1/*
2* Copyright (C) 2019 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. ``AS IS'' AND ANY
14* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24*/
25
26#pragma once
27
28#include <wtf/HashTraits.h>
29
30namespace WTF {
31class PrintStream;
32}
33
34namespace JSC {
35
36class BytecodeIndex {
37public:
38 BytecodeIndex() = default;
39 BytecodeIndex(WTF::HashTableDeletedValueType)
40 : m_offset(deletedValue().asBits())
41 {
42 }
43 explicit BytecodeIndex(uint32_t bytecodeOffset)
44 : m_offset(bytecodeOffset)
45 { }
46
47 uint32_t offset() const { return m_offset; }
48 uint32_t asBits() const { return m_offset; }
49
50 unsigned hash() const { return WTF::intHash(m_offset); }
51 static BytecodeIndex deletedValue() { return fromBits(invalidOffset - 1); }
52 bool isHashTableDeletedValue() const { return *this == deletedValue(); }
53
54 static BytecodeIndex fromBits(uint32_t bits);
55
56 // Comparison operators.
57 explicit operator bool() const { return m_offset != invalidOffset && m_offset != deletedValue().offset(); }
58 bool operator ==(const BytecodeIndex& other) const { return asBits() == other.asBits(); }
59 bool operator !=(const BytecodeIndex& other) const { return !(*this == other); }
60
61 bool operator <(const BytecodeIndex& other) const { return asBits() < other.asBits(); }
62 bool operator >(const BytecodeIndex& other) const { return asBits() > other.asBits(); }
63 bool operator <=(const BytecodeIndex& other) const { return asBits() <= other.asBits(); }
64 bool operator >=(const BytecodeIndex& other) const { return asBits() >= other.asBits(); }
65
66
67 void dump(WTF::PrintStream&) const;
68
69private:
70 static constexpr uint32_t invalidOffset = std::numeric_limits<uint32_t>::max();
71
72 uint32_t m_offset { invalidOffset };
73};
74
75inline BytecodeIndex BytecodeIndex::fromBits(uint32_t bits)
76{
77 BytecodeIndex result;
78 result.m_offset = bits;
79 return result;
80}
81
82struct BytecodeIndexHash {
83 static unsigned hash(const BytecodeIndex& key) { return key.hash(); }
84 static bool equal(const BytecodeIndex& a, const BytecodeIndex& b) { return a == b; }
85 static constexpr bool safeToCompareToEmptyOrDeleted = true;
86};
87
88} // namespace JSC
89
90namespace WTF {
91
92template<typename T> struct DefaultHash;
93template<> struct DefaultHash<JSC::BytecodeIndex> {
94 typedef JSC::BytecodeIndexHash Hash;
95};
96
97template<typename T> struct HashTraits;
98template<> struct HashTraits<JSC::BytecodeIndex> : SimpleClassHashTraits<JSC::BytecodeIndex> {
99 static constexpr bool emptyValueIsZero = false;
100};
101
102} // namespace WTF
103