5 unstable releases

0.3.2	Aug 19, 2023
0.3.1	Aug 14, 2023
0.3.0	Aug 12, 2023
0.2.0	Jul 6, 2023
0.1.0	Jun 1, 2023

#69 in Memory management

48 downloads per month

MIT/Apache

160KB
3.5K SLoC

`hipstr`

Yet another string for Rust 🦀

no copy borrow via borrowed (a const constructor) or from_static
no alloc small strings (23 bytes on 64-bit platform)
no copy owned slices
zero dependency

And bytes too!

⚡ Examples

use hipstr::HipStr;

let simple_greetings = HipStr::from_static("Hello world");
let _clone = simple_greetings.clone(); // no copy

let user = "John";
let greetings = HipStr::from(format!("Hello {}", user));
let _user = greetings.slice(6..): // no copy

✏️ Features

serde: provides serialization/deserialization support with serde crate
unstable: exposes internal Backend trait that may change at any moment

☣️ Safety of `hipstr`

This crate uses unsafe extensively. 🤷

It exploits the 1-bit alignment niche in pointers existing on most platforms (I think all Rustc supported platforms) to distinguish the inline representation from the other representations.

To make things safer, Rust is tested thoroughly on multiple platforms, normally and with Miri (the MIR interpreter).

🧪 Testing

☔ Coverage

This crate has near full line coverage:

cargo llvm-cov --all-features --html
# or
cargo tarpaulin --all-features --out html --engine llvm

Check out the current coverage on Codecov:

Coverage grid

🖥️ Cross-platform testing

You can easily run the test on various platforms with cross:

cross test --target mips-unknown-linux-gnu          # 32-bit BE
cross test --target mips64-unknown-linux-gnuabi64   # 64-bit BE
cross test --target i686-unknown-linux-gnu          # 32-bit LE
cross test --target x86_64-unknown-linux-gnu        # 64-bit LE

🔍 Miri

This crate runs successfully with Miri:

MIRIFLAGS=-Zmiri-symbolic-alignment-check cargo +nightly miri test

for SEED in $(seq 0 10); do
  echo "Trying seed: $SEED"
  MIRIFLAGS="-Zmiri-seed=$SEED" cargo +nightly miri test || { echo "Failing seed: $SEED"; break; };
done

To check with different word size and endianness:

# Big endian, 64-bit
cargo +nightly miri test --target mips64-unknown-linux-gnuabi64
# Little endian, 32-bit
cargo +nightly miri test --target i686-unknown-linux-gnu

📦 Similar crates

#[non_exhaustive]

Name	Thread-safe cheap-clone	Local cheap-clone	Inline	Cheap slice	Bytes	Cow<'a>	Comment
`hipstr`	🟢	🟢	🟢	🟢	🟢	🟢	obviously!
`arcstr`	🟢*	❌	❌	❌**	❌	❌	use a custom thin `Arc`, *heavy slice (with dedicated substring type)
`flexstr`	🟢*	🟢	🟢	❌	❌	❌	*use an `Arc<str>` instead of an `Arc<String>` (remove one level of indirection but use fat pointers)
`imstr`	🟢	🟢	❌	🟢	❌	❌
`faststr`	🟢	❌	🟢	🟢	❌	❌	zero-doc with complex API
`fast-str`	🟢	❌	🟢	🟢	❌	❌	inline repr is opt-in
`ecow`	🟢*	❌	🟢	❌	🟢**	❌	on two words only 🤤, *even any `T`
`cowstr`	🟢	❌	❌	❌*	❌	❌**	heavy slice, *contrary to its name
`compact_str`	❌	❌	🟢	❌	🟢*	❌	*opt-in via `smallvec`
`inline_string`	❌	❌	🟢	❌	❌	❌
`smartstring`	❌	❌	🟢	❌	❌	❌
`smallstr`	❌	❌	🟢	❌	❌	❌
`smol_str`	❌	❌	🟢*	❌	❌	❌	*but only inline string, here for reference

skipping specialized string types like tinystr (ASCII-only, bounded), or bstr, or bytestring, or...

In short, HipStr, one string type to rule them all 😉

🏎️ Performances

While speed is not the main motivator for hipstr, it seems to be doing OK on that front.

On my i7-8550U, under Arch Linux over Windows 11/WSL 2 (yeah I know 😅), the creation of a HipStr from a slice is competitive with other crates and the std:

string-comparison/chart.svg

📖 Author and licenses

For now, just me PoLazarus 👻
Help welcome! 🚨

MIT + Apache

Dependencies

~190KB