agent_ptr_compare.hpp

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/*
  SObjectizer 5.
*/
 
/*!
 * \file
 * \brief A special comparison for agent pointers.
 *
 * \since v.5.5.8
 */
 
#pragma once
 
#include <so_5/fwd.hpp>
 
#include <functional>
 
namespace so_5 {
 
namespace impl {
 
/*!
 * \brief A special comparison for agent pointers with respect to
 * agent's priorities.
 *
 * \retval true if \a a is less than \a b.
 *
 * \since v.5.5.8
 */
[[nodiscard]]
inline bool
special_agent_ptr_compare( const agent_t & a, const agent_t & b ) noexcept
  {
    // Use std::less for compare pointers.
    // NOTE: it's UB to compare pointers that do not belong to the same array.
    using ptr_comparator_t = std::less< const agent_t * >;
 
    auto p1 = a.so_priority();
    auto p2 = b.so_priority();
 
    // NOTE: there should be inversion -- agent with higher
    // priority must be first.
    return ( p1 > p2 || (p1 == p2 && ptr_comparator_t{}( &a, &b ) ) );
  }
 
} /* namespace impl */
 
} /* namespace so_5 */