ethers.js/lib.esm/utils/base58.js

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/**
* 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.
*
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* @_subsection: api/utils:Base58 Encoding [about-base58]
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*/
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import { getBytes } from "./data.js";
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import { assertArgument } from "./errors.js";
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import { toBigInt } from "./maths.js";
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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];
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assertArgument(result != null, `invalid base58 value`, "letter", letter);
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return result;
}
const BN_0 = BigInt(0);
const BN_58 = BigInt(58);
/**
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* Encode %%value%% as a Base58-encoded string.
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*/
export function encodeBase58(_value) {
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const bytes = getBytes(_value);
let value = toBigInt(bytes);
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let result = "";
while (value) {
result = Alphabet[Number(value % BN_58)] + result;
value /= BN_58;
}
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// Account for leading padding zeros
for (let i = 0; i < bytes.length; i++) {
if (bytes[i]) {
break;
}
result = Alphabet[0] + result;
}
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return result;
}
/**
* Decode the Base58-encoded %%value%%.
*/
export function decodeBase58(value) {
let result = BN_0;
for (let i = 0; i < value.length; i++) {
result *= BN_58;
result += getAlpha(value[i]);
}
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return result;
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}
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