<?php class Image { public function __construct($path) { $this->image = imagecreatefromjpeg($path); } public function getSize() { return array(imagesx($this->image), imagesy($this->image)); } } class ImageProxy extends Image { protected $image; public function __construct($path) { $this->path = $path; } private function init() { if ( ! $this->image) { $this->image = new Image($this->path); } } public function getSize() { $this->init(); return $this->image->getSize(); } } $img1 = new ImageProxy('/path/to/image1.jpg'); var_dump(memory_get_usage()); // ~200Kb $img2 = new ImageProxy('/path/to/image2.jpg'); var_dump(memory_get_usage()); // ~200Kb $img3 = new ImageProxy('/path/to/image3.jpg'); var_dump(memory_get_usage()); // ~200Kb $size1 = $img1->getSize(); var_dump(memory_get_usage()); // ~4Mb $size2 = $img2->getSize(); var_dump(memory_get_usage()); // ~8Mb
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