uuid.hpp

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// uuid.hpp - v1.1
/*
 *  Copyright (c) 2007 Leigh Johnston.
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 *     * Neither the name of Leigh Johnston nor the names of any
 *       other contributors to this software may be used to endorse or
 *       promote products derived from this software without specific prior
 *       written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 *  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 *  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 *  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 *  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
 
#pragma once
 
#include <neolib/neolib.hpp>
#include <string>
#include <cstdint>
#include <array>
#include <tuple>
#include <utility>
#include <iostream>
#include <sstream>
#include <iomanip>
 
namespace neolib
{
    struct uuid
    {
        typedef uuid abstract_type;
        uint32_t part1;
        uint16_t part2;
        uint16_t part3;
        uint16_t part4;
        std::array<uint8_t, 6> part5;
 
        auto operator<=>(const uuid&) const = default;
    };
 
    inline uuid make_uuid(const std::string& aHyphenatedHexString /* "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" */)
    {
        uuid result;
        result.part1 = static_cast<uint32_t>(std::strtoul(aHyphenatedHexString.substr(0, 8).c_str(), 0, 16));
        result.part2 = static_cast<uint16_t>(std::strtoul(aHyphenatedHexString.substr(9, 4).c_str(), 0, 16));
        result.part3 = static_cast<uint16_t>(std::strtoul(aHyphenatedHexString.substr(14, 4).c_str(), 0, 16));
        result.part4 = static_cast<uint16_t>(std::strtoul(aHyphenatedHexString.substr(19, 4).c_str(), 0, 16));
        uint64_t bytes = static_cast<uint64_t>(std::strtoull(aHyphenatedHexString.substr(24, 12).c_str(), 0, 16));
        for (size_t i = 0; i <= 5; ++i)
            result.part5[i] = static_cast<uint8_t>((bytes >> (5 - i) * 8) & 0xFF);
        return result;
    }
 
    struct unable_to_generate_uuid : std::runtime_error { unable_to_generate_uuid() : std::runtime_error("neolib::unable_to_generate_uuid") {} };
 
    NEOLIB_EXPORT uuid generate_uuid();
 
    inline std::istream& operator>>(std::istream& aStream, uuid& aId)
    {
        std::string hyphenatedHexString;
        aStream >> hyphenatedHexString;
        aId = make_uuid(hyphenatedHexString);
        return aStream;
    }
 
    inline std::ostream& operator<<(std::ostream& aStream, const uuid& aId)
    {
        char oldFill = aStream.fill('0');
        aStream << std::hex << std::uppercase << std::setw(8) << aId.part1 << "-";
        aStream << std::hex << std::uppercase << std::setw(4) << aId.part2 << "-";
        aStream << std::hex << std::uppercase << std::setw(4) << aId.part3 << "-";
        aStream << std::hex << std::uppercase << std::setw(4) << aId.part4 << "-";
        for (size_t i = 0; i <= 5; ++i)
            aStream << std::hex << std::uppercase << std::setw(2) << static_cast<uint32_t>(aId.part5[i]);
        aStream << std::dec;
        aStream.fill(oldFill);
        return aStream;
    }
 
    inline std::string uuid_to_string(const uuid& aId)
    {
        std::ostringstream oss;
        oss << aId;
        return oss.str();
    }
 
    struct quick_uuid_hash
    {
        typedef neolib::uuid argument_type;
        typedef std::size_t result_type;
        result_type operator()(argument_type const& aUuid) const
        {
            return aUuid.part1;
        }
    };
}
 
namespace std
{
    template <> struct hash<neolib::uuid>
    {
        typedef neolib::uuid argument_type;
        typedef std::size_t result_type;
        result_type operator()(argument_type const& aUuid) const
        {
            if constexpr (sizeof(std::size_t) == sizeof(uint64_t))
            {
                // type punning is serious business...
                struct badf00d
                {
                    uint64_t bat;
                    uint64_t pangolin;
                };
                badf00d covid19;
                std::memcpy(&covid19, &aUuid, sizeof(covid19));
                return covid19.bat ^ covid19.pangolin;
            }
            else
            {
                // type punning is serious business...
                struct badf00d
                {
                    uint32_t bat1;
                    uint32_t bat2;
                    uint32_t pangolin1;
                    uint32_t pangolin2;
                };
                badf00d covid19;
                std::memcpy(&covid19, &aUuid, sizeof(covid19));
                return covid19.bat1 ^ covid19.bat2 ^ covid19.pangolin1 ^ covid19.pangolin2;
            }
        }
    };
}