McRegion.php

<?php
 
/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
 */
 
declare(strict_types=1);
 
namespace pocketmine\world\format\io\region;
 
use pocketmine\block\Block;
use pocketmine\data\bedrock\BiomeIds;
use pocketmine\nbt\BigEndianNbtSerializer;
use pocketmine\nbt\NbtDataException;
use pocketmine\nbt\tag\ByteArrayTag;
use pocketmine\nbt\tag\ByteTag;
use pocketmine\nbt\tag\CompoundTag;
use pocketmine\nbt\tag\IntArrayTag;
use pocketmine\nbt\tag\ListTag;
use pocketmine\world\format\Chunk;
use pocketmine\world\format\io\ChunkData;
use pocketmine\world\format\io\ChunkUtils;
use pocketmine\world\format\io\exception\CorruptedChunkException;
use pocketmine\world\format\io\LoadedChunkData;
use pocketmine\world\format\PalettedBlockArray;
use pocketmine\world\format\SubChunk;
use function strlen;
use function zlib_decode;
 
class McRegion extends RegionWorldProvider{
    protected function deserializeChunk(string $data, \Logger $logger) : ?LoadedChunkData{
        $decompressed = @zlib_decode($data);
        if($decompressed === false){
            throw new CorruptedChunkException("Failed to decompress chunk NBT");
        }
        $nbt = new BigEndianNbtSerializer();
        try{
            $chunk = $nbt->read($decompressed)->mustGetCompoundTag();
        }catch(NbtDataException $e){
            throw new CorruptedChunkException($e->getMessage(), 0, $e);
        }
        $chunk = $chunk->getTag("Level");
        if(!($chunk instanceof CompoundTag)){
            throw new CorruptedChunkException("'Level' key is missing from chunk NBT");
        }
 
        $legacyGeneratedTag = $chunk->getTag("TerrainGenerated");
        if($legacyGeneratedTag instanceof ByteTag && $legacyGeneratedTag->getValue() === 0){
            //In legacy PM before 3.0, PM used to save MCRegion chunks even when they weren't generated. In these cases
            //(we'll see them in old worlds), some of the tags which we expect to always be present, will be missing.
            //If TerrainGenerated (PM-specific tag from the olden days) is false, toss the chunk data and don't bother
            //trying to read it.
            return null;
        }
 
        $makeBiomeArray = function(string $biomeIds) : PalettedBlockArray{
            if(strlen($biomeIds) !== 256){
                throw new CorruptedChunkException("Expected biome array to be exactly 256 bytes, got " . strlen($biomeIds));
            }
            return ChunkUtils::extrapolate3DBiomes($biomeIds);
        };
        if(($biomeColorsTag = $chunk->getTag("BiomeColors")) instanceof IntArrayTag){
            $biomes3d = $makeBiomeArray(ChunkUtils::convertBiomeColors($biomeColorsTag->getValue())); //Convert back to original format
        }elseif(($biomesTag = $chunk->getTag("Biomes")) instanceof ByteArrayTag){
            $biomes3d = $makeBiomeArray($biomesTag->getValue());
        }else{
            $biomes3d = new PalettedBlockArray(BiomeIds::OCEAN);
        }
 
        $subChunks = [];
        $fullIds = self::readFixedSizeByteArray($chunk, "Blocks", 32768);
        $fullData = self::readFixedSizeByteArray($chunk, "Data", 16384);
 
        for($y = 0; $y < 8; ++$y){
            $subChunks[$y] = new SubChunk(Block::EMPTY_STATE_ID, [$this->palettizeLegacySubChunkFromColumn(
                $fullIds,
                $fullData,
                $y,
                new \PrefixedLogger($logger, "Subchunk y=$y"),
            )], clone $biomes3d);
        }
        for($y = Chunk::MIN_SUBCHUNK_INDEX; $y <= Chunk::MAX_SUBCHUNK_INDEX; ++$y){
            if(!isset($subChunks[$y])){
                $subChunks[$y] = new SubChunk(Block::EMPTY_STATE_ID, [], clone $biomes3d);
            }
        }
 
        return new LoadedChunkData(
            data: new ChunkData(
                $subChunks,
                $chunk->getByte("TerrainPopulated", 0) !== 0,
                ($entitiesTag = $chunk->getTag("Entities")) instanceof ListTag ? self::getCompoundList("Entities", $entitiesTag) : [],
                ($tilesTag = $chunk->getTag("TileEntities")) instanceof ListTag ? self::getCompoundList("TileEntities", $tilesTag) : [],
            ),
            upgraded: true,
            fixerFlags: LoadedChunkData::FIXER_FLAG_ALL
        );
    }
 
    protected static function getRegionFileExtension() : string{
        return "mcr";
    }
 
    protected static function getPcWorldFormatVersion() : int{
        return 19132;
    }
 
    public function getWorldMinY() : int{
        return 0;
    }
 
    public function getWorldMaxY() : int{
        //TODO: add world height options
        return 128;
    }
}