cpp/CLAUDE.md

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# CLAUDE.md — C++ Module

This file provides guidance to Claude Code (claude.ai/code) when working with the C++ module.

## Build Commands

```bash
# Build (Release, default)
bash build.sh

# Build variants
bash build.sh -t=Debug
bash build.sh -t=RelWithDebInfo
bash build.sh -a=ON              # Enable AddressSanitizer
bash build.sh -c=ON              # Enable code coverage

# Disable optional compression libraries
bash build.sh --disable-snappy --disable-lz4 --disable-lzokay --disable-zlib

# Or use CMake directly
mkdir -p build/Release && cd build/Release
cmake ../.. -DCMAKE_BUILD_TYPE=Release -DBUILD_TEST=ON
make -j$(nproc)

# Via Maven from repo root
./mvnw clean verify -P with-cpp

# Run all tests
./build/Release/lib/TsFile_Test

# Run specific test suite
./build/Release/lib/TsFile_Test --gtest_filter=SnappyCompressorTest.*
```

## Build Options (CMake)

All `ON` by default unless noted:

| Option | Purpose |
|--------|---------|
| `BUILD_TEST` | Compile tests (GTest 1.12.1, auto-downloaded) |
| `ENABLE_ANTLR4` | ANTLR4 parser runtime |
| `ENABLE_SNAPPY` / `ENABLE_LZ4` / `ENABLE_LZOKAY` / `ENABLE_ZLIB` | Compression libraries |
| `ENABLE_THREADS` | Multi-threaded read/write via pthreads |
| `ENABLE_ASAN` | AddressSanitizer (`OFF` by default) |
| `ENABLE_SIMDE` | SIMD Everywhere (`OFF` by default) |

## Source Structure

```
cpp/src/
├── common/        # Core types: Schema, Tablet, DeviceId, TsBlock, allocators, config
├── compress/      # Compression: Snappy, LZ4, LZOKAY, Zlib (factory pattern)
├── encoding/      # Encoding: Plain, TS2Diff, Gorilla, Dictionary, RLE, Zigzag, SPRINTZ
├── file/          # File I/O: TsFileIOReader/Writer, RestorableTsFileIOWriter
├── reader/        # Read path: TsFileReader, QueryExecutor, filters, result sets
├── writer/        # Write path: TsFileWriter, TsFileTableWriter, ChunkWriter, PageWriter
├── parser/        # ANTLR4 path parser (grammars + generated code)
├── cwrapper/      # C language bindings (used by Python module)
└── utils/         # Utilities: error codes, date handling, fault injection
```

## Architecture Notes

- **C++11** standard, targets CMake 3.11+
- Dual data model: **tree-view** (`TsFileTreeWriter/Reader`) and **table-view** (`TsFileTableWriter`, `TableQueryExecutor`)
- Parallel column encoding in table write path, controlled by `ENABLE_THREADS`
- Third-party libraries are bundled under `third_party/` (ANTLR4, Snappy, LZ4, LZOKAY, Zlib, SIMDe)
- `cwrapper/` provides the C API that the Python module binds to via Cython

## Code Style

- **Formatter**: clang-format (Google style), configured in `.clang-format`
- After modifying C++ code, run from the repo root to format: `./mvnw spotless:apply -P with-cpp`

## Testing

- **Framework**: Google Test 1.12.1 (auto-downloaded during build, or supply `third_party/googletest-release-1.12.1.zip`)
- Tests in `cpp/test/`, mirroring `src/` structure
- Test discovery via `gtest_discover_tests()`

## License Header

Every new file must include the Apache License 2.0 header at the top. For C/C++ files, use the `/* */` block comment style. See any existing `.h` or `.cc` file for the exact wording.

## Git Commit

- Do NOT add `Co-Authored-By` trailer to commit messages.