<?php
class SharedArray implements ArrayAccess, IteratorAggregate, Countable {
 	private $db = NULL;
	private $result;

	public function __construct() {
		if ($this->db === NULL && $this->db = sqlite_open('shared_array.db')) {
			@sqlite_query(
				$this->db,
				'CREATE TABLE shared_array
				(offset varchar(32) PRIMARY KEY,
				value  text);'
			);
		}
 	}

	public function __destruct() {
		if ($this->db !== NULL) {
			sqlite_close($this->db);
		}
		$this->db = NULL;
	}

	public function offsetExists($offset) {
		$result = sqlite_query(
			$this->db,
			"SELECT offset
			   FROM shared_array
			  WHERE offset = '$offset';"
			);

		if ($result === FALSE) {
			return FALSE;
		} else {
			return TRUE;
		}
	}

	public function offsetGet($offset) {
		return sqlite_fetch_single(
			sqlite_query(
			  $this->db,
			  "SELECT value
			     FROM shared_array
			    WHERE offset = '$offset';"
			)
		);
	}

	public function offsetSet($offset, $value) {
		sqlite_query(
		  $this->db,
		  "REPLACE INTO shared_array
		           (offset, value)
		    VALUES ('$offset', '$value');"
		);
	}

	public function offsetUnset($offset) {
		sqlite_query(
		  $this->db,
		  "DELETE FROM shared_array
		    WHERE offset = '$offset'"
		);
	}

	// wegen interface IteratorAggregate
	public function getIterator() {
		return new SharedArrayIterator($this->db);
	}

	// wegen interface Countable
	public function count() {
		$this->result = sqlite_query($this->db, 'SELECT * FROM shared_array');
		return sqlite_num_rows($this->result);
	}

	public function purge() {
		sqlite_query(
			$this->db,
			"DELETE FROM shared_array"
		);
	}
}

class SharedArrayIterator implements Iterator {
	private $result;
	private $position;

	public function __construct(&$resource) {
		$this->result = sqlite_query($resource, "SELECT offset, value FROM shared_array");
	}

	public function rewind() {
		$this->position = 0;
	}

	public function valid() {
		return $this->position < sqlite_num_rows($this->result);
	}

	public function key() {
		$current = sqlite_current($this->result);
		return $current['offset'];
	}

	public function current() {
		$current = sqlite_current($this->result);
		return $current['value'];
	}

	public function next() {
		sqlite_next($this->result);
		$this->position++;
	}
}
?>