A few versions of AbstractUri::cleanPath()

UriCleanPath.php

<?php

$max = 0;

// class Profiler
// {
//     private $_data_array = array();
//     private $max = 0;
//
//     function __construct()
//     {
//         register_tick_function( array( $this, "tick" ) );
//         declare(ticks = 1);
//     }
//
//     function __destruct()
//     {
//         unregister_tick_function( array( $this, "tick" ) );
//     }
//
//     function tick()
//     {
//         //$this->_data_array[] = array(
//             //"memory" => memory_get_usage(),
//             //"time" => microtime( TRUE ),
//             //if you need a backtrace you can uncomment this next line
//             //"backtrace" => debug_backtrace( FALSE ),
//         //);
//         $this->max = max($this->max, memory_get_usage());
//     }
//
//     function getDataArray()
//     {
//         return $this->max;//_data_array;
//     }
// }

function set_memory_usage($memory) {
	global $max;

	if ($memory > $max) $max = $memory;
}

function cleanPath1($path)
{
	$path = explode('/', preg_replace('#(/+)#', '/', $path));

	for ($i = 0, $n = \count($path); $i < $n; $i++)
	{
		if ($path[$i] == '.' || $path[$i] == '..')
		{
			if (($path[$i] == '.') || ($path[$i] == '..' && $i == 1 && $path[0] == ''))
			{
				unset($path[$i]);
				$path = array_values($path);
				$i--;
				$n--;
			}
			elseif ($path[$i] == '..' && ($i > 1 || ($i == 1 && $path[0] != '')))
			{
				unset($path[$i]);
				unset($path[$i - 1]);
				$path = array_values($path);
				$i -= 2;
				$n -= 2;
			}
		}
	}

	set_memory_usage(memory_get_usage());

	return implode('/', $path);
}

function cleanPath2($path)
{
	$length = strlen($path);

	if ($length && $path[0] === '/')
	{
		// Keep the first slash
		$blocks = array('');
		$total = 1;
		$offset = 1;
	}
	else
	{
		$blocks = array();
		$total  = 0;
		$offset = 0;
	}

	while ($offset < $length)
	{
		$end = strpos($path, '/', $offset);

		if ($end === $offset)
		{
			$offset++;

			continue;
		}

		if ($end === false)
		{
			// Keep the last segment
			$end = $length;
		}

		$block  = substr($path, $offset, $end - $offset);
		$offset = $end + 1;

		if ($block === '.')
		{
			// Remove './'
			continue;
		}

		if ($block === '..')
		{
			if ($total === 1 && $blocks[0] === '')
			{
				// Replace /../foo.php with /foo.php
				continue;
			}

			if ($total >= 1)
			{
				// Replace foo/../boo.php with boo.php
				unset($blocks[$total - 1]);
				$total--;

				continue;
			}
		}

		$blocks[] = $block;
		$total++;
	}

	if ($path[$length - 1] === '/')
	{
		// Keep the last slash
		$blocks[] = '';
	}

	set_memory_usage(memory_get_usage());

	return implode('/', $blocks);
}

function cleanPath3($path)
{
	$segments = explode('/', $path);

	$total  = 0;
	$blocks = array();

	foreach ($segments as $i => $segment)
	{
		if ($segment === '')
		{
			if ($i === 0)
			{
				// Keep the first slash
				$blocks[] = '';
				$total++;
			}

			continue;
		}

		if ($segment === '.')
		{
			// Remove './'
			continue;
		}

		if ($segment === '..')
		{
			if ($total === 1 && $blocks[0] === '')
			{
				// Replace /../foo.php with /foo.php
				continue;
			}

			if ($total >= 1)
			{
				// Replace foo/../boo.php with boo.php
				unset($blocks[$total - 1]);
				$total--;

				continue;
			}
		}

		$blocks[] = $segment;
		$total++;
	}

	if ($path[strlen($path) - 1] === '/')
	{
		// Keep the last slash
		$blocks[] = '';
	}

	set_memory_usage(memory_get_usage());

	return implode('/', $blocks);
}

function cleanPath4($path)
{
	if ($path !== '' && $path[0] === '/')
	{
		// Keep the first slash
		$blocks = array('');
		$total = 1;
	}
	else
	{
		$blocks = array();
		$total  = 0;
	}

