libstdc++: hash_eq_fn.hpp Source File

libstdc++

hash_eq_fn.hpp
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25// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
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35
36/**
37 * @file hash_eq_fn.hpp
38 * Contains 2 equivalence 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 <ext/pb_ds/detail/types_traits.hpp>
47#include <debug/debug.h>
48
49namespace __gnu_pbds
50{
51 namespace detail
52 {
53 /// Primary template.
54 template<typename Key, typename Eq_Fn, typename _Alloc, bool Store_Hash>
55 struct hash_eq_fn;
56
57 /// Specialization 1 - The client requests that hash values not be stored.
58 template<typename Key, typename Eq_Fn, typename _Alloc>
59 struct hash_eq_fn<Key, Eq_Fn, _Alloc, false> : public Eq_Fn
60 {
61 typedef Eq_Fn eq_fn_base;
62 typedef typename rebind_traits<_Alloc, Key>::const_reference
63 key_const_reference;
64
65 hash_eq_fn() { }
66
67 hash_eq_fn(const Eq_Fn& r_eq_fn) : Eq_Fn(r_eq_fn) { }
68
69 bool
70 operator()(key_const_reference r_lhs_key,
71 key_const_reference r_rhs_key) const
72 { return eq_fn_base::operator()(r_lhs_key, r_rhs_key); }
73
74 void
75 swap(const hash_eq_fn& other)
76 { std::swap((Eq_Fn&)(*this), (Eq_Fn&)other); }
77 };
78
79
80 /// Specialization 2 - The client requests that hash values be stored.
81 template<typename Key, class Eq_Fn, class _Alloc>
82 struct hash_eq_fn<Key, Eq_Fn, _Alloc, true> : public Eq_Fn
83 {
84 typedef typename _Alloc::size_type size_type;
85 typedef Eq_Fn eq_fn_base;
86 typedef typename rebind_traits<_Alloc, Key>::const_reference
87 key_const_reference;
88
89 hash_eq_fn() { }
90
91 hash_eq_fn(const Eq_Fn& r_eq_fn) : Eq_Fn(r_eq_fn) { }
92
93 bool
94 operator()(key_const_reference r_lhs_key, size_type lhs_hash,
95 key_const_reference r_rhs_key, size_type rhs_hash) const
96 {
97 _GLIBCXX_DEBUG_ASSERT(!eq_fn_base::operator()(r_lhs_key, r_rhs_key)
98 || lhs_hash == rhs_hash);
99
100 return (lhs_hash == rhs_hash &&
101 eq_fn_base::operator()(r_lhs_key, r_rhs_key));
102 }
103
104 void
105 swap(const hash_eq_fn& other)
106 { std::swap((Eq_Fn&)(*this), (Eq_Fn&)(other)); }
107 };
108 } // namespace detail
109} // namespace __gnu_pbds
110
111#endif
utility
debug.h
types_traits.hpp
__gnu_pbds
GNU extensions for policy-based data structures for public use.
Definition assoc_container.hpp:52
__gnu_pbds::detail::hash_eq_fn
Primary template.
Definition hash_eq_fn.hpp:55