🧱 strbuilder

StringBuilder for Rust without reallocations

📦 Installation

This project is published on crates.io. You can add it to your project by running:

cargo add strbuilder
# or
cargo add strbuilder --features safe

🌟 Key features

• No Reallocations: Data never gets reallocated to a new, larger memory segment when the text grows. It simply links a new chunk onto the stack/heap
• Cache-Line Alignment: Every text chunk (StringChunk) is forced to align tightly to 64-byte boundaries
• Two sides: You can use unsafe but perfomant (the default) or safe but more slower variants of code by switching the safe feature

🚀 Usage Example

use strbuilder::StringBuilder;

let mut string_builder = StringBuilder::from("Hello,");
// or
let mut string_builder = StringBuilder::new();

string_builder.push_str(" ");
string_builder.push_str("world!");

let result = string_builder.to_string();
// or
println!("{:?}", string_builder);

⚙️ How it works

• StringChunk: A backward-linked list under the hood, utilizing byte chunks that fit perfectly into a single CPU cache-line
• StringBuilder: A lightweight controller containing a pointer to the last node of the linked list and the total byte count

[ first StringChunk (64B) ] <--- [ second StringChunk (64B) ] <--- [ third StringChunk (64B) ]
  |-- bytes: [u8; 56]              |-- bytes: [u8; 56]               |-- bytes: [u8; 56]
  |-- prev: null                   |-- prev: *const Chunk (first)    |-- prev: *const Chunk (second)

[ StringBuilder (16B) ]
  |-- bytes_count: usize
  |-- last_chunk: *mut StringChunk (third)

🧑‍⚖️ License

Copyright (c) 2026 Illia Diadenchuk
Licensed under Zlib license