better error handling for invalid NBT data, added ext-json to composer.json

Author: KurtThiemann

composer.json

@@ -17,6 +17,7 @@
   "require": {
     "pocketmine/binaryutils": "^0.2.1",
     "php-64bit": "*",
-    "ext-zlib": "*"
+    "ext-zlib": "*",
+    "ext-json": "*"
   }
 }

src/IO/Reader/GZipCompressedStringReader.php

@@ -2,10 +2,18 @@
 
 namespace Aternos\Nbt\IO\Reader;
 
+use Exception;
+
 class GZipCompressedStringReader extends StringReader
 {
+    /**
+     * @throws Exception
+     */
     public function __construct(string $data, int $format)
     {
-        parent::__construct(gzdecode($data), $format);
+        if(($uncompressed = @gzdecode($data)) === false) {
+            throw new Exception("Invalid GZip data");
+        }
+        parent::__construct($uncompressed, $format);
     }
 }

src/IO/Reader/ZLibCompressedStringReader.php

@@ -2,10 +2,18 @@
 
 namespace Aternos\Nbt\IO\Reader;
 
+use Exception;
+
 class ZLibCompressedStringReader extends StringReader
 {
+    /**
+     * @throws Exception
+     */
     public function __construct(string $data, int $format)
     {
-        parent::__construct(zlib_decode($data), $format);
+        if(($uncompressed = @zlib_decode($data)) === false) {
+            throw new Exception("Invalid ZLib data");
+        }
+        parent::__construct($uncompressed, $format);
     }
 }

src/IO/Writer/GZipCompressedStringWriter.php

@@ -2,10 +2,18 @@
 
 namespace Aternos\Nbt\IO\Writer;
 
+use Exception;
+
 class GZipCompressedStringWriter extends StringWriter
 {
+    /**
+     * @throws Exception
+     */
     public function getStringData(): string
     {
-        return gzencode(parent::getStringData());
+        if(($compressed = @gzencode(parent::getStringData())) === false) {
+            throw new Exception("Failed to apply GZip compression");
+        }
+        return $compressed;
     }
 }

src/IO/Writer/ZLibCompressedStringWriter.php

@@ -2,10 +2,18 @@
 
 namespace Aternos\Nbt\IO\Writer;
 
+use Exception;
+
 class ZLibCompressedStringWriter extends StringWriter
 {
+    /**
+     * @throws Exception
+     */
     public function getStringData(): string
     {
-        return zlib_encode(parent::getStringData(), ZLIB_ENCODING_DEFLATE);
+        if(($compressed = @zlib_encode(parent::getStringData(), ZLIB_ENCODING_DEFLATE)) === false) {
+            throw new Exception("Failed to apply ZLib compression");
+        }
+        return $compressed;
     }
 }

src/Tag/Tag.php

@@ -7,8 +7,9 @@
 use Aternos\Nbt\NbtFormat;
 use Aternos\Nbt\Serializer\NbtSerializer;
 use Exception;
+use JsonSerializable;
 
-abstract class Tag implements \JsonSerializable
+abstract class Tag implements JsonSerializable
 {
     public const TYPE = -1;
 
@@ -143,22 +144,6 @@ public function write(Writer $writer): Tag
         return $this;
     }
 
-    /**
-     * @param string $type
-     * @param string $value
-     * @return mixed
-     * @throws Exception
-     * @deprecated
-     */
-    protected function unpack(string $type, string $value)
-    {
-        $unpacked = @unpack($type, $value);
-        if($unpacked === false) {
-            throw new Exception("Failed to unpack " . $type . " from " . bin2hex($value));
-        }
-        return $unpacked[1];
-    }
-
     /**
      * @param string $str
      * @return string
@@ -195,7 +180,7 @@ abstract protected function getValueString(): string;
      */
     public static function getTagClass(int $type): ?string
     {
-        return static::TAGS[$type] ?: null;
+        return static::TAGS[$type] ?? null;
     }
 
     /**