v0.2.0

[v0.2.0] - 2026-02-20

Added

• SpscQueue: Lock-free single-producer single-consumer queue (loon/spsc.hpp)

  • O(1) push and pop operations
  • Cache-line padding to prevent false sharing (4.9x faster than mutex queues)
  • Compile-time fixed capacity
  • Static assertion for lock-free atomic operations

• RingBuffer: Fixed-size circular buffer (loon/ring_buffer.hpp)

  • Optional override mode for oldest elements
  • 3.2x faster than std::queue

• Comprehensive benchmarks using Google Benchmark

  • RingBuffer vs std::queue comparisons
  • SpscQueue vs mutex-protected queue comparisons
  • LRU Cache operation benchmarks
  • RedisList vs std::deque and std::list comparisons

• MkDocs documentation site with Material theme

  • Full API reference
  • Performance benchmarks
  • Getting started guide

Changed

• SpscQueue performance improvement: Added alignas(CACHE_LINE_SIZE) to head and tail atomics
  • Prevents false sharing between producer and consumer threads
  • 27% faster interleaved operations (12.6 ns → 9.1 ns)
  • 4.9x speedup vs mutex-protected queues (up from 3.4x)

Fixed

• SpscQueue bug: Fixed incorrect atomic variable usage in pop() method
  • Was using head_ instead of local head variable in store operation
  • This caused an unnecessary extra atomic load on each pop

Performance Highlights

Component	Latency	Throughput	vs std::
RingBuffer	1.9 ns	2.1G ops/s	3.2x faster
SpscQueue	9.1 ns	220M ops/s	4.9x faster
LRU Cache	7.8 ns	130M ops/s	O(1) ops
RedisList	3.6 ns	560M ops/s	22x vs std::list

[v0.1.0] - 2024-12-01

Added

• LRU Cache: O(1) least recently used cache (loon/lru.hpp)

  • Hash map + doubly-linked list implementation
  • Automatic eviction of least recently used items
  • Reference semantics for zero-copy access

• RedisList: Redis-style doubly-linked list (loon/redis_list.hpp)

  • lpush/rpush/lpop/rpop operations
  • lrange with negative index support
  • Backed by std::deque for cache efficiency

• Initial project structure

• CMake build system

• Conan package support

• MIT License

Full Changelog: v0.1.0...v0.2.0

v0.1.0

loon v0.1.0 - Initial Release

First public release of loon, a high-performance header-only C++ library.

Components

• LRU (loon/lru.hpp) - O(1) get/put/remove operations
• RedisList (loon/redis_list.hpp) - Redis-compatible list with lpush/rpush/lpop/rpop/lrange

Features

• Header-only, zero dependencies
• C++23 compatible
• Conan package support
• Comprehensive test suite

Documentation

• API documentation: https://jsrivaya.github.io/loon/