Xpath descendant benchmark

gistfile1.aw

<?php

require 'Benchmark/Timer.php';
$timer = new Benchmark_Timer();
$nb_iterations = 1000;

/**
 * BOOTSTRAP
 **/

$dom = @DOMDocument::loadHTMLFile('https://github.com/ju1ius/symfony/commit/48117d32ab40f84866ba66ec756ebdaa4268bcff');
$dom->recover = true;
$dom->strictErrorChecking = false;

$xpath = new DOMXpath($dom);

function get_class_query($class)
{
  return "contains(concat(' ',normalize-space(@class),' '), ' $class ')";
}

// Queries unsing *[name() = '%s']
$div_q_1 = "*[name() = 'div' and " . get_class_query('diff-view') . "]";
$el_q_1 = "*[name() = 'td' and " . get_class_query('line_numbers') . "]";

$descendant_query = "//$div_q_1/descendant::$el_q_1";
//var_dump($descendant_query);

$descendant_shortcut_query = "//$div_q_1//$el_q_1";
//var_dump($descendant_shortcut_query);

// Queries unsing tag name
$div_q_2 = "div[".get_class_query('diff-view')."]";
$el_q_2 = "td[".get_class_query('line_numbers')."]";

$descendant_query_2 = "//$div_q_2/descendant::$el_q_2";
//var_dump($descendant_query_2);

$descendant_shortcut_query_2 = "//$div_q_2//$el_q_2";
//var_dump($descendant_shortcut_query_2);


/**
 * TEST RUN
 **/

$timer->start();

for ($i = 0; $i < $nb_iterations; $i++) {
  $nodeset = $xpath->query($descendant_query);
}
var_dump($nodeset->length);
$timer->setMarker('descendant::');

for ($i = 0; $i < $nb_iterations; $i++) {
  $nodeset = $xpath->query($descendant_shortcut_query);
}
var_dump($nodeset->length);
$timer->setMarker('//');

for ($i = 0; $i < $nb_iterations; $i++) {
  $nodeset = $xpath->query($descendant_query_2);
}
var_dump($nodeset->length);
$timer->setMarker('descendant:: with tag');

for ($i = 0; $i < $nb_iterations; $i++) {
  $nodeset = $xpath->query($descendant_shortcut_query_2);
}
var_dump($nodeset->length);
$timer->setMarker('// with tag');


printf("Memory: %s\n", memory_get_usage(true));
printf("Memory peak: %s\n", memory_get_peak_usage(true));

echo $timer->getOutput();

//echo $dom->saveHTML();