parse paths in php

path parse.php

class fpParser{
    
    public $path;
    public $basename;
    public $basename_noext;
    public $basename_noext_noiteration;
    public $extention;
    public $directory_sep;
    public $dir_tree;
    public $iteration;
    
    public function __construct($path, $directory_sep = '/'){
        $this->directory_sep = $directory_sep;
        $this->path = $path;
        $this->parsePath();
    }
    
    private function parsePath(){
        $path_parts = explode($this->directory_sep, $this->path);
        if(empty($path_parts)) throw new Error("What you talkin' 'bout, Willis?");
        $this->basename = array_pop($path_parts);
        $this->dir_tree = $path_parts;
        if(substr($this->basename, 0, 1) === '.'){
            $this->basename_noext = $this->basename;
        }else{
            $name_parts = explode(".", $this->basename, 2);
            $this->basename_noext = array_shift($name_parts);
            if(!empty($name_parts)){
                $this->extention = array_shift($name_parts);
            }
        }
        
        preg_match('/.*\_(\d+)$/', $this->basename_noext, $matches);
        
        if(!empty($matches)){
            $strlen = strlen($this->basename_noext) - (strlen($matches[1]) + 1);
            $this->basename_noext_noiteration = substr($this->basename_noext, 0, $strlen);
            $this->iteration = intval($matches[1]);
        }else{
            $this->basename_noext_noiteration = $this->basename_noext;
        }
    }
    
    private function rebuildPath(){
        $path = '';
        
        if(!empty($this->dir_tree)){
            $path .= implode($this->directory_sep, $this->dir_tree);
            $path .= $this->directory_sep;
        }
        
        $path .= $this->basename_noext_noiteration;
        
        if(!empty($this->iteration)){
            $path .= "_" . $this->iteration;
        }
        if(!empty($this->extention)){
            $path .= "." . $this->extention;
        }
        $this->path = $path;
        $this->parsePath();
    }
    
    public static function sanitizeBasename($basename){
        return preg_replace('/[^a-zA-Z0-9\-\_\.]+/', '_', $basename);
    }
    
    public function iterate(){
        if(empty($this->iteration)) $this->iteration = 0;
        $this->iteration++;
        $this->rebuildPath();
    }
    
}

$basename = fpParser::sanitizeBasename("asdf3$@%$^#$%^@#452345345433.po.pop");
$parser = new fpParser($basename);

echo $parser->path . "\n";

$parser->iterate();
echo $parser->path . "\n";

$parser->iterate();
echo $parser->path . "\n";