file_split('g:/tmp/tmp.rar', 4);
function file_split($file, $partsize = 10){
$partsize *= 1048576;
$fh = fopen($file, 'rb');
$fileinfo = pathinfo($file);
$part = 1;
$size = 0;
$filename = "{$fileinfo['dirname']}/{$fileinfo['filename']}.p%02d.{$fileinfo['extension']}";
$fp = fopen(sprintf($filename, $part), 'wb');
while($s = fread($fh, 61440)){
$size += strlen($s);
if($size >= $partsize){
$size = $size - $partsize;
fwrite($fp, substr($s, 0, -$size));
$part++;
$s = substr($s, -$size);
$fp = fopen(sprintf($filename, $part), 'wb');
}
fwrite($fp, $s);
}
}