gauche-rs

Left-hand traffic area classifier for Point, Line, and Bbox queries over well_known left-right-hand-traffic.osm.

Targets

Target	Command	Purpose
Library	cargo test / cargo build	Core Rust classifier API
CLI	cargo run -- point <lat> <lon>	Query a point, line, or bbox from the terminal
web	cargo web	Generates dist/gauche-wasm-map.html
bench	cargo bench	Runs the root ffi-vs-rust and queries Criterion benches
FFI wasm	cargo build --manifest-path ffi/Cargo.toml --target wasm32-unknown-unknown --release	Opaque-handle wasm API for C/C++ consumers
generate-c	cargo generate-c	Regenerate checked-in c/gauche_ffi.c and c/gauche_ffi.h from wasm via w2c2
C++ wrapper	cmake -S cpp -B cpp/build && cmake --build cpp/build	Consumable C++ library and example over the checked-in C FFI
release-all	cargo release-all	Rebuild release targets, then regenerate c/ and dist/ artifacts

Query semantics

• point returns yes or no
• line and bbox return yes, no, or partially
• partially results fall back to exact geometry checks

Examples

cargo run -- point 51.5072 -0.1276
cargo run -- line 51.5 -0.1 52.0 0.2
cargo run -- bbox 49.0 -5.0 55.0 2.0

Using the C++ library from CMake

Option 1: Vendored (recommended)

If your project vendors this repository, add the cpp/ directory and link the target:

add_subdirectory(path/to/gauche-rs/cpp)
target_link_libraries(my_app PRIVATE gauche::cpp)

Then include:

#include <gauche/gauche.hpp>

Option 2: Installed artifacts

cpp/CMakeLists.txt installs headers, library, and exported targets.

For single-config generators (Ninja/Unix Makefiles):

cmake -S cpp -B cpp/build -DGAUCHE_BUILD_EXAMPLES=OFF -DCMAKE_BUILD_TYPE=Release
cmake --build cpp/build
cmake --install cpp/build --prefix /your/prefix

For multi-config generators (Visual Studio/Xcode):

cmake -S cpp -B cpp/build -DGAUCHE_BUILD_EXAMPLES=OFF
cmake --build cpp/build --config Release
cmake --install cpp/build --prefix /your/prefix --config Release

The install currently exports targets but does not provide a gaucheConfig.cmake, so use:

include("/your/prefix/lib/cmake/gauche/gaucheCppTargets.cmake")
target_link_libraries(my_app PRIVATE gauche::gauche_cpp)

Generated artifacts

• preprocessed/bitmap.bin stores the 0.1° bitmap used at runtime.
• dist/gauche-wasm-map.html is the generated web artifact.
• c/gauche_ffi.c, c/gauche_ffi.h, and c/w2c2/w2c2/ are checked in and regenerated from the wasm FFI target.

Layout

• src/lib.rs — core classifier
• src/main.rs — CLI
• src/bin/web-build.rs — web target generator
• src/bin/generate-c.rs — wasm-to-C generator
• ffi/ — wasm FFI crate
• benches/ffi-vs-rust.rs — Root ffi-vs-rust Criterion benchmark
• benches/queries.rs — Root query Criterion benchmark
• cpp/ — CMake-based C++ wrapper and example