summaryrefslogtreecommitdiffstats
path: root/src/common/uuid.cpp
blob: 035df7fe011b2a7bfa24d0e94d2f9cba39b5d982 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#include <bit>
#include <optional>
#include <random>

#include <fmt/format.h>

#include "common/assert.h"
#include "common/tiny_mt.h"
#include "common/uuid.h"

namespace Common {

namespace {

constexpr size_t RawStringSize = sizeof(UUID) * 2;
constexpr size_t FormattedStringSize = RawStringSize + 4;

std::optional<u8> HexCharToByte(char c) {
    if (c >= '0' && c <= '9') {
        return static_cast<u8>(c - '0');
    }
    if (c >= 'a' && c <= 'f') {
        return static_cast<u8>(c - 'a' + 10);
    }
    if (c >= 'A' && c <= 'F') {
        return static_cast<u8>(c - 'A' + 10);
    }
    ASSERT_MSG(false, "{} is not a hexadecimal digit!", c);
    return std::nullopt;
}

std::array<u8, 0x10> ConstructFromRawString(std::string_view raw_string) {
    std::array<u8, 0x10> uuid;

    for (size_t i = 0; i < RawStringSize; i += 2) {
        const auto upper = HexCharToByte(raw_string[i]);
        const auto lower = HexCharToByte(raw_string[i + 1]);
        if (!upper || !lower) {
            return {};
        }
        uuid[i / 2] = static_cast<u8>((*upper << 4) | *lower);
    }

    return uuid;
}

std::array<u8, 0x10> ConstructFromFormattedString(std::string_view formatted_string) {
    std::array<u8, 0x10> uuid{};

    size_t i = 0;

    // Process the first 8 characters.
    const auto* str = formatted_string.data();

    for (; i < 4; ++i) {
        const auto upper = HexCharToByte(*(str++));
        const auto lower = HexCharToByte(*(str++));
        if (!upper || !lower) {
            return {};
        }
        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
    }

    // Process the next 4 characters.
    ++str;

    for (; i < 6; ++i) {
        const auto upper = HexCharToByte(*(str++));
        const auto lower = HexCharToByte(*(str++));
        if (!upper || !lower) {
            return {};
        }
        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
    }

    // Process the next 4 characters.
    ++str;

    for (; i < 8; ++i) {
        const auto upper = HexCharToByte(*(str++));
        const auto lower = HexCharToByte(*(str++));
        if (!upper || !lower) {
            return {};
        }
        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
    }

    // Process the next 4 characters.
    ++str;

    for (; i < 10; ++i) {
        const auto upper = HexCharToByte(*(str++));
        const auto lower = HexCharToByte(*(str++));
        if (!upper || !lower) {
            return {};
        }
        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
    }

    // Process the last 12 characters.
    ++str;

    for (; i < 16; ++i) {
        const auto upper = HexCharToByte(*(str++));
        const auto lower = HexCharToByte(*(str++));
        if (!upper || !lower) {
            return {};
        }
        uuid[i] = static_cast<u8>((*upper << 4) | *lower);
    }

    return uuid;
}

std::array<u8, 0x10> ConstructUUID(std::string_view uuid_string) {
    const auto length = uuid_string.length();

    if (length == 0) {
        return {};
    }

    // Check if the input string contains 32 hexadecimal characters.
    if (length == RawStringSize) {
        return ConstructFromRawString(uuid_string);
    }

    // Check if the input string has the length of a RFC 4122 formatted UUID string.
    if (length == FormattedStringSize) {
        return ConstructFromFormattedString(uuid_string);
    }

    ASSERT_MSG(false, "UUID string has an invalid length of {} characters!", length);

    return {};
}

} // Anonymous namespace

UUID::UUID(std::string_view uuid_string) : uuid{ConstructUUID(uuid_string)} {}

std::string UUID::RawString() const {
    return fmt::format("{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}"
                       "{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}",
                       uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5], uuid[6], uuid[7],
                       uuid[8], uuid[9], uuid[10], uuid[11], uuid[12], uuid[13], uuid[14],
                       uuid[15]);
}

std::string UUID::FormattedString() const {
    return fmt::format("{:02x}{:02x}{:02x}{:02x}"
                       "-{:02x}{:02x}-{:02x}{:02x}-{:02x}{:02x}-"
                       "{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}",
                       uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5], uuid[6], uuid[7],
                       uuid[8], uuid[9], uuid[10], uuid[11], uuid[12], uuid[13], uuid[14],
                       uuid[15]);
}

size_t UUID::Hash() const noexcept {
    u64 upper_hash;
    u64 lower_hash;

    std::memcpy(&upper_hash, uuid.data(), sizeof(u64));
    std::memcpy(&lower_hash, uuid.data() + sizeof(u64), sizeof(u64));

    return upper_hash ^ std::rotl(lower_hash, 1);
}

u128 UUID::AsU128() const {
    u128 uuid_old;
    std::memcpy(&uuid_old, uuid.data(), sizeof(UUID));
    return uuid_old;
}

UUID UUID::MakeRandom() {
    std::random_device device;

    return MakeRandomWithSeed(device());
}

UUID UUID::MakeRandomWithSeed(u32 seed) {
    // Create and initialize our RNG.
    TinyMT rng;
    rng.Initialize(seed);

    UUID uuid;

    // Populate the UUID with random bytes.
    rng.GenerateRandomBytes(uuid.uuid.data(), sizeof(UUID));

    return uuid;
}

UUID UUID::MakeRandomRFC4122V4() {
    auto uuid = MakeRandom();

    // According to Proposed Standard RFC 4122 Section 4.4, we must:

    // 1. Set the two most significant bits (bits 6 and 7) of the
    //    clock_seq_hi_and_reserved to zero and one, respectively.
    uuid.uuid[8] = 0x80 | (uuid.uuid[8] & 0x3F);

    // 2. Set the four most significant bits (bits 12 through 15) of the
    //    time_hi_and_version field to the 4-bit version number from Section 4.1.3.
    uuid.uuid[6] = 0x40 | (uuid.uuid[6] & 0xF);

    return uuid;
}

} // namespace Common