diff --git a/src/pocketmine/resourcepacks/ZippedResourcePack.php b/src/pocketmine/resourcepacks/ZippedResourcePack.php
index 40977d5d2..f65506bbe 100644
--- a/src/pocketmine/resourcepacks/ZippedResourcePack.php
+++ b/src/pocketmine/resourcepacks/ZippedResourcePack.php
@@ -49,6 +49,9 @@ class ZippedResourcePack implements ResourcePack{
 	/** @var string */
 	protected $sha256 = null;
 
+	/** @var resource */
+	protected $fileResource;
+
 
 	public function __construct(string $zipPath){
 		$this->path = $zipPath;
@@ -74,6 +77,12 @@ class ZippedResourcePack implements ResourcePack{
 		}
 
 		$this->manifest = $manifest;
+
+		$this->fileResource = fopen($zipPath, "rb");
+	}
+
+	public function __destruct(){
+		fclose($this->fileResource);
 	}
 
 	public function getPackName() : string{
@@ -100,6 +109,10 @@ class ZippedResourcePack implements ResourcePack{
 	}
 
 	public function getPackChunk(int $start, int $length) : string{
-		return substr(file_get_contents($this->path), $start, $length);
+		fseek($this->fileResource, $start);
+		if(feof($this->fileResource)){
+			throw new \RuntimeException("Requested a resource pack chunk with invalid start offset");
+		}
+		return fread($this->fileResource, $length);
 	}
 }
\ No newline at end of file