From e554d30bf6df4d930a489fd55c09504f39053437 Mon Sep 17 00:00:00 2001
From: Erki <erki@skullnet.me>
Date: Sun, 26 Jun 2022 17:53:40 +0300
Subject: [PATCH] Utility: add the ability to generate static functions from
 IFunction

---
 Peripherals/Inc/peripherals_utility.hpp |  4 ---
 Tests/function.cpp                      | 47 +++++++++++++++++++++++++
 Utility/Inc/utility_function.hpp        |  8 +++++
 Utility/Inc/utility_tag.hpp             | 12 +++++++
 4 files changed, 67 insertions(+), 4 deletions(-)
 create mode 100644 Utility/Inc/utility_tag.hpp

diff --git a/Peripherals/Inc/peripherals_utility.hpp b/Peripherals/Inc/peripherals_utility.hpp
index 34b2691..0ab29af 100644
--- a/Peripherals/Inc/peripherals_utility.hpp
+++ b/Peripherals/Inc/peripherals_utility.hpp
@@ -15,10 +15,6 @@
 namespace Peripherals
 {
 
-#define SKULLC_CONCAT_IMPL(x, y) x##y
-#define SKULLC_CONCAT(x, y) SKULLC_CONCAT_IMPL(x, y)
-#define SKULLC_TAG struct SKULLC_CONCAT(SkullCTag_, __COUNTER__)
-
 template<typename T>
 constexpr const T& clamp(const T& v, const T& lo, const T& hi)
 {
diff --git a/Tests/function.cpp b/Tests/function.cpp
index a9dbe19..c7383fc 100644
--- a/Tests/function.cpp
+++ b/Tests/function.cpp
@@ -5,6 +5,7 @@
 #include <catch2/catch.hpp>
 
 #include <utility_function.hpp>
+#include <utility_tag.hpp>
 
 TEST_CASE("Function calls function appropriately.", "[utility],[function]")
 {
@@ -38,6 +39,26 @@ TEST_CASE("Function passes arguments appropriately.", "[utility],[function]")
   REQUIRE(bool_to_set == true);
 }
 
+TEST_CASE("Function works with toStaticFunction.", "[utility],[function]")
+{
+  static int int_to_set = 0;
+  static bool bool_to_set = false;
+
+  auto func_to_call = [](const int i, const bool b) {
+    int_to_set = i;
+    bool_to_set = b;
+  };
+
+  Utility::Function<void(int, bool)> function(func_to_call);
+  using signature = void (*)(int, bool);
+
+  signature func_pointer = function.toStaticFunction<SKULLC_TAG>();
+  func_pointer(10, true);
+
+  REQUIRE(int_to_set == 10);
+  REQUIRE(bool_to_set == true);
+}
+
 TEST_CASE("FunctionOwned calls function appropriately.", "[utility],[function]")
 {
   struct S
@@ -82,3 +103,29 @@ TEST_CASE("FunctionOwned passes arguments appropriately.", "[utility],[function]
   REQUIRE(subject.int_to_set == 10);
   REQUIRE(subject.bool_to_set == false);
 }
+
+TEST_CASE("FunctionOwned works with toStaticFunction.", "[utility],[function]")
+{
+  struct S
+  {
+    int int_to_set = 0;
+    bool bool_to_set = true;
+
+    void toCall(const int i, const bool b)
+    {
+      int_to_set = i;
+      bool_to_set = b;
+    }
+  };
+
+  S subject;
+
+  Utility::FunctionOwned<S, void(int, bool)> function(subject, &S::toCall);
+  using signature = void (*)(int, bool);
+
+  signature func_pointer = function.toStaticFunction<SKULLC_TAG>();
+  func_pointer(10, true);
+
+  REQUIRE(subject.int_to_set == 10);
+  REQUIRE(subject.bool_to_set == true);
+}
diff --git a/Utility/Inc/utility_function.hpp b/Utility/Inc/utility_function.hpp
index 4d9f200..e01078c 100644
--- a/Utility/Inc/utility_function.hpp
+++ b/Utility/Inc/utility_function.hpp
@@ -19,11 +19,19 @@ class IFunction<R(Args...)>
 {
 public:
   using result_type = R;
+  using static_signature = R (*)(Args...);
 
   virtual ~IFunction()
   {}
 
   virtual result_type operator()(Args... args) = 0;
+
+  template<typename Tag>
+  static_signature toStaticFunction()
+  {
+    static decltype(this) h = this;
+    return +[](Args... args) { (*h)(args...); };
+  }
 };
 
 template<class>
diff --git a/Utility/Inc/utility_tag.hpp b/Utility/Inc/utility_tag.hpp
new file mode 100644
index 0000000..99eb900
--- /dev/null
+++ b/Utility/Inc/utility_tag.hpp
@@ -0,0 +1,12 @@
+//
+// Created by erki on 26.06.22.
+//
+
+#ifndef SKULLC_UTILITY_TAG_HPP_
+#define SKULLC_UTILITY_TAG_HPP_
+
+#define SKULLC_CONCAT_IMPL(x, y) x##y
+#define SKULLC_CONCAT(x, y) SKULLC_CONCAT_IMPL(x, y)
+#define SKULLC_TAG struct SKULLC_CONCAT(SkullCTag_, __COUNTER__)
+
+#endif// SKULLC_UTILITY_TAG_HPP_