Merge pull request #135 from orange-cpp/feature/crypto_var

Feature/crypto var

CMakeLists.txt

@@ -27,7 +27,7 @@ option(OMATH_SUPRESS_SAFETY_CHECKS "Supress some safety checks in release build
 option(OMATH_USE_UNITY_BUILD "Will enable unity build to speed up compilation" OFF)
 option(OMATH_ENABLE_LEGACY "Will enable legacy classes that MUST be used ONLY for backward compatibility" ON)
 option(OMATH_ENABLE_COVERAGE "Enable coverage" OFF)
-
+option(OMATH_ENABLE_FORCE_INLINE "Will for compiler to make some functions to be force inlined no matter what" ON)
 if (VCPKG_MANIFEST_FEATURES)
     foreach (omath_feature IN LISTS VCPKG_MANIFEST_FEATURES)
         if (omath_feature STREQUAL "imgui")
@@ -112,6 +112,10 @@ if (OMATH_ENABLE_LEGACY)
     target_compile_definitions(${PROJECT_NAME} PUBLIC OMATH_ENABLE_LEGACY)
 endif ()
 
+if (OMATH_ENABLE_FORCE_INLINE)
+    target_compile_definitions(${PROJECT_NAME} PUBLIC OMATH_ENABLE_FORCE_INLINE)
+endif ()
+
 set_target_properties(${PROJECT_NAME} PROPERTIES
         ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/out/${CMAKE_BUILD_TYPE}"
         LIBRARY_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/out/${CMAKE_BUILD_TYPE}"

