ve

More compact version of Vec, uses 2 bytes/characters instead of 3. Currently targeting only 64-bits machine and aim to be drop in replacement for Vec.

This crate is work in progress, requires nightly and is highly experimental. Porting is done by hand based on rust liballoc, String may be next target.

```rust const WORD: usize = std::mem::size_of::();

asserteq!(std::mem::sizeof::>(), 3 * WORD); asserteq!(std::mem::sizeof::>(), 2 * WORD); ```

How does it work?

                 +-----------+-----------+-----------+
std::vec::Vec    | Pointer   | Length    | Capacity  |
                 +-----------+-----------+-----------+

                 +-----------+-----------+
ve::Vec          | Pointer   | Cap | Len |
                 +-----------+-----------+

ve::Vec have capacity of 4294967295 compared to Vec 18446744073709551615. If you don't need that much digits, ve::Vec should be safe.

Inspired by https://github.com/maciejhirsz/beef.

Benchmarks

Work in progress, so far creation time is slower.

test bench_new ... bench: 7 ns/iter (+/- 0) test bench_new_std ... bench: 2 ns/iter (+/- 0) test bench_with_capacity_0000 ... bench: 3 ns/iter (+/- 0) test bench_with_capacity_0000_std ... bench: 3 ns/iter (+/- 0) test bench_with_capacity_0010 ... bench: 17 ns/iter (+/- 1) = 588 MB/s test bench_with_capacity_0010_std ... bench: 17 ns/iter (+/- 2) = 588 MB/s test bench_with_capacity_0100 ... bench: 17 ns/iter (+/- 1) = 5882 MB/s test bench_with_capacity_0100_std ... bench: 17 ns/iter (+/- 0) = 5882 MB/s test bench_with_capacity_1000 ... bench: 54 ns/iter (+/- 1) = 18518 MB/s test bench_with_capacity_1000_std ... bench: 54 ns/iter (+/- 0) = 18518 MB/s

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.

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.