yuzu/src/common/uuid.cpp

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// Copyright 2022 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <bit>
#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;
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 u8{0};
}
std::array<u8, 0x10> ConstructFromRawString(std::string_view raw_string) {
std::array<u8, 0x10> uuid;
for (size_t i = 0; i < RawStringSize; i += 2) {
uuid[i / 2] =
static_cast<u8>((HexCharToByte(raw_string[i]) << 4) | HexCharToByte(raw_string[i + 1]));
}
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) {
uuid[i] = static_cast<u8>((HexCharToByte(*(str++)) << 4));
uuid[i] |= HexCharToByte(*(str++));
}
// Process the next 4 characters.
++str;
for (; i < 6; ++i) {
uuid[i] = static_cast<u8>((HexCharToByte(*(str++)) << 4));
uuid[i] |= HexCharToByte(*(str++));
}
// Process the next 4 characters.
++str;
for (; i < 8; ++i) {
uuid[i] = static_cast<u8>((HexCharToByte(*(str++)) << 4));
uuid[i] |= HexCharToByte(*(str++));
}
// Process the next 4 characters.
++str;
for (; i < 10; ++i) {
uuid[i] = static_cast<u8>((HexCharToByte(*(str++)) << 4));
uuid[i] |= HexCharToByte(*(str++));
}
// Process the last 12 characters.
++str;
for (; i < 16; ++i) {
uuid[i] = static_cast<u8>((HexCharToByte(*(str++)) << 4));
uuid[i] |= HexCharToByte(*(str++));
}
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 hash;
u64 temp;
std::memcpy(&hash, uuid.data(), sizeof(u64));
std::memcpy(&temp, uuid.data() + 8, sizeof(u64));
return hash ^ std::rotl(temp, 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