Project 1: Build a Simple Arena Allocator

An arena allocator that allocates objects from a contiguous memory region and deallocates all at once when the arena is dropped, demonstrating RAII and ownership.

Quick Reference

Attribute Value
Primary Language Rust
Alternative Languages C++ (for comparison)
Difficulty Level 3: Advanced
Time Estimate 1-2 weeks
Knowledge Area Memory Management / Systems Programming
Tooling Rust standard library, unsafe Rust
Prerequisites Basic Rust, understanding of memory allocation

What You Will Build

An arena allocator that allocates objects from a contiguous memory region and deallocates all at once when the arena is dropped, demonstrating RAII and ownership.

Why It Matters

This project builds core skills that appear repeatedly in real-world systems and tooling.

Core Challenges

  • Managing raw memory with unsafe → maps to understanding ownership at the lowest level
  • Preventing references from outliving the arena → maps to lifetime bounds in practice
  • Implementing Drop correctly → maps to RAII and automatic resource cleanup
  • Handling alignment requirements → maps to low-level memory layout

Key Concepts

  • Ownership and Drop: “The Rust Programming Language” Chapter 15.3
  • Arena Allocation: “Memory Management” chapter in “Programming Rust” by Blandy & Orendorff
  • Unsafe Rust: “The Rustonomicon” - official guide to unsafe Rust
  • RAII Pattern: “Effective Modern C++” Item 18 (for comparison)

Real-World Outcome

Deliver a working demo with observable output that proves the feature is correct.

Implementation Guide

  1. Reproduce the simplest happy-path scenario.
  2. Build the smallest working version of the core feature.
  3. Add input validation and error handling.
  4. Add instrumentation/logging to confirm behavior.
  5. Refactor into clean modules with tests.

Milestones

  • Milestone 1: Minimal working program that runs end-to-end.
  • Milestone 2: Correct outputs for typical inputs.
  • Milestone 3: Robust handling of edge cases.
  • Milestone 4: Clean structure and documented usage.

Validation Checklist

  • Output matches the real-world outcome example
  • Handles invalid inputs safely
  • Provides clear errors and exit codes
  • Repeatable results across runs

References

  • Main guide: RUST_BORROW_CHECKER_LIFETIME_PHILOSOPHY.md
  • “The Rustonomicon” (official unsafe Rust guide)