1 // -*- C++ -*- 2 3 // Copyright (C) 2005, 2006, 2009, 2011 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 50 namespace __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
