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| 1 /* |
| 2 * Copyright 2016 Google Inc. |
| 3 * |
| 4 * Use of this source code is governed by a BSD-style license that can be |
| 5 * found in the LICENSE file. |
| 6 */ |
| 7 #ifndef SkSinglyLinkedList_DEFINED |
| 8 #define SkSinglyLinkedList_DEFINED |
| 9 |
| 10 #include <utility> |
| 11 |
| 12 #include "SkTypes.h" |
| 13 |
| 14 template <typename T> class SkSinglyLinkedList { |
| 15 struct Node; |
| 16 public: |
| 17 SkSinglyLinkedList() : fHead(nullptr), fTail(nullptr) {} |
| 18 ~SkSinglyLinkedList() { this->reset(); } |
| 19 void reset() { |
| 20 SkASSERT(fHead != nullptr || nullptr == fTail); |
| 21 Node* node = fHead; |
| 22 while (node) { |
| 23 Node* next = node->fNext; |
| 24 SkASSERT(next != nullptr || node == fTail); |
| 25 delete node; |
| 26 node = next; |
| 27 } |
| 28 fHead = nullptr; |
| 29 fTail = nullptr; |
| 30 } |
| 31 T* back() { return fTail ? &fTail->fData : nullptr; } |
| 32 T* front() { return fHead ? &fHead->fData : nullptr; } |
| 33 #ifdef SK_DEBUG |
| 34 int count() { // O(n), debug only. |
| 35 int count = 0; |
| 36 for (Node* node = fHead; node; node = node->fNext) { |
| 37 ++count; |
| 38 } |
| 39 return count; |
| 40 } |
| 41 #endif |
| 42 void pop_front() { |
| 43 if (Node* node = fHead) { |
| 44 fHead = node->fNext; |
| 45 delete node; |
| 46 if (fHead == nullptr) { |
| 47 fTail = nullptr; |
| 48 } |
| 49 } |
| 50 } |
| 51 template <class... Args> T* emplace_front(Args&&... args) { |
| 52 Node* n = new Node(std::forward<Args>(args)...); |
| 53 n->fNext = fHead; |
| 54 if (!fTail) { |
| 55 fTail = n; |
| 56 SkASSERT(!fHead); |
| 57 } |
| 58 fHead = n; |
| 59 return &n->fData; |
| 60 } |
| 61 template <class... Args> T* emplace_back(Args&&... args) { |
| 62 Node* n = new Node(std::forward<Args>(args)...); |
| 63 if (fTail) { |
| 64 fTail->fNext = n; |
| 65 } else { |
| 66 fHead = n; |
| 67 } |
| 68 fTail = n; |
| 69 return &n->fData; |
| 70 } |
| 71 class ConstIter { |
| 72 public: |
| 73 void operator++() { fNode = fNode->fNext; } |
| 74 const T& operator*() const { return fNode->fData; } |
| 75 bool operator!=(const ConstIter& rhs) const { return fNode != rhs.fNode;
} |
| 76 ConstIter(const Node* n) : fNode(n) {} |
| 77 private: |
| 78 const Node* fNode; |
| 79 }; |
| 80 ConstIter begin() const { return ConstIter(fHead); } |
| 81 ConstIter end() const { return ConstIter(nullptr); } |
| 82 |
| 83 private: |
| 84 struct Node { |
| 85 T fData; |
| 86 Node* fNext; |
| 87 template <class... Args> |
| 88 Node(Args&&... args) : fData(std::forward<Args>(args)...), fNext(nullptr
) {} |
| 89 }; |
| 90 Node* fHead; |
| 91 Node* fTail; |
| 92 SkSinglyLinkedList(const SkSinglyLinkedList<T>&) = delete; |
| 93 SkSinglyLinkedList& operator=(const SkSinglyLinkedList<T>&) = delete; |
| 94 }; |
| 95 #endif // SkSinglyLinkedList_DEFINED |
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