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KString
===========
> Key String: Optimized for map keys.
[](https://crates.io/crates/kstring)
## Background
Considerations:
- Large maps
- Most keys live and drop without being used in any other way
- Most keys are relatively small (single to double digit bytes)
- Keys are immutable
- Allow zero-cost abstractions between structs and maps (e.g. no allocating
when dealing with struct field names)
Ramifications:
- Inline small strings rather than going to the heap.
- Preserve `&'static str` across strings (`KString`),
references (`KStringRef`), and lifetime abstractions (`KStringCow`) to avoid
allocating for struct field names.
- Use `Box<str>` rather than `String` to use less memory.
Features
- `max_inline`: Instead of aligning the inline-string for performance (15 bytes + length on 64-bit), use the full width (22 bytes on 64-bit)
- `arc`: Instead of using `Box<str>`, use `Arc<str>`. Note: allocations are fast enough that this can actually slow things down for small enough strings.
Alternatives
- [`smol_str`](https://crates.io/crates/smol_str)
- Size of String
- Always uses `Arc` instead of `Box`
- Always inlines 22 bytes
- Whitespace-only optimizations
- [`smartstring`](https://crates.io/crates/smartstring)
- Size of String
- Allows mutability at the cost of relying on implementation details of `String`
- Always inlines 23 bytes
- [`compact_str`](https://crates.io/crates/compact_str)
- Size of String
- Always uses `Arc` instead of `Box`
- Inlines 22-23 bytes, depending on implementation
## License
Licensed under either of
* Apache License, Version 2.0, (http://www.apache.org/licenses/LICENSE-2.0)
* MIT license (http://opensource.org/licenses/MIT)
at your option.
### Contribution
Unless you explicitly state otherwise, any contribution intentionally
submitted for inclusion in the work by you, as defined in the Apache-2.0
license, shall be dual licensed as above, without any additional terms or
conditions.
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