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1 | | -#ifndef JSONCPP_BATCHALLOCATOR_H_INCLUDED |
2 | | -# define JSONCPP_BATCHALLOCATOR_H_INCLUDED |
3 | | - |
4 | | -# include <stdlib.h> |
5 | | -# include <assert.h> |
6 | | - |
7 | | -# ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION |
8 | | - |
9 | | -namespace Json { |
10 | | - |
11 | | -/* Fast memory allocator. |
12 | | - * |
13 | | - * This memory allocator allocates memory for a batch of object (specified by |
14 | | - * the page size, the number of object in each page). |
15 | | - * |
16 | | - * It does not allow the destruction of a single object. All the allocated objects |
17 | | - * can be destroyed at once. The memory can be either released or reused for future |
18 | | - * allocation. |
19 | | - * |
20 | | - * The in-place new operator must be used to construct the object using the pointer |
21 | | - * returned by allocate. |
22 | | - */ |
23 | | -template<typename AllocatedType |
24 | | - ,const unsigned int objectPerAllocation> |
25 | | -class BatchAllocator |
26 | | -{ |
27 | | -public: |
28 | | - typedef AllocatedType Type; |
29 | | - |
30 | | - BatchAllocator( unsigned int objectsPerPage = 255 ) |
31 | | - : freeHead_( 0 ) |
32 | | - , objectsPerPage_( objectsPerPage ) |
33 | | - { |
34 | | -// printf( "Size: %d => %s\n", sizeof(AllocatedType), typeid(AllocatedType).name() ); |
35 | | - assert( sizeof(AllocatedType) * objectPerAllocation >= sizeof(AllocatedType *) ); // We must be able to store a slist in the object free space. |
36 | | - assert( objectsPerPage >= 16 ); |
37 | | - batches_ = allocateBatch( 0 ); // allocated a dummy page |
38 | | - currentBatch_ = batches_; |
39 | | - } |
40 | | - |
41 | | - ~BatchAllocator() |
42 | | - { |
43 | | - for ( BatchInfo *batch = batches_; batch; ) |
44 | | - { |
45 | | - BatchInfo *nextBatch = batch->next_; |
46 | | - free( batch ); |
47 | | - batch = nextBatch; |
48 | | - } |
49 | | - } |
50 | | - |
51 | | - /// allocate space for an array of objectPerAllocation object. |
52 | | - /// @warning it is the responsability of the caller to call objects constructors. |
53 | | - AllocatedType *allocate() |
54 | | - { |
55 | | - if ( freeHead_ ) // returns node from free list. |
56 | | - { |
57 | | - AllocatedType *object = freeHead_; |
58 | | - freeHead_ = *(AllocatedType **)object; |
59 | | - return object; |
60 | | - } |
61 | | - if ( currentBatch_->used_ == currentBatch_->end_ ) |
62 | | - { |
63 | | - currentBatch_ = currentBatch_->next_; |
64 | | - while ( currentBatch_ && currentBatch_->used_ == currentBatch_->end_ ) |
65 | | - currentBatch_ = currentBatch_->next_; |
66 | | - |
67 | | - if ( !currentBatch_ ) // no free batch found, allocate a new one |
68 | | - { |
69 | | - currentBatch_ = allocateBatch( objectsPerPage_ ); |
70 | | - currentBatch_->next_ = batches_; // insert at the head of the list |
71 | | - batches_ = currentBatch_; |
72 | | - } |
73 | | - } |
74 | | - AllocatedType *allocated = currentBatch_->used_; |
75 | | - currentBatch_->used_ += objectPerAllocation; |
76 | | - return allocated; |
77 | | - } |
78 | | - |
79 | | - /// Release the object. |
80 | | - /// @warning it is the responsability of the caller to actually destruct the object. |
