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/*
* Copyright 2020 Max Kellermann <max.kellermann@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef GENERATE_ARRAY_HXX
#define GENERATE_ARRAY_HXX
#include <array>
#include <utility>
template<std::size_t N, typename F, std::size_t... I>
constexpr auto
_GenerateArray(F &&f, std::index_sequence<I...>) noexcept
{
using T = decltype(f(0));
/* double curly braces for compatibility with older compilers
which are not 100% C++17 compliant (e.g. Apple xcode
9.4) */
return std::array<T, N>{{f(I)...}};
}
/**
* Generate a `constexpr` std::array at compile time by calling the
* given function for each index.
*
* @param N the number of elements in the array
* @param F the function (called N times with the index as only parameter)
*/
template<std::size_t N, typename F>
constexpr auto
GenerateArray(F &&f) noexcept
{
return _GenerateArray<N>(std::forward<F>(f),
std::make_index_sequence<N>());
}
#endif