Members, __set, __get, ArrayAccess and Iterator

Lessons learned:

• __set() is 5 times slower than setting a member
• __get() + __set() is 13 times slower than incrementing a member
• Iterator is 4 times slower than using a member
• ArrayAccess is 3 times slower than setting an element in a member array
• ArrayAccess is 6 times slower than incrementing an element in a member array

Here is the code:

class test1 {
  public $test = null;
  private $_test = null;

  public function __set($id, $val) {
    $this->_test = $val;
  }
}

$start = microtime(true);
$c = new test1();
for ($i=0; $i<1000000; $i++) $c->test = $i;
echo number_format(microtime(true)-$start, 4)."\n"; // 0.1830s

$start = microtime(true);
$c = new test1();
for ($i=0; $i<1000000; $i++) $c->test2 = $i;
echo number_format(microtime(true)-$start, 4)."\n"; // 0.9570s


class test2 {
  private $_data = ['test4'=>0];
  public $test3 = 0;

  public function __set($id, $val) {
    $this->_data[$id] = $val;
  }
  public function __get($id) {
    return $this->_data[$id];
  }
}

$start = microtime(true);
$c = new test2();
for ($i=0; $i<1000000; $i++) $c->test3++;
echo number_format(microtime(true)-$start, 4)."\n"; // 0.1495s

$start = microtime(true);
$c = new test2();
for ($i=0; $i<1000000; $i++) $c->test4++;
echo number_format(microtime(true)-$start, 4)."\n"; // 2.0083s


class test3 implements ArrayAccess {
  private $_data = [0];
  public $data = [0];
  
  public function offsetSet($key, $val) {
    $this->_data[$key] = $val;
  }
  public function offsetGet($key) {
    return $this->_data[$key];
  }
  public function offsetExists($key) {
    return isset($this->_data[$key]);
  }
  public function offsetUnset($key) {
    unset($this->_data[$key]);
  }
}

$start = microtime(true);
$c = new test3();
for ($i=0; $i<1000000; $i++) $c->data[0] = $i;
echo number_format(microtime(true)-$start, 4)."\n"; // 0.2739s

$start = microtime(true);
$c = new test3();
for ($i=0; $i<1000000; $i++) $c[0] = $i;
echo number_format(microtime(true)-$start, 4)."\n"; // 0.9724s

$start = microtime(true);
$c = new test3();
for ($i=0; $i<1000000; $i++) $c->data[0]++;
echo number_format(microtime(true)-$start, 4)."\n"; // 0.2694s

$start = microtime(true);
$c = new test3();
for ($i=0; $i<1000000; $i++) $c[0] = $c[0]+1; // $c[0]++ does not work here
echo number_format(microtime(true)-$start, 4)."\n"; // 1.6771s

$start = microtime(true);
$c = new test3();
for ($i=0; $i<1000000; $i++) $c->data[] = $i;
echo number_format(microtime(true)-$start, 4)."\n"; // 0.4906s

$start = microtime(true);
$c = new test3();
for ($i=0; $i<1000000; $i++) $c[$i] = $i; // $c[] does not work here
echo number_format(microtime(true)-$start, 4)."\n"; // 1.3456s


class test4 {
  public $data = [];
  
  public function __construct() {
    $this->data = range(0,500000);
  }
}

$start = microtime(true);
$c = new test4();
foreach ($c->data as $val) {}
echo number_format(microtime(true)-$start, 4)."\n"; // 0.2541s

$start = microtime(true);
$c = new test4();
foreach ($c->data as $key=>$val) {}
echo number_format(microtime(true)-$start, 4)."\n"; // 0.2704s


class test5 implements Iterator {
  private $_pos = 0;
  private $_data = [];

  public function __construct() {
    $this->_data = range(0,500000);
  }
  function rewind() {
    $this->_pos = 0;
  }
  function current() {
    return $this->_data[$this->_pos];
  }
  function key() {
    return $this->_pos;
  }
  function next() {
    $this->_pos++;
  }
  function valid() {
    return isset($this->_data[$this->_pos]);
  }
}

$start = microtime(true);
$c = new test5();
foreach ($c as $val) {}
echo number_format(microtime(true)-$start, 4)."\n"; // 0.9770s

$start = microtime(true);
$c = new test5();
foreach ($c as $key=>$val) {}
echo number_format(microtime(true)-$start, 4)."\n"; // 1.0400s

Tested with PHP 5.4.5