Splitting and combining files - php

Question

I have sort of a "beginning" of a solution.
I wrote this function (Sorry about the spacings):
<?php
set_time_limit(0);
// Just to get the remote filesize
function checkFilesize($url, $user = "", $pw = ""){
ob_start();
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch, CURLOPT_NOBODY, 1);
if(!empty($user) && !empty($pw)){
$headers = array('Authorization: Basic ' . base64_encode("$user:$pw"));
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
}
$ok = curl_exec($ch);
curl_close($ch);
$head = ob_get_contents();
ob_end_clean();
$regex = '/Content-Length:\s([0-9].+?)\s/';
$count = preg_match($regex, $head, $matches);
return isset($matches[1]) ? $matches[1] : "unknown";
}
// Split filesize to threads
function fileCutter($filesize,$threads){
$calc = round($filesize / count($threads));
$count = 0;
foreach($threads as $thread){
$rounds[$count] = $calc;
$count++;
}
$count = 0;
foreach($rounds as $round){
$set = $count + 1;
if($count == 0){
$from = 0;
} else {
$from = ($round * $count);
}
$cal = ($round * $set);
$final[$count] = array('from'=>$from,'to'=>$cal);
$count++;
}
// Correct the "Rounded" result
$end = end($final);
$differance = $filesize - $end['to'];
if (strpos($differance,'-') !== false) {} else {$add = '+';}
$end_result = ($end['to'].$add.$differance);
$value=eval("return ($end_result);");
$end_id = end(array_keys($final));
$final[$end_id]['to'] = $value;
// Return the complete array with the corrected result
return $final;
}
$threads = array(
0=>'test',
1=>'test',
2=>'test',
3=>'test',
4=>'test',
5=>'test',
);
$file = 'http://www.example.com/file.zip';
$filesize = checkFilesize($file);
$cuts = fileCutter($filesize,$threads);
print_r($cuts);
?>
(Again, Sorry. :) )
It gives "directions" to split the file in specific bytes.
I've tried to do something like so:
foreach($cuts as $cut){
$start = $cut['from'];
$finish = $cut['to'];
$f = fopen($file, "rb");
fseek($f, $start, SEEK_SET);
while(!(ftell($f) > $finish)){
$data = fgetc($f);
}
fclose($f);
But it's going to a endless loop.
What is the problem? or, is there another solution in PHP to split and combine files?

Answer 1

Instead of reading the file manually and byte-wise you could just use file_get_contents() with the according parameters $offset and $maxlen:
// $incp $ctx $offset $maxlen
$data = file_get_contents($fn, FALSE, NULL, $start, $finish-$start);
That'll do the seeking and cutting for you.