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| 1 | +<!-- SPDX-License-Identifier: Apache-2.0 --> |
| 2 | +<!-- SPDX-FileCopyrightText: (C) 2026 Intel Corporation --> |
| 3 | + |
| 4 | +# Intel Secure C++ Specifics |
| 5 | + |
| 6 | +## Purpose |
| 7 | + |
| 8 | +This skill provides guidance for secure C++ coding in SceneScape's geometry and vision components, grounded in Intel Secure Coding Standards - C++ Specifics. |
| 9 | + |
| 10 | +**Applies to:** |
| 11 | + |
| 12 | +- `scene_common/src/fast_geometry/` (C++ geometry extension) |
| 13 | +- `controller/src/robot_vision/` (C++ vision processing) |
| 14 | +- `tracker/` (C++ tracking component) |
| 15 | +- Any new C++ modules |
| 16 | + |
| 17 | +--- |
| 18 | + |
| 19 | +## Core Principles |
| 20 | + |
| 21 | +### Memory Management (RAII) |
| 22 | + |
| 23 | +✅ **DO:** |
| 24 | + |
| 25 | +```cpp |
| 26 | +// Use RAII: Resource Acquisition Is Initialization |
| 27 | +class CameraMatrix { |
| 28 | + std::unique_ptr<float[]> data_; |
| 29 | + size_t size_; |
| 30 | +public: |
| 31 | + CameraMatrix(size_t n) : data_(new float[n]), size_(n) {} |
| 32 | + ~CameraMatrix() { /* automatically freed by unique_ptr */ } |
| 33 | +}; |
| 34 | + |
| 35 | +// Use smart pointers |
| 36 | +std::unique_ptr<Geometry> geom(new Geometry()); // Prefer unique_ptr |
| 37 | +std::shared_ptr<Camera> cam(new Camera()); // Use shared_ptr only if needed |
| 38 | +``` |
| 39 | +
|
| 40 | +❌ **DON'T:** |
| 41 | +
|
| 42 | +```cpp |
| 43 | +// Raw new/delete |
| 44 | +float* data = new float[1024]; |
| 45 | +// ... risk of memory leak if exception or early return ... |
| 46 | +delete[] data; |
| 47 | +
|
| 48 | +// malloc/free (C-style) |
| 49 | +float* data = (float*)malloc(1024 * sizeof(float)); |
| 50 | +free(data); |
| 51 | +``` |
| 52 | + |
| 53 | +### String Handling |
| 54 | + |
| 55 | +✅ **DO:** |
| 56 | + |
| 57 | +```cpp |
| 58 | +std::string camera_name = "camera_1"; |
| 59 | +std::string full_path = camera_name + "_calibration.json"; |
| 60 | + |
| 61 | +// Use std::string_view for non-owning references |
| 62 | +void process_camera(std::string_view name) { |
| 63 | + // read-only access without copying |
| 64 | +} |
| 65 | + |
| 66 | +// Use std::format (C++20) or fmt::format |
| 67 | +std::string message = std::format("Camera {} position: {}", id, pos); |
| 68 | +``` |
| 69 | +
|
| 70 | +❌ **DON'T:** |
| 71 | +
|
| 72 | +```cpp |
| 73 | +// C-style strings and unsafe functions |
| 74 | +char name[255]; |
| 75 | +strcpy(name, user_input); // Buffer overflow risk |
| 76 | +strcat(name, ".json"); // Dangerous |
| 77 | +
|
| 78 | +// printf family |
| 79 | +printf("Position: %d %d\n", x, y); // Prone to format string attacks |
| 80 | +sprintf(buffer, "Name: %s", name); // No bounds checking |
| 81 | +``` |
| 82 | + |
| 83 | +### Type Safety & Const Correctness |
| 84 | + |
| 85 | +✅ **DO:** |
| 86 | + |
| 87 | +```cpp |
| 88 | +// Use strong typing |
| 89 | +struct Point { float x, y, z; }; |
| 90 | +struct Camera { float focal_length; }; |
| 91 | + |
| 92 | +// Explicit casts |
| 93 | +int size = static_cast<int>(data.size()); |
| 94 | + |
| 95 | +// Const for read-only |
| 96 | +const Point& get_position() const { return position_; } |
| 97 | +void set_position(const Point& p) { position_ = p; } |
| 98 | + |
| 99 | +// nullptr for null pointers |
| 100 | +Point* position = nullptr; // Strongly typed |
| 101 | +if (position != nullptr) { /* ... */ } |
| 102 | +``` |
| 103 | +
|
| 104 | +❌ **DON'T:** |
| 105 | +
|
| 106 | +```cpp |
| 107 | +// Weak typing (void*) |
| 108 | +void* data = geometry_data; // What type is this? |
| 109 | +
|
| 110 | +// Implicit casting |
| 111 | +int size = data.size(); // May lose precision |
| 112 | +
|
| 113 | +// NULL macro (C-style) |
| 114 | +Point* position = NULL; |
| 115 | +
|
| 116 | +// Uninitialized pointers |
| 117 | +Point* position; // May contain garbage |
| 118 | +``` |
| 119 | + |
| 120 | +### Integer Arithmetic |
| 121 | + |
| 122 | +✅ **DO:** |
| 123 | + |
| 124 | +```cpp |
| 125 | +// Check for overflow before operations |
| 126 | +size_t total_size = num_cameras * points_per_camera; |
| 127 | +if (num_cameras > SIZE_MAX / points_per_camera) { |
| 128 | + throw std::overflow_error("Size calculation overflow"); |