81 | | - void release( AllocatedType *object ) |
82 | | - { |
83 | | - assert( object != 0 ); |
84 | | - *(AllocatedType **)object = freeHead_; |
85 | | - freeHead_ = object; |
86 | | - } |
87 | | - |
88 | | -private: |
89 | | - struct BatchInfo |
90 | | - { |
91 | | - BatchInfo *next_; |
92 | | - AllocatedType *used_; |
93 | | - AllocatedType *end_; |
94 | | - AllocatedType buffer_[objectPerAllocation]; |
95 | | - }; |
96 | | - |
97 | | - // disabled copy constructor and assignement operator. |
98 | | - BatchAllocator( const BatchAllocator & ); |
99 | | - void operator =( const BatchAllocator &); |
100 | | - |
101 | | - static BatchInfo *allocateBatch( unsigned int objectsPerPage ) |
102 | | - { |
103 | | - const unsigned int mallocSize = sizeof(BatchInfo) - sizeof(AllocatedType)* objectPerAllocation |
104 | | - + sizeof(AllocatedType) * objectPerAllocation * objectsPerPage; |
105 | | - BatchInfo *batch = static_cast<BatchInfo*>( malloc( mallocSize ) ); |
106 | | - batch->next_ = 0; |
107 | | - batch->used_ = batch->buffer_; |
108 | | - batch->end_ = batch->buffer_ + objectsPerPage; |
109 | | - return batch; |
110 | | - } |
111 | | - |
112 | | - BatchInfo *batches_; |
113 | | - BatchInfo *currentBatch_; |
114 | | - /// Head of a single linked list within the allocated space of freeed object |
115 | | - AllocatedType *freeHead_; |
116 | | - unsigned int objectsPerPage_; |
117 | | -}; |
118 | | - |
119 | | - |
120 | | -} // namespace Json |
121 | | - |
122 | | -# endif // ifndef JSONCPP_DOC_INCLUDE_IMPLEMENTATION |
123 | | - |
124 | | -#endif // JSONCPP_BATCHALLOCATOR_H_INCLUDED |
125 | | - |
| 1 | +#ifndef JSONCPP_BATCHALLOCATOR_H_INCLUDED |
| 2 | +# define JSONCPP_BATCHALLOCATOR_H_INCLUDED |
| 3 | + |
| 4 | +# include <stdlib.h> |
| 5 | +# include <assert.h> |
| 6 | + |
| 7 | +# ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION |
| 8 | + |
| 9 | +namespace Json { |
| 10 | + |
| 11 | +/* Fast memory allocator. |
| 12 | + * |
| 13 | + * This memory allocator allocates memory for a batch of object (specified by |
| 14 | + * the page size, the number of object in each page). |
| 15 | + * |
| 16 | + * It does not allow the destruction of a single object. All the allocated objects |
| 17 | + * can be destroyed at once. The memory can be either released or reused for future |
| 18 | + * allocation. |
| 19 | + * |
| 20 | + * The in-place new operator must be used to construct the object using the pointer |
| 21 | + * returned by allocate. |
| 22 | + */ |
| 23 | +template<typename AllocatedType |
| 24 | + ,const unsigned int objectPerAllocation> |
| 25 | +class BatchAllocator |
| 26 | +{ |
| 27 | +public: |
| 28 | + typedef AllocatedType Type; |
| 29 | + |
| 30 | + BatchAllocator( unsigned int objectsPerPage = 255 ) |
| 31 | + : freeHead_( 0 ) |
| 32 | + , objectsPerPage_( objectsPerPage ) |
| 33 | + { |
| 34 | +// printf( "Size: %d => %s\n", sizeof(AllocatedType), typeid(AllocatedType).name() ); |
| 35 | + assert( sizeof(AllocatedType) * objectPerAllocation >= sizeof(AllocatedType *) ); // We must be able to store a slist in the object free space. |
| 36 | + assert( objectsPerPage >= 16 ); |
| 37 | + batches_ = allocateBatch( 0 ); // allocated a dummy page |
| 38 | + currentBatch_ = batches_; |
