| 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. |
