BlockParam: remove _extern_address and create a new class BlockParamExt for this

In most cases, _extern_address was unused, thus wasting cycles & RAM. This
adds a separate class BlockParamExt with the field and uses it in ekf2_main

Frees roughly 0.5KB of RAM on Pixracer

src/lib/controllib/block/BlockParam.cpp

@@ -82,10 +82,9 @@ BlockParamBase::BlockParamBase(Block *parent, const char *name, bool parent_pref
 
 template <class T>
 BlockParam<T>::BlockParam(Block *block, const char *name,
-			  bool parent_prefix, T *extern_address) :
+			  bool parent_prefix) :
 	BlockParamBase(block, name, parent_prefix),
-	_val(),
-	_extern_address(extern_address)
+	_val()
 {
 	update();
 }
@@ -97,10 +96,6 @@ template <class T>
 void BlockParam<T>::set(T val)
 {
 	_val = val;
-
-	if (_extern_address != NULL) {
-		*_extern_address = val;
-	}
 }
 
 template <class T>
@@ -108,10 +103,6 @@ void BlockParam<T>::update()
 {
 	if (_handle != PARAM_INVALID) {
 		param_get(_handle, &_val);
-
-		if (_extern_address != NULL) {
-			*_extern_address = _val;
-		}
 	}
 }
 
@@ -127,4 +118,36 @@ BlockParam<T>::~BlockParam() {};
 template class __EXPORT BlockParam<float>;
 template class __EXPORT BlockParam<int>;
 
+
+template <class T>
+BlockParamExt<T>::BlockParamExt(Block *block, const char *name,
+				bool parent_prefix, T &extern_val) :
+	BlockParam<T>(block, name, parent_prefix),
+	_extern_val(extern_val)
+{
+	update();
+}
+
+template <class T>
+void BlockParamExt<T>::set(T val)
+{
+	this->_val = val;
+	_extern_val = val;
+}
+
+template <class T>
+void BlockParamExt<T>::update()
+{
+	if (this->_handle != PARAM_INVALID) {
+		param_get(this->_handle, &this->_val);
+		_extern_val = this->_val;
+	}
+}
+
+template <class T>
+BlockParamExt<T>::~BlockParamExt() {};
+
+template class __EXPORT BlockParamExt<float>;
+template class __EXPORT BlockParamExt<int>;
+
 } // namespace control

src/lib/controllib/block/BlockParam.hpp

@@ -77,21 +77,45 @@ class BlockParam : public BlockParamBase
 {
 public:
 	BlockParam(Block *block, const char *name,
-		   bool parent_prefix = true, T *extern_address = NULL);
+		   bool parent_prefix = true);
 	BlockParam(const BlockParam &) = delete;
 	BlockParam &operator=(const BlockParam &) = delete;
 
 	T get();
 	void commit();
 	void set(T val);
-	void update();
+	void update() override;
 	virtual ~BlockParam();
 protected:
 	T _val;
-	T *_extern_address;
 };
 
 typedef BlockParam<float> BlockParamFloat;
 typedef BlockParam<int> BlockParamInt;
 
+
+/**
+ * Same as BlockParam, but in addition with a pointer to an external field that will be
+ * set to the value of the parameter.
+ * (BlockParam should be prefered over this)
+ */
+template <class T>
+class BlockParamExt : public BlockParam<T>
+{
+public:
+	BlockParamExt(Block *block, const char *name,
+		      bool parent_prefix, T &extern_val);
+	BlockParamExt(const BlockParamExt &) = delete;
+	BlockParamExt &operator=(const BlockParamExt &) = delete;
+
+	void set(T val);
+	void update() override;
+	virtual ~BlockParamExt();
+protected:
+	T &_extern_val;
+};
+
+typedef BlockParamExt<float> BlockParamExtFloat;
+typedef BlockParamExt<int> BlockParamExtInt;
+
 } // namespace control