enum_for_each.hpp

/*
MIT License
 
Copyright (c) 2024 mguludag
 
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of this software and associated documentation files (the "Software"), to deal
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The above copyright notice and this permission notice shall be included in all
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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*/
 
#ifndef DETAIL_ENUM_FOR_EACH_HPP
#define DETAIL_ENUM_FOR_EACH_HPP
 
#include "meta.hpp"
#include "mgutility/std/string_view.hpp"
 
#include <cstdint>
#include <utility>
 
namespace mgutility {
namespace detail {
template <typename T>
using string_or_view_t =
    typename std::conditional<has_bit_or<T>::value, std::string,
                              mgutility::string_view>::type;
 
template <typename Enum>
using enum_pair = std::pair<Enum, detail::string_or_view_t<Enum>>;
} // namespace detail
 
template <typename Enum> class enum_for_each {
  using value_type = const detail::enum_pair<Enum>;
  using size_type = std::size_t;
 
  struct enum_iter {
    using const_iter_type = decltype(enum_range<Enum>::min);
    using iter_type = detail::remove_const_t<const_iter_type>;
    using iterator_category = std::forward_iterator_tag;
    using value_type = const detail::enum_pair<Enum>;
    using difference_type = std::ptrdiff_t;
    using pointer = value_type *;
    using reference = value_type &;
 
    enum_iter() : m_pos{} {}
 
    enum_iter(iter_type value) : m_pos{value} {}
 
    auto operator++() -> enum_iter & {
      ++m_pos;
      return *this;
    }
 
    auto operator++(int) -> enum_iter {
      m_pos++;
      return *this;
    }
 
    auto operator!=(const enum_iter &other) const -> bool {
      return m_pos != other.m_pos;
    }
 
    auto operator==(const enum_iter &other) const -> bool {
      return m_pos == other.m_pos;
    }
 
    auto operator*() const -> value_type;
 
  private:
    iter_type m_pos; 
  };
 
public:
  enum_for_each() = default;
 
  auto begin() -> enum_iter & { return m_begin; }
 
  auto end() -> enum_iter & { return m_end; }
 
  auto size() -> std::size_t {
    return enum_range<Enum>::max - enum_range<Enum>::min;
  }
 
private:
  enum_iter m_begin{enum_range<Enum>::min}; 
  enum_iter m_end{enum_range<Enum>::max};   
};
} // namespace mgutility
 
#endif // DETAIL_ENUM_FOR_EACH_HPP