1/*
2 * Copyright (C) 2014 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/EnumTraits.h>
29#include <wtf/SHA1.h>
30#include <wtf/persistence/PersistentCoder.h>
31
32namespace WTF {
33namespace Persistence {
34
35class Decoder {
36 WTF_MAKE_FAST_ALLOCATED;
37public:
38 WTF_EXPORT_PRIVATE Decoder(const uint8_t* buffer, size_t bufferSize);
39 WTF_EXPORT_PRIVATE ~Decoder();
40
41 size_t length() const { return m_bufferEnd - m_buffer; }
42 size_t currentOffset() const { return m_bufferPosition - m_buffer; }
43
44 WTF_EXPORT_PRIVATE bool verifyChecksum();
45
46 WTF_EXPORT_PRIVATE bool decodeFixedLengthData(uint8_t*, size_t);
47
48 WTF_EXPORT_PRIVATE bool decode(bool&);
49 WTF_EXPORT_PRIVATE bool decode(uint8_t&);
50 WTF_EXPORT_PRIVATE bool decode(uint16_t&);
51 WTF_EXPORT_PRIVATE bool decode(uint32_t&);
52 WTF_EXPORT_PRIVATE bool decode(uint64_t&);
53 WTF_EXPORT_PRIVATE bool decode(int32_t&);
54 WTF_EXPORT_PRIVATE bool decode(int64_t&);
55 WTF_EXPORT_PRIVATE bool decode(float&);
56 WTF_EXPORT_PRIVATE bool decode(double&);
57
58 template<typename E> auto decode(E& e) -> std::enable_if_t<std::is_enum<E>::value, bool>
59 {
60 uint64_t value;
61 if (!decode(value))
62 return false;
63 if (!isValidEnum<E>(value))
64 return false;
65
66 e = static_cast<E>(value);
67 return true;
68 }
69
70 template<typename T> bool decodeEnum(T& result)
71 {
72 static_assert(sizeof(T) <= 8, "Enum type T must not be larger than 64 bits!");
73
74 uint64_t value;
75 if (!decode(value))
76 return false;
77
78 result = static_cast<T>(value);
79 return true;
80 }
81
82 template<typename T> auto decode(T& t) -> std::enable_if_t<!std::is_enum<T>::value, bool>
83 {
84 return Coder<T>::decode(*this, t);
85 }
86
87 template<typename T>
88 bool bufferIsLargeEnoughToContain(size_t numElements) const
89 {
90 static_assert(std::is_arithmetic<T>::value, "Type T must have a fixed, known encoded size!");
91
92 if (numElements > std::numeric_limits<size_t>::max() / sizeof(T))
93 return false;
94
95 return bufferIsLargeEnoughToContain(numElements * sizeof(T));
96 }
97
98 static const bool isIPCDecoder = false;
99
100private:
101 WTF_EXPORT_PRIVATE bool bufferIsLargeEnoughToContain(size_t) const;
102 template<typename Type> bool decodeNumber(Type&);
103
104 const uint8_t* m_buffer;
105 const uint8_t* m_bufferPosition;
106 const uint8_t* m_bufferEnd;
107
108 SHA1 m_sha1;
109};
110
111}
112}
113
114