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enumerate.hpp
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enumerate.hpp
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/*
* MIT License
*
* Copyright (c) 2018 Tobias Widlund
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#pragma once
#include <type_traits>
#include <cstddef>
#include <utility>
namespace en
{
template <typename container_type>
struct enumerate_wrapper
{
using iterator_type = std::conditional_t<std::is_const_v<container_type>, typename container_type::const_iterator, typename container_type::iterator>;
using pointer_type = std::conditional_t<std::is_const_v<container_type>, typename container_type::const_pointer, typename container_type::pointer>;
using reference_type = std::conditional_t<std::is_const_v<container_type>, typename container_type::const_reference, typename container_type::reference>;
constexpr enumerate_wrapper(container_type& c): container(c)
{
}
struct enumerate_wrapper_iter
{
size_t index;
iterator_type value;
constexpr bool operator!=(const iterator_type& other) const
{
return value != other;
}
constexpr enumerate_wrapper_iter& operator++()
{
++index;
++value;
return *this;
}
constexpr std::pair<size_t, reference_type> operator*() {
return std::pair<size_t, reference_type>{index, *value};
}
};
constexpr enumerate_wrapper_iter begin()
{
return {0, std::begin(container)};
}
constexpr iterator_type end()
{
return std::end(container);
}
container_type& container;
};
template <typename container_type>
constexpr auto enumerate(container_type& c)
{
return enumerate_wrapper(c);
}
template <typename container_type>
constexpr auto const_enumerate(const container_type& c)
{
return enumerate_wrapper(c);
}
}