Minimum file size upload

This is my php script for uploading. How to display error and not upload file if it is less then 1kb

<?php

//set where you want to store files
//in this example we keep file in folder upload
//$HTTP_POST_FILES['ufile']['name']; = upload file name
$path= "temp/".$HTTP_POST_FILES['ufile']['name'];
if($ufile !=none)
{
if(copy($HTTP_POST_FILES['ufile']['tmp_name'], $path))
{

echo "<strong>Successful</strong><BR><BR>";

//$HTTP_POST_FILES['ufile']['name'] = file name
//$HTTP_POST_FILES['ufile']['size'] = file size
//$HTTP_POST_FILES['ufile']['type'] = type of file
$_SESSION['kbsize']=round($HTTP_POST_FILES['ufile']['size']/1024);
$_SESSION[name]=$HTTP_POST_FILES['ufile']['name'];

echo "<strong>File Name: </strong>".$HTTP_POST_FILES['ufile']['name']."<BR><BR>";
echo "<strong>File Size: </strong><br>".$HTTP_POST_FILES['ufile']['size']." bytes<BR>"
.$_SESSION['kbsize']. ' Kb<BR>'
.round($HTTP_POST_FILES['ufile']['size']/(1024*1024),3) . ' Mb<BR><BR>';

echo "<strong>Price: </strong>".round($HTTP_POST_FILES['ufile']['size']/1024) ." $<BR><BR>";
echo "<strong>File Type: </strong>".$HTTP_POST_FILES['ufile']['type']."<BR><BR>";

}
else
{
echo "Error";
}
}

?>

Off Topic:

$HTTP_POST_FILES is deprecated, rather use: $_FILES

<?php 

//set where you want to store files 
//in this example we keep file in folder upload 
//$HTTP_POST_FILES['ufile']['name']; = upload file name 
$path= "temp/".$HTTP_POST_FILES['ufile']['name']; 
if($ufile !=none) 
{ 
if($HTTP_POST_FILES['ufile']['size'] <1024)
{
echo "File size is less than 1kb, so it can not be uploaded<br/>";
exit;
}
if(copy($HTTP_POST_FILES['ufile']['tmp_name'], $path)) 
{ 

echo "<strong>Successful</strong><BR><BR>"; 

//$HTTP_POST_FILES['ufile']['name'] = file name 
//$HTTP_POST_FILES['ufile']['size'] = file size 
//$HTTP_POST_FILES['ufile']['type'] = type of file 
$_SESSION['kbsize']=round($HTTP_POST_FILES['ufile']['size']/1024); 
$_SESSION[name]=$HTTP_POST_FILES['ufile']['name']; 

echo "<strong>File Name: </strong>".$HTTP_POST_FILES['ufile']['name']."<BR><BR>"; 
echo "<strong>File Size: </strong><br>".$HTTP_POST_FILES['ufile']['size']." bytes<BR>" 
.$_SESSION['kbsize']. ' Kb<BR>' 
.round($HTTP_POST_FILES['ufile']['size']/(1024*1024),3) . ' Mb<BR><BR>'; 

echo "<strong>Price: </strong>".round($HTTP_POST_FILES['ufile']['size']/1024) ." $<BR><BR>"; 
echo "<strong>File Type: </strong>".$HTTP_POST_FILES['ufile']['type']."<BR><BR>"; 

} 
else 
{ 
echo "Unrecognized error code: ".$HTTP_POST_FILES['ufile']['error'];
} 
} 

?>

thanks a lot.

PHPycho. Why $_FILES?

Obvious answer: $HTTP_POST_FILES is deprecated
http://php.net/manual/en/reserved.variables.files.php