Merge pull request #672 from peace-maker/null_natives_fixed

Add natives to check for NULL_VECTOR and NULL_STRING

public/IForwardSys.h

@@ -50,7 +50,7 @@
 using namespace SourcePawn;
 
 #define SMINTERFACE_FORWARDMANAGER_NAME		"IForwardManager"
-#define SMINTERFACE_FORWARDMANAGER_VERSION	3
+#define SMINTERFACE_FORWARDMANAGER_VERSION	4
 
 /*
  * There is some very important documentation at the bottom of this file.
@@ -118,6 +118,7 @@ namespace SourceMod
 		cell_t val;
 		ByrefInfo byref;
 		ParamType pushedas;
+		bool isnull;
 	};
 	
 	class IForwardFilter
@@ -177,12 +178,21 @@ namespace SourceMod
 		 * @brief Pushes an array of cells onto the current call.  Different rules than ICallable.
 		 * NOTE: On Execute, the pointer passed will be modified according to the copyback rule.
 		 *
-		 * @param inarray	Array to copy.  Cannot be NULL, unlike ICallable's version.
+		 * @param inarray	Array to copy.  If NULL and cells is 3 pushes a reference to the NULL_VECTOR pubvar to each callee.
+		 *                  Pushing other number of cells is not allowed, unlike ICallable's version.
 		 * @param cells		Number of cells to allocate and optionally read from the input array.
 		 * @param flags		Whether or not changes should be copied back to the input array.
 		 * @return			Error code, if any.
 		 */
 		virtual int PushArray(cell_t *inarray, unsigned int cells, int flags=0) =0;
+
+		/**
+		* @brief Pushes a string onto the current call.
+		*
+		* @param string  String to push.  If NULL pushes a reference to the NULL_STRING pubvar to each callee.
+		* @return      Error code, if any.
+		*/
+		virtual int PushString(const char *string) = 0;
 	};
 
 	/**