// emulate large fseek($fp, $pos, SEEK_SET) on 32-bit system
// requires bcmath
function emulated_fseek($fp, $pos) {
    if(bccomp((string)PHP_INT_MAX, $pos, 0) > -1) // small, do it natively
        fseek($fp, (int)$pos, SEEK_SET);
    else {
        fseek($fp, PHP_INT_MAX, SEEK_SET);
        fread($fp, 1); // get past fseek limitation
        $pos = bcsub(bcsub($pos, (string)PHP_INT_MAX), 1);

        $chunk = 8192-1; // get around weird 8KB limitation
        while($pos) {
            if(bccomp((string)$chunk, $pos, 0) > -1) {
                fseek($fp, (int)$pos, SEEK_CUR);
                break;
            }
            else {
                fseek($fp, $chunk, SEEK_CUR);
                fread($fp, 1);
                $pos = bcsub($pos, (string)($chunk+1));
            }
        }
    }
}