# google/cityhash

Automatically exported from code.google.com/p/cityhash

Repository: https://github.com/google/cityhash
Canonical: https://ross.abutalabs.com/products/cityhash
Language: Shell
License: MIT
License Family: permissive
Archived: true
Last push: 2024-04-22T10:17:49+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4037, "days_push": 863, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1233, forks 198 (observed 2026-08-28T04:04:04.567163+00:00)

## What it is
CityHash is a family of fast, non-cryptographic hash functions for strings, implemented in C++ under the MIT license. It offers 32-, 64-, 128-, and 256-bit variants optimized for speed on both short hash-table keys and long strings.

## Use cases
- fast string hashing for hash tables
- non-cryptographic checksum of strings
- hash long strings quickly on 64-bit CPUs
- replace murmur hash in performance-critical code
- compute 128-bit or 256-bit string hashes

## When to choose
- you need very fast, high-quality non-cryptographic string hashes
- you are building hash tables with short string keys
- your CPU supports CRC32 instructions and you want maximum throughput

## When to avoid
- you need cryptographic or security-sensitive hashing
- you need a stable hash across versions or platforms for persistence
- you are on AMD CPUs or lack CRC32 instructions, where SpookyHash may be better

## Facets
- artifact type: library
- maturity: maintenance
- function: cryptography, serialization
- domain: performance, developer-tools
- platform: cpp, cross-platform
- tags: hash-functions, non-cryptographic-hashing, string-hashing, hash-tables, algorithms

## Member repositories
- google/cityhash (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:04.567163+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T08:22:15.958144+00:00, confidence not recorded.
  - readme: https://github.com/google/cityhash (fetched 2026-08-28T04:04:04.567163+00:00, sha 24872d5399a9)
- Data as of 2026-08-30T08:39:29.467469+00:00.