etl/test/test_invoke.cpp

/******************************************************************************
The MIT License(MIT)

Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com

Copyright(c) 2025 John Wellbelove

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#include "unit_test_framework.h"

#include "etl/invoke.h"
#include <etl/type_traits.h>

namespace
{
  struct TestClass
  {
    int         member_obj = 42;
    std::string member_str = "hello";

    int get_int()
    {
      return member_obj;
    }

    int const_get_int() const
    {
      return member_obj + 10;
    }
    void set_int(int v)
    {
      member_obj = v;
    }
    static int static_func(int x)
    {
      return x * 2;
    }
  };

  int standalone_func(int a, int b)
  {
    return a + b;
  }

  struct Functor
  {
    int operator()(int x) const
    {
      return x * 5;
    }
  };

  SUITE(test_invoke)
  {
    //*************************************************************************
    TEST(test_type_traits_functions)
    {
      CHECK_TRUE(etl::is_function<int(int)>::value);
      CHECK_TRUE(!etl::is_function<int>::value);
      CHECK_TRUE(!etl::is_function<int*>::value);
      CHECK_TRUE(!etl::is_function<int&>::value);
      CHECK_TRUE(!etl::is_function<int&&>::value);
    }

    //*************************************************************************
    TEST(test_type_traits_member_pointers)
    {
      using MemObjPtr = int TestClass::*;
      using MemFnPtr = int (TestClass::*)();

      CHECK_TRUE(etl::is_member_pointer<MemObjPtr>::value);
      CHECK_TRUE(etl::is_member_pointer<MemFnPtr>::value);
      CHECK_TRUE(!etl::is_member_pointer<int*>::value);

      CHECK_TRUE(etl::is_member_object_pointer<MemObjPtr>::value);
      CHECK_TRUE(!etl::is_member_object_pointer<MemFnPtr>::value);

      CHECK_TRUE(!etl::is_member_function_pointer<MemObjPtr>::value);
      CHECK_TRUE(etl::is_member_function_pointer<MemFnPtr>::value);
    }

    //*************************************************************************
    TEST(test_invoke_callable)
    {
      CHECK_EQUAL(30, etl::invoke(standalone_func, 10, 20));

      auto lambda = [](int x)
      { return x * 3; };
      CHECK_EQUAL(15, etl::invoke(lambda, 5));

      Functor f;
      CHECK_EQUAL(60, etl::invoke(f, 12));

      CHECK_EQUAL(8, etl::invoke(TestClass::static_func, 4));
    }

    //*************************************************************************
    TEST(test_invoke_mem_func_ptr)
    {
      TestClass       obj;
      TestClass*      ptr = &obj;
      const TestClass const_obj;

      CHECK_EQUAL(42, etl::invoke(&TestClass::get_int, obj));
      CHECK_EQUAL(42, etl::invoke(&TestClass::get_int, ptr));
      CHECK_EQUAL(52, etl::invoke(&TestClass::const_get_int, const_obj));

      etl::invoke(&TestClass::set_int, obj, 99);
      CHECK_EQUAL(99, obj.member_obj);

      etl::invoke(&TestClass::set_int, ptr, 101);
      CHECK_EQUAL(101, ptr->member_obj);
    }

    //*************************************************************************
    TEST(test_invoke_mem_obj_ptr)
    {
      TestClass  obj;
      TestClass* ptr = &obj;

      CHECK_EQUAL(42, etl::invoke(&TestClass::member_obj, obj));
      CHECK_EQUAL(42, etl::invoke(&TestClass::member_obj, ptr));
      CHECK_EQUAL("hello", etl::invoke(&TestClass::member_str, obj));

      etl::invoke(&TestClass::member_obj, obj) = 1000;
      CHECK_EQUAL(1000, obj.member_obj);

      etl::invoke(&TestClass::member_obj, ptr) = 2000;
      CHECK_EQUAL(2000, ptr->member_obj);
    }

    //*************************************************************************
    TEST(test_invoke_result_t)
    {
      using MemFnPtr = decltype(&TestClass::get_int);
      using ConstMemFnPtr = decltype(&TestClass::const_get_int);
      using MemObjPtr_int = decltype(&TestClass::member_obj);
      using FnPtr = int (*)(int, int);
    
      auto val = etl::is_same<etl::invoke_result_t<FnPtr, int, int>, int>::value;
      CHECK_TRUE(val);

      val = etl::is_same<etl::invoke_result_t<MemFnPtr, TestClass&>, int>::value;
      CHECK_TRUE(val);
      
      val = etl::is_same<etl::invoke_result_t<MemFnPtr, TestClass*>, int>::value;
      CHECK_TRUE(val);
      
      val = etl::is_same<etl::invoke_result_t<ConstMemFnPtr, const TestClass&>, int>::value;
      CHECK_TRUE(val);
      
      val = etl::is_same<etl::invoke_result_t<MemObjPtr_int, TestClass&>, int&>::value;
      CHECK_TRUE(val);
      
      val = etl::is_same<etl::invoke_result_t<MemObjPtr_int, const TestClass&>, const int&>::value;
      CHECK_TRUE(val);
      
      val = etl::is_same<etl::invoke_result_t<MemObjPtr_int, TestClass*>, int&>::value;
      CHECK_TRUE(val);
    }
  }
}