# Task 2 Report

status: DONE_WITH_CONCERNS

## Files created/modified

- CMakeLists.txt
- include/mag160c/mag160c.h
- src/core/tcm_frame.hpp
- src/core/tcm_frame.cpp
- src/c_api.cpp
- tests/cpp/test_c_api.cpp
- tests/cpp/test_tcm_frame.cpp
- progress.md

## Commands run

```powershell
g++ -std=c++17 -DMAG160C_STATIC -DMAG160C_HAS_LIBUSB=0 -Iinclude -Isrc src\core\error.cpp src\core\context.cpp src\core\tcm_frame.cpp src\c_api.cpp tests\cpp\test_c_api.cpp -o build_task2_c_api_test.exe
.\build_task2_c_api_test.exe
g++ -std=c++17 -DMAG160C_STATIC -DMAG160C_HAS_LIBUSB=0 -Iinclude -Isrc src\core\error.cpp src\core\context.cpp src\core\tcm_frame.cpp src\c_api.cpp tests\cpp\test_tcm_frame.cpp -o build_task2_tcm_frame_test.exe
.\build_task2_tcm_frame_test.exe
```

## Test results

- Direct MinGW C++17 compile/run verification passed for test_c_api.
- Direct MinGW C++17 compile/run verification passed for test_tcm_frame.

## Concerns

- CMake/CTest verification remains unavailable because cmake is not installed or not on PATH in this environment.
- Generated local executables build_task2_c_api_test.exe and build_task2_tcm_frame_test.exe exist from substitute verification.

## Self-review notes

- TCM encode exact vector for rotate +5 is implemented and tested.
- Header checksum and body checksum use additive uint8_t wrapping.
- C ABI encode reports required size when output buffer is too small.
- C ABI decode_header delegates to decode_tcm_frame and returns parsed main/sub/frame/payload size.
- Public header now includes stddef.h and stdint.h because Task 2 introduced size_t and fixed-width integer types.

## Fix report: oversized TCM payload safety

status: DONE

### Files modified

- src/core/tcm_frame.cpp
- src/c_api.cpp
- tests/cpp/test_c_api.cpp
- tests/cpp/test_tcm_frame.cpp

### Commands run

```powershell
g++ -std=c++17 -DMAG160C_STATIC -DMAG160C_HAS_LIBUSB=0 -Iinclude -Isrc src\core\error.cpp src\core\context.cpp src\core\tcm_frame.cpp src\c_api.cpp tests\cpp\test_c_api.cpp -o build_task2_c_api_test.exe
.\build_task2_c_api_test.exe
g++ -std=c++17 -DMAG160C_STATIC -DMAG160C_HAS_LIBUSB=0 -Iinclude -Isrc src\core\error.cpp src\core\context.cpp src\core\tcm_frame.cpp src\c_api.cpp tests\cpp\test_tcm_frame.cpp -o build_task2_tcm_frame_test.exe
.\build_task2_tcm_frame_test.exe
```

### Test results

- Direct MinGW C++17 compile/run verification passed for test_c_api.
- Direct MinGW C++17 compile/run verification passed for test_tcm_frame.

### Self-review

- Oversized payloads are rejected before allocation/copy.
- C ABI oversized payload path returns MAG160C_ERR_INVALID_ARGUMENT, sets out_size to 0, and sets last_error containing "too large".
- Core encode_tcm_frame oversized payload path is covered by a std::length_error test.