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rippled/include/xrpl/basics/comparators.h
2025-11-18 20:21:35 -05:00

58 lines
1.2 KiB
C++

#ifndef XRPL_BASICS_COMPARATORS_H_INCLUDED
#define XRPL_BASICS_COMPARATORS_H_INCLUDED
#include <functional>
namespace ripple {
#ifdef _MSC_VER
/*
* MSVC 2019 version 16.9.0 added [[nodiscard]] to the std comparison
* operator() functions. boost::bimap checks that the comparator is a
* BinaryFunction, in part by calling the function and ignoring the value.
* These two things don't play well together. These wrapper classes simply
* strip [[nodiscard]] from operator() for use in boost::bimap.
*
* See also:
* https://www.boost.org/doc/libs/1_75_0/libs/bimap/doc/html/boost_bimap/the_tutorial/controlling_collection_types.html
*/
template <class T = void>
struct less
{
using result_type = bool;
constexpr bool
operator()(T const& left, T const& right) const
{
return std::less<T>()(left, right);
}
};
template <class T = void>
struct equal_to
{
using result_type = bool;
constexpr bool
operator()(T const& left, T const& right) const
{
return std::equal_to<T>()(left, right);
}
};
#else
template <class T = void>
using less = std::less<T>;
template <class T = void>
using equal_to = std::equal_to<T>;
#endif
} // namespace ripple
#endif