Added LevelProvider->getAllChunks() method

this returns a generator which yields known chunks. This will be used in the future for world format conversions.

src/pocketmine/level/format/io/LevelProvider.php

@@ -206,4 +206,11 @@ interface LevelProvider{
 	 */
 	public function close();
 
+	/**
+	 * Returns a generator which yields all the chunks in this level.
+	 *
+	 * @return \Generator|Chunk[]
+	 */
+	public function getAllChunks() : \Generator;
+
 }

src/pocketmine/level/format/io/leveldb/LevelDB.php

@@ -535,4 +535,16 @@ class LevelDB extends BaseLevelProvider{
 	public function close(){
 		$this->db->close();
 	}
+
+	public function getAllChunks() : \Generator{
+		foreach($this->db->getIterator() as $key => $_){
+			if(strlen($key) === 9 and substr($key, -1) === self::TAG_VERSION){
+				$chunkX = Binary::readLInt(substr($key, 0, 4));
+				$chunkZ = Binary::readLInt(substr($key, 4, 4));
+				if(($chunk = $this->loadChunk($chunkX, $chunkZ)) !== null){
+					yield $chunk;
+				}
+			}
+		}
+	}
 }

src/pocketmine/level/format/io/region/McRegion.php

@@ -413,4 +413,29 @@ class McRegion extends BaseLevelProvider{
 
 		$this->getRegion($regionX, $regionZ)->writeChunk($chunkX & 0x1f, $chunkZ & 0x1f, $this->nbtSerialize($chunk));
 	}
+
+	public function getAllChunks() : \Generator{
+		$iterator = new \RegexIterator(
+			new \FilesystemIterator(
+				$this->path . '/region/',
+				\FilesystemIterator::CURRENT_AS_PATHNAME | \FilesystemIterator::SKIP_DOTS | \FilesystemIterator::UNIX_PATHS
+			),
+			'/\/r\.(-?\d+)\.(-?\d+)\.' . static::REGION_FILE_EXTENSION . '$/',
+			\RegexIterator::GET_MATCH
+		);
+
+		foreach($iterator as $region){
+			$rX = ((int) $region[1]) << 5;
+			$rZ = ((int) $region[2]) << 5;
+
+			for($chunkX = $rX; $chunkX < $rX + 32; ++$chunkX){
+				for($chunkZ = $rZ; $chunkZ < $rZ + 32; ++$chunkZ){
+					$chunk = $this->loadChunk($chunkX, $chunkZ);
+					if($chunk !== null){
+						yield $chunk;
+					}
+				}
+			}
+		}
+	}
 }