| // -*-c++-*- |
| // vim: set ft=cpp: |
| |
| /* Distributed under the OSI-approved BSD 3-Clause License. See accompanying |
| file Copyright.txt or https://cmake.org/licensing for details. */ |
| #ifndef cmext_iterator |
| #define cmext_iterator |
| |
| #include <iterator> |
| |
| #include <cm/type_traits> |
| |
| namespace cm { |
| |
| // checks if a type is an iterator type |
| template <typename I> |
| using is_iterator = |
| std::is_integral<typename std::iterator_traits<I>::difference_type>; |
| |
| // checks if a type is an input iterator type |
| template <typename I> |
| using is_input_iterator = |
| std::is_base_of<std::input_iterator_tag, |
| typename std::iterator_traits<I>::iterator_category>; |
| |
| // checks if a type is a range type: std::begin() and std::end() are supported |
| template <typename Range> |
| using is_range = cm::bool_constant< |
| cm::is_iterator<decltype(std::begin(std::declval<const Range>()))>::value && |
| cm::is_iterator<decltype(std::end(std::declval<const Range>()))>::value>; |
| |
| // checks if a type is an input range type: std::begin() and std::end() are |
| // returning an input iterator |
| template <typename Range> |
| using is_input_range = |
| #if defined(_MSC_VER) && _MSC_VER < 1920 |
| // MS C++ is not able to evaluate complex type introspection, |
| // so use a simplified version |
| cm::bool_constant<std::is_class<Range>::value || |
| std::is_pointer<Range>::value || |
| std::is_array<Range>::value>; |
| #else |
| cm::bool_constant<cm::is_input_iterator<decltype( |
| std::begin(std::declval<const Range>()))>::value && |
| cm::is_input_iterator<decltype( |
| std::end(std::declval<const Range>()))>::value>; |
| #endif |
| |
| } // namespace cm |
| |
| #endif |