# BurntSushi/memchr

Optimized string search routines for Rust.

Repository: https://github.com/BurntSushi/memchr
Canonical: https://ross.abutalabs.com/products/memchr
Language: Rust
License: Unlicense
License Family: permissive
Topics: rust, memchr, string, string-searching, bytes, twoway, simd, rabin-karp
Last push: 2026-08-10T17:32:21+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 35, longevity 100
- inputs: {"age_days": 4101, "days_push": 23, "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 1542, forks 151 (observed 2026-08-28T04:05:01.177405+00:00)

## What it is
A Rust library providing heavily optimized byte and substring search routines, accelerated with SIMD on x86_64, aarch64, and wasm32. It operates on raw bytes without regard to encoding and supports no_std environments.

## Use cases
- find the position of a byte in a slice as fast as possible
- search for a substring in a byte buffer
- parse large text or binary files quickly in Rust
- write a no_std crate that needs fast byte searching
- speed up tokenization or splitting on delimiters
- implement a custom text search engine or regex engine

## When to choose
- you need maximum-performance byte or substring search in Rust
- you want SIMD acceleration with portable fallbacks
- you need no_std support
- you are building parsers, regex engines, or text processing tools

## When to avoid
- you need Unicode-aware string search with encoding semantics
- you need regex or multi-pattern search (use the regex or aho-corasick crates)
- you are not working in Rust

## Facets
- artifact type: library
- maturity: stable
- function: search-engine, parser, developer-tools
- domain: performance, developer-tools, parsers
- platform: rust, wasm, cross-platform
- tags: memchr, substring-search, simd, no-std, bytes, string-searching, rabin-karp, twoway, algorithms

## Member repositories
- BurntSushi/memchr (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:01.177405+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 2026-08-30T04:30:42.844531+00:00, confidence not recorded.
  - readme: https://github.com/BurntSushi/memchr (fetched 2026-08-28T04:05:01.177405+00:00, sha 687793f2dc11)
  - registry_crates: https://crates.io/api/v1/crates/memchr (fetched 2026-08-29T11:31:59.030402+00:00, sha caa8cfa00046)
- Data as of 2026-08-30T08:39:29.467469+00:00.