summaryrefslogtreecommitdiffstats
path: root/src/corelib/tools/qarraydata.cpp
blob: 2d744f97c0654977d0ce5b84ce43cc6b33a30607 (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
/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** 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 Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QtCore/qarraydata.h>
#include <QtCore/private/qtools_p.h>

#include <stdlib.h>

QT_BEGIN_NAMESPACE

#if defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__  >= 406) && !defined(Q_CC_INTEL)
  #pragma GCC diagnostic push
  #pragma GCC diagnostic ignored "-Wmissing-field-initializers"
#endif

const QArrayData QArrayData::shared_null[2] = {
    { Q_REFCOUNT_INITIALIZE_STATIC, 0, 0, 0, sizeof(QArrayData) }, // shared null
    /* zero initialized terminator */};

static const QArrayData qt_array[3] = {
    { Q_REFCOUNT_INITIALIZE_STATIC, 0, 0, 0, sizeof(QArrayData) }, // shared empty
    { { Q_BASIC_ATOMIC_INITIALIZER(0) }, 0, 0, 0, sizeof(QArrayData) }, // unsharable empty
    /* zero initialized terminator */};

#if defined (__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__  >= 406) && !defined(Q_CC_INTEL)
  #pragma GCC diagnostic pop
#endif

static const QArrayData &qt_array_empty = qt_array[0];
static const QArrayData &qt_array_unsharable_empty = qt_array[1];

QArrayData *QArrayData::allocate(size_t objectSize, size_t alignment,
        size_t capacity, AllocationOptions options) Q_DECL_NOTHROW
{
    // Alignment is a power of two
    Q_ASSERT(alignment >= Q_ALIGNOF(QArrayData)
            && !(alignment & (alignment - 1)));

    // Don't allocate empty headers
    if (!(options & RawData) && !capacity) {
#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
        if (options & Unsharable)
            return const_cast<QArrayData *>(&qt_array_unsharable_empty);
#endif
        return const_cast<QArrayData *>(&qt_array_empty);
    }

    size_t headerSize = sizeof(QArrayData);

    // Allocate extra (alignment - Q_ALIGNOF(QArrayData)) padding bytes so we
    // can properly align the data array. This assumes malloc is able to
    // provide appropriate alignment for the header -- as it should!
    // Padding is skipped when allocating a header for RawData.
    if (!(options & RawData))
        headerSize += (alignment - Q_ALIGNOF(QArrayData));

    // Allocate additional space if array is growing
    if (options & Grow)
        capacity = qAllocMore(int(objectSize * capacity), int(headerSize)) / int(objectSize);

    size_t allocSize = headerSize + objectSize * capacity;

    QArrayData *header = static_cast<QArrayData *>(::malloc(allocSize));
    if (header) {
        quintptr data = (quintptr(header) + sizeof(QArrayData) + alignment - 1)
                & ~(alignment - 1);

        header->ref.atomic.store(bool(!(options & Unsharable)));
        header->size = 0;
        header->alloc = capacity;
        header->capacityReserved = bool(options & CapacityReserved);
        header->offset = data - quintptr(header);
    }

    return header;
}

void QArrayData::deallocate(QArrayData *data, size_t objectSize,
        size_t alignment) Q_DECL_NOTHROW
{
    // Alignment is a power of two
    Q_ASSERT(alignment >= Q_ALIGNOF(QArrayData)
            && !(alignment & (alignment - 1)));
    Q_UNUSED(objectSize) Q_UNUSED(alignment)

#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
    if (data == &qt_array_unsharable_empty)
        return;
#endif

    Q_ASSERT_X(!data->ref.isStatic(), "QArrayData::deallocate", "Static data can not be deleted");
    ::free(data);
}

QT_END_NAMESPACE