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feat(encoding): add ascii85 module (denoland/deno#6711)
This commit is contained in:
Opliko
denobot
parent
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commit
856d3de0c4
@ -2,6 +2,7 @@
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Helper module for dealing with external data structures.
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- [`ascii85`](#ascii85)
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- [`base32`](#base32)
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- [`binary`](#binary)
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- [`csv`](#csv)
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@ -322,3 +323,58 @@ console.log(binaryData);
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console.log(encode(binaryData));
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// => RC2E6GA=
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```
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## ascii85
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Ascii85/base85 encoder and decoder with support for multiple standards
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### Basic usage
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`encode` encodes a `Uint8Array` to a ascii85 representation, and `decode`
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decodes the given ascii85 representation to a `Uint8Array`.
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```ts
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import { encode, decode } from "https://deno.land/std/encoding/ascii85.ts";
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const a85Repr = "LpTqp";
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const binaryData = decode(a85Repr);
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console.log(binaryData);
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// => Uint8Array [ 136, 180, 79, 24 ]
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console.log(encode(binaryData));
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// => LpTqp
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```
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### Specifying a standard and delimeter
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By default all functions are using the most popular Adobe version of ascii85 and
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not adding any delimeter. However, there are three more standards supported -
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btoa (different delimeter and additional compression of 4 bytes equal to 32),
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[Z85](https://rfc.zeromq.org/spec/32/) and
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[RFC 1924](https://tools.ietf.org/html/rfc1924). It's possible to use a
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different encoding by specifying it in `options` object as a second parameter.
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Similarly, it's possible to make `encode` add a delimeter (`<~` and `~>` for
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Adobe, `xbtoa Begin` and `xbtoa End` with newlines between the delimeters and
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encoded data for btoa. Checksums for btoa are not supported. Delimeters are not
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supported by other encodings.)
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encoding examples:
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```ts
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import { encode, decode } from "https://deno.land/std/encoding/ascii85.ts";
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const binaryData = new Uint8Array([136, 180, 79, 24]);
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console.log(encode(binaryData));
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// => LpTqp
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console.log(encode(binaryData, { standard: "Adobe", delimeter: true }));
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// => <~LpTqp~>
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console.log(encode(binaryData, { standard: "btoa", delimeter: true }));
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/* => xbtoa Begin
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LpTqp
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xbtoa End */
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console.log(encode(binaryData, { standard: "RFC 1924" }));
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// => h_p`_
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console.log(encode(binaryData, { standard: "Z85" }));
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// => H{P}{
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```
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129
encoding/ascii85.ts
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129
encoding/ascii85.ts
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@ -0,0 +1,129 @@
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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
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/** This module is browser compatible. */
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export type Ascii85Standard = "Adobe" | "btoa" | "RFC 1924" | "Z85";
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/**
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* encoding/decoding options
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* @property standard - characterset and delimeter (if supported and used). Defaults to Adobe
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* @property delimeter - whether to use a delimeter (if supported) - "<~" and "~>" by default
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*/
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export interface Ascii85Options {
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standard?: Ascii85Standard;
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delimiter?: boolean;
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}
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const rfc1924 =
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"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
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const Z85 =
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"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-:+=^!/*?&<>()[]{}@%$#";
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/**
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* Encodes a given Uint8Array into ascii85, supports multiple standards
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* @param uint8 input to encode
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* @param [options] encoding options
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* @param [options.standard=Adobe] encoding standard (Adobe, btoa, RFC 1924 or Z85)
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* @param [options.delimeter] whether to use a delimeter, if supported by encoding standard
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*/
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export function encode(uint8: Uint8Array, options?: Ascii85Options): string {
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const standard = options?.standard ?? "Adobe";
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let output: string[] = [],
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v: number,
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n = 0,
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difference = 0;
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if (uint8.length % 4 !== 0) {
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const tmp = uint8;
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difference = 4 - (tmp.length % 4);
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uint8 = new Uint8Array(tmp.length + difference);
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uint8.set(tmp);
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}
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const view = new DataView(uint8.buffer);
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for (let i = 0, len = uint8.length; i < len; i += 4) {
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v = view.getUint32(i);
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// Adobe and btoa standards compress 4 zeroes to single "z" character
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if (
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(standard === "Adobe" || standard === "btoa") &&
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v === 0 &&
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i < len - difference - 3
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) {
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output[n++] = "z";
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continue;
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}
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// btoa compresses 4 spaces - that is, bytes equal to 32 - into single "y" character
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if (standard === "btoa" && v === 538976288) {
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output[n++] = "y";
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continue;
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}
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for (let j = 4; j >= 0; j--) {
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output[n + j] = String.fromCharCode((v % 85) + 33);
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v = Math.trunc(v / 85);
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}
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n += 5;
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}
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switch (standard) {
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case "Adobe":
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if (options?.delimiter) {
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return `<~${output.slice(0, output.length - difference).join("")}~>`;
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}
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break;
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case "btoa":
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if (options?.delimiter) {
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return `xbtoa Begin\n${output
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.slice(0, output.length - difference)
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.join("")}\nxbtoa End`;
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}
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break;
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case "RFC 1924":
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output = output.map((val) => rfc1924[val.charCodeAt(0) - 33]);
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break;
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case "Z85":
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output = output.map((val) => Z85[val.charCodeAt(0) - 33]);
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break;
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}
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return output.slice(0, output.length - difference).join("");
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}
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/**
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* Decodes a given ascii85 encoded string.
