Bugfix in __getstate__

After mutation some token has non zero initialized useless data that should not
be copied in state.

python_rpnexpr.c

@@ -273,6 +273,7 @@ PyObject* rpnexpr_getstate(PyObject *self, PyObject *noargs)
 	total_sz += expr_self->rpn->toks.tokens_sz * sizeof(rpn_token_t);
 	total_sz += expr_self->rpn->stack_sz * sizeof(rpn_value_t);
 
+	bzero(&resbuf, sizeof(resbuf));
 	resbuf.total_sz = total_sz;
 	resbuf.argc = expr_self->rpn->args_count;
 	resbuf.stack_sz = expr_self->rpn->stack_sz;
@@ -298,23 +299,39 @@ PyObject* rpnexpr_getstate(PyObject *self, PyObject *noargs)
 	}
 	if(resbuf.token_sz)
 	{
-		for(i=0; i<expr_self->rpn->toks.tokens_sz;i++)
+		/**@todo can lead to stack overflow on huge expressions ? */
+		rpn_token_t tokens[resbuf.token_sz];
+		bzero(tokens, sizeof(rpn_token_t) * resbuf.token_sz);
+
+		for(i=0; i<expr_self->rpn->toks.tokens_sz; i++)
 		{
-			// restore op pointers
-			expr_self->rpn->toks.tokens[i].op = NULL;
+			const rpn_token_t *cur = &expr_self->rpn->toks.tokens[i];
+			tokens[i].type = cur->type;
+			switch(tokens[i].type)
+			{
+				case RPN_op:
+					tokens[i].op_n = cur->op_n;
+					tokens[i].op = NULL;
+					break;
+				case RPN_arg:
+					tokens[i].arg_n = cur->arg_n;
+					break;
+				case RPN_val:
+					tokens[i].value = cur->value;
+					break;
+				default:
+					PyErr_SetString(PyExc_RuntimeError,
+							"__getstate__ invalid token");
+					return NULL;
+			}
 		}
-	
+
 		if(!(part=PyBytes_FromStringAndSize(
-				(char*)expr_self->rpn->toks.tokens,
+				(char*)tokens,
 				sizeof(rpn_token_t) * resbuf.token_sz)))
 		{
 			return NULL;
 		}
-		for(i=0; i<expr_self->rpn->toks.tokens_sz;i++)
-		{
-			// restore op pointers
-			expr_self->rpn->toks.tokens[i].op = &(rpn_ops[expr_self->rpn->toks.tokens[i].op_n]);
-		}
 	
 		PyBytes_ConcatAndDel(&res, part);
 		if(!res)

tests/tests_rpn_copy.py

@@ -69,6 +69,7 @@ class TestRpnExprState(unittest.TestCase):
                          msg="EXPR: %r != %r (%r != %r)" % (e, e2, ds_e, ds_e2))
         for i in range(100):
             e = pyrpn.RPNExpr(pyrpn.random_expr(0), 2)
+            e.mutate(n_mutations=15);
 
             e2 = pickle.loads(pickle.dumps(e))