src/Zend/Filter/File/Rename.php
public function filter($value)
    {
        $file   = $this->getNewName($value, true);
        if (is_string($file)) {
            return $file;
        }

        $result = rename($file['source'], $file['target']);

        if ($result === true) {
            return $file['target'];
        }

        throw new Zend_Filter_Exception(sprintf("File '%s' could not be renamed. An error occured while processing the file.", $value));
    }
public function filter($value)
    {
        $file   = $this->getNewName($value, true);
        if (is_string($file)) {
            return $file;
        }

        $result = rename($file['source'], $file['target']);

        if ($result === true) {
            return $file['target'];
        }

        throw new Zend_Filter_Exception(sprintf("File '%s' could not be renamed. An error occured while processing the file.", $value));
    }
Defined by Zend_Filter_Interface

Renames the file $value to the new name set before
Returns the file $value, removing all but digit characters

@param  string $value Full path of file to change
@throws Zend_Filter_Exception
@return string The new filename which has been set, or false when there were errors