Improve performance of isfield from linear time to constant time (bug #58105) Patch author: Anonymous in Bug #58105 Comment #7 https://savannah.gnu.org/bugs/index.php?58105#comment7 The isfield function was taking time proportional to the number of fields in a struct to determine whether something was a member or not. With this change, isfield performance becomes constant irrespective of the number of fields, speeding up performance by over 200X, and also allowing the use of struct as a hashmap if the user desires. ov-base.h: Add new isfield function declaration ov-base.cc: Add new isfield function definition ov-struct.h: Add new isfield function definitions ov-struct.cc: Do not call map_value ov.h: Add new isfield function definition

--- a/libinterp/octave-value/ov-base.h	Wed Oct 05 10:55:13 2022 +0200
+++ b/libinterp/octave-value/ov-base.h	Wed Oct 05 10:35:31 2022 -0400
@@ -670,6 +670,8 @@
 
   virtual string_vector map_keys (void) const;
 
+  virtual bool isfield (const std::string&) const;
+
   virtual std::size_t nparents (void) const;
 
   virtual std::list<std::string> parent_class_name_list (void) const;