Smoren /
containers-php
| Total Complexity | 58 |
| Total Lines | 504 |
| Duplicated Lines | 0 % |
| Changes | 0 | ||
Complex classes like LinkedList often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use LinkedList, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 14 | class LinkedList implements IteratorAggregate, Countable |
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| 15 | { |
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| 16 | /** |
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| 17 | * @var LinkedListItem|null first element of list |
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| 18 | */ |
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| 19 | protected ?LinkedListItem $first = null; |
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| 20 | /** |
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| 21 | * @var LinkedListItem|null last element of list |
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| 22 | */ |
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| 23 | protected ?LinkedListItem $last = null; |
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| 24 | /** |
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| 25 | * @var int List size |
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| 26 | */ |
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| 27 | protected int $length = 0; |
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| 28 | |||
| 29 | /** |
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| 30 | * Create new list by merging several another lists |
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| 31 | * @param LinkedList ...$lists |
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| 32 | * @return LinkedList |
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| 33 | */ |
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| 34 | public static function merge(LinkedList ...$lists): LinkedList |
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| 35 | { |
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| 36 | $result = new LinkedList(); |
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| 37 | |||
| 38 | foreach($lists as $list) { |
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| 39 | foreach($list as $value) { |
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| 40 | $result->pushBack($value); |
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| 41 | } |
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| 42 | } |
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| 43 | |||
| 44 | return $result; |
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| 45 | } |
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| 46 | |||
| 47 | /** |
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| 48 | * LinkedList constructor. |
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| 49 | * @param array $input default list content |
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| 50 | */ |
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| 51 | public function __construct(array $input = []) |
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| 52 | { |
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| 53 | foreach($input as $item) { |
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| 54 | $this->pushBack($item); |
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| 55 | } |
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| 56 | } |
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| 57 | |||
| 58 | /** |
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| 59 | * Pushes element to front of list |
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| 60 | * @param mixed $data data value of element |
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| 61 | * @return LinkedListItem |
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| 62 | */ |
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| 63 | public function pushFront($data): LinkedListItem |
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| 64 | { |
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| 65 | return $this->pushAfter(null, $data); |
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| 66 | } |
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| 67 | |||
| 68 | /** |
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| 69 | * Pushes element to back of list |
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| 70 | * @param mixed $data data value of element |
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| 71 | * @return LinkedListItem |
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| 72 | */ |
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| 73 | public function pushBack($data): LinkedListItem |
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| 74 | { |
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| 75 | return $this->pushBefore(null, $data); |
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| 76 | } |
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| 77 | |||
| 78 | /** |
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| 79 | * Pushes new element to after target element position |
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| 80 | * @param LinkedListItem|null $item target element position |
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| 81 | * @param mixed $data data value of new element |
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| 82 | * @return LinkedListItem |
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| 83 | */ |
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| 84 | public function pushAfter(?LinkedListItem $item, $data): LinkedListItem |
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| 85 | { |
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| 86 | $newItem = new LinkedListItem($data, null, null); |
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| 87 | |||
| 88 | if($item === null) { |
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| 89 | if($this->first !== null) { |
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| 90 | return $this->pushBefore($this->first, $data); |
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| 91 | } |
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| 92 | $this->first = $newItem; |
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| 93 | $this->last = $newItem; |
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| 94 | } else { |
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| 95 | $bufNext = $item->getNext(); |
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| 96 | $item->setNext($newItem); |
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| 97 | $newItem->setPrev($item); |
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| 98 | $newItem->setNext($bufNext); |
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| 99 | |||
| 100 | if($bufNext === null) { |
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| 101 | $this->last = $newItem; |
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| 102 | } else { |
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| 103 | $bufNext->setPrev($newItem); |
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| 104 | } |
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| 105 | } |
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| 106 | |||
| 107 | $this->length++; |
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| 108 | |||
| 109 | return $newItem; |
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| 110 | } |
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| 111 | |||
| 112 | /** |
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| 113 | * Pushes new element to before target element position |
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| 114 | * @param LinkedListItem|null $item target element position |
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| 115 | * @param mixed $data data value of new element |
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| 116 | * @return LinkedListItem |
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| 117 | */ |
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| 118 | public function pushBefore(?LinkedListItem $item, $data): LinkedListItem |
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| 119 | { |
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| 120 | $newItem = new LinkedListItem($data, null, null); |
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| 121 | |||
| 122 | if($item === null) { |
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| 123 | if($this->last !== null) { |
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| 124 | return $this->pushAfter($this->last, $data); |
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| 125 | } |
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| 126 | $this->first = $newItem; |
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| 127 | $this->last = $newItem; |
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| 128 | } else { |
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| 129 | $bufPrev = $item->getPrev(); |
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| 130 | $item->setPrev($newItem); |
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| 131 | $newItem->setNext($item); |
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| 132 | $newItem->setPrev($bufPrev); |
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| 133 | |||
| 134 | if($bufPrev === null) { |
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| 135 | $this->first = $newItem; |
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| 136 | } else { |
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| 137 | $bufPrev->setNext($newItem); |
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| 138 | } |
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| 139 | } |
