1/*
2 * Copyright (C) 2016 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <wtf/HashFunctions.h>
29#include <wtf/HashTraits.h>
30
31class DeletedAddressOfOperator {
32public:
33 DeletedAddressOfOperator()
34 : m_value(0)
35 {
36 }
37
38 DeletedAddressOfOperator(unsigned value)
39 : m_value(value)
40 {
41 }
42
43 DeletedAddressOfOperator* operator&() = delete;
44
45 unsigned value() const
46 {
47 return m_value;
48 }
49
50 friend bool operator==(const DeletedAddressOfOperator& a, const DeletedAddressOfOperator& b)
51 {
52 return a.m_value == b.m_value;
53 }
54
55private:
56 unsigned m_value;
57};
58
59namespace WTF {
60
61template<> struct HashTraits<DeletedAddressOfOperator> : public GenericHashTraits<DeletedAddressOfOperator> {
62 static const bool emptyValueIsZero = true;
63
64 static void constructDeletedValue(DeletedAddressOfOperator& slot) { slot = DeletedAddressOfOperator(std::numeric_limits<unsigned>::max()); }
65 static bool isDeletedValue(const DeletedAddressOfOperator& slot) { return slot.value() == std::numeric_limits<unsigned>::max(); }
66};
67
68template<> struct DefaultHash<DeletedAddressOfOperator> {
69 struct Hash {
70 static unsigned hash(const DeletedAddressOfOperator& key)
71 {
72 return intHash(key.value());
73 }
74
75 static bool equal(const DeletedAddressOfOperator& a, const DeletedAddressOfOperator& b)
76 {
77 return a == b;
78 }
79
80 static const bool safeToCompareToEmptyOrDeleted = true;
81 };
82};
83}
84
85