forked from enlightenment/efl
84 lines
1.9 KiB
C++
84 lines
1.9 KiB
C++
#ifndef EINA_CXX_EINA_INTEGER_SEQUENCE_HH
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#define EINA_CXX_EINA_INTEGER_SEQUENCE_HH
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/**
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* @addtogroup Eina_Cxx_Data_Types_Group
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*
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* @{
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*/
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namespace efl { namespace eina {
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/**
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* @defgroup Eina_Cxx_Integer_Sequence_Group Integer Sequence
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* @ingroup Eina_Cxx_Data_Types_Group
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*
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* @{
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*/
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/**
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* Compile-time sequence of integers.
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*/
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template <typename T, T... Ints>
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struct integer_sequence
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{
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typedef T value_type; /**< Type of the integers. */
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/**
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* @brief Get the number of elements in the sequence.
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* @return <tt>std::size_t</tt> representing the sequence size.
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*/
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static constexpr std::size_t size() { return sizeof...(Ints); }
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typedef integer_sequence<T, Ints...> type; /**< Type for the sequence instantiation. */
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};
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template<class S1, class S2> struct concat;
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/**
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* Compile-time concatenation of two integer sequences.
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*/
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template<typename T, T... I1, T... I2>
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struct concat<integer_sequence<T, I1...>, integer_sequence<T, I2...> >
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: integer_sequence<T, I1..., (sizeof...(I1)+I2)...> {};
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template<class S1, class S2>
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using Concat = typename concat<S1, S2>::type;
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template<typename T, T N> struct gen_seq;
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/**
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* Make a compile time sequence of integers from @c 0 to <tt>N-1</tt>.
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*/
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template<typename T, T N> using make_integer_sequence = typename gen_seq<T, N>::type;
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template<typename T, T N>
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struct gen_seq : Concat<make_integer_sequence<T, N/2>
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, make_integer_sequence<T, N - N/2>>{};
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template<> struct gen_seq<std::size_t, 0> : integer_sequence<std::size_t>{};
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template<> struct gen_seq<std::size_t, 1> : integer_sequence<std::size_t, 0>{};
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/**
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* Compile time sequence of indexes.
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*/
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template <std::size_t... I>
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using index_sequence = integer_sequence<std::size_t, I...>;
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/**
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* Make a compile time sequence of indexes from @c 0 to <tt>N-1</tt>.
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*/
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template <std::size_t I>
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using make_index_sequence = make_integer_sequence<std::size_t, I>;
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/**
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* @}
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*/
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} }
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/**
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* @}
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*/
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#endif
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