MemcacheCollection.php

<?php

class MemcacheCollection {

	protected function getIndexes() {
		$result = $this->instance->get('collection_indexes');

		return json_decode($result);
	}

	protected function updateIndexes(array $indexes) {
		$value = json_encode($indexes);

		$this->instance->set('collection_indexes', $value);
	}

	protected function getFirstIndex() {
		$indexes = $this->getIndexes();

		return min($indexes);
	}

	protected function getLastIndex() {
		$indexes = $this->getIndexes();

		return max($indexes);
	}

	protected function createNextIndex() {
		$indexes = $this->getIndexes();

		$key = max($indexes) + 1;

		$indexes[] = $key;

		$this->updateIndexes($indexes);

		return $key;
	}

	public function push($value) {
		$key = $this->createNextIndex();

		$this->instance->set(sprintf('collection:%d', $key), $value);
	}

	protected function removeIndex($key) {
		$indexes = $this->getIndexes();

		$index = array_search($key, $indexes);

		unset($indexes[$index]);

		$this->updateIndexes($indexes);
	}

	protected function get($key) {
		$this->removeIndex($key);

		$result = $this->instance->get(sprintf('collection:%d', $key));

		$this->instance->delete(sprintf('collection:%d', $key));

		return $result;
	}

	public function pop() {
		$key = $this->getLastIndex();

		return $this->get($key);
	}

	public function shift() {
		$key = $this->getFirstIndex();

		return $this->get($key);
	}

}