1// -*- C++ -*- 2 3// Copyright (C) 2005-2015 Free Software Foundation, Inc. 4// 5// This file is part of the GNU ISO C++ Library. This library is free 6// software; you can redistribute it and/or modify it under the terms 7// of the GNU General Public License as published by the Free Software 8// Foundation; either version 3, or (at your option) any later 9// version. 10 11// This library is distributed in the hope that it will be useful, but 12// WITHOUT ANY WARRANTY; without even the implied warranty of 13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14// General Public License for more details. 15 16// Under Section 7 of GPL version 3, you are granted additional 17// permissions described in the GCC Runtime Library Exception, version 18// 3.1, as published by the Free Software Foundation. 19 20// You should have received a copy of the GNU General Public License and 21// a copy of the GCC Runtime Library Exception along with this program; 22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23// <http://www.gnu.org/licenses/>. 24 25// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. 26 27// Permission to use, copy, modify, sell, and distribute this software 28// is hereby granted without fee, provided that the above copyright 29// notice appears in all copies, and that both that copyright notice 30// and this permission notice appear in supporting documentation. None 31// of the above authors, nor IBM Haifa Research Laboratories, make any 32// representation about the suitability of this software for any 33// purpose. It is provided "as is" without express or implied 34// warranty. 35 36/** 37 * @file eq_by_less.hpp 38 * Contains an equivalence function. 39 */ 40 41#ifndef PB_DS_EQ_BY_LESS_HPP 42#define PB_DS_EQ_BY_LESS_HPP 43 44#include <utility> 45#include <functional> 46#include <vector> 47#include <assert.h> 48#include <ext/pb_ds/detail/types_traits.hpp> 49 50namespace __gnu_pbds 51{ 52 namespace detail 53 { 54 /// Equivalence function. 55 template<typename Key, class Cmp_Fn> 56 struct eq_by_less : private Cmp_Fn 57 { 58 bool 59 operator()(const Key& r_lhs, const Key& r_rhs) const 60 { 61 const bool l = Cmp_Fn::operator()(r_lhs, r_rhs); 62 const bool g = Cmp_Fn::operator()(r_rhs, r_lhs); 63 return !(l || g); 64 } 65 }; 66 } // namespace detail 67} // namespace __gnu_pbds 68 69#endif // #ifndef PB_DS_EQ_BY_LESS_HPP 70