Skip to content

Add xxHash32 algorithm implementation #14037

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Open
rodrigobnogueira wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Add xxHash32 algorithm implementation #14037

rodrigobnogueira wants to merge 1 commit into from

Conversation

@rodrigobnogueira
Copy link

@rodrigobnogueira rodrigobnogueira commented Dec 25, 2025 •
edited
Loading

Description

Implements the xxHash32 algorithm, an extremely fast non-cryptographic hash function designed to operate at RAM speed limits. xxHash is widely used in high-performance applications.

Changes

  • Added hashes/xxhash.py with complete implementation
  • Uses 4 parallel accumulators for maximum speed
  • Processes data in optimized 16-byte stripes
  • Carefully selected prime constants (0x9E3779B1, etc.)
  • Optional seed parameter for hash variation
  • 15 comprehensive doctests including:
    • Empty and small inputs
    • Large inputs
    • Edge cases (null bytes)
    • Seed functionality

Features

  • Fast: One of the fastest hash algorithms
  • Excellent distribution: Passes SMHasher test suite
  • Production-ready: Used in Zstandard, LZ4, rsync
  • Seed support: Optional seed for different hash families

Real-world Applications

  • Zstandard compression (Facebook's compression algorithm)
  • LZ4 compression
  • rsync file synchronization
  • Database indexing and deduplication
  • Hash tables requiring high performance

References

Testing

  • All 15 doctests pass
  • Passes ruff linting
  • Passes mypy type checking
  • Tested with various inputs and seeds

Checklist

  • I have read and followed the contributing guidelines
  • This pull request is not a duplicate
  • The algorithm is implemented from scratch
  • The code follows the repository style
  • I have read CONTRIBUTING.md
  • This pull request is all my own work -- I have not plagiarized
  • I know that pull requests will not be merged if they fail the automated tests
  • This PR only changes one algorithm file
  • All new Python files are placed inside an existing directory (hashes/)
  • All filenames are in all lowercase characters with no spaces or dashes
  • All functions and variable names follow Python naming conventions
  • All function parameters and return values are annotated with Python type hints
  • All functions have doctests that pass the automated testing
  • All new algorithms include at least one URL that points to Wikipedia or another similar explanation

feat: add xxHash32 algorithm implementation
6720d8d 
- Implement xxHash32 with 4-accumulator parallel processing
- Add 15 comprehensive doctests with seed support
- Full type hints and English documentation
- Passes ruff and mypy checks

xxHash is extremely fast and used in Zstandard, LZ4, and rsync.
Features optimized processing with carefully selected prime constants.
@algorithms-keeper algorithms-keeper bot added the awaiting reviews This PR is ready to be reviewed label Dec 25, 2025
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

No reviews

Assignees

No one assigned

Labels

awaiting reviews This PR is ready to be reviewed

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

1 participant

@rodrigobnogueira