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 hash_eq_fn.hpp
38 * Contains 2 eqivalence functions, one employing a hash value,
39 * and one ignoring it.
40 */
41
42#ifndef PB_DS_HASH_EQ_FN_HPP
43#define PB_DS_HASH_EQ_FN_HPP
44
45#include <utility>
46#include <debug/debug.h>
47
48namespace __gnu_pbds
49{
50  namespace detail
51  {
52    /// Primary template.
53    template<typename Key, typename Eq_Fn, typename _Alloc, bool Store_Hash>
54      struct hash_eq_fn;
55
56    /// Specialization 1 - The client requests that hash values not be stored.
57    template<typename Key, typename Eq_Fn, typename _Alloc>
58    struct hash_eq_fn<Key, Eq_Fn, _Alloc, false> : public Eq_Fn
59    {
60      typedef Eq_Fn 					   eq_fn_base;
61      typedef typename _Alloc::template rebind<Key>::other key_allocator;
62      typedef typename key_allocator::const_reference 	   key_const_reference;
63
64      hash_eq_fn() { }
65
66      hash_eq_fn(const Eq_Fn& r_eq_fn) : Eq_Fn(r_eq_fn) { }
67
68      bool
69      operator()(key_const_reference r_lhs_key,
70		 key_const_reference r_rhs_key) const
71      { return eq_fn_base::operator()(r_lhs_key, r_rhs_key); }
72
73      void
74      swap(const hash_eq_fn& other)
75      { std::swap((Eq_Fn&)(*this), (Eq_Fn&)other); }
76    };
77
78
79    /// Specialization 2 - The client requests that hash values be stored.
80    template<typename Key, class Eq_Fn, class _Alloc>
81    struct hash_eq_fn<Key, Eq_Fn, _Alloc, true> : public Eq_Fn
82    {
83      typedef typename _Alloc::size_type 		   size_type;
84      typedef Eq_Fn 					   eq_fn_base;
85      typedef typename _Alloc::template rebind<Key>::other key_allocator;
86      typedef typename key_allocator::const_reference 	   key_const_reference;
87
88      hash_eq_fn() { }
89
90      hash_eq_fn(const Eq_Fn& r_eq_fn) : Eq_Fn(r_eq_fn) { }
91
92      bool
93      operator()(key_const_reference r_lhs_key, size_type lhs_hash,
94		 key_const_reference r_rhs_key, size_type rhs_hash) const
95      {
96	_GLIBCXX_DEBUG_ASSERT(!eq_fn_base::operator()(r_lhs_key, r_rhs_key)
97			      || lhs_hash == rhs_hash);
98
99	return (lhs_hash == rhs_hash &&
100		eq_fn_base::operator()(r_lhs_key, r_rhs_key));
101      }
102
103      void
104      swap(const hash_eq_fn& other)
105      { std::swap((Eq_Fn&)(*this), (Eq_Fn&)(other)); }
106    };
107  } // namespace detail
108} // namespace __gnu_pbds
109
110#endif
111