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| 140 | |||
| 141 | $this->length++; |
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| 142 | |||
| 143 | return $newItem; |
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| 144 | } |
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| 145 | |||
| 146 | /** |
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| 147 | * Removes element from the front of list |
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| 148 | * @return mixed data value of removed element |
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| 149 | * @throws LinkedListException |
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| 150 | */ |
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| 151 | public function popFront() |
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| 152 | { |
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| 153 | if(!$this->length) { |
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| 154 | throw new LinkedListException('empty', LinkedListException::STATUS_EMPTY); |
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| 155 | } |
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| 156 | return $this->popFrontPosition()->getData(); |
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| 157 | } |
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| 158 | |||
| 159 | /** |
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| 160 | * Removes element from the back of list |
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| 161 | * @return mixed data value of removed element |
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| 162 | * @throws LinkedListException |
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| 163 | */ |
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| 164 | public function popBack() |
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| 165 | { |
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| 166 | return $this->popBackPosition()->getData(); |
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| 167 | } |
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| 168 | |||
| 169 | /** |
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| 170 | * Removes element from the front of list |
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| 171 | * @return LinkedListItem removed element position |
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| 172 | * @throws LinkedListException |
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| 173 | */ |
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| 174 | public function popFrontPosition(): LinkedListItem |
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| 175 | { |
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| 176 | if(!$this->length) { |
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| 177 | throw new LinkedListException('empty', LinkedListException::STATUS_EMPTY); |
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| 178 | } |
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| 179 | return $this->delete($this->first); |
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|
Bug
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| 180 | } |
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| 181 | |||
| 182 | /** |
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| 183 | * Removes element from the back of list |
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| 184 | * @return LinkedListItem removed element position |
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| 185 | * @throws LinkedListException |
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| 186 | */ |
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| 187 | public function popBackPosition(): LinkedListItem |
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| 188 | { |
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| 189 | if(!$this->length) { |
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| 190 | throw new LinkedListException('empty', LinkedListException::STATUS_EMPTY); |
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| 191 | } |
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| 192 | return $this->delete($this->last); |
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| 193 | } |
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| 194 | |||
| 195 | /** |
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| 196 | * Removes element from target element position |
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| 197 | * @param LinkedListItem $item target element position |
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| 198 | * @return LinkedListItem old position of element |
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| 199 | */ |
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| 200 | public function delete(LinkedListItem $item): LinkedListItem |
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| 201 | { |
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| 202 | $prev = $item->getPrev(); |
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| 203 | $next = $item->getNext(); |
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| 204 | |||
| 205 | if($prev !== null) { |
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| 206 | $prev->setNext($next); |
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| 207 | } else { |
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| 208 | $this->first = $next; |
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| 209 | } |
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| 210 | |||
| 211 | if($next !== null) { |
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| 212 | $next->setPrev($prev); |
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| 213 | } else { |
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| 214 | $this->last = $prev; |
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| 215 | } |
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| 216 | |||
| 217 | $this->length--; |
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| 218 | |||
| 219 | return $item; |
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| 220 | } |
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| 221 | |||
| 222 | /** |
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| 223 | * Swaps two elements |
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| 224 | * @param LinkedListItem $lhs first element position |
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| 225 | * @param LinkedListItem $rhs second element position |
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| 226 | * @return $this |
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| 227 | */ |
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| 228 | public function swap(LinkedListItem $lhs, LinkedListItem $rhs): self |
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| 270 | } |
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| 271 | |||
| 272 | /** |
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| 273 | * Clears list |
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| 274 | * @return $this |
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| 275 | */ |
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| 276 | public function clear(): self |
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| 277 | { |
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| 278 | $this->first = null; |
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| 279 | $this->last = null; |
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| 280 | $this->length = 0; |
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| 281 | return $this; |
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| 282 | } |
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| 283 | |||
| 284 | /** |
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| 285 | * Sorts element via comparator callback |
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| 286 | * @param callable $comparator comparator callback |
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| 287 | * @return $this |
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| 288 | * @throws Exception |
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| 289 | */ |
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| 290 | public function sort(callable $comparator): self |
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| 291 | { |
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| 292 | if($this->length <= 1) { |
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| 293 | return $this; |
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| 294 | } |
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| 295 | |||
| 296 | do { |
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| 297 | $flagStop = true; |
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| 298 | $it = $this->getIterator(); |
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| 299 | $it->rewind(); |
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| 300 | for($i=0; $i<$this->length-1; $i++) { |
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| 301 | $lhs = $it->current(); |
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| 302 | /** @var LinkedListItem $lhsItem */ |
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| 303 | $lhsItem = $it->key(); |
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| 304 | |||
| 305 | $it->next(); |
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| 306 | $rhs = $it->current(); |
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| 307 | /** @var LinkedListItem $rhsItem */ |
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| 308 | $rhsItem = $it->key(); |
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| 309 | |||
| 310 | if($comparator($lhs, $rhs, $lhsItem, $rhsItem)) { |
