import { rfc4648 } from "../../deps.ts";import { Base32String } from "../util/doc-types.ts";import { ValidationError } from "../util/errors.ts";
const { codec } = rfc4648;
// For base32 encoding we use rfc4648, no padding, lowercase, prefixed with "b".//// Base32 character set: `abcdefghijklmnopqrstuvwxyz234567`//// The Multibase format adds a "b" prefix to specify this particular encoding.// We leave the "b" prefix there because we don't want the encoded string// to start with a number (so we can use it as a URL location).//// When decoding, we require it to start with a "b" --// no other multibase formats are allowed.//// The decoding must be strict (it doesn't allow a 1 in place of an i, etc).
const myEncoding = { // this should match b32chars from characters.ts chars: "abcdefghijklmnopqrstuvwxyz234567", bits: 5,};
/** Encode uint8array bytes to base32 string */export function base32BytesToString(bytes: Uint8Array): Base32String { return "b" + codec.stringify(bytes, myEncoding, { pad: false });}
/** Decode base32 string to a uint8array of bytes. Throw a ValidationError if the string is bad. */export function base32StringToBytes(str: Base32String): Uint8Array { if (!str.startsWith("b")) { throw new ValidationError( "can't decode base32 string - it should start with a 'b'. " + str, ); }
// this library combines padding and looseness settings into a single "loose" option, so // we have to set "loose: true" in order to handle unpadded inputs. // with a custom codec, loose mode: // -- allows padding or no padding -- we have to check for this // -- does not allow uppercase -- good // -- does not allow 1/i substitution -- good
// make sure no padding characters are on the end if (str[str.length - 1] === "=") { throw new ValidationError( "can't decode base32 string - it contains padding characters ('=')", ); } return codec.parse(str.slice(1), myEncoding, { loose: true });}