thirtytwo

Base32 encoding and decoding for Gleam, targeting both Erlang and JavaScript.

Supports five base32 variants:

RFC 4648 (encode / decode) — the standard alphabet with optional padding and case-insensitive decoding.
Extended Hex (hex_encode / hex_decode) — preserves sort order of the underlying binary data (RFC 4648 §7).
Crockford (crockford_encode / crockford_decode) — omits I, L, O, U to reduce ambiguity; supports hyphens, character aliases, and an optional mod-37 check digit.
z-base-32 (z_base_32_encode / z_base_32_decode) — human-oriented lowercase alphabet optimized for readability.
Geohash (geohash_encode / geohash_decode) — the alphabet used by the Geohash geocoding system.

Examples

thirtytwo.encode(<<"wibble":utf8>>, padding: True)
// -> "O5UWEYTMMU======"

thirtytwo.decode("O5UWEYTMMU======")
// -> Ok(<<"wibble":utf8>>)

thirtytwo.crockford_encode(<<"wibble":utf8>>, check: False)
// -> "EXMP4RKCCM"

Values

crockford_decode

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pub fn crockford_decode(
  input: String,
  check check: Bool,
) -> Result(BitArray, Nil)

Decode a Crockford base32 string. Hyphens are stripped, decoding is case-insensitive, and the aliases O→0, I/L→1 are normalized. When check is True, the trailing check digit is validated. Returns Error(Nil) on invalid input or a failed check.

crockford_encode

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pub fn crockford_encode(
  input: BitArray,
  check check: Bool,
) -> String

Encode a bit array using Crockford’s base32 alphabet. The output is always unpadded and uppercase. The input must be byte-aligned; non-byte-aligned bit arrays produce undefined results. When check is True, a mod-37 check digit is appended.

decode

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pub fn decode(input: String) -> Result(BitArray, Nil)

Decode a standard RFC 4648 base32 string. Padding is optional and decoding is case-insensitive. Returns Error(Nil) on invalid input.

encode

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pub fn encode(input: BitArray, padding padding: Bool) -> String

Encode a bit array using the standard RFC 4648 base32 alphabet. The input must be byte-aligned; non-byte-aligned bit arrays produce undefined results. When padding is True, the output is padded with = to a multiple of 8.

geohash_decode

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pub fn geohash_decode(input: String) -> Result(BitArray, Nil)

Decode a Geohash base32 string. Decoding is case-sensitive. Returns Error(Nil) on invalid input.

geohash_encode

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pub fn geohash_encode(input: BitArray) -> String

Encode a bit array using the Geohash base32 alphabet. The output is always lowercase and unpadded. The input must be byte-aligned; non-byte-aligned bit arrays produce undefined results.

hex_decode

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pub fn hex_decode(input: String) -> Result(BitArray, Nil)

Decode a base32hex string. Padding is optional and decoding is case-insensitive. Returns Error(Nil) on invalid input.

hex_encode

</>

pub fn hex_encode(
  input: BitArray,
  padding padding: Bool,
) -> String

Encode a bit array using the base32hex alphabet (RFC 4648 section 7). Preserves sort order of the underlying data. The input must be byte-aligned; non-byte-aligned bit arrays produce undefined results. When padding is True, the output is padded with = to a multiple of 8.

z_base_32_decode

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pub fn z_base_32_decode(input: String) -> Result(BitArray, Nil)

Decode a z-base-32 string. Decoding is case-sensitive. Returns Error(Nil) on invalid input.

z_base_32_encode

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pub fn z_base_32_encode(input: BitArray) -> String

Encode a bit array using the z-base-32 alphabet. The output is always lowercase and unpadded. The input must be byte-aligned; non-byte-aligned bit arrays produce undefined results.