possibly_const_range.hpp

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//
// Created by YongGyu Lee on 3/27/24.
//
 
#ifndef VCCC_RANGES_POSSIBLY_CONST_RANGE_HPP_
#define VCCC_RANGES_POSSIBLY_CONST_RANGE_HPP_
 
#include <type_traits>
 
#include "vccc/__ranges/constant_range.hpp"
#include "vccc/__ranges/input_range.hpp"
#include "vccc/__type_traits/conjunction.hpp"
#include "vccc/__type_traits/negation.hpp"
 
namespace vccc {
namespace ranges {
namespace detail {
 
template<typename R>
constexpr auto& possibly_const_range_impl(R& r, std::true_type) noexcept {
  return const_cast<const R&>(r);
}
 
template<typename R>
constexpr auto& possibly_const_range_impl(R& r, std::false_type) noexcept {
  return r;
}
 
} // namespace detail
 
 
template<typename R, std::enable_if_t<input_range<R>::value, int> = 0>
constexpr auto& possibly_const_range(R& r) noexcept {
  return detail::possibly_const_range_impl(r, conjunction<constant_range<const R>, negation<constant_range<R>>>{});
}
 
 
} // namespace ranges
} // namespace vccc
 
#endif // VCCC_RANGES_POSSIBLY_CONST_RANGE_HPP_