From 47a0b179cd9aaaa7f3f3e5273b1ca7fabf3578ae Mon Sep 17 00:00:00 2001
From: Kawe Mazidjatari <48657826+Mauler125@users.noreply.github.com>
Date: Thu, 27 Jun 2024 11:08:40 +0200
Subject: [PATCH] Tier1: add xorstr tools

---
 src/public/tier1/xorstr.h | 116 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 src/public/tier1/xorstr.h

diff --git a/src/public/tier1/xorstr.h b/src/public/tier1/xorstr.h
new file mode 100644
index 00000000..2c121f6f
--- /dev/null
+++ b/src/public/tier1/xorstr.h
@@ -0,0 +1,116 @@
+//=============================================================================//
+// 
+// Purpose: simple class for XOR'ing strings
+// 
+//-----------------------------------------------------------------------------
+// taken from https://stackoverflow.com/a/34981037
+//=============================================================================//
+#ifndef TIER1_XORSTR_H
+#define TIER1_XORSTR_H
+
+#include <array>
+
+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 CRandomGenerator
+    {
+    private:
+        static constexpr unsigned a = 16807;      // 7^5
+        static constexpr unsigned m = 2147483647; // 2^31 - 1
+
+        static constexpr unsigned s = CRandomGenerator< N - 1 >::value;
+        static constexpr unsigned lo = a * ( s & 0xFFFF );              // Multiply lower 16 bits by 16807
+        static constexpr unsigned hi = a * ( s >> 16 );                 // Multiply higher 16 bits by 16807
+        static constexpr unsigned lo2 = lo + ( ( hi & 0x7FFF ) << 16 ); // Combine lower 15 bits of hi with lo's upper bits
+        static constexpr unsigned hi2 = hi >> 15;                       // 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 CRandomGenerator< 0 >
+    {
+        static constexpr unsigned value = seed;
+    };
+
+    template < int N, int M >
+    struct CRandomInt
+    {
+        static constexpr auto value = CRandomGenerator< N + 1 >::value % M;
+    };
+
+    template < int N >
+    struct CRandomChar
+    {
+        static const char value = static_cast< char >( 1 + CRandomInt< N, 0x7F - 1 >::value );
+    };
+
+    template < size_t N, int K, typename Char >
+    struct CXorString
+    {
+    private:
+        const char m_key;
+        std::array< Char, N + 1 > m_data;
+
+        constexpr Char Encrypt( Char c ) const
+        {
+            return c ^ m_key;
+        }
+
+        Char Decrypt( Char c ) const
+        {
+            return c ^ m_key;
+        }
+
+    public:
+        template < size_t... Is >
+        constexpr __forceinline CXorString( const Char* str, std::index_sequence< Is... > )
+            : m_key( CRandomChar< K >::value )
+            , m_data{ Encrypt( str[ Is ] )... }
+        {
+        }
+
+        __forceinline decltype( auto ) Decrypt( void )
+        {
+            for ( size_t i = 0; i < N; ++i )
+            {
+                m_data[ i ] = Decrypt( m_data[ i ] );
+            }
+
+            m_data[ N ] = '\0';
+            return m_data.data();
+        }
+    };
+}
+
+//--------------------------------------------------------------------------------
+//-- Note: XorStr will __NOT__ work directly with functions like printf.
+//         To work with them you need a wrapper function that takes a const char*
+//         as parameter and passes it to printf and alike.
+//
+//         The Microsoft Compiler/Linker is not working correctly with variadic 
+//         templates!
+//--------------------------------------------------------------------------------
+
+// Wrapper functions to work in all functions
+#define XorStr( s )  []{ constexpr XorCompileTime::CXorString< sizeof( s )/sizeof( char ) - 1,    __COUNTER__, char >    expr( s, std::make_index_sequence< sizeof( s )/sizeof( char ) - 1 >() );    return expr; }().Decrypt()
+#define XorStrW( s ) []{ constexpr XorCompileTime::CXorString< sizeof( s )/sizeof( wchar_t ) - 1, __COUNTER__, wchar_t > expr( s, std::make_index_sequence< sizeof( s )/sizeof( wchar_t ) - 1 >() ); return expr; }().Decrypt()
+
+#endif // TIER1_XORSTR_H