|
| 1 | +module d.gc.dequeue; |
| 2 | + |
| 3 | +template DEQueue(T, uint Entries) { |
| 4 | + struct DEQueue { |
| 5 | + private: |
| 6 | + uint _front = 0; |
| 7 | + uint _back = 0; |
| 8 | + uint _count = 0; |
| 9 | + T[Entries] _buffer; |
| 10 | + |
| 11 | + public: |
| 12 | + enum Size = Entries; |
| 13 | + |
| 14 | + @property |
| 15 | + auto buffer() { |
| 16 | + assert(empty, "Buffer is not empty!"); |
| 17 | + |
| 18 | + return _buffer.ptr; |
| 19 | + } |
| 20 | + |
| 21 | + void clear() { |
| 22 | + _front = 0; |
| 23 | + _back = 0; |
| 24 | + _count = 0; |
| 25 | + } |
| 26 | + |
| 27 | + void pushBackAdvance(uint delta) { |
| 28 | + assert(empty, "Cannot pushBackAdvance: not empty!"); |
| 29 | + assert(delta <= Entries, |
| 30 | + "Cannot pushBackAdvance: delta exceeds Entries!"); |
| 31 | + |
| 32 | + _front = 0; |
| 33 | + _back = delta % Entries; |
| 34 | + _count = delta; |
| 35 | + } |
| 36 | + |
| 37 | + void pushBack(T item) { |
| 38 | + assert(!full, "Cannot pushBack: full!"); |
| 39 | + |
| 40 | + _buffer[_back] = item; |
| 41 | + _back = (_back + 1) % Entries; |
| 42 | + _count++; |
| 43 | + } |
| 44 | + |
| 45 | + T popFront() { |
| 46 | + assert(!empty, "Cannot popFront: empty!"); |
| 47 | + |
| 48 | + auto item = _buffer[_front]; |
| 49 | + _front = (_front + 1) % Entries; |
| 50 | + _count--; |
| 51 | + |
| 52 | + return item; |
| 53 | + } |
| 54 | + |
| 55 | + void pushFront(T item) { |
| 56 | + assert(!full, "Cannot pushFront: full!"); |
| 57 | + |
| 58 | + _front = (_front > 0 ? _front : Entries) - 1; |
| 59 | + _buffer[_front] = item; |
| 60 | + _count++; |
| 61 | + } |
| 62 | + |
| 63 | + T popBack() { |
| 64 | + assert(!empty, "Cannot popBack: empty!"); |
| 65 | + |
| 66 | + _back = (_back > 0 ? _back : Entries) - 1; |
| 67 | + auto item = _buffer[_back]; |
| 68 | + _count--; |
| 69 | + |
| 70 | + return item; |
| 71 | + } |
| 72 | + |
| 73 | + @property |
| 74 | + auto length() { |
| 75 | + return _count; |
| 76 | + } |
| 77 | + |
| 78 | + @property |
| 79 | + bool empty() { |
| 80 | + return _count == 0; |
| 81 | + } |
| 82 | + |
| 83 | + @property |
| 84 | + bool full() { |
| 85 | + return _count == Entries; |
| 86 | + } |
| 87 | + } |
| 88 | +} |
| 89 | + |
| 90 | +unittest DEQueue { |
| 91 | + static DEQueue!(uint, 3) q; |
| 92 | + assert(q.empty); |
| 93 | + |
| 94 | + q.pushBack(1); |
| 95 | + q.pushBack(2); |
| 96 | + q.pushBack(3); |
| 97 | + assert(q.full); |
| 98 | + assert(q.popFront() == 1); |
| 99 | + assert(q.popFront() == 2); |
| 100 | + assert(q.popFront() == 3); |
| 101 | + assert(q.empty); |
| 102 | + |
| 103 | + q.pushBack(1); |
| 104 | + q.pushBack(2); |
| 105 | + q.pushBack(3); |
| 106 | + assert(q.full); |
| 107 | + assert(q.popBack() == 3); |
| 108 | + assert(q.popBack() == 2); |
| 109 | + assert(q.popBack() == 1); |
| 110 | + assert(q.empty); |
| 111 | + |
| 112 | + q.pushFront(1); |
| 113 | + q.pushFront(2); |
| 114 | + q.pushFront(3); |
| 115 | + assert(q.full); |
| 116 | + assert(q.popFront() == 3); |
| 117 | + assert(q.popFront() == 2); |
| 118 | + assert(q.popFront() == 1); |
| 119 | + assert(q.empty); |
| 120 | + |
| 121 | + q.pushFront(1); |
| 122 | + q.pushFront(2); |
| 123 | + q.pushFront(3); |
| 124 | + assert(q.full); |
| 125 | + assert(q.popBack() == 1); |
| 126 | + assert(q.popBack() == 2); |
| 127 | + assert(q.popBack() == 3); |
| 128 | + assert(q.empty); |
| 129 | + |
| 130 | + q.pushBack(1); |
| 131 | + q.pushFront(2); |
| 132 | + q.pushBack(3); |
| 133 | + assert(q.full); |
| 134 | + assert(q.popFront() == 2); |
| 135 | + assert(q.popBack() == 3); |
| 136 | + assert(q.popFront() == 1); |
| 137 | + assert(q.empty); |
| 138 | + |
| 139 | + q.pushBack(1); |
| 140 | + q.pushFront(2); |
| 141 | + q.pushBack(3); |
| 142 | + assert(q.full); |
| 143 | + assert(q.popBack() == 3); |
| 144 | + assert(q.popFront() == 2); |
| 145 | + assert(q.popBack() == 1); |
| 146 | + assert(q.empty); |
| 147 | +} |
0 commit comments