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| 311 | $this->swap($lhsItem, $rhsItem); |
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| 312 | $flagStop = false; |
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| 313 | } |
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| 314 | } |
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| 315 | } while(!$flagStop); |
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| 316 | |||
| 317 | return $this; |
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| 318 | } |
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| 319 | |||
| 320 | /** |
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| 321 | * Converts list to array |
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| 322 | * @return array |
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| 323 | */ |
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| 324 | public function toArray(): array |
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| 325 | { |
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| 326 | $result = []; |
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| 327 | foreach($this as $val) { |
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| 328 | $result[] = $val; |
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| 329 | } |
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| 330 | |||
| 331 | return $result; |
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| 332 | } |
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| 333 | |||
| 334 | /** |
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| 335 | * Returns first position of list |
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| 336 | * @return LinkedListItem|null |
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| 337 | */ |
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| 338 | public function getFirst(): ?LinkedListItem |
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| 339 | { |
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| 340 | return $this->first; |
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| 341 | } |
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| 342 | |||
| 343 | /** |
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| 344 | * Returns last position of list |
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| 345 | * @return LinkedListItem|null |
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| 346 | */ |
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| 347 | public function getLast(): ?LinkedListItem |
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| 348 | { |
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| 349 | return $this->last; |
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| 350 | } |
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| 351 | |||
| 352 | /** |
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| 353 | * Returns list iterator |
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| 354 | * @return LinkedListIterator |
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| 355 | */ |
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| 356 | public function getIterator(): LinkedListIterator |
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| 357 | { |
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| 358 | return new LinkedListIterator($this); |
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| 359 | } |
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| 360 | |||
| 361 | /** |
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| 362 | * Returns list size |
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| 363 | * @return int |
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| 364 | */ |
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| 365 | public function count(): int |
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| 366 | { |
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| 367 | return $this->length; |
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| 368 | } |
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| 369 | |||
| 370 | /** |
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| 371 | * Inserts element before specified position |
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| 372 | * @param LinkedListItem|null $positionFor position to insert before |
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| 373 | * @param LinkedListItem $element element to insert |
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| 374 | * @return $this |
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| 375 | */ |
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| 376 | protected function setPrevFor(?LinkedListItem $positionFor, LinkedListItem $element): self |
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| 377 | { |
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| 378 | if($positionFor !== null) { |
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| 379 | $positionFor->setPrev($element); |
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| 380 | } else { |
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| 381 | $this->last = $element; |
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| 382 | } |
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| 383 | |||
| 384 | return $this; |
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| 385 | } |
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| 386 | |||
| 387 | /** |
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| 388 | * Inserts element after specified position |
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| 389 | * @param LinkedListItem|null $positionFor position to insert after |
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| 390 | * @param LinkedListItem $element element to insert |
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| 391 | * @return $this |
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| 392 | */ |
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| 393 | protected function setNextFor(?LinkedListItem $positionFor, LinkedListItem $element): self |
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| 394 | { |
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| 395 | if($positionFor !== null) { |
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| 396 | $positionFor->setNext($element); |
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| 397 | } else { |
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| 398 | $this->first = $element; |
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| 399 | } |
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| 400 | |||
| 401 | return $this; |
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| 402 | } |
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| 403 | |||
| 404 | /** |
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| 405 | * Returns positions array |
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| 406 | * @return LinkedListItem[] |
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| 407 | */ |
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| 408 | public function getPositionsArray(?callable $mapper = null): array |
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| 409 | { |
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| 410 | $result = []; |
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| 411 | |||
| 412 | foreach($this as $pos => $val) { |
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| 413 | if(is_callable($mapper)) { |
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| 414 | $result[$mapper($pos)] = $pos; |
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| 415 | } else { |
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| 416 | $result[] = $pos; |
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| 417 | } |
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| 418 | } |
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| 419 | |||
| 420 | return $result; |
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| 421 | } |
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| 422 | |||
| 423 | /** |
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| 424 | * Returns index of position in list |
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| 425 | * @param LinkedListItem $position position to get index |
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| 426 | * @return int |
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| 427 | */ |
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| 428 | public function getIndexOf(LinkedListItem $position): int |
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| 439 | } |
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| 440 | |||
| 441 | /** |
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| 442 | * Debug method to check integrity of list structure |
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| 443 | * @return $this |
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| 444 | * @throws LinkedListException |
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| 445 | */ |
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| 446 | public function checkIntegrity(): self |
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| 498 | } |
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| 499 | |||
| 500 | /** |
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| 501 | * Clones object |
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| 502 | */ |
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| 503 | public function __clone() |
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| 518 | } |
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| 519 | } |
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| 520 | } |
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| 521 |
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