dairy

A more compact, user friendly clone-on-write smart pointer.

use std::path::Path;
use dairy::Cow;

let borrowed: Cow<str> = Cow::borrowed("Hello World!");
let owned: Cow<str> = Cow::owned(String::from("Hello World!"));

Introduction

dairy::Cow is an improved version of the standard library std::borrow::Cow. It is just 2 words wide, storing the length, capacity, and the ownership tag all in one word. See tests/size.rs.

dairy::Cow has many more From and PartialEq implementations. Most notably for Cow<Path> making Into<Cow<Path>> just as nice to use as Cow<str>.

Unfortunately these benefits come with some caveats:

• Only str, [T], OsStr, CStr and Path types are supported.
• Additionally, OsStr and Path are only supported on Unix.
• On 32-bit operating systems the maximum length is u16::MAX which is not sufficient for all use cases.

Getting started

Add the following to your Cargo manifest.

[dependencies]
dairy = { version = "0.1", features = ["unix"] }

Acknowledgements

Some implementation details taken from the excellent beef crate.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.