Simple breadcrumb for PHP scripts apps deployed by mapping request paths to the server's filesystem

.htaccess

RewriteEngine On
RewriteRule   index.php index.php            [END]
RewriteRule   (.*)      index.php?request=$1 [END]

index.php

<?php
// This file is UTF-8 encoded
define('BASE_URL', '/breadcrumbs');

function parse($script, $directorySeparator, $skip) {
  mb_regex_encoding('UTF-8');
  mb_internal_encoding('UTF-8');
  $offset = mb_strlen($skip, 'UTF-8');
  $length = mb_strlen($script, 'UTF-8') - $offset;
  $script = mb_substr($script, $offset, $length, 'UTF-8');
  $directorySeparator = preg_quote($directorySeparator);
  return mb_split($directorySeparator, $script);
}

function makeHref($crumbs, $idx, $urlBase) {
  $dst = array();
  foreach (array_slice($crumbs, 0, $idx + 1) as $crumb) {
    $dst []= rawurlencode($crumb);
  }
  return $urlBase . '/' . implode('/', $dst);
}

function makeHtmlWidget($crumbs, $urlBase = '', $separator = '::') {
  $out = '';
  // WARNING: use an appropriate function here, even if XML special characters
  // are invalid in file names of most filesystems out there
  $sanitizeHtml = function($in) { return $in; };
  $caption = function($in) { return $in; };
  $current_separator = '';
  foreach ($crumbs as $idx => $crumb) {
    $href = makeHref($crumbs, $idx, $urlBase);
    $displayLink = $caption($crumb);
    $out .= $current_separator . "<a href='$href'>$displayLink</a>";
    $current_separator = $separator;
  }
  return $out;
}

header("Content-Type: text/html; charset=utf-8");

function test($in, $separator, $skip, $base) {
  $crumbs = parse($in, $separator, $skip);
  echo '<li>' . makeHtmlWidget($crumbs, $base) . '</li>';
}

echo "<ul>";
test('/var/www/app/TR/Pròdùçts/Tàrgét.php', '/', '/var/www/app/', BASE_URL);
test('C:\\xampp\\htdocs\\app\\TR\\Pròduçts\\Tàrgét.php', '\\', 'C:\\xampp\\htdocs\\app\\', BASE_URL);
echo "</ul>";