Contributing

Before creating a pull request

Ensure that the code compiles without warnings and all tests pass.
Format the source code using clang-format. Running clang-format -i *.cc *.h will format source and header files in the current directory to match Agora's code style. There are also editor plugins for clang-format (example). We recommend using clang-format version 11 or above.

Currently the code is not fully consistent with these style guidelines. It is a work in progress.
At a high level, we aim to follow Google's C++ style guide.
Naming:
- lower_camel_case for variable names.
- UpperCamelCase for class, struct, and function names.
- kConstant for static storage duration constants. Otherwise the usual variable nameing rules apply.
- Source file names should end in .cc, header file names in .h.
Classes:
- Mark eligible class functions and members as const, private, or static.
- Eligible classes should have corresponding tests.
Avoid macros unless absolutely necessary. For example, macros are acceptable to disable compilation of files that depend on proprietary libraries. So instead of:
```
#ifdef USE_LDPC
    std::string raw_data_filename = x;
#else
    std::string raw_data_filename = y;
#endif
```
prefer:
```
std::string raw_data_filename = kUseLDPC ? x : y;
```

Avoid magic numbers. Instead of:

n_rows = (ldpc_config.bg == 1) ? 46 : 42;

prefer:

n_rows = (ldpc_config.bg == 1) ? kBg1RowTotal : kBg2RowTotal;

Avoid variable copies. Instead of size_t fft_thread_num = cfg->fft_thread_num;, prefer using cfg->fft_thread_num directly.

Use enum classes instead of enums or macros. So instead of:

#define PRINT_RX_PILOTS 0
#define PRINT_RX 1

prefer:

enum class PrintType {kRXPilots, kRX};

Add newlines between distinct blocks of code. See the vertical whitespace section.
Comments (link):
- Use proper grammar and capitalization in comment text.
- Comments should fit in 80 columns.
- Add comments for non-obvious blocks of code.
- Avoid commented-out blocks of code. For example, if a block of code is needed for debugging, wrap it inside a boolean flag (e.g., kVerbose).
Use size_t as the integer type unless negative integers are needed.
Mark eligible function arguments and implementation variables as const.
Use C++-style casts with static_cast and reinterpret_cast instead of C-style casts.

Use auto type deduction when the type is clear. So instead of:

struct Packet *pkt = new struct Packet[kNumPackets];

prefer:

auto *pkt = new Packet[kNumPackets];

Each file must have a comment at the top explaining what the file's purpose.
Each class must have a top-level comment explaining the class's purpose.
Non-trivial class members and functions should have documentation comments in the class header file.