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// -*-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. */
#pragma once
#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
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