fpassthru should get an optional length argument

> ref https://bugs.php.net/bug.php?id=39135 , > i was thinking about how to implement HTTP Range requests/HTTP 206 Partial > Content in userland php, > and ofc it's possible to implement using fread() loops, but it'd be easier > (and faster? presumably) to implement if fpassthru() natively supported a > $max_bytes=null argument, > > an example of where it would be useful: > > <?php > $h=tmpfile(); > fwrite($h,"123456789ABCDEF"); > // this is _NOT_ a proper http-range-parser! > $range = $_SERVER['HTTP_RANGE'] ?? "bytes=5-9"; > $range=explode("-",explode("=",$range,2)[1],2); > $start = (int)$range[0]; > $byte_count = (-$start) + ((int)$range[1]) + 1; // the range format is > weird.. "Range: bytes=5-5" means "seek to byte #5 and serve 1 byte", 5-6 > means "seek to byte #5 and serve 2 bytes"~ > fseek($h,$start,SEEK_SET); > http_response_code(206); // HTTP 206 Partial Content > //echo fread($h,$byte_count); // << this is not suitable for large files, > if 1GB bytes is requested, this will use 1GB ram... > fpassthru($h, $byte_count); > // should print 6789A >