CFile::realPath PHP Method

    private function realPath($supplied_path, $dir_separator = DIRECTORY_SEPARATOR)
    {
        $current_path = $supplied_path;
        if (!strlen($current_path)) {
            return $dir_separator;
        }
        $win_drive = '';
        // Windows OS path type detection
        if (!strncasecmp(PHP_OS, 'win', 3)) {
            $current_path = preg_replace('/[\\\\\\/]/', $dir_separator, $current_path);
            if (preg_match('/([a-zA-Z]\\:)(.*)/', $current_path, $matches)) {
                $win_drive = $matches[1];
                $current_path = $matches[2];
            } else {
                $workingDir = getcwd();
                $win_drive = substr($workingDir, 0, 2);
                if ($current_path[0] !== $dir_separator[0]) {
                    $current_path = substr($workingDir, 3) . $dir_separator . $current_path;
                }
            }
        } elseif ($current_path[0] !== $dir_separator) {
            $current_path = getcwd() . $dir_separator . $current_path;
        }
        $paths = array();
        foreach (explode($dir_separator, $current_path) as $path) {
            if (strlen($path) && $path !== '.') {
                if ($path == '..') {
                    array_pop($paths);
                } else {
                    $paths[] = $path;
                }
            }
        }
        $realpath = $win_drive . $dir_separator . implode($dir_separator, $paths);
        if ($current_path != $supplied_path) {
            $this->addLog('Path "' . $supplied_path . '" resolved into "' . $realpath . '"', 'trace');
        }
        return $realpath;
    }