File download from server in php. Why the browser thinks the file size is bigger than it is?

$this->file_size equal filesize($this->file_addr) , and this 1163748924 (1,08 GB)

But the browser thinks the file is 1.16.


I see that if the number of bytes to transfer in Gigabytes by dividing by 1024, you get a 1.08 (actual file size), but if by dividing by 1000, we get to 1.16. Given to browser (int)$file_size/1024/1024/1024*1000*1000*1000 - he saw 1.08 GB, but it has no effect.


If the Content-length header to remove, the download works.
With the files that are 500 MB, 50 MB and less is working. The file size of 1.08, or 1.16, 1,27 GB found the described problem.

The problem is this: the server gives the browser the file to the end and stops as it should. But the Browser thinks that the file is not transmitted to the end and believes that the transfer failed. The size of the downloaded file is of 1.08 and it opened quietly.

This assumption appeared after the file is transferred to the end, the browser is expecting something else from the server, and server just shuts down.

Here is the server code:

header('Content-Description: File Transfer');
 header('Content-Type: application/octet-stream');
 header('Content-Disposition: attachment; filename="'.$this->file_name.'"');
 header('Content-Length:' . $this->file_size);
flush();

ignore_user_abort(false);
 ini_set('output_buffering', 0);
 ini_set('zlib.output_compression', 0);

ob_end_flush();
 $handle = fopen($this->file_addr, "rb");
 while (!feof($handle)){
 echo fread($handle, 8192);
 ob_flush(); // flush output
flush();
}
 fclose($handle);

Here's the headlines:

Cache-Control 
no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Connection 
keep-alive
Content-Description 
File Transfer
Content-Disposition 
attachment; filename="Файл_1.tif"
Content-Length 
1163748924
Content-Type 
image/tiff
Date 
Wed, 18 May 2016 13:35:20 GMT
Expires 
Thu, 19 Nov 1981 08:52:00 GMT
Pragma 
no-cache
Server 
nginx
X-Powered-By 
PHP/5.4.45-0+deb7u2
content-transfer-encoding 
binary