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comparison: gfx/skia/trunk/include/core/SkDeque.h
gfx/skia/trunk/include/core/SkDeque.h
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- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:b269df995373 |
|---|---|
| 1 | |
| 2 /* | |
| 3 * Copyright 2006 The Android Open Source Project | |
| 4 * | |
| 5 * Use of this source code is governed by a BSD-style license that can be | |
| 6 * found in the LICENSE file. | |
| 7 */ | |
| 8 | |
| 9 | |
| 10 #ifndef SkDeque_DEFINED | |
| 11 #define SkDeque_DEFINED | |
| 12 | |
| 13 #include "SkTypes.h" | |
| 14 | |
| 15 /* | |
| 16 * The deque class works by blindly creating memory space of a specified element | |
| 17 * size. It manages the memory as a doubly linked list of blocks each of which | |
| 18 * can contain multiple elements. Pushes and pops add/remove blocks from the | |
| 19 * beginning/end of the list as necessary while each block tracks the used | |
| 20 * portion of its memory. | |
| 21 * One behavior to be aware of is that the pops do not immediately remove an | |
| 22 * empty block from the beginning/end of the list (Presumably so push/pop pairs | |
| 23 * on the block boundaries don't cause thrashing). This can result in the first/ | |
| 24 * last element not residing in the first/last block. | |
| 25 */ | |
| 26 class SK_API SkDeque : SkNoncopyable { | |
| 27 public: | |
| 28 /** | |
| 29 * elemSize specifies the size of each individual element in the deque | |
| 30 * allocCount specifies how many elements are to be allocated as a block | |
| 31 */ | |
| 32 explicit SkDeque(size_t elemSize, int allocCount = 1); | |
| 33 SkDeque(size_t elemSize, void* storage, size_t storageSize, int allocCount = 1); | |
| 34 ~SkDeque(); | |
| 35 | |
| 36 bool empty() const { return 0 == fCount; } | |
| 37 int count() const { return fCount; } | |
| 38 size_t elemSize() const { return fElemSize; } | |
| 39 | |
| 40 const void* front() const { return fFront; } | |
| 41 const void* back() const { return fBack; } | |
| 42 | |
| 43 void* front() { | |
| 44 return (void*)((const SkDeque*)this)->front(); | |
| 45 } | |
| 46 | |
| 47 void* back() { | |
| 48 return (void*)((const SkDeque*)this)->back(); | |
| 49 } | |
| 50 | |
| 51 /** | |
| 52 * push_front and push_back return a pointer to the memory space | |
| 53 * for the new element | |
| 54 */ | |
| 55 void* push_front(); | |
| 56 void* push_back(); | |
| 57 | |
| 58 void pop_front(); | |
| 59 void pop_back(); | |
| 60 | |
| 61 private: | |
| 62 struct Block; | |
| 63 | |
| 64 public: | |
| 65 class Iter { | |
| 66 public: | |
| 67 enum IterStart { | |
| 68 kFront_IterStart, | |
| 69 kBack_IterStart | |
| 70 }; | |
| 71 | |
| 72 /** | |
| 73 * Creates an uninitialized iterator. Must be reset() | |
| 74 */ | |
| 75 Iter(); | |
| 76 | |
| 77 Iter(const SkDeque& d, IterStart startLoc); | |
| 78 void* next(); | |
| 79 void* prev(); | |
| 80 | |
| 81 void reset(const SkDeque& d, IterStart startLoc); | |
| 82 | |
| 83 private: | |
| 84 SkDeque::Block* fCurBlock; | |
| 85 char* fPos; | |
| 86 size_t fElemSize; | |
| 87 }; | |
| 88 | |
| 89 // Inherit privately from Iter to prevent access to reverse iteration | |
| 90 class F2BIter : private Iter { | |
| 91 public: | |
| 92 F2BIter() {} | |
| 93 | |
| 94 /** | |
| 95 * Wrap Iter's 2 parameter ctor to force initialization to the | |
| 96 * beginning of the deque | |
| 97 */ | |
| 98 F2BIter(const SkDeque& d) : INHERITED(d, kFront_IterStart) {} | |
| 99 | |
| 100 using Iter::next; | |
| 101 | |
| 102 /** | |
| 103 * Wrap Iter::reset to force initialization to the beginning of the | |
| 104 * deque | |
| 105 */ | |
| 106 void reset(const SkDeque& d) { | |
| 107 this->INHERITED::reset(d, kFront_IterStart); | |
| 108 } | |
| 109 | |
| 110 private: | |
| 111 typedef Iter INHERITED; | |
| 112 }; | |
| 113 | |
| 114 private: | |
| 115 // allow unit test to call numBlocksAllocated | |
| 116 friend class DequeUnitTestHelper; | |
| 117 | |
| 118 void* fFront; | |
| 119 void* fBack; | |
| 120 | |
| 121 Block* fFrontBlock; | |
| 122 Block* fBackBlock; | |
| 123 size_t fElemSize; | |
| 124 void* fInitialStorage; | |
| 125 int fCount; // number of elements in the deque | |
| 126 int fAllocCount; // number of elements to allocate per block | |
| 127 | |
| 128 Block* allocateBlock(int allocCount); | |
| 129 void freeBlock(Block* block); | |
| 130 | |
| 131 /** | |
| 132 * This returns the number of chunk blocks allocated by the deque. It | |
| 133 * can be used to gauge the effectiveness of the selected allocCount. | |
| 134 */ | |
| 135 int numBlocksAllocated() const; | |
| 136 }; | |
| 137 | |
| 138 #endif |
