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39
40#ifndef QQMLJSMEMORYPOOL_P_H
41#define QQMLJSMEMORYPOOL_P_H
42
43//
44// W A R N I N G
45// -------------
46//
47// This file is not part of the Qt API. It exists purely as an
48// implementation detail. This header file may change from version to
49// version without notice, or even be removed.
50//
51// We mean it.
52//
53
54#include <QtCore/qglobal.h>
55#include <QtCore/qshareddata.h>
56#include <QtCore/qdebug.h>
57
58#include <cstring>
59
60QT_BEGIN_NAMESPACE
61
62namespace QQmlJS {
63
64class Managed;
65
66class MemoryPool : public QSharedData
67{
68 MemoryPool(const MemoryPool &other);
69 void operator =(const MemoryPool &other);
70
71public:
72 MemoryPool() {}
73
74 ~MemoryPool()
75 {
76 if (_blocks) {
77 for (int i = 0; i < _allocatedBlocks; ++i) {
78 if (char *b = _blocks[i])
79 free(ptr: b);
80 }
81
82 free(ptr: _blocks);
83 }
84 qDeleteAll(c: strings);
85 }
86
87 inline void *allocate(size_t size)
88 {
89 size = (size + 7) & ~size_t(7);
90 if (Q_LIKELY(_ptr && (_ptr + size < _end))) {
91 void *addr = _ptr;
92 _ptr += size;
93 return addr;
94 }
95 return allocate_helper(size);
96 }
97
98 void reset()
99 {
100 _blockCount = -1;
101 _ptr = _end = nullptr;
102 }
103
104 template <typename Tp> Tp *New() { return new (this->allocate(size: sizeof(Tp))) Tp(); }
105 template <typename Tp, typename... Ta> Tp *New(Ta... args)
106 { return new (this->allocate(size: sizeof(Tp))) Tp(args...); }
107
108 QStringRef newString(const QString &string) {
109 strings.append(t: new QString(string));
110 return QStringRef(strings.last());
111 }
112
113private:
114 Q_NEVER_INLINE void *allocate_helper(size_t size)
115 {
116 size_t currentBlockSize = DEFAULT_BLOCK_SIZE;
117 while (Q_UNLIKELY(size >= currentBlockSize))
118 currentBlockSize *= 2;
119
120 if (++_blockCount == _allocatedBlocks) {
121 if (! _allocatedBlocks)
122 _allocatedBlocks = DEFAULT_BLOCK_COUNT;
123 else
124 _allocatedBlocks *= 2;
125
126 _blocks = reinterpret_cast<char **>(realloc(ptr: _blocks, size: sizeof(char *) * size_t(_allocatedBlocks)));
127 Q_CHECK_PTR(_blocks);
128
129 for (int index = _blockCount; index < _allocatedBlocks; ++index)
130 _blocks[index] = nullptr;
131 }
132
133 char *&block = _blocks[_blockCount];
134
135 if (! block) {
136 block = reinterpret_cast<char *>(malloc(size: currentBlockSize));
137 Q_CHECK_PTR(block);
138 }
139
140 _ptr = block;
141 _end = _ptr + currentBlockSize;
142
143 void *addr = _ptr;
144 _ptr += size;
145 return addr;
146 }
147
148private:
149 char **_blocks = nullptr;
150 int _allocatedBlocks = 0;
151 int _blockCount = -1;
152 char *_ptr = nullptr;
153 char *_end = nullptr;
154 QVector<QString*> strings;
155
156 enum
157 {
158 DEFAULT_BLOCK_SIZE = 8 * 1024,
159 DEFAULT_BLOCK_COUNT = 8
160 };
161};
162
163class Managed
164{
165 Q_DISABLE_COPY(Managed)
166public:
167 Managed() = default;
168 ~Managed() = default;
169
170 void *operator new(size_t size, MemoryPool *pool) { return pool->allocate(size); }
171 void operator delete(void *) {}
172 void operator delete(void *, MemoryPool *) {}
173};
174
175} // namespace QQmlJS
176
177QT_END_NAMESPACE
178
179#endif
180

source code of qtdeclarative/src/qml/common/qqmljsmemorypool_p.h