gUUID.h

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//
// Created by Metehan Gezer on 14/09/2025.
//
 
#ifndef UTILS_GUUID_H
#define UTILS_GUUID_H
 
#include <array>
#include <cstdint>
#include <string>
 
class gUUID {
public:
    using bytes = std::array<std::uint8_t, 16>;
 
    gUUID() noexcept;
    explicit gUUID(const bytes& b) noexcept;
 
    static gUUID generateV4();
 
    static gUUID fromString(std::string s, bool* ok = nullptr) noexcept;
 
    std::string toString() const;
 
    bytes toBytes() const noexcept;
 
    bool isNil() const noexcept { return hi == 0 && lo == 0; }
 
    friend bool operator==(const gUUID& a, const gUUID& b) noexcept {
        return a.hi == b.hi && a.lo == b.lo;
    }
 
    friend bool operator!=(const gUUID& a, const gUUID& b) noexcept {
        return !(a == b);
    }
 
    friend bool operator<(const gUUID& a, const gUUID& b) noexcept {
        return a.hi < b.hi || (a.hi == b.hi && a.lo < b.lo);
    }
 
 
    std::uint64_t getHigh() const noexcept { return hi; }
 
    std::uint64_t getLow() const noexcept { return lo; }
 
private:
    std::uint64_t hi;
    std::uint64_t lo;
 
    void fromBytes(const bytes& b) noexcept;
 
};
 
 
// hashing support
namespace std {
template<> struct hash<gUUID> {
    size_t operator()(const gUUID& u) const noexcept {
        // 64-bit mix (xorshift64*)
        std::uint64_t x = u.getHigh() ^ (u.getLow() * 0x9E3779B97F4A7C15ull);
        x ^= x >> 30; x *= 0xBF58476D1CE4E5B9ull;
        x ^= x >> 27; x *= 0x94D049BB133111EBull;
        x ^= x >> 31;
        return x;
    }
};
}
 
#endif//UTILS_GUUID_H