diff --git a/src/pocketmine/level/format/io/ChunkUtils.php b/src/pocketmine/level/format/io/ChunkUtils.php
index e9e35e8ce..3a02ba04f 100644
--- a/src/pocketmine/level/format/io/ChunkUtils.php
+++ b/src/pocketmine/level/format/io/ChunkUtils.php
@@ -23,84 +23,86 @@ declare(strict_types=1);
 
 namespace pocketmine\level\format\io;
 
-class ChunkUtils{
+if(!extension_loaded('pocketmine_chunkutils')){
+	class ChunkUtils{
 
-	/**
-	 * Re-orders a byte array (YZX -> XZY and vice versa)
-	 *
-	 * @param string $array length 4096
-	 *
-	 * @return string length 4096
-	 */
-	final public static function reorderByteArray(string $array) : string{
-		$result = str_repeat("\x00", 4096);
-		if($array !== $result){
-			$i = 0;
-			for($x = 0; $x < 16; ++$x){
-				$zM = $x + 256;
-				for($z = $x; $z < $zM; $z += 16){
-					$yM = $z + 4096;
-					for($y = $z; $y < $yM; $y += 256){
-						$result{$i} = $array{$y};
-						++$i;
-					}
-				}
-			}
-		}
-
-		return $result;
-	}
-
-	/**
-	 * Re-orders a nibble array (YZX -> XZY and vice versa)
-	 *
-	 * @param string $array length 2048
-	 * @param string $commonValue length 1 common value to fill the default array with and to expect, may improve sort time
-	 *
-	 * @return string length 2048
-	 */
-	final public static function reorderNibbleArray(string $array, string $commonValue = "\x00") : string{
-		$result = str_repeat($commonValue, 2048);
-
-		if($array !== $result){
-			$i = 0;
-			for($x = 0; $x < 8; ++$x){
-				for($z = 0; $z < 16; ++$z){
-					$zx = (($z << 3) | $x);
-					for($y = 0; $y < 8; ++$y){
-						$j = (($y << 8) | $zx);
-						$j80 = ($j | 0x80);
-						if($array{$j} === $commonValue and $array{$j80} === $commonValue){
-							//values are already filled
-						}else{
-							$i1 = ord($array{$j});
-							$i2 = ord($array{$j80});
-							$result{$i}        = chr(($i2 << 4) | ($i1 & 0x0f));
-							$result{$i | 0x80} = chr(($i1 >> 4) | ($i2 & 0xf0));
+		/**
+		 * Re-orders a byte array (YZX -> XZY and vice versa)
+		 *
+		 * @param string $array length 4096
+		 *
+		 * @return string length 4096
+		 */
+		final public static function reorderByteArray(string $array) : string{
+			$result = str_repeat("\x00", 4096);
+			if($array !== $result){
+				$i = 0;
+				for($x = 0; $x < 16; ++$x){
+					$zM = $x + 256;
+					for($z = $x; $z < $zM; $z += 16){
+						$yM = $z + 4096;
+						for($y = $z; $y < $yM; $y += 256){
+							$result{$i} = $array{$y};
+							++$i;
 						}
-						$i++;
 					}
 				}
-				$i += 128;
 			}
+
+			return $result;
 		}
 
-		return $result;
-	}
+		/**
+		 * Re-orders a nibble array (YZX -> XZY and vice versa)
+		 *
+		 * @param string $array length 2048
+		 * @param string $commonValue length 1 common value to fill the default array with and to expect, may improve sort time
+		 *
+		 * @return string length 2048
+		 */
+		final public static function reorderNibbleArray(string $array, string $commonValue = "\x00") : string{
+			$result = str_repeat($commonValue, 2048);
 
-	/**
-	 * Converts pre-MCPE-1.0 biome color array to biome ID array.
-	 *
-	 * @param int[] $array of biome color values
-	 *
-	 * @return string
-	 */
-	public static function convertBiomeColors(array $array) : string{
-		$result = str_repeat("\x00", 256);
-		foreach($array as $i => $color){
-			$result{$i} = chr(($color >> 24) & 0xff);
+			if($array !== $result){
+				$i = 0;
+				for($x = 0; $x < 8; ++$x){
+					for($z = 0; $z < 16; ++$z){
+						$zx = (($z << 3) | $x);
+						for($y = 0; $y < 8; ++$y){
+							$j = (($y << 8) | $zx);
+							$j80 = ($j | 0x80);
+							if($array{$j} === $commonValue and $array{$j80} === $commonValue){
+								//values are already filled
+							}else{
+								$i1 = ord($array{$j});
+								$i2 = ord($array{$j80});
+								$result{$i}        = chr(($i2 << 4) | ($i1 & 0x0f));
+								$result{$i | 0x80} = chr(($i1 >> 4) | ($i2 & 0xf0));
+							}
+							$i++;
+						}
+					}
+					$i += 128;
+				}
+			}
+
+			return $result;
 		}
-		return $result;
-	}
 
+		/**
+		 * Converts pre-MCPE-1.0 biome color array to biome ID array.
+		 *
+		 * @param int[] $array of biome color values
+		 *
+		 * @return string
+		 */
+		public static function convertBiomeColors(array $array) : string{
+			$result = str_repeat("\x00", 256);
+			foreach($array as $i => $color){
+				$result{$i} = chr(($color >> 24) & 0xff);
+			}
+			return $result;
+		}
+
+	}
 }
\ No newline at end of file