Rather than implementing empty default constructors, make sure that AP_Var and friends have useful default constructors instead. This works around AP_Meta_class::meta_cast requiring a default constructor without having empty ctors scattered around.
Add accessors to AP_Var so that the global variable list can be traversed and the group/variable relationship comprehended by outsiders.
git-svn-id: https://arducopter.googlecode.com/svn/trunk@1523 f9c3cf11-9bcb-44bc-f272-b75c42450872
The format is a simple TLV format; a tag identifying the variable, a length for the variable, and then the actual data. This format could ultimately be extended to include waypoint/commands as well.
This allows us to load and save groups of variables to EEPROM without having to have a static EEPROM map.
Still needs unit tests and (probably) bugfixing.
git-svn-id: https://arducopter.googlecode.com/svn/trunk@1522 f9c3cf11-9bcb-44bc-f272-b75c42450872
The overriding principle here is to keep the use of AP_Vars as simple as possible, whilst letting the implementation do useful things behind the scenes. To that end, we define AP_Float, AP_Int8, AP_Int16 and AP_Int32. These are strongly typed, so that there is no ambiguity about what a variable "really" is.
The classes behave like the variables they are storing; you can use an AP_Float in most places you would use a regular float; you can add to it, multiply by it, etc. If it has been given an address in EEPROM you can load and save it.
Variables can be given names, and if they are named then they can be looked up. This allows e.g. a GCS or a test tool to find and traffic in variables that it may not explicitly know about.
AP_Var does not attempt to solve the problem of EEPROM address space management.
git-svn-id: https://arducopter.googlecode.com/svn/trunk@1399 f9c3cf11-9bcb-44bc-f272-b75c42450872
