# serge-sans-paille/frozen

a header-only, constexpr alternative to gperf for C++14 users

Repository: https://github.com/serge-sans-paille/frozen
Canonical: https://ross.abutalabs.com/products/frozen
Language: C++
License: Apache-2.0
License Family: permissive
Last push: 2026-04-20T21:27:53+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 78, release rhythm 35, longevity 100
- inputs: {"age_days": 3390, "days_push": 135, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1571, forks 116 (observed 2026-08-28T04:05:05.429742+00:00)

## What it is
Frozen is a header-only C++14 library providing constexpr-compatible immutable containers (set, map, unordered variants) with zero-cost initialization and perfect hashing, serving as a constexpr alternative to gperf. It also offers fixed-capacity constinit-compatible maps and compile-time string search algorithms like Boyer-Moore and Knuth-Morris-Pratt.

## Use cases
- compile-time lookup tables in C++
- replace gperf with constexpr perfect hash maps
- fast immutable string-to-value mappings
- zero-cost initialization of static containers
- constexpr string search with Boyer-Moore
- fixed-capacity maps with compile-time keys

## When to choose
- you need compile-time initialized immutable containers in C++14
- you want faster lookups via perfect hashing without runtime setup
- you want a modern constexpr alternative to gperf
- you need zero-cost static lookup tables

## When to avoid
- you need mutable containers or runtime-modifiable keys
- your compiler is older than C++14 (e.g. GCC 5)
- you need dynamically sized containers
- you need frequent container updates after initialization

## Facets
- artifact type: library
- maturity: maintenance
- function: search-engine, serialization
- domain: developer-tools, performance
- platform: cpp, cross-platform
- tags: header-only, constexpr, perfect-hashing, immutable-containers, gperf-alternative, c++14, algorithms

## Member repositories
- serge-sans-paille/frozen (main) score 67

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:05.429742+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 2026-08-30T03:58:26.765121+00:00, confidence not recorded.
  - readme: https://github.com/serge-sans-paille/frozen (fetched 2026-08-28T04:05:05.429742+00:00, sha 47f58de186d6)
- Data as of 2026-08-30T08:39:29.467469+00:00.