So You Think You Can Hash
Talkat CppCon 2024 · on Monday, 2024-09-16· at 14:00· Cottonwood 8/9, 6700 North Gaylord Rockies Boulevard·
summary
Claims a concrete API: repackaged hashers with init consume finalize stages, and a uniform hash_append protocol so aggregate types contribute salient bits without leaking the numeric algorithm. Shows that std::hash typically uses fnv 1A, demonstrates removing ad-hoc hash_combine, provides a templated wrapper that plugs into unordered_map and swaps algorithms (e.g., SipHash/Murmur variants) for controlled benchmarking framework experiments and comparison.
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chapters (9)
- 0:00Introduction and motivation
- 1:34Hashing fundamentals
- 7:12Challenges with composite types
- 13:27Limitations of std::hash and combine
- 23:24Repackaging the hashing algorithm
- 28:24Recursive hash append pattern
- 40:24Framework and benchmarking
- 44:27Parallels with Rust's hashing
- 55:56Conclusion and takeaways
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