writing a geometry to fgb format

point.rs

fn point() {
    let mut file = File::create("test_point.fgb").expect("failed to write point");

    let hex = decode_hex("6667620366676201").unwrap();
    file.write(&hex);

    let mut fbb = flatbuffers::FlatBufferBuilder::new();
    let column_args = ColumnArgs {
        name: Some(fbb.create_string("STATE_FIPS")),
        type_: ColumnType::String,
        ..Default::default()
    };
    let column = Column::create(&mut fbb, &column_args);
    let header_args = HeaderArgs {
        name: Some(fbb.create_string("Test1")),
        geometry_type: GeometryType::Point,
        columns: Some(fbb.create_vector(&[column])),
        features_count: 1,
        index_node_size: 0,
        ..Default::default()
    };

    let header = Header::create(&mut fbb, &header_args);
    fbb.finish(header, None);
    let buf = fbb.finished_data();
    file.write(&buf);

    let mut fbb = flatbuffers::FlatBufferBuilder::new();
    let g1 = Geometry::create(&mut fbb, &Default::default());
    fbb.finish(g1, None);
    let buf = fbb.finished_data();
    let size = buf.len();
    assert_eq!(size, 12);

    file.write(&buf);

    let mut fbb = flatbuffers::FlatBufferBuilder::new();
    let xy = fbb.create_vector(&[0.0, 0.0]);
    let g2 = Geometry::create(
        &mut fbb,
        &GeometryArgs {
            xy: Some(xy),
            ..Default::default()
        },
    );
    fbb.finish(g2, None);
    let buf = fbb.finished_data();
    let size = buf.len();
    assert_eq!(size, 40);

    file.write(&buf);

    let mut fbb = flatbuffers::FlatBufferBuilder::new();
    let xy = fbb.create_vector(&[0.0, 0.0]);
    let g3 = Geometry::create(
        &mut fbb,
        &GeometryArgs {
            xy: Some(xy),
            ..Default::default()
        },
    );
    let f = Feature::create(
        &mut fbb,
        &FeatureArgs {
            geometry: Some(g3),
            ..Default::default()
        },
    );
    fbb.finish(f, None);
    let buf = fbb.finished_data();
    let size = buf.len();
    assert_eq!(size, 56);

    file.write(&buf);
    file.flush();
}