hash_eq_fn.hpp
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// -*- C++ -*-
// Copyright (C) 2005-2013 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the terms
// of the GNU General Public License as published by the Free Software
// Foundation; either version 3, or (at your option) any later
// version.
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
// Permission to use, copy, modify, sell, and distribute this software
// is hereby granted without fee, provided that the above copyright
// notice appears in all copies, and that both that copyright notice
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/**
* @file hash_eq_fn.hpp
* Contains 2 eqivalence functions, one employing a hash value,
* and one ignoring it.
*/
#ifndef PB_DS_HASH_EQ_FN_HPP
#define PB_DS_HASH_EQ_FN_HPP
#include <utility>
#include <debug/debug.h>
namespace __gnu_pbds
{
namespace detail
{
/// Primary template.
template<typename Key, typename Eq_Fn, typename _Alloc, bool Store_Hash>
struct hash_eq_fn;
/// Specialization 1 - The client requests that hash values not be stored.
template<typename Key, typename Eq_Fn, typename _Alloc>
struct hash_eq_fn<Key, Eq_Fn, _Alloc, false> : public Eq_Fn
{
typedef Eq_Fn eq_fn_base;
typedef typename _Alloc::template rebind<Key>::other key_allocator;
typedef typename key_allocator::const_reference key_const_reference;
hash_eq_fn() { }
hash_eq_fn(const Eq_Fn& r_eq_fn) : Eq_Fn(r_eq_fn) { }
bool
operator()(key_const_reference r_lhs_key,
key_const_reference r_rhs_key) const
{ return eq_fn_base::operator()(r_lhs_key, r_rhs_key); }
void
swap(const hash_eq_fn& other)
{ std::swap((Eq_Fn&)(*this), (Eq_Fn&)other); }
};
/// Specialization 2 - The client requests that hash values be stored.
template<typename Key, class Eq_Fn, class _Alloc>
struct hash_eq_fn<Key, Eq_Fn, _Alloc, true> : public Eq_Fn
{
typedef typename _Alloc::size_type size_type;
typedef Eq_Fn eq_fn_base;
typedef typename _Alloc::template rebind<Key>::other key_allocator;
typedef typename key_allocator::const_reference key_const_reference;
hash_eq_fn() { }
hash_eq_fn(const Eq_Fn& r_eq_fn) : Eq_Fn(r_eq_fn) { }
bool
operator()(key_const_reference r_lhs_key, size_type lhs_hash,
key_const_reference r_rhs_key, size_type rhs_hash) const
{
_GLIBCXX_DEBUG_ASSERT(!eq_fn_base::operator()(r_lhs_key, r_rhs_key)
|| lhs_hash == rhs_hash);
return (lhs_hash == rhs_hash &&
eq_fn_base::operator()(r_lhs_key, r_rhs_key));
}
void
swap(const hash_eq_fn& other)
{ std::swap((Eq_Fn&)(*this), (Eq_Fn&)(other)); }
};
} // namespace detail
} // namespace __gnu_pbds
#endif