| 39 | + } |
| 40 | + |
| 41 | + ~BatchAllocator() |
| 42 | + { |
| 43 | + for ( BatchInfo *batch = batches_; batch; ) |
| 44 | + { |
| 45 | + BatchInfo *nextBatch = batch->next_; |
| 46 | + free( batch ); |
| 47 | + batch = nextBatch; |
| 48 | + } |
| 49 | + } |
| 50 | + |
| 51 | + /// allocate space for an array of objectPerAllocation object. |
| 52 | + /// @warning it is the responsability of the caller to call objects constructors. |
| 53 | + AllocatedType *allocate() |
| 54 | + { |
| 55 | + if ( freeHead_ ) // returns node from free list. |
| 56 | + { |
| 57 | + AllocatedType *object = freeHead_; |
| 58 | + freeHead_ = *(AllocatedType **)object; |
| 59 | + return object; |
| 60 | + } |
| 61 | + if ( currentBatch_->used_ == currentBatch_->end_ ) |
| 62 | + { |
| 63 | + currentBatch_ = currentBatch_->next_; |
| 64 | + while ( currentBatch_ && currentBatch_->used_ == currentBatch_->end_ ) |
| 65 | + currentBatch_ = currentBatch_->next_; |
| 66 | + |
| 67 | + if ( !currentBatch_ ) // no free batch found, allocate a new one |
| 68 | + { |
| 69 | + currentBatch_ = allocateBatch( objectsPerPage_ ); |
| 70 | + currentBatch_->next_ = batches_; // insert at the head of the list |
| 71 | + batches_ = currentBatch_; |
| 72 | + } |
| 73 | + } |
| 74 | + AllocatedType *allocated = currentBatch_->used_; |
| 75 | + currentBatch_->used_ += objectPerAllocation; |
| 76 | + return allocated; |
| 77 | + } |
| 78 | + |
| 79 | + /// Release the object. |
| 80 | + /// @warning it is the responsability of the caller to actually destruct the object. |
| 81 | + void release( AllocatedType *object ) |
| 82 | + { |
| 83 | + assert( object != 0 ); |
| 84 | + *(AllocatedType **)object = freeHead_; |
| 85 | + freeHead_ = object; |
| 86 | + } |
| 87 | + |
| 88 | +private: |
| 89 | + struct BatchInfo |
| 90 | + { |
| 91 | + BatchInfo *next_; |
| 92 | + AllocatedType *used_; |
| 93 | + AllocatedType *end_; |
| 94 | + AllocatedType buffer_[objectPerAllocation]; |
| 95 | + }; |
| 96 | + |
| 97 | + // disabled copy constructor and assignement operator. |
| 98 | + BatchAllocator( const BatchAllocator & ); |
| 99 | + void operator =( const BatchAllocator &); |
| 100 | + |
| 101 | + static BatchInfo *allocateBatch( unsigned int objectsPerPage ) |
| 102 | + { |
| 103 | + const unsigned int mallocSize = sizeof(BatchInfo) - sizeof(AllocatedType)* objectPerAllocation |
| 104 | + + sizeof(AllocatedType) * objectPerAllocation * objectsPerPage; |
| 105 | + BatchInfo *batch = static_cast<BatchInfo*>( malloc( mallocSize ) ); |
| 106 | + batch->next_ = 0; |
| 107 | + batch->used_ = batch->buffer_; |
| 108 | + batch->end_ = batch->buffer_ + objectsPerPage; |
| 109 | + return batch; |
| 110 | + } |
| 111 | + |
| 112 | + BatchInfo *batches_; |
| 113 | + BatchInfo *currentBatch_; |
| 114 | + /// Head of a single linked list within the allocated space of freeed object |
| 115 | + AllocatedType *freeHead_; |
| 116 | + unsigned int objectsPerPage_; |
| 117 | +}; |
| 118 | + |
| 119 | + |
| 120 | +} // namespace Json |
| 121 | + |
| 122 | +# endif // ifndef JSONCPP_DOC_INCLUDE_IMPLEMENTATION |
| 123 | + |
| 124 | +#endif // JSONCPP_BATCHALLOCATOR_H_INCLUDED |
| 125 | + |
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