feat: C++ bindings support

.gitignore

@@ -71,4 +71,6 @@ src/rust/fcb_core/tests/data/*.json
 flamegraph*
 .roo
 .serena/
-*.so
+*.so
+
+build/

.vscode/settings.json

@@ -17,5 +17,6 @@
   ],
   "cursorpyright.analysis.extraPaths": [
     "${workspaceFolder}/src/rust/fcb_py/python"
-  ]
+  ],
+  "cmake.sourceDirectory": "${workspaceFolder}/src/cpp"
 }

src/cpp/CMakeLists.txt

@@ -0,0 +1,83 @@
+cmake_minimum_required(VERSION 3.16)
+project(fcb_cpp VERSION 0.1.0 LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# Find cxxbridge CLI tool
+find_program(CXXBRIDGE cxxbridge)
+if(NOT CXXBRIDGE)
+    message(STATUS "cxxbridge not found, installing via cargo...")
+    execute_process(
+        COMMAND cargo install cxxbridge-cmd
+        RESULT_VARIABLE CXXBRIDGE_INSTALL_RESULT
+    )
+    find_program(CXXBRIDGE cxxbridge REQUIRED)
+endif()
+
+# Configuration
+set(RUST_LIB_DIR ${CMAKE_SOURCE_DIR}/../rust)
+set(GENERATED_DIR ${CMAKE_BINARY_DIR}/generated)
+file(MAKE_DIRECTORY ${GENERATED_DIR})
+
+# Build Rust static library
+add_custom_command(
+    OUTPUT ${RUST_LIB_DIR}/target/release/libfcb_cpp.a
+    COMMAND cargo build --release -p fcb_cpp
+    WORKING_DIRECTORY ${RUST_LIB_DIR}
+    DEPENDS ${RUST_LIB_DIR}/fcb_cpp/src/lib.rs
+    DEPENDS ${RUST_LIB_DIR}/fcb_cpp/src/reader.rs
+    DEPENDS ${RUST_LIB_DIR}/fcb_cpp/src/writer.rs
+    COMMENT "Building Rust fcb_cpp library"
+)
+
+add_custom_target(rust_library DEPENDS ${RUST_LIB_DIR}/target/release/libfcb_cpp.a)
+
+# Generate C++ bridge code
+add_custom_command(
+    OUTPUT ${GENERATED_DIR}/lib.rs.h
+    COMMAND ${CXXBRIDGE} ${RUST_LIB_DIR}/fcb_cpp/src/lib.rs --header > ${GENERATED_DIR}/lib.rs.h
+    DEPENDS ${RUST_LIB_DIR}/fcb_cpp/src/lib.rs
+    COMMENT "Generating C++ header from CXX bridge"
+)
+
+add_custom_command(
+    OUTPUT ${GENERATED_DIR}/lib.rs.cc
+    COMMAND ${CXXBRIDGE} ${RUST_LIB_DIR}/fcb_cpp/src/lib.rs > ${GENERATED_DIR}/lib.rs.cc
+    DEPENDS ${RUST_LIB_DIR}/fcb_cpp/src/lib.rs
+    COMMENT "Generating C++ source from CXX bridge"
+)
+
+# Create fcb library
+add_library(fcb STATIC
+    ${GENERATED_DIR}/lib.rs.cc
+)
+
+add_dependencies(fcb rust_library)
+
+target_include_directories(fcb PUBLIC
+    ${GENERATED_DIR}
+    ${CMAKE_SOURCE_DIR}/include
+)
+
+target_link_libraries(fcb
+    ${RUST_LIB_DIR}/target/release/libfcb_cpp.a
+)
+
+# Platform-specific linking
+if(APPLE)
+    target_link_libraries(fcb
+        "-framework Security"
+        "-framework CoreFoundation"
+        "-framework SystemConfiguration"
+    )
+endif()
+
+# Example executable
+add_executable(fcb_example examples/example.cpp ${GENERATED_DIR}/lib.rs.h)
+target_link_libraries(fcb_example fcb)
+target_include_directories(fcb_example PRIVATE ${GENERATED_DIR})
+
+# Install targets
+install(TARGETS fcb ARCHIVE DESTINATION lib)
+install(FILES ${GENERATED_DIR}/lib.rs.h DESTINATION include/fcb)

src/cpp/examples/example.cpp

@@ -0,0 +1,62 @@
+#include "lib.rs.h"
+#include <iostream>
+#include <stdexcept>
+#include <string>
+
+int main(int argc, char *argv[]) {
+  if (argc < 2) {
+    std::cerr << "Usage: " << argv[0] << " <fcb_file>" << std::endl;
+    return 1;
+  }
+
+  std::string path = argv[1];
+
+  try {
+    // Open FCB file
+    auto reader = fcb::fcb_reader_open(path);
+
+    // Get metadata
+    auto meta = fcb::fcb_reader_metadata(*reader);
+    std::cout << "=== FCB File Metadata ===" << std::endl;
+    std::cout << "Version: " << static_cast<int>(meta.version) << std::endl;
+    std::cout << "Features count: " << meta.features_count << std::endl;
+    std::cout << "Has spatial index: "
+              << (meta.has_spatial_index ? "yes" : "no") << std::endl;
+    std::cout << "Has attribute index: "
+              << (meta.has_attribute_index ? "yes" : "no") << std::endl;
+    std::cout << std::endl;
+
+    // Select all features
+    auto iter = fcb::fcb_reader_select_all(std::move(reader));
+
+    std::cout << "=== Features ===" << std::endl;
+    size_t count = 0;
+    while (fcb::fcb_iterator_next(*iter)) {
+      auto feature = fcb::fcb_iterator_current(*iter);
+      std::cout << "Feature " << count << ": ID=" << std::string(feature.id)
+                << std::endl;
+
+      // Print first 200 chars of JSON
+      std::string json = std::string(feature.json);
+      if (json.length() > 200) {
+        json = json.substr(0, 200) + "...";
+      }
+      std::cout << "  JSON: " << json << std::endl;
+
+      count++;
+      if (count >= 5) {
+        std::cout << "  ... (showing first 5 features)" << std::endl;
+        break;
+      }
+    }
+
+    std::cout << std::endl;
+    std::cout << "Total features iterated: " << count << std::endl;
+
+  } catch (const std::exception &e) {
+    std::cerr << "Error: " << e.what() << std::endl;
+    return 1;
+  }
+
+  return 0;
+}

src/rust/Cargo.toml

@@ -1,6 +1,6 @@
 
 [workspace]
-members = ["cli", "fcb_core", "wasm", "fcb_api", "fcb_py"]
+members = ["cli", "fcb_core", "fcb_cpp", "wasm", "fcb_api", "fcb_py"]
 resolver = "2"
 
 [workspace.dependencies]
@@ -52,6 +52,8 @@ proj4rs = "0.1.9"
 crs-definitions = "0.3.1"
 indicatif = "0.17"
 console = "0.15"
+cxx = "1.0"
+cxx-build = "1.0"
 
 #---WASM dependencies---
 getrandom = { version = "0.3.3" }

src/rust/fcb_cpp/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "fcb_cpp"
+version = "0.1.0"
+edition = "2021"
+authors = ["Hidemichi Baba <baba.papa1120.ba@gmail.com>"]
+license = "MIT"
+description = "C++ bindings for FlatCityBuf core library"
+
+[lib]
+crate-type = ["staticlib"]
+
+[dependencies]
+fcb_core = { workspace = true }
+cxx = { workspace = true }
+cjseq = { workspace = true }
+serde_json = { workspace = true }
+
+[build-dependencies]
+cxx-build = { workspace = true }