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* @param ascii85 input to decode
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* @param [options] decoding options
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* @param [options.standard=Adobe] encoding standard used in the input string (Adobe, btoa, RFC 1924 or Z85)
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*/
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export function decode(ascii85: string, options?: Ascii85Options): Uint8Array {
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const encoding = options?.standard ?? "Adobe";
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// translate all encodings to most basic adobe/btoa one and decompress some special characters ("z" and "y")
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switch (encoding) {
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case "Adobe":
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ascii85 = ascii85.replaceAll(/(<~|~>)/g, "").replaceAll("z", "!!!!!");
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break;
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case "btoa":
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ascii85 = ascii85
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.replaceAll(/(xbtoa Begin|xbtoa End|\n)/g, "")
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.replaceAll("z", "!!!!!")
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.replaceAll("y", "+<VdL");
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break;
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case "RFC 1924":
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ascii85 = ascii85.replaceAll(/./g, (match) =>
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String.fromCharCode(rfc1924.indexOf(match) + 33)
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);
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break;
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case "Z85":
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ascii85 = ascii85.replaceAll(/./g, (match) =>
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String.fromCharCode(Z85.indexOf(match) + 33)
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);
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break;
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}
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//remove all invalid characters
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ascii85 = ascii85.replaceAll(/[^!-u]/g, "");
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const len = ascii85.length,
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output = new Uint8Array(len + 4 - (len % 4));
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const view = new DataView(output.buffer);
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let v = 0,
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n = 0,
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max = 0;
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for (let i = 0; i < len; ) {
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for (max += 5; i < max; i++) {
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v = v * 85 + (i < len ? ascii85.charCodeAt(i) : 117) - 33;
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}
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view.setUint32(n, v);
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v = 0;
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n += 4;
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}
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return output.slice(0, Math.trunc(len * 0.8));
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}
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178
encoding/ascii85_test.ts
Normal file
178
encoding/ascii85_test.ts
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@ -0,0 +1,178 @@
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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
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import { assertEquals } from "../testing/asserts.ts";
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import { encode, decode, Ascii85Standard } from "./ascii85.ts";
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type TestCases = Partial<{ [index in Ascii85Standard]: string[][] }>;
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const utf8encoder = new TextEncoder();
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const testCasesNoDelimeter: TestCases = {
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Adobe: [
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["test", "FCfN8"],
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["ascii85", "@<5pmBfIs"],
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["Hello world!", "87cURD]j7BEbo80"],
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//wikipedia example
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[
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"Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.",
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"9jqo^BlbD-BleB1DJ+*+F(f,q/0JhKF<GL>Cj@.4Gp$d7F!,L7@<6@)/0JDEF<G%<+EV:2F!,O<DJ+*.@<*K0@<6L(Df-\\0Ec5e;DffZ(EZee.Bl.9pF\"AGXBPCsi+DGm>@3BB/F*&OCAfu2/AKYi(DIb:@FD,*)+C]U=@3BN#EcYf8ATD3s@q?d$AftVqCh[NqF<G:8+EV:.+Cf>-FD5W8ARlolDIal(DId<j@<?3r@:F%a+D58'ATD4$Bl@l3De:,-DJs`8ARoