A C++ template library for embedded applications
MIT licensed
Designed and
maintained by
John Wellbelove
utility.h

Utility


A few useful utility functions and classes.
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pair
template <typename T1, typename T2>
struct pair
A clone of std::pair

C++03
template <typename T1, typename T2>
pair<T1, T2> make_pair(T1 a, T2 b)

C++11 and above
template <typename T1, typename T2>
pair<T1, T2> make_pair(T1&& a, T2&& b)
Returns a pair.
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Template deduction guides
C++17 and above

template <typename T1, typename T2>
pair(T1, T2) ->pair<T1, T2>;
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exchange

template <typename T, typename U = T>
T exchange(T& object, const U& new_value)
Copies the new value to object and returns the old value.
Note: This is not an atomic operation.
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add_const

template <typename T>
typename etl::add_const<T>::type& as_const(T& t)
Returns a value of type T as a const T.
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coordinate_2d


template <typename T>
struct coordinate_2d

Member types

T x;
T y;
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In_place disambiguation tags.


struct in_place_t

inline constexpr in_place_t in_place{}; // C++17
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template <typename T> struct in_place_type_t

template <typename T>
inline constexpr in_place_type_t<T> in_place_type{}; // C++17
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template <size_t I> struct in_place_index_t

template <size_t I>
inline constexpr in_place_index_t<I> in_place_index{}; // C++17
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declval


template <typename T>
typename etl::add_rvalue_reference<T>::type declval() ETL_NOEXCEPT;
C++11
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functor
For C++11 and above.
20.27.0

template <typename TReturn, typename... TParams>
class functor
Wraps a free/global function in a functor.
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constexpr functor(TReturn(*ptr_)(TParams...))
Constructs a functor from a function pointer.
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constexpr TReturn operator()(TParams... args) const
Function operator.
Calls the wrapped function with the forwarded parameters.
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Example


void int Function(int i)
{
  return i;
}

// Note that the functor deduces the template parameters.
constexpr etl::functor f(Function);
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member_function_wrapper
For C++11 and above.
20.27.0

template <typename TReturn, typename... TParams>
class member_function_wrapper<TReturn(TParams...)>
Wraps a member function in a static member function.
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template <typename T, T& Instance, TReturn(T::* Method)(TParams...)>
static constexpr TReturn function(TParams... params)
The static function that calls the member function.
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Example


class MyClass
{
public:

  int MemberFunction(int i)
  {
    return 2 * i;
  }
};

MyClass test;

constexpr int(*pf)(int)
        = &etl::member_function_wrapper<int(int)>::function<MyClass, test, &MyClass::MemberFunction>;

// Call
int result = pf(1);
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functor_wrapper
For C++11 and above.
20.27.0

template <typename TReturn, typename... TParams>
class functor_wrapper<TReturn(TParams...)>
Wraps a functor in a static member function.
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template <typename TFunctor, TFunctor& Instance>
static constexpr TReturn function(TParams... params)
The static function that calls the member function.
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Example


class MyClass
{
public:

  int operator()(int i)
  {
    return 2 * i;
  }
};

MyClass test;

constexpr int(*pf)(int) = &etl::functor_wrapper<int(int)>::function<MyClass, test>;

// Call
int result = pf(1);
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integer_sequence
20.14.0

template <typename T, T... Integers>
class integer_sequence
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index_sequence
20.14.0

template <size_t... Indices>
using index_sequence = etl::integer_sequence<size_t, Indices...>;

template <size_t N>
make_index_sequence