File upload in codeiginter

/*
+-----------------------------------------+
This Function will return file upload or not.
@params : $uploadFile -> input file name
$filetype -> file type parameter eg. img, doc..
$folder -> upload folder path name
$fileName -> file name
+-----------------------------------------+
*/
function uploadFile($uploadFile, $filetype, $folder, $watermark=false, $fileName='')
{
$resultArr = array();

$config['max_size'] = '1024000';
if($filetype == 'img') $config['allowed_types'] = 'gif|jpg|png|jpeg|JPEG';
if($filetype == 'All') $config['allowed_types'] = '*';
if($filetype == 'pdf') $config['allowed_types'] = 'pdf';
if($filetype == 'doc') $config['allowed_types'] = 'pdf|doc|docx|xls|ppt|rtf|xlsx|pptx|swf|gif|jpg|png|jpeg|txt|csv|text|TEXT|ACL|AFP|ANS|CSV|CWK|STW|RPT|PDAX|PAP|PAGES|SXW|STW|QUOX|WRI|XML|HTML|MCW|XPS|TXT|ABW|JPEG|PNG|SWF|PPT|PPTX|PDF|DOC|DOCX|XLS|XLSX|TeX';
if($filetype == 'csv') $config['allowed_types'] = 'csv';
if($filetype == 'swf') $config['allowed_types'] = 'swf';
if($filetype == 'video') $config['allowed_types'] = 'flv|mp4|mov';

$config['upload_path'] = $folder;
if($fileName != "")
$config['file_name'] = $fileName;

$this->load->library('upload', $config);
$this->upload->initialize($config);

if(!$this->upload->do_upload($uploadFile))
{
$resultArr['success'] = false;
$resultArr['error'] = $this->upload->display_errors();
}
else //if file upload
{
$resArr = $this->upload->data();
$fullname = $resArr['file_name'];

$resultArr['success'] = true;
$resultArr['path'] = $folder."/".$fullname;

if($watermark) //if watermark image
$this->watermark($fullname);
}
return $resultArr;
}