jamhash

A fast, non-cryptographic hash function designed for genomics and general-purpose hashing.

Features

• jamhash_u64: Optimized for hashing genomic k-mers encoded as u64 (2-bit encoding)
• jamhash_bytes: Size-optimized byte hashing with paths for short (≤16), medium (17-128), long (129-4095), and ultra-long (≥4KB) inputs
• JamHasher: Streaming hasher implementing std::hash::Hasher
• Dual-path accumulation: Strong avalanche properties with minimal overhead
• Tested: Low collision rates with canonical k-mers up to k=21

Genomics Use Cases

The jamhash_u64 function is specifically designed for bioinformatics workflows:

• MinHash sketching of DNA/RNA sequences
• K-mer counting and frequency analysis
• Sequence similarity estimation and comparison

use jamhash::jamhash_u64;

// Hash a k-mer encoded as u64 (2-bit encoding: A=00, C=01, G=10, T=11)
let kmer: u64 = 0x00011011;
let hash = jamhash_u64(kmer);

General Purpose Hashing

use jamhash::{jamhash_bytes, JamHasher};
use std::hash::Hasher;

// Hash arbitrary bytes
let hash = jamhash_bytes(b"hello world");

// Streaming std::hash::Hasher implementation
let mut hasher = JamHasher::new();
hasher.write(b"hello ");
hasher.write(b"world");
let hash = hasher.finish();

Installation

Add to your Cargo.toml:

[dependencies]
jamhash = "0.1"

Quality Verification

jamhash passes all 188 tests in SMHasher3, the comprehensive hash function test suite:

Overall result: pass (188 / 188 passed)

Full test results are available in smhasher3_jamhash.txt.

Inspirations

jamhash draws inspiration from:

• rapidhash
• foldhash
• ahash

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.