summaryrefslogtreecommitdiffstats
path: root/src/qml/parser/qqmljsmemorypool_p.h
blob: ae9f1d82574797a2ecbb5d5e462ba9e1f9961e9b (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
/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtQml module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** 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 http://www.qt.io/terms-conditions. For further
** information use the contact form at http://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 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QQMLJSMEMORYPOOL_P_H
#define QQMLJSMEMORYPOOL_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 "qqmljsglobal_p.h"

#include <QtCore/qglobal.h>
#include <QtCore/qshareddata.h>
#include <QtCore/qdebug.h>

#include <cstring>

QT_QML_BEGIN_NAMESPACE

namespace QQmlJS {

class Managed;

class QML_PARSER_EXPORT MemoryPool : public QSharedData
{
    MemoryPool(const MemoryPool &other);
    void operator =(const MemoryPool &other);

public:
    MemoryPool()
        : _blocks(0),
          _allocatedBlocks(0),
          _blockCount(-1),
          _ptr(0),
          _end(0)
    { }

    ~MemoryPool()
    {
        if (_blocks) {
            for (int i = 0; i < _allocatedBlocks; ++i) {
                if (char *b = _blocks[i])
                    free(b);
            }

            free(_blocks);
        }
    }

    inline void *allocate(size_t size)
    {
        size = (size + 7) & ~7;
        if (_ptr && (_ptr + size < _end)) {
            void *addr = _ptr;
            _ptr += size;
            return addr;
        }
        return allocate_helper(size);
    }

    void reset()
    {
        _blockCount = -1;
        _ptr = _end = 0;
    }

    template <typename Tp> Tp *New() { return new (this->allocate(sizeof(Tp))) Tp(); }

private:
    void *allocate_helper(size_t size)
    {
        Q_ASSERT(size < BLOCK_SIZE);

        if (++_blockCount == _allocatedBlocks) {
            if (! _allocatedBlocks)
                _allocatedBlocks = DEFAULT_BLOCK_COUNT;
            else
                _allocatedBlocks *= 2;

            _blocks = (char **) realloc(_blocks, sizeof(char *) * _allocatedBlocks);

            for (int index = _blockCount; index < _allocatedBlocks; ++index)
                _blocks[index] = 0;
        }

        char *&block = _blocks[_blockCount];

        if (! block)
            block = (char *) malloc(BLOCK_SIZE);

        _ptr = block;
        _end = _ptr + BLOCK_SIZE;

        void *addr = _ptr;
        _ptr += size;
        return addr;
    }

private:
    char **_blocks;
    int _allocatedBlocks;
    int _blockCount;
    char *_ptr;
    char *_end;

    enum
    {
        BLOCK_SIZE = 8 * 1024,
        DEFAULT_BLOCK_COUNT = 8
    };
};

class QML_PARSER_EXPORT Managed
{
    Managed(const Managed &other);
    void operator = (const Managed &other);

public:
    Managed() {}
    ~Managed() {}

    void *operator new(size_t size, MemoryPool *pool) { return pool->allocate(size); }
    void operator delete(void *) {}
    void operator delete(void *, MemoryPool *) {}
};

} // namespace QQmlJS

QT_QML_END_NAMESPACE

#endif