All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

Added

• NIL

Changed

• NIL

Deprecated

• NIL

Removed

• NIL

Fixed

• NIL

Security

• NIL

[0.1.2] - 2025-11-27

Changed

• Consolidated packaging tool detection in CMake configuration

Fixed

• Removed incorrect runtime dependencies from DEB/RPM packages

[0.1.1] - 2025-11-15

Changed

• Performance Optimization: Added compile-time SSE4.2 fast path in crc32c() to eliminate runtime CPU detection overhead when compiled with -march=native, -msse4.2, or /arch:AVX flags
• Benchmark Accuracy: Fixed single-step hash benchmarks to use dependency chains, preventing compiler pre-computation and ensuring realistic performance measurements

[0.1.0] - 2025-11-13 - Initial Release

Added

• hash<T>: Template-based hash function for clean, STL-style hashing
• Hasher<HashType, Seed>: General-purpose STL-compatible hash functor
• CRC32-C (Castagnoli): Hardware-accelerated hash using SSE4.2 intrinsics with software fallback
  • Polynomial: 0x1EDC6F41 (Castagnoli polynomial)
  • Runtime CPU detection: checks SSE4.2 support at first call, caches result
  • Hardware: uses _mm_crc32_u8 (MSVC) or __builtin_ia32_crc32qi (GCC/Clang)
  • Software: pure C++ implementation matching SSE4.2 behavior
  • Single binary deployment: optimally runs on both old and new CPUs
  • Dual-stream 64-bit implementation: low 32 bits (normal bytes), high 32 bits (inverted bytes byte ^ 0xFF)
• FNV-1a: Fast non-cryptographic hash (32-bit and 64-bit variants)
  • XOR-multiply algorithm with prime constants
  • Fully constexpr for compile-time hashing
• Larson Hash: Simple multiplicative hash (37 * hash + ch)
  • Provided for benchmarking comparisons
  • Supports 32-bit and 64-bit variants
• Integer Hashing: Optimized multiplicative hashing for integral types
  • 32-bit: Knuth's multiplicative constant (0x45d9f3b)
  • 64-bit: Wang's avalanche mixing (0xbf58476d1ce4e5b9, 0x94d049bb133111eb)
• Hash Combining: Two combination strategies
  • FNV-1a style: XOR then multiply by prime
  • Boost + MurmurHash3 finalizer: golden ratio mixing with avalanche finalization
• Seed Mixing: Hash table probing utilities
  • 32-bit: Thomas Wang's bit-mixing algorithm
  • 64-bit: MurmurHash3 avalanche mixing
• Samples
  • Sample_Hash.cpp - Unified hash<T> API demonstration
  • Sample_Hasher.cpp - STL container integration with Hasher<> functor
  • Sample_LowLevelHashing.cpp - Direct use of low-level hash primitives
  • Sample_AdvancedHashing.cpp - Advanced techniques (custom seeds, transparent lookup)
• Build System
  • CMake 3.20+ configuration with modular structure
  • Header-only interface library target
  • Cross-platform support (Linux GCC/Clang, Windows MinGW/Clang/MSVC)
  • Google Test integration for unit testing
  • Google Benchmark integration for performance benchmarking
  • Doxygen documentation generation with GitHub Pages deployment
  • CPack packaging for distribution (DEB, RPM, TGZ, ZIP, WiX MSI)
  • Installation support with CMake package config files
• Documentation
  • README with feature overview and usage examples
  • Detailed API documentation with Doxygen comments and RFC references
  • Sample applications
  • Build and installation instructions
• Testing & Benchmarking
  • Unit test suite
  • Performance benchmarks for all operations
  • Cross-compiler performance validation
• CI/CD: GitHub Actions workflows for automated testing, documentation and release deployment