AcknowledgePacket.php

<?php
 
/*
 * This file is part of RakLib.
 * Copyright (C) 2014-2022 PocketMine Team <https://github.com/pmmp/RakLib>
 *
 * RakLib is not affiliated with Jenkins Software LLC nor RakNet.
 *
 * RakLib is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 */
 
declare(strict_types=1);
 
namespace raklib\protocol;
 
use pocketmine\utils\Binary;
use function chr;
use function count;
use function sort;
use const SORT_NUMERIC;
 
abstract class AcknowledgePacket extends Packet{
    private const RECORD_TYPE_RANGE = 0;
    private const RECORD_TYPE_SINGLE = 1;
 
    public array $packets = [];
 
    protected function encodePayload(PacketSerializer $out) : void{
        $payload = "";
        sort($this->packets, SORT_NUMERIC);
        $count = count($this->packets);
        $records = 0;
 
        if($count > 0){
            $pointer = 1;
            $start = $this->packets[0];
            $last = $this->packets[0];
 
            while($pointer < $count){
                $current = $this->packets[$pointer++];
                $diff = $current - $last;
                if($diff === 1){
                    $last = $current;
                }elseif($diff > 1){ //Forget about duplicated packets (bad queues?)
                    if($start === $last){
                        $payload .= chr(self::RECORD_TYPE_SINGLE);
                        $payload .= Binary::writeLTriad($start);
                        $start = $last = $current;
                    }else{
                        $payload .= chr(self::RECORD_TYPE_RANGE);
                        $payload .= Binary::writeLTriad($start);
                        $payload .= Binary::writeLTriad($last);
                        $start = $last = $current;
                    }
                    ++$records;
                }
            }
 
            if($start === $last){
                $payload .= chr(self::RECORD_TYPE_SINGLE);
                $payload .= Binary::writeLTriad($start);
            }else{
                $payload .= chr(self::RECORD_TYPE_RANGE);
                $payload .= Binary::writeLTriad($start);
                $payload .= Binary::writeLTriad($last);
            }
            ++$records;
        }
 
        $out->putShort($records);
        $out->put($payload);
    }
 
    protected function decodePayload(PacketSerializer $in) : void{
        $count = $in->getShort();
        $this->packets = [];
        $cnt = 0;
        for($i = 0; $i < $count and !$in->feof() and $cnt < 4096; ++$i){
            if($in->getByte() === self::RECORD_TYPE_RANGE){
                $start = $in->getLTriad();
                $end = $in->getLTriad();
                if(($end - $start) > 512){
                    $end = $start + 512;
                }
                for($c = $start; $c <= $end; ++$c){
                    $this->packets[$cnt++] = $c;
                }
            }else{
                $this->packets[$cnt++] = $in->getLTriad();
            }
        }
    }
}