Allow strings to grow in size

This lets us use QString for building larger strings

Signed-off-by: Anthony Liguori <[email protected]>
diff --git a/qstring.h b/qstring.h
index e012cb7..65905d4 100644
--- a/qstring.h
+++ b/qstring.h
@@ -6,10 +6,14 @@
 typedef struct QString {
     QObject_HEAD;
     char *string;
+    size_t length;
+    size_t capacity;
 } QString;
 
+QString *qstring_new(void);
 QString *qstring_from_str(const char *str);
 const char *qstring_get_str(const QString *qstring);
+void qstring_append(QString *qstring, const char *str);
 QString *qobject_to_qstring(const QObject *obj);
 
 #endif /* QSTRING_H */