How save file from after base64 decode?

I am using signature pad and i after click save i can save image in tmp folder. In file model i created saveFile function

public function saveFile($data) {    
    $fileInfo = $this->saveTempFile($data);
}

private function saveTempFile($source) {
    $extension = $source->file('file')->getClientOriginalExtension();
    $dir = rtrim(sys_get_temp_dir(), DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR;
    $fileName = uniqid() . '_' . time() . '.' . $extension;
    $source->file('file')->move($dir, $fileName);

}

When i am taking data from file form is ok i can save. But in signature pad i am using base64 decode and save file like this:

public function saveTempFileFromString($data, $ext) {
    $tempFilename = uniqid();
    $tempFilepath = rtrim(sys_get_temp_dir(), DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR . $tempFilename . '.' . $ext;

    file_put_contents($tempFilepath, $data);
}

 // get base64 data
    $img = str_replace('data:image/png;base64,', '', $request->signature);
    $img = str_replace(' ', '+', $img);

    // decode base64
    $data = base64_decode($img);

    // save to tmp folder from string
    $file = new File;
    $fileInfo = $file->saveTempFileFromString($data, 'png');

How can i use only first function for file from form and file from base64 decode ? is possible to do this ?

via Chebli Mohamed