turboxl 0.1.3

Fast XLSX to CSV converter (C++ core with Python bindings)

TurboXL

Fast, read-only XLSX to CSV converter with C++20 core and Python bindings.

Performance

Real-world benchmarks on Chicago Crime dataset (21.9MB, 146,574 rows):

Metric	TurboXL	OpenPyXL	Improvement
Speed	2.4s	63.1s	26.7x faster
Memory	33.5MB	66.9MB	2.0x less
Throughput	62,040 rows/sec	2,321 rows/sec	26.7x faster

Dataset: Chicago Crimes 2025

🚀 Recent Optimizations Implemented:

• zlib-ng integration - Up to 2.5x faster ZIP decompression
• Release build optimizations - -O3 -march=native -flto for GCC/Clang, /O2 /GL /arch:AVX2 for MSVC
• Arena-based shared strings - Memory-efficient string storage
• Chunked ZIP reading - 512 KiB buffer optimization

What It Does

• ✅ Read XLSX files and convert to CSV
• ✅ Handle shared strings, numbers, dates, booleans
• ✅ Process multiple worksheets
• ✅ Memory-efficient streaming (33.5MB for 146k rows)
• ✅ Cross-platform (Linux, macOS, Windows)

What It Doesn't Do

• ❌ Write or modify XLSX files
• ❌ Formula evaluation (uses cached values)
• ❌ Charts, images, pivot tables
• ❌ Password-protected files

Quick Start

Python

import turboxl

# Convert first sheet
csv_data = turboxl.read_sheet_to_csv("data.xlsx")

# Convert specific sheet
csv_data = turboxl.read_sheet_to_csv("data.xlsx", sheet="Sheet2")

# Custom options
csv_data = turboxl.read_sheet_to_csv(
    "data.xlsx",
    sheet=0,
    delimiter=";",
    date_mode="iso"
)

# Save to file
with open("output.csv", "w", encoding="utf-8") as f:
    f.write(csv_data)

C++

#include <xlsxcsv.hpp>
#include <iostream>

int main() {
    try {
        std::string csv = xlsxcsv::readSheetToCsv("data.xlsx");
        std::cout << csv << std::endl;
    } catch (const std::exception& e) {
        std::cerr << "Error: " << e.what() << std::endl;
    }
    return 0;
}

Building

Prerequisites

Install system dependencies (used via pkg-config/CMake):

# macOS (Recommended for best performance)
brew install libxml2 minizip-ng zlib-ng cmake pybind11 pkg-config

# Ubuntu/Debian (Recommended for best performance)
sudo apt-get install -y libxml2-dev libminizip-dev cmake build-essential pkg-config
# For zlib-ng on Ubuntu/Debian, build from source:
# git clone https://github.com/zlib-ng/zlib-ng.git
# cd zlib-ng && cmake -B build && cmake --build build -j && sudo cmake --install build

# Windows (vcpkg)
vcpkg install libxml2 minizip-ng zlib-ng

Performance Note: Installing zlib-ng provides significant performance improvements (up to 2.5x faster decompression). The build system automatically detects and uses zlib-ng if available, falling back to standard zlib otherwise.

Build C++ Core (library only)

Build the C++ core without Python bindings (no Python/pybind11 required):

# From repo root
cmake -S . -B build \
  -DCMAKE_BUILD_TYPE=Release \
  -DBUILD_TESTS=OFF \
  -DBUILD_PYTHON=OFF \
  -DBUILD_CLI=OFF
cmake --build build -j4

Artifacts:

• Static library: build/libturboxl_core.a

Build Modes:

• Release (Recommended): Enables -O3 -march=native -flto optimizations
• Debug: Enables debugging symbols and assertions

Build Options

• BUILD_TESTS=ON/OFF - Build test suite (default: ON)
• BUILD_PYTHON=ON/OFF - Build Python bindings (default: ON)
• BUILD_CLI=ON/OFF - Build command-line tool (default: OFF)

---

Python Wheel

TurboXL ships a PEP 517/518 build powered by scikit-build-core. The wheel builds the C++ core and Python extension in Release mode using CMake.

Python prerequisites

python3 -m pip install -U pip build scikit-build-core pybind11

System dependencies listed above (libxml2, minizip-ng, zlib-ng, cmake, compiler) must be installed and discoverable by CMake/pkg-config.

Build the wheel

# From repo root
python3 -m build -w

Outputs go to dist/, for example:

• dist/turboxl-0.1.0-<python>-<abi>-<platform>.whl

Install the built wheel locally:

pip install python/dist/turboxl-*.whl

Tips:

• Parallel CMake build: CMAKE_BUILD_PARALLEL_LEVEL=4 python3 -m build -w
• macOS arch (defaults to arm64 via pyproject.toml): to override, you can pass --config-setting=cmake.define.CMAKE_OSX_ARCHITECTURES="arm64;x86_64" to python -m build.

Requirements

• C++: C++20 compiler (GCC 10+, Clang 12+, MSVC 2019+)
• Build: CMake 3.20+
• Python: 3.8-3.12 (for Python bindings)

API Reference

Python

turboxl.read_sheet_to_csv(
    xlsx_path: str,
    sheet: Union[str, int] = None,  # First sheet if None
    delimiter: str = ",",
    newline: Literal["LF", "CRLF"] = "LF",
    include_bom: bool = False,
    date_mode: Literal["iso", "rawNumber"] = "iso"
) -> str

C++

struct CsvOptions {
    std::string sheetByName;
    int sheetByIndex = -1;
    char delimiter = ',';
    bool includeBom = false;
    // ... more options
};

std::string readSheetToCsv(
    const std::string& xlsxPath,
    const CsvOptions& opts = {}
);

License

MIT License - see LICENSE file for details.