	$block = strtok($path, '/');

	while ($block !== false)
	{
		if ($block === '.')
		{
			// Remove './'
			$block = strtok('/');

			continue;
		}

		if ($block === '..')
		{
			if ($total === 1 && $blocks[0] === '')
			{
				// Replace /../foo.php with /foo.php
				$block = strtok('/');

				continue;
			}

			if ($total >= 1)
			{
				// Replace foo/../boo.php with boo.php
				unset($blocks[$total - 1]);
				$total--;

				$block = strtok('/');

				continue;
			}
		}

		$blocks[] = $block;
		$total++;

		$block = strtok('/');
	}

	if ($path[strlen($path) - 1] === '/')
	{
		// Keep the last slash
		$blocks[] = '';
	}

	set_memory_usage(memory_get_usage());

	return implode('/', $blocks);
}

$paths = [
	'/foo/bar/boo.php',
	'/fo1/bar/boo.php',
	'/fo2/bar/boo.php',
	'/fo3/bar/boo.php',
	'/fo4/bar/boo.php',
	'/fo5/bar/boo.php',
	'/fo6/bar/boo.php',
	'/fo7/bar/boo.php',
	'/fo9/bar/boo.php',
	'/fo8/bar/boo.php',
	'/fo0/bar/boo.php',
	'/foe/bar//boo.php',
	'/foo/bar/../boo.php',
	'/foo/bar/../../boo.php',
	'/foo/bar/.././/boo.php',
	'//.//foo//bar//..//.//.//boo.php',
	'/..//foo//bar//..//.//.//boo.php',
	'foo/../boo.php',
	'.//boo.php',
	'../boo.php',
	'boo.php',
	'/',
	'//',
	'/./',
	'./',
	'/folder/',
	'/.',
	'/..',
	'/foo/..',
];

if (!isset($argv[1]) || $argv[1] == '1')
{
	function cleanPath($path) { return cleanPath1($path); }
}
elseif ($argv[1] == '2')
{
	function cleanPath($path) { return cleanPath2($path); }
}
elseif ($argv[1] == '3')
{
	function cleanPath($path) { return cleanPath3($path); }
}
elseif ($argv[1] == '4')
{
	function cleanPath($path) { return cleanPath4($path); }
}

$start = microtime(true);

printf("CleanPath" . (isset($argv[1]) ? $argv[1] : '1') . ":\n");

//$profiler = new Profiler(); //starts logging when created

$m = memory_get_usage();

for ($i=0; $i < 50000; $i++) {
	if ($i === 0) {
		foreach ($paths as $path) {
			printf("\t%s => %s\n", $path, cleanPath($path));
		}
		echo "Total: ";
	}
	else {
		foreach ($paths as $path) cleanPath($path);
	}
}

//$data_array = $profiler->getDataArray();

//unset( $profiler ); //stops logging when __destruct is called

printf("%.4f\tMemory peak: %d\t Function memory peak: %d\n", (microtime(true) - $start), memory_get_peak_usage(), $max - $m);

/*
$start = microtime(true);

printf("CleanPath2:\n");

$profiler = new Profiler(); //starts logging when created

for ($i=0; $i < 50000; $i++) {
        if ($i === 0) {
                foreach ($paths as $path) {
                        printf("\t%s => %s\n", $path, cleanPath2($path));
                }
        }
        else {
                foreach ($paths as $path) cleanPath2($path);
        }
}

$data_array = $profiler->getDataArray();

unset( $profiler ); //stops logging when __destruct is called

printf("Total: %.4f\n\n", (microtime(true) - $start));

print_r($data_array);echo "\n\n";

$start = microtime(true);

printf("CleanPath3:\n");

$profiler = new Profiler(); //starts logging when created

for ($i=0; $i < 50000; $i++) {
        if ($i === 0) {
                foreach ($paths as $path) {
                        printf("\t%s => %s\n", $path, cleanPath3($path));
                }
        }
        else {
                foreach ($paths as $path) cleanPath3($path);
        }
}

$data_array = $profiler->getDataArray();

unset( $profiler ); //stops logging when __destruct is called

printf("Total: %.4f\n\n", (microtime(true) - $start));

print_r($data_array);echo "\n\n";
*/