phoros

A ring buffer for state snapshotting and rollback in Rust.

phoros tracks historical state changes using byte deltas anchored to periodic snapshots.
Storage is fully generic over stack arrays, borrowed buffers, or heap slices, making it usable in both #![no_std] and standard environments.

Usage

Add phoros to your Cargo.toml:

[dependencies]
phoros = "0.1"

For #![no_std] environments, disable default features:

[dependencies]
phoros = { version = "0.1", default-features = false }

Quickstart

Heap-backed

use phoros::{bprb, BufferError};

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
struct TransformState {
    coords: (i32, i32),
    scale: i32,
    rot: i32,
}

fn main() -> Result<(), BufferError> {
    // Allocate 1MB arena on the heap, anchor every 60 frames.
    let mut history = bprb!(TransformState => boxed(1024 * 1024, 60))?;
    let mut state = TransformState { coords: (0, 0), scale: 1, rot: 0 };

    for _ in 0..100 {
        state.coords.0 += 1;
        history.snapshot(&state)?;
    }

    let restored = history.rollback_to(42)?;
    assert_eq!(restored.coords.0, 43);

    Ok(())
}

Stack-backed

use phoros::bprb;

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
struct EmbeddedState {
    sensor_val: u32,
}

fn run() {
    // 16KB arena on the stack.
    let mut history = bprb!(EmbeddedState => stack(16384)).unwrap();
    let state = EmbeddedState { sensor_val: 42 };

    history.snapshot(&state).unwrap();
}

Type Constraints