Add cryptography header for the future

include/Cryptography.h

@@ -0,0 +1,113 @@
+// Copyright Anonymous275 8/11/2020
+
+#pragma once
+#include <array>
+#include <cstdarg>
+#include <string>
+
+namespace Crypto {
+
+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 XorString(const Char* str, std::index_sequence<Is...>)
+        : _key(RandomChar<K>::value)
+        , _encrypted { enc(str[Is])... } { }
+
+    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_s = [](char* buf, size_t buf_size, const char* fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    vsprintf(buf, 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 = vsprintf(buf, fmt, args);
+    va_end(args);
+    return ret;
+};
+
+#define XOR_C(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 XOR_W(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()
+
+}