData
{
    class iterator {
        T *i = nullptr;
    public:
        typedef std::random_access_iterator_tag  iterator_category;
        typedef qsizetype difference_type;
        typedef T value_type;
        typedef T *pointer;
        typedef T &reference;

        inline constexpr iterator() = default;
        inline iterator(T *n) : i(n) {}
        inline T &operator*() const { return *i; }
        inline T *operator->() const { return i; }
        inline T &operator[](qsizetype j) const { return *(i + j); }
        inline constexpr bool operator==(iterator o) const { return i == o.i; }
        inline constexpr bool operator!=(iterator o) const { return i != o.i; }
        inline constexpr bool operator<(iterator other) const { return i < other.i; }
        inline constexpr bool operator<=(iterator other) const { return i <= other.i; }
        inline constexpr bool operator>(iterator other) const { return i > other.i; }
        inline constexpr bool operator>=(iterator other) const { return i >= other.i; }
        inline constexpr bool operator==(pointer p) const { return i == p; }
        inline constexpr bool operator!=(pointer p) const { return i != p; }
        inline iterator &operator++() { ++i; return *this; }
        inline iterator operator++(int) { T *n = i; ++i; return n; }
        inline iterator &operator--() { i--; return *this; }
        inline iterator operator--(int) { T *n = i; i--; return n; }
        inline iterator &operator+=(qsizetype j) { i+=j; return *this; }
        inline iterator &operator-=(qsizetype j) { i-=j; return *this; }
        inline iterator operator+(qsizetype j) const { return iterator(i+j); }
        inline iterator operator-(qsizetype j) const { return iterator(i-j); }
        friend inline iterator operator+(qsizetype j, iterator k) { return k + j; }
        inline qsizetype operator-(iterator j) const { return i - j.i; }
        inline operator T*() const { return i; }
    };

    class const_iterator {
        const T *i = nullptr;
    public:
        typedef std::random_access_iterator_tag  iterator_category;
        typedef qsizetype difference_type;
        typedef T value_type;
        typedef const T *pointer;
        typedef const T &reference;

        inline constexpr const_iterator() = default;
        inline const_iterator(const T *n) : i(n) {}
        inline constexpr const_iterator(iterator o): i(o) {}
        inline const T &operator*() const { return *i; }
        inline const T *operator->() const { return i; }
        inline const T &operator[](qsizetype j) const { return *(i + j); }
        inline constexpr bool operator==(const_iterator o) const { return i == o.i; }
        inline constexpr bool operator!=(const_iterator o) const { return i != o.i; }
        inline constexpr bool operator<(const_iterator other) const { return i < other.i; }
        inline constexpr bool operator<=(const_iterator other) const { return i <= other.i; }
        inline constexpr bool operator>(const_iterator other) const { return i > other.i; }
        inline constexpr bool operator>=(const_iterator other) const { return i >= other.i; }
        inline constexpr bool operator==(iterator o) const { return i == const_iterator(o).i; }
        inline constexpr bool operator!=(iterator o) const { return i != const_iterator(o).i; }
        inline constexpr bool operator==(pointer p) const { return i == p; }
        inline constexpr bool operator!=(pointer p) const { return i != p; }
        inline const_iterator &operator++() { ++i; return *this; }
        inline const_iterator operator++(int) { const T *n = i; ++i; return n; }
        inline const_iterator &operator--() { i--; return *this; }
        inline const_iterator operator--(int) { const T *n = i; i--; return n; }
        inline const_iterator &operator+=(qsizetype j) { i+=j; return *this; }
        inline const_iterator &operator-=(qsizetype j) { i-=j; return *this; }
        inline const_iterator operator+(qsizetype j) const { return const_iterator(i+j); }
        inline const_iterator operator-(qsizetype j) const { return const_iterator(i-j); }
        friend inline const_iterator operator+(qsizetype j, const_iterator k) { return k + j; }
        inline qsizetype operator-(const_iterator j) const { return i - j.i; }
        inline operator const T*() const { return i; }
    };

    class AlignmentDummy { QArrayData header; T data; };

    Q_REQUIRED_RESULT static QPair<QTypedArrayData *, T *> allocate(qsizetype capacity,
            ArrayOptions options = DefaultAllocationFlags)
    {
        static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
        QArrayData *d;
        void *result = QArrayData::allocate(&d, sizeof(T), alignof(AlignmentDummy), capacity, options);
#if (defined(Q_CC_GNU) && Q_CC_GNU >= 407) || QT_HAS_BUILTIN(__builtin_assume_aligned)
        result = __builtin_assume_aligned(result, Q_ALIGNOF(AlignmentDummy));
#endif
        return qMakePair(static_cast<QTypedArrayData *>(d), static_cast<T *>(result));
    }

    static QPair<QTypedArrayData *, T *>
    reallocateUnaligned(QTypedArrayData *data, T *dataPointer, qsizetype capacity,
            ArrayOptions options = DefaultAllocationFlags)
    {
        static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
        QPair<QArrayData *, void *> pair =
                QArrayData::reallocateUnaligned(data, dataPointer, sizeof(T), capacity, options);
        return qMakePair(static_cast<QTypedArrayData *>(pair.first), static_cast<T *>(pair.second));
    }

    static void deallocate(QArrayData *data) noexcept
    {
        static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
        QArrayData::deallocate(data, sizeof(T), alignof(AlignmentDummy));
    }
};

namespace QtPrivate {
struct Q_CORE_EXPORT QContainerImplHelper
{
    enum CutResult { Null, Empty, Full, Subset };
    static constexpr CutResult mid(qsizetype originalLength, qsizetype *_position, qsizetype *_length)
    {
        qsizetype &position = *_position;
        qsizetype &length = *_length;
        if (position > originalLength) {
            position = 0;
            length = 0;
            return Null;
        }

        if (position < 0) {
            if (length < 0 || length + position >= originalLength) {
                position = 0;
                length = originalLength;
                return Full;
            }
            if (length + position <= 0) {
                position = length = 0;
                return Null;
            }
            length += position;
            position = 0;
        } else if (size_t(length) > size_t(originalLength - position)) {
            length = originalLength - position;
        }

        if (position == 0 && length == originalLength)
            return Full;

        return length > 0 ? Subset : Empty;
    }
};
}

QT_END_NAMESPACE

#endif // include guard