include/omath/containers/encrypted_variable.hpp

@@ -0,0 +1,201 @@
+//
+// Created by Vladislav on 04.01.2026.
+//
+#pragma once
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <span>
+#ifdef OMATH_ENABLE_FORCE_INLINE
+#ifdef _MSC_VER
+#define OMATH_FORCE_INLINE __forceinline
+#else
+#define OMATH_FORCE_INLINE __attribute__((always_inline)) inline
+#endif
+#else
+#define OMATH_FORCE_INLINE
+#endif
+
+namespace omath::detail
+{
+    [[nodiscard]]
+    consteval std::uint64_t fnv1a_64(const char* s)
+    {
+        std::uint64_t h = 14695981039346656037ull;
+        while (*s)
+        {
+            h ^= static_cast<unsigned char>(*s++);
+            h *= 1099511628211ull;
+        }
+        return h;
+    }
+
+    // SplitMix64 mixer (good quality for seeding / scrambling)
+    [[nodiscard]]
+    consteval std::uint64_t splitmix64(std::uint64_t x)
+    {
+        x += 0x9E3779B97F4A7C15ull;
+        x = (x ^ (x >> 30)) * 0xBF58476D1CE4E5B9ull;
+        x = (x ^ (x >> 27)) * 0x94D049BB133111EBull;
+        return x ^ (x >> 31);
+    }
+
+    // Choose your policy:
+    // - If you want reproducible builds, REMOVE __DATE__/__TIME__.
+    // - If you want "different each build", keep them.
+    [[nodiscard]]
+    consteval std::uint64_t base_seed()
+    {
+        std::uint64_t h = 0;
+        h ^= fnv1a_64(__FILE__);
+        h ^= splitmix64(fnv1a_64(__DATE__));
+        h ^= splitmix64(fnv1a_64(__TIME__));
+        return splitmix64(h);
+    }
+
+    // Produce a "random" 64-bit value for a given stream index (compile-time)
+    template<std::uint64_t Stream>
+    [[nodiscard]]
+    consteval std::uint64_t rand_u64()
+    {
+        // Stream is usually __COUNTER__ so each call site differs
+        return splitmix64(base_seed() + 0xD1B54A32D192ED03ull * (Stream + 1));
+    }
+
+    [[nodiscard]]
+    consteval std::uint64_t bounded_u64(const std::uint64_t x, const std::uint64_t bound)
+    {
+        return (x * bound) >> 64;
+    }
+
+    template<std::int64_t Lo, std::int64_t Hi, std::uint64_t Stream>
+    [[nodiscard]]
+    consteval std::int64_t rand_uint8_t()
+    {
+        static_assert(Lo <= Hi);
+        const std::uint64_t span = static_cast<std::uint64_t>(Hi - Lo) + 1ull;
+        const std::uint64_t r = rand_u64<Stream>();
+        return static_cast<std::int64_t>(bounded_u64(r, span)) + Lo;
+    }
+    [[nodiscard]]
+    consteval std::uint64_t rand_u64(const std::uint64_t seed, const std::uint64_t i)
+    {
+        return splitmix64(seed + 0xD1B54A32D192ED03ull * (i + 1ull));
+    }
+
+    // Convert to int (uses low 32 bits; you can also use high bits if you prefer)
+    [[nodiscard]]
+    consteval std::uint8_t rand_uint8t(const std::uint64_t seed, const std::uint64_t i)
+    {
+        return static_cast<std::uint8_t>(rand_u64(seed, i)); // narrowing is fine/deterministic
+    }
+    template<std::size_t N, std::uint64_t Seed, std::size_t... I>
+    [[nodiscard]]
+    consteval std::array<std::uint8_t, N> make_array_impl(std::index_sequence<I...>)
+    {
+        return {rand_uint8t(Seed, static_cast<std::uint64_t>(I))...};
+    }
+
+    template<std::size_t N, std::uint64_t Seed>
+    [[nodiscard]]
+    consteval std::array<std::uint8_t, N> make_array()
+    {
+        return make_array_impl<N, Seed>(std::make_index_sequence<N>{});
+    }
+} // namespace omath::detail
+
+namespace omath
+{
+    template<class T>
+    class VarAnchor;
+
+    template<class T, std::size_t key_size, std::array<std::uint8_t, key_size> key>
+    class EncryptedVariable final
+    {
+        using value_type = std::remove_cvref_t<T>;
+
+        bool m_is_encrypted{};
+        value_type m_data{};
+
+        OMATH_FORCE_INLINE constexpr void xor_contained_var_by_key()
+        {
+            // Safe, keeps const-correctness, and avoids reinterpret_cast issues
+            auto bytes = std::as_writable_bytes(std::span<value_type, 1>{&m_data, 1});
+
+            for (std::size_t i = 0; i < bytes.size(); ++i)
+            {
+                const std::uint8_t k = static_cast<std::uint8_t>(key[i % key_size] + (i * key_size));
+                bytes[i] ^= static_cast<std::byte>(k);
+            }
+        }
+
+    public:
+        OMATH_FORCE_INLINE constexpr explicit EncryptedVariable(const value_type& data)
+            : m_is_encrypted(false), m_data(data)
+        {
+            encrypt();
+        }
+
+        [[nodiscard]] constexpr bool is_encrypted() const
+        {
+            return m_is_encrypted;
+        }
+
+        OMATH_FORCE_INLINE constexpr void decrypt()
+        {
+            if (!m_is_encrypted)
+                return;
+            xor_contained_var_by_key();
+            m_is_encrypted = false;
+        }
+
+        OMATH_FORCE_INLINE constexpr void encrypt()
+        {
+            if (m_is_encrypted)
+                return;
+            xor_contained_var_by_key();
+            m_is_encrypted = true;
+        }
+
+        [[nodiscard]] OMATH_FORCE_INLINE constexpr value_type& value()
+        {
+            return m_data;
+        }
+        [[nodiscard]] OMATH_FORCE_INLINE constexpr const value_type& value() const
+        {
+            return m_data;
+        }
+
+        constexpr OMATH_FORCE_INLINE ~EncryptedVariable()
+        {
+            decrypt();
+        }
+
+        [[nodiscard]] constexpr OMATH_FORCE_INLINE auto drop_anchor()
+        {
+            return VarAnchor{*this};
+        }
+    };
+
+    template<class EncryptedVarType>
+    class VarAnchor final
+    {
+    public:
+        // ReSharper disable once CppNonExplicitConvertingConstructor
+        OMATH_FORCE_INLINE constexpr VarAnchor(EncryptedVarType& var): m_var(var)
+        {
+            m_var.decrypt();
+        }
+        OMATH_FORCE_INLINE constexpr ~VarAnchor()
+        {
+            m_var.encrypt();
+        }
+
+    private:
+        EncryptedVarType& m_var;
+    };
+} // namespace omath
+
+#define OMATH_CT_RAND_ARRAY_BYTE(N)                                                                                    \
+    (::omath::detail::make_array<(N), (::omath::detail::base_seed() ^ static_cast<std::uint64_t>(__COUNTER__))>())
+#define OMATH_DEF_CRYPT_VAR(TYPE, KEY_SIZE) omath::EncryptedVariable<TYPE, KEY_SIZE, OMATH_CT_RAND_ARRAY_BYTE(KEY_SIZE)>

tests/general/unit_test_var_encryption.cpp

@@ -0,0 +1,17 @@
+//
+// Created by Vladislav on 04.01.2026.
+//
+#include "omath/linear_algebra/vector3.hpp"
+#include <gtest/gtest.h>
+#include <omath/containers/encrypted_variable.hpp>
+TEST(Enc, Test)
+{
+    constexpr omath::Vector3<float> original = {1.f, 2.f, 3.f};
+    OMATH_DEF_CRYPT_VAR(omath::Vector3<float>, 128) var{original};
+    {
+        omath::VarAnchor _ = var.drop_anchor();
+
+        EXPECT_EQ(original, var.value());
+    }
+    EXPECT_NE(original, var.value());
+}