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39
40#ifndef QRECYCLEPOOL_P_H
41#define QRECYCLEPOOL_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
54QT_BEGIN_NAMESPACE
55
56#define QRECYCLEPOOLCOOKIE 0x33218ADF
57
58template<typename T, int Step>
59class QRecyclePoolPrivate
60{
61public:
62 QRecyclePoolPrivate()
63 : recyclePoolHold(true), outstandingItems(0), cookie(QRECYCLEPOOLCOOKIE),
64 currentPage(nullptr), nextAllocated(nullptr)
65 {
66 }
67
68 bool recyclePoolHold;
69 int outstandingItems;
70 quint32 cookie;
71
72 struct PoolType : public T {
73 union {
74 QRecyclePoolPrivate<T, Step> *pool;
75 PoolType *nextAllocated;
76 };
77 };
78
79 struct Page {
80 Page *nextPage;
81 unsigned int free;
82 union {
83 char array[Step * sizeof(PoolType)];
84 qint64 q_for_alignment_1;
85 double q_for_alignment_2;
86 };
87 };
88
89 Page *currentPage;
90 PoolType *nextAllocated;
91
92 inline T *allocate();
93 static inline void dispose(T *);
94 inline void releaseIfPossible();
95};
96
97template<typename T, int Step = 1024>
98class QRecyclePool
99{
100public:
101 inline QRecyclePool();
102 inline ~QRecyclePool();
103
104 inline T *New();
105 template<typename T1>
106 inline T *New(const T1 &);
107 template<typename T1>
108 inline T *New(T1 &);
109
110 static inline void Delete(T *);
111
112private:
113 QRecyclePoolPrivate<T, Step> *d;
114};
115
116template<typename T, int Step>
117QRecyclePool<T, Step>::QRecyclePool()
118: d(new QRecyclePoolPrivate<T, Step>())
119{
120}
121
122template<typename T, int Step>
123QRecyclePool<T, Step>::~QRecyclePool()
124{
125 d->recyclePoolHold = false;
126 d->releaseIfPossible();
127}
128
129template<typename T, int Step>
130T *QRecyclePool<T, Step>::New()
131{
132 T *rv = d->allocate();
133 new (rv) T;
134 return rv;
135}
136
137template<typename T, int Step>
138template<typename T1>
139T *QRecyclePool<T, Step>::New(const T1 &a)
140{
141 T *rv = d->allocate();
142 new (rv) T(a);
143 return rv;
144}
145
146template<typename T, int Step>
147template<typename T1>
148T *QRecyclePool<T, Step>::New(T1 &a)
149{
150 T *rv = d->allocate();
151 new (rv) T(a);
152 return rv;
153}
154
155template<typename T, int Step>
156void QRecyclePool<T, Step>::Delete(T *t)
157{
158 t->~T();
159 QRecyclePoolPrivate<T, Step>::dispose(t);
160}
161
162template<typename T, int Step>
163void QRecyclePoolPrivate<T, Step>::releaseIfPossible()
164{
165 if (recyclePoolHold || outstandingItems)
166 return;
167
168 Page *p = currentPage;
169 while (p) {
170 Page *n = p->nextPage;
171 free(p);
172 p = n;
173 }
174
175 delete this;
176}
177
178template<typename T, int Step>
179T *QRecyclePoolPrivate<T, Step>::allocate()
180{
181 PoolType *rv = nullptr;
182 if (nextAllocated) {
183 rv = nextAllocated;
184 nextAllocated = rv->nextAllocated;
185 } else if (currentPage && currentPage->free) {
186 rv = (PoolType *)(currentPage->array + (Step - currentPage->free) * sizeof(PoolType));
187 currentPage->free--;
188 } else {
189 Page *p = (Page *)malloc(size: sizeof(Page));
190 p->nextPage = currentPage;
191 p->free = Step;
192 currentPage = p;
193
194 rv = (PoolType *)currentPage->array;
195 currentPage->free--;
196 }
197
198 rv->pool = this;
199 ++outstandingItems;
200 return rv;
201}
202
203template<typename T, int Step>
204void QRecyclePoolPrivate<T, Step>::dispose(T *t)
205{
206 PoolType *pt = static_cast<PoolType *>(t);
207 Q_ASSERT(pt->pool && pt->pool->cookie == QRECYCLEPOOLCOOKIE);
208
209 QRecyclePoolPrivate<T, Step> *This = pt->pool;
210 pt->nextAllocated = This->nextAllocated;
211 This->nextAllocated = pt;
212 --This->outstandingItems;
213 This->releaseIfPossible();
214}
215
216QT_END_NAMESPACE
217
218#endif // QRECYCLEPOOL_P_H
219

source code of qtdeclarative/src/qml/qml/ftw/qrecyclepool_p.h