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<?php |
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namespace Chadicus\Spl\DataStructures; |
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/** |
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* Unordered bag collection. |
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*/ |
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final class Bag implements BagInterface, \JsonSerializable |
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{ |
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/** |
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* @var array |
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*/ |
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private $elements = []; |
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/** |
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* @var integer |
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*/ |
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private $position; |
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/** |
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* Adds a new element to the bag. |
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* |
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* @param mixed $element The element to add. |
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* |
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* @return Bag |
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*/ |
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public function add($element) |
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{ |
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array_unshift($this->elements, $element); |
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shuffle($this->elements); |
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return $this; |
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} |
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/** |
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* Removes a random element from the bag. |
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* |
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* @return mixed |
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* |
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* @throws \RuntimeException Thrown if remove is called on an empty bag. |
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*/ |
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public function remove() |
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{ |
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if (empty($this->elements)) { |
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throw new \RuntimeException('Bag is empty'); |
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} |
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return array_pop($this->elements); |
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} |
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/** |
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* Returns true if the bag contains no elements. |
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* |
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* @return boolean |
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*/ |
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public function isEmpty() |
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{ |
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return empty($this->elements); |
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} |
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/** |
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* @see \Iterator::rewind() |
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* |
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* @return void |
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*/ |
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public function rewind() |
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{ |
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$this->position = 0; |
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shuffle($this->elements); |
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} |
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/** |
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* @see \Iterator::current() |
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* |
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* @return mixed |
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*/ |
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public function current() |
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{ |
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return $this->elements[$this->position]; |
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} |
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/** |
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* @see \Iterator::key() |
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* |
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* @return integer |
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*/ |
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public function key() |
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{ |
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return $this->position; |
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} |
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/** |
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* @see \Iterator::next() |
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* |
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* @return void |
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*/ |
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public function next() |
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{ |
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++$this->position; |
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} |
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/** |
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* @see \Iterator::valid() |
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* |
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* @return boolean |
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*/ |
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public function valid() |
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{ |
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return isset($this->elements[$this->position]); |
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} |
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/** |
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* @see \JsonSerializable::jsonSerialize() |
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* |
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* @return array |
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*/ |
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public function jsonSerialize() |
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{ |
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return $this->elements; |
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} |
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/** |
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* @see \Countable::count() |
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* |
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* @return integer |
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*/ |
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public function count() |
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{ |
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return count($this->elements); |
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} |
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/** |
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* @see CollectionInterface::clear() |
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* |
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* @return Bag |
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*/ |
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public function clear() |
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{ |
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$this->elements = []; |
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return $this; |
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} |
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} |
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