From 3271099fea41d5adc0003c02c8481b334772296a Mon Sep 17 00:00:00 2001
From: Morph <39850852+Morph1984@users.noreply.github.com>
Date: Fri, 4 Feb 2022 23:44:02 -0500
Subject: common: Implement NewUUID

This is a fixed and revised implementation of UUID that uses an array of bytes as its internal representation of a UUID instead of a u128 (which was an array of 2 u64s).
In addition to this, the generation of RFC 4122 Version 4 compliant UUIDs is also implemented.
---
 src/common/new_uuid.h | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 src/common/new_uuid.h

(limited to 'src/common/new_uuid.h')

diff --git a/src/common/new_uuid.h b/src/common/new_uuid.h
new file mode 100644
index 000000000..bd4468ad2
--- /dev/null
+++ b/src/common/new_uuid.h
@@ -0,0 +1,138 @@
+// Copyright 2022 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <functional>
+#include <string>
+#include <string_view>
+
+#include "common/common_types.h"
+
+namespace Common {
+
+struct NewUUID {
+    std::array<u8, 0x10> uuid{};
+
+    /// Constructs an invalid UUID.
+    constexpr NewUUID() = default;
+
+    /// Constructs a UUID from a reference to a 128 bit array.
+    constexpr explicit NewUUID(const std::array<u8, 16>& uuid_) : uuid{uuid_} {}
+
+    /**
+     * Constructs a UUID from either:
+     * 1. A 32 hexadecimal character string representing the bytes of the UUID
+     * 2. A RFC 4122 formatted UUID string, in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+     *
+     * The input string may contain uppercase or lowercase characters, but they must:
+     * 1. Contain valid hexadecimal characters (0-9, a-f, A-F)
+     * 2. Not contain the "0x" hexadecimal prefix
+     *
+     * Should the input string not meet the above requirements,
+     * an assert will be triggered and an invalid UUID is set instead.
+     */
+    explicit NewUUID(std::string_view uuid_string);
+
+    ~NewUUID() = default;
+
+    constexpr NewUUID(const NewUUID&) noexcept = default;
+    constexpr NewUUID(NewUUID&&) noexcept = default;
+
+    constexpr NewUUID& operator=(const NewUUID&) noexcept = default;
+    constexpr NewUUID& operator=(NewUUID&&) noexcept = default;
+
+    /**
+     * Returns whether the stored UUID is valid or not.
+     *
+     * @returns True if the stored UUID is valid, false otherwise.
+     */
+    constexpr bool IsValid() const {
+        return uuid != std::array<u8, 0x10>{};
+    }
+
+    /**
+     * Returns whether the stored UUID is invalid or not.
+     *
+     * @returns True if the stored UUID is invalid, false otherwise.
+     */
+    constexpr bool IsInvalid() const {
+        return !IsValid();
+    }
+
+    /**
+     * Returns a 32 hexadecimal character string representing the bytes of the UUID.
+     *
+     * @returns A 32 hexadecimal character string of the UUID.
+     */
+    std::string RawString() const;
+
+    /**
+     * Returns a RFC 4122 formatted UUID string in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
+     *
+     * @returns A RFC 4122 formatted UUID string.
+     */
+    std::string FormattedString() const;
+
+    /**
+     * Returns a 64-bit hash of the UUID for use in hash table data structures.
+     *
+     * @returns A 64-bit hash of the UUID.
+     */
+    size_t Hash() const noexcept;
+
+    /**
+     * Creates a default UUID "yuzu Default UID".
+     *
+     * @returns A UUID with its bytes set to the ASCII values of "yuzu Default UID".
+     */
+    static constexpr NewUUID MakeDefault() {
+        return NewUUID{
+            {'y', 'u', 'z', 'u', ' ', 'D', 'e', 'f', 'a', 'u', 'l', 't', ' ', 'U', 'I', 'D'},
+        };
+    }
+
+    /**
+     * Creates a random UUID.
+     *
+     * @returns A random UUID.
+     */
+    static NewUUID MakeRandom();
+
+    /**
+     * Creates a random UUID with a seed.
+     *
+     * @param seed A seed to initialize the Mersenne-Twister RNG
+     *
+     * @returns A random UUID.
+     */
+    static NewUUID MakeRandomWithSeed(u32 seed);
+
+    /**
+     * Creates a random UUID. The generated UUID is RFC 4122 Version 4 compliant.
+     *
+     * @returns A random UUID that is RFC 4122 Version 4 compliant.
+     */
+    static NewUUID MakeRandomRFC4122V4();
+
+    friend constexpr bool operator==(const NewUUID& lhs, const NewUUID& rhs) = default;
+};
+static_assert(sizeof(NewUUID) == 0x10, "UUID has incorrect size.");
+
+/// An invalid UUID. This UUID has all its bytes set to 0.
+constexpr NewUUID InvalidUUID = {};
+
+} // namespace Common
+
+namespace std {
+
+template <>
+struct hash<Common::NewUUID> {
+    size_t operator()(const Common::NewUUID& uuid) const noexcept {
+        return uuid.Hash();
+    }
+};
+
+} // namespace std
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