Crockford Base32 Encoding for OCaml

An OCaml implementation of Douglas Crockford's Base32 encoding with ISO 7064 checksum support. Provides encoding and decoding of int64 values to URI-friendly base32 strings, with optional checksum validation, padding, splitting, and random ID generation. Ported from https://github.com/front-matter/commonmeta.

Installation

opam install crockford

Or add to your dune-project:

(package
  (depends
    (crockford)))

Usage

Basic Encoding and Decoding

(* Encode a number *)
let encoded = Crockford.encode 1234567890L in
(* "16jkpa2" *)

(* Decode back to number *)
let decoded = Crockford.decode "16jkpa2" in
(* 1234567890L *)

With Checksum

(* Encode with checksum *)
let encoded = Crockford.encode ~checksum:true 1234567890L in
(* "16jkpa2d" *)

(* Decode and validate checksum *)
let decoded = Crockford.decode ~checksum:true "16jkpa2d" in
(* 1234567890L - or raises Checksum_mismatch if invalid *)

Formatted Output

(* Split with dashes for readability *)
let encoded = Crockford.encode ~split_every:4 1234567890L in
(* "16jk-pa2" *)

(* With minimum length (zero-padded) *)
let encoded = Crockford.encode ~min_length:10 1234L in
(* "000000016j" *)

Random ID Generation

Random.self_init ();

(* Generate random IDs *)
let id = Crockford.generate ~length:8 ~checksum:true () in
(* e.g., "a3x7m9q5" *)

(* Generate formatted IDs *)
let id = Crockford.generate ~length:16 ~split_every:4 ~checksum:true () in
(* e.g., "7n2q-8xkm-5pwt-3hr9" *)

Normalization

(* Handles common character confusions *)
let decoded = Crockford.decode "ILO" in  (* Treated as "110" *)
let decoded = Crockford.decode "16-JK-PA" in  (* Dashes ignored *)

License

MIT License

Author

Anil Madhavapeddy anil@recoil.org (based on code from https://github.com/front-matter/commonmeta)