BeamMP-Server/include/Security/Xor.h

///
/// Created by Anonymous275 on 8/11/2020
///
#pragma once
#include <string>
#include <array>
#include <cstdarg>
#include <cstdio>

#define BEGIN_NAMESPACE(x) namespace x {
#define END_NAMESPACE }

BEGIN_NAMESPACE(XorCompileTime)

    constexpr auto time = __TIME__;
    constexpr auto seed = static_cast<int>(time[7]) + static_cast<int>(time[6]) * 10 + static_cast<int>(time[4]) * 60 + static_cast<int>(time[3]) * 600 + static_cast< int >(time[1]) * 3600 + static_cast< int >(time[0]) * 36000;

// 1988, Stephen Park and Keith Miller
// "Random Number Generators: Good Ones Are Hard To Find", considered as "minimal standard"
// Park-Miller 31 bit pseudo-random number generator, implemented with G. Carta's optimisation:
// with 32-bit math and without division

    template <int N>
    struct RandomGenerator{
    private:
        static constexpr unsigned a = 16807; // 7^5
        static constexpr unsigned m = 2147483647; // 2^31 - 1

        static constexpr unsigned s = RandomGenerator< N - 1 >::value;
        static constexpr unsigned lo = a * (s & 0xFFFFu); // Multiply lower 16 bits by 16807
        static constexpr unsigned hi = a * (s >> 16u); // Multiply higher 16 bits by 16807
        static constexpr unsigned lo2 = lo + ((hi & 0x7FFFu) << 16u); // Combine lower 15 bits of hi with lo's upper bits
        static constexpr unsigned hi2 = hi >> 15u; // Discard lower 15 bits of hi
        static constexpr unsigned lo3 = lo2 + hi;

    public:
        static constexpr unsigned max = m;
        static constexpr unsigned value = lo3 > m ? lo3 - m : lo3;
    };

    template <>
    struct RandomGenerator< 0 >{
        static constexpr unsigned value = seed;
    };

    template <int N, int M>
    struct RandomInt{
        static constexpr auto value = RandomGenerator< N + 1 >::value % M;
    };

    template <int N>
    struct RandomChar{
        static const char value = static_cast< char >(1 + RandomInt< N, 0x7F - 1 >::value);
    };

    template <size_t N, int K, typename Char>
    struct XorString{
    private:
        const char _key;
        std::array< Char, N + 1 > _encrypted;

        constexpr Char enc(Char c) const{
            return c ^ _key;
        }

        Char dec(Char c) const{
            return c ^ _key;
        }

    public:
        template <size_t... Is>
        constexpr inline XorString(const Char* str, std::index_sequence< Is... >) : _key(RandomChar< K >::value), _encrypted{ enc(str[Is])... }
        {}

        inline decltype(auto) decrypt(){
            for (size_t i = 0; i < N; ++i) {
                _encrypted[i] = dec(_encrypted[i]);
            }
            _encrypted[N] = '\0';
            return _encrypted.data();
        }
    };

    static auto w_printf = [](const char* fmt, ...) {
        va_list args;
                va_start(args, fmt);
        vprintf(fmt, args);
                va_end(args);
    };

    static auto w_printf_s = [](const char* fmt, ...) {
        va_list args;
                va_start(args, fmt);
        vprintf(fmt, args);
                va_end(args);
    };

    /*static auto w_sprintf = [](char* buf, const char* fmt, ...) {
        va_list args;
                va_start(args, fmt);
        vsprintf(buf, fmt, args);
                va_end(args);
    };*/

    /*static auto w_sprintf_ret = [](char* buf, const char* fmt, ...) {
        int ret;
        va_list args;
                va_start(args, fmt);
        ret = vsprintf(buf, fmt, args);
                va_end(args);
        return ret;
    };*/

    static auto w_sprintf_s = [](char* buf, size_t buf_size, const char* fmt, ...) {
        va_list args;
                va_start(args, fmt);
        vsnprintf(buf, buf_size, fmt, args);
                va_end(args);
    };

    static auto w_sprintf_s_ret = [](char* buf, size_t buf_size, const char* fmt, ...) {
        int ret;
        va_list args;
                va_start(args, fmt);
        ret = vsnprintf(buf, buf_size, fmt, args);
                va_end(args);
        return ret;
    };
#define Sec( s ) []{ constexpr XorCompileTime::XorString< sizeof(s)/sizeof(char) - 1, __COUNTER__, char > expr( s, std::make_index_sequence< sizeof(s)/sizeof(char) - 1>() ); return expr; }().decrypt()
#define SecW( s ) []{ constexpr XorCompileTime::XorString< sizeof(s)/sizeof(wchar_t) - 1, __COUNTER__, wchar_t > expr( s, std::make_index_sequence< sizeof(s)/sizeof(wchar_t) - 1>() ); return expr; }().decrypt()
END_NAMESPACE