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<?php |
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namespace Ds\Traits; |
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/** |
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* Common to structures that deal with an internal capacity. While none of the |
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* PHP implementations actually make use of a capacity, it's important to keep |
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* consistent with the extension. |
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*/ |
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trait Capacity |
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{ |
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/** |
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* @var int internal capacity |
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*/ |
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private $capacity = self::MIN_CAPACITY; |
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/** |
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* Returns the current capacity. |
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* |
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* @return int |
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*/ |
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public function capacity(): int |
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{ |
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return $this->capacity; |
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} |
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/** |
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* Ensures that enough memory is allocated for a specified capacity. This |
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* potentially reduces the number of reallocations as the size increases. |
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* |
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* @param int $capacity The number of values for which capacity should be |
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* allocated. Capacity will stay the same if this value |
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* is less than or equal to the current capacity. |
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*/ |
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public function allocate(int $capacity) |
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{ |
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$this->capacity = max($capacity, $this->capacity); |
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} |
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/** |
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* Called when capacity should be increased to accommodate new values. |
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*/ |
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abstract protected function increaseCapacity(); |
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/** |
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* Adjusts the structure's capacity according to its current size. |
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*/ |
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1922 |
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private function adjustCapacity() |
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{ |
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1922 |
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$size = count($this); |
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// Automatically truncate the allocated buffer when the size of the |
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// structure drops low enough. |
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1922 |
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if ($size < $this->capacity / 4) { |
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$this->capacity = max(self::MIN_CAPACITY, $this->capacity / 2); |
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} else { |
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// Also check if we should increase capacity when the size changes. |
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if ($size >= $this->capacity) { |
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$this->increaseCapacity(); |
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} |
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} |
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} |
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} |
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php-ds /
polyfill
