EncryptedString.hpp

Go to the documentation of this file.

//
//  CeresEngine - A game development framework
//
//  Created by Rogiel Sulzbach.
//  Copyright (c) 2018-2022 Rogiel Sulzbach. All rights reserved.
//
 
#pragma once
 
#include "Hash.hpp"
#include "String.hpp"
 
namespace CeresEngine {
 
    template<typename Sequence> class EncryptedString;
    template<std::size_t... Index> class EncryptedString<std::index_sequence<Index...>> {
    private:
        mutable char mValue[sizeof...(Index) + 1];
        mutable bool mEncrypted = true;
 
    public:
        constexpr EncryptedString(StringView plainString) noexcept : mValue{encryptCharacter(plainString[Index], Index)...} {}
 
        [[nodiscard]] StringView decrypt() const noexcept {
            if(mEncrypted) {
                for(std::size_t t = 0; t < sizeof...(Index); t++) {
                    mValue[t] = mValue[t] ^ (XORKEY + t);
                }
                mValue[sizeof...(Index)] = '\0';
                mEncrypted = false;
            }
 
            return mValue;
        }
 
    private:
        template<typename T> static constexpr T linearCongruentGenerator(T rounds) noexcept {
            return 1013904223 + 1664525 * ((rounds > 0) ? linearCongruentGenerator(rounds - 1) : staticHash32(StringView(__TIME__)) & 0xFFFFFFFF);
        }
 
        template<typename T> static constexpr T random() noexcept { return linearCongruentGenerator(10); }
        template<typename T> static constexpr T randomNumber(T minimum, T maximum) noexcept { return minimum + (random<T>() % (maximum - minimum + 1)); }
 
        static const char XORKEY = randomNumber<int>(0, 0xFF);
        static constexpr char encryptCharacter(const char character, const std::size_t index) noexcept { return character ^ (XORKEY + index); }
    };
 
#define CE_ENCRYPTED_STRING(X, String) ::CeresEngine::EncryptedString<std::make_index_sequence<sizeof(String) - 1>> X(String);
 
} // namespace CeresEngine