| 129 | +} |
| 130 | + |
| 131 | +// Guard division by zero |
| 132 | +if (divisor != 0) { |
| 133 | + result = numerator / divisor; |
| 134 | +} else { |
| 135 | + throw std::runtime_error("Division by zero"); |
| 136 | +} |
| 137 | + |
| 138 | +// Check INT_MIN/-1 for signed division |
| 139 | +if (!(value == INT_MIN && divisor == -1)) { |
| 140 | + result = value / divisor; |
| 141 | +} |
| 142 | +``` |
| 143 | + |
| 144 | +❌ **DON'T:** |
| 145 | + |
| 146 | +```cpp |
| 147 | +// Unsigned/signed mix |
| 148 | +int signed_val = -10; |
| 149 | +unsigned int unsigned_val = 20; |
| 150 | +int result = signed_val + unsigned_val; // Unexpected conversion |
| 151 | + |
| 152 | +// Unguarded division |
| 153 | +result = a / b; // May crash if b == 0 |
| 154 | + |
| 155 | +// Integer overflow |
| 156 | +int overflow = INT_MAX + 1; // Undefined behavior |
| 157 | +``` |
| 158 | + |
| 159 | +### Error Handling |
| 160 | + |
| 161 | +✅ **DO:** |
| 162 | + |
| 163 | +```cpp |
| 164 | +// Check return values |
| 165 | +int result = calibrate_camera(cam); |
| 166 | +if (result != SUCCESS) { |
| 167 | + log_error("Camera calibration failed"); |
| 168 | + throw std::runtime_error("Calibration error"); |
| 169 | +} |
| 170 | + |
| 171 | +// Use exceptions, not assert for security |
| 172 | +if (!validate_matrix(M)) { |
| 173 | + throw std::invalid_argument("Invalid matrix"); |
| 174 | +} |
| 175 | + |
| 176 | +// Use std::optional for optional results |
| 177 | +std::optional<Point> find_feature(const Image& img) { |
| 178 | + if (/* found */) return Point{x, y}; |
| 179 | + return std::nullopt; |
| 180 | +} |
| 181 | +``` |
| 182 | +
|
| 183 | +❌ **DON'T:** |
| 184 | +
|
| 185 | +```cpp |
| 186 | +// Ignore return values |
| 187 | +calibrate_camera(cam); // Result ignored; may fail silently |
| 188 | +
|
| 189 | +// Use assert for runtime validation |
| 190 | +assert(validate_matrix(M)); // Removed in release builds! |
| 191 | +
|
| 192 | +// Silent failures |
| 193 | +if (load_config(file)) { /* continue */ } // What failed? |
| 194 | +``` |
| 195 | + |
| 196 | +### Function Design |
| 197 | + |
| 198 | +✅ **DO:** |
| 199 | + |
| 200 | +```cpp |
| 201 | +// Limit parameters (ideally ≤6) |
| 202 | +Point apply_transform(const Point& p, const Matrix& M, const Vector& t) { |
| 203 | + return M * p + t; |
| 204 | +} |
| 205 | + |
| 206 | +// Clear error handling |
| 207 | +[[nodiscard]] bool validate_image(const Image& img); |
| 208 | + |
| 209 | +// Pure functions where possible |
| 210 | +float distance(const Point& a, const Point& b) { |
| 211 | + return std::sqrt((a.x - b.x) * (a.x - b.x) + |
| 212 | + (a.y - b.y) * (a.y - b.y)); |
| 213 | +} |
| 214 | +``` |
| 215 | +
|
| 216 | +❌ **DON'T:** |
| 217 | +
|
| 218 | +```cpp |
| 219 | +// Too many parameters |
| 220 | +Point complex_op(int a, int b, int c, int d, int e, int f, int g) { /* ... */ } |
| 221 | +
|
| 222 | +// Variadic functions (error-prone) |
| 223 | +void log_message(const char* fmt, ...); // Use std::format instead |
| 224 | +
|
| 225 | +// Functions with hidden side effects |
| 226 | +Point get_position(); // Modifies global state? Unclear |
| 227 | +``` |
| 228 | + |
| 229 | +--- |
| 230 | + |
| 231 | +## Review Checklist |
| 232 | + |
| 233 | +When reviewing or generating C++ code: |
| 234 | + |
| 235 | +- [ ] All heap allocations use `std::unique_ptr<T>` or `std::shared_ptr<T>` (no raw `new`/`delete`) |
| 236 | +- [ ] No `malloc`/`free` (C-style memory management) |
| 237 | +- [ ] All pointers initialized to `nullptr` (not `NULL`) |
| 238 | +- [ ] All strings use `std::string` (not C-style char arrays) |
| 239 | +- [ ] No `printf` family functions (use `std::format` or `fmt::format`) |
| 240 | +- [ ] Return values checked for all functions that may fail |
| 241 | +- [ ] Integer arithmetic guarded against overflow/underflow |
| 242 | +- [ ] Division by zero prevented (checked divisor) |
| 243 | +- [ ] Const-correctness enforced (const members, const references) |
| 244 | +- [ ] Assert not used for security validation (use exceptions) |
| 245 | +- [ ] Type casts use `static_cast<T>`, `const_cast<T>` explicitly (never C-style casts) |
| 246 | +- [ ] No `void*` for type safety |
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