Alternative implementation of Cow that's more compact in memory.
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```rust use beef::Cow;
let borrowed = Cow::borrowed("Hello"); let owned = Cow::from(String::from("World"));
assert_eq!( format!("{} {}!", borrowed, owned), "Hello World!", );
// beef::Cow is 3 word sized, while std::borrow::Cow is 4 word sized
assert!(std::mem::sizeof::
The standard library Cow is an enum with two variants:
rust
pub enum Cow<'a, B> where
B: 'a + ToOwned + ?Sized,
{
Borrowed(&'a B),
Owned(<B as ToOwned>::Owned),
}
For the most common pairs of values - &str and String, or &[u8] and Vec<u8> - this
means that the entire enum is 4 words wide:
```text Padding | v +----------+----------+----------+----------+ Borrowed: | Tag | Pointer | Length | XXXXXXXX | +----------+----------+----------+----------+
+----------+----------+----------+----------+
Owned: | Tag | Pointer | Length | Capacity | +----------+----------+----------+----------+ ```
Instead of being an enum with a tag, beef::Cow uses capacity to determine whether the
value it's holding is owned (capacity is greater than 0), or borrowed (capacity is 0).
This crate is distributed under the terms of both the MIT license and the Apache License (Version 2.0). Choose whichever one works best for you.
See LICENSE-APACHE and LICENSE-MIT for details.