ethers.js/lib.commonjs/utils/base58.js
2024-01-02 19:12:56 -05:00

68 lines
2.1 KiB
JavaScript

"use strict";
/**
* The [Base58 Encoding](link-base58) scheme allows a **numeric** value
* to be encoded as a compact string using a radix of 58 using only
* alpha-numeric characters. Confusingly similar characters are omitted
* (i.e. ``"l0O"``).
*
* Note that Base58 encodes a **numeric** value, not arbitrary bytes,
* since any zero-bytes on the left would get removed. To mitigate this
* issue most schemes that use Base58 choose specific high-order values
* to ensure non-zero prefixes.
*
* @_subsection: api/utils:Base58 Encoding [about-base58]
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.decodeBase58 = exports.encodeBase58 = void 0;
const data_js_1 = require("./data.js");
const errors_js_1 = require("./errors.js");
const maths_js_1 = require("./maths.js");
const Alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
let Lookup = null;
function getAlpha(letter) {
if (Lookup == null) {
Lookup = {};
for (let i = 0; i < Alphabet.length; i++) {
Lookup[Alphabet[i]] = BigInt(i);
}
}
const result = Lookup[letter];
(0, errors_js_1.assertArgument)(result != null, `invalid base58 value`, "letter", letter);
return result;
}
const BN_0 = BigInt(0);
const BN_58 = BigInt(58);
/**
* Encode %%value%% as a Base58-encoded string.
*/
function encodeBase58(_value) {
const bytes = (0, data_js_1.getBytes)(_value);
let value = (0, maths_js_1.toBigInt)(bytes);
let result = "";
while (value) {
result = Alphabet[Number(value % BN_58)] + result;
value /= BN_58;
}
// Account for leading padding zeros
for (let i = 0; i < bytes.length; i++) {
if (bytes[i]) {
break;
}
result = Alphabet[0] + result;
}
return result;
}
exports.encodeBase58 = encodeBase58;
/**
* Decode the Base58-encoded %%value%%.
*/
function decodeBase58(value) {
let result = BN_0;
for (let i = 0; i < value.length; i++) {
result *= BN_58;
result += getAlpha(value[i]);
}
return result;
}
exports.decodeBase58 = decodeBase58;
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