uuidtoa

优化了带有连字符的UUID ASCII表示的序列化到io::Write输出。

此crate导出的两个函数是write_lower和write_upper；以下是它们的签名

fn write_lower<W: io::Write>(io: &mut W, uuid: &Uuid) -> io::Result<usize>;
fn write_upper<W: io::Write>(io: &mut W, uuid: &Uuid) -> io::Result<usize>;

将内容写入缓冲区的示例

let uuid = Uuid::from_str("e098d1f6-7e49-4c34-99f6-e9c6cef8fcce").unwrap();
let mut buf: Vec<u8> = Vec::with_capacity(36);
write_lower(&mut buf, &uuid).unwrap();

这比来自uuid crate的等效fmt::Display实现快约10倍。

let uuid = Uuid::from_str("e098d1f6-7e49-4c34-99f6-e9c6cef8fcce").unwrap();
let buf = format!("{}", uuid.hyphenated());

这两种方法的基准测试结果如下。

test benches::bench_fmt   ... bench:         522 ns/iter (+/- 6)
test benches::bench_lower ... bench:          45 ns/iter (+/- 0)

要自己运行，请使用bench特性和nightly编译器。

cargo bench --feature bench