microstr 0.1.0

Stack-allocated string with fixed capacity
Documentation

MicroStr

crates.io
Documentation
License

A lightweight, stack-allocated string with fixed capacity and UTF-8 support.
Ideal for no_std environments, embedded systems, and performance-critical code.

[dependencies]
microstr = "0.1"

Features

  • ✅ No heap allocations — fully stack-based.
  • ✅ UTF-8 safe — always valid string content.
  • ✅ no_std by default — works without std.
  • ✅ Const generic capacity — size known at compile time.
  • ✅ Truncation-aware — safely appends strings without overflow.
  • ✅ Seamless std integration — supports Display, Debug, From<String>, etc.
  • ✅ Optional serde support — JSON (de)serialization with length checking.

Usage

use microstr::MicroStr;

// Create a string with capacity of 16 bytes
let mut s: MicroStr<16> = MicroStr::new();

s.push_str("Hello");
s.push('!');

assert_eq!(s.as_str(), "Hello!");
assert_eq!(s.len(), 6);           // 6 Unicode chars
assert_eq!(s.bytes_len(), 6);     // 6 bytes
assert!(s.push_str(" this won't fit entirely") > 0); // Truncated safely

You can also use it like a regular &str thanks to Deref:

if s.starts_with("Hello") {
    println!("Greeting: {}", s);
}

Features

Enable optional features in Cargo.toml:

[dependencies]
microstr = { version = "0.1", features = ["std", "serde"] }
Feature Description
std (default: on) Enables Display, Debug, From<String>, and ToString. Required for serde.
serde Enables .to_json() and StackString::from_json() with capacity checks.

Example with serde

#[cfg(feature = "serde")]
{
    let s = MicroStr::from_str::<10>("hello");
    let json = s.to_json().unwrap();
    assert_eq!(json, r#""hello""#);

    let s2 = MicroStr::from_json(r#""world""#).unwrap();
    assert_eq!(s2, "world");
}

Why MicroStr?

  • Predictable performance: No allocations, no heap usage.
  • Memory safety: Always valid UTF-8, no buffer overflows.
  • Great for constrained environments: Embedded, kernels, WASM.
  • Easy migration: Drop-in replacement for String in many cases.

API Documentation

📚 Full documentation: https://docs.rs/microstr

License

MIT License

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you shall be dual licensed as above, without any additional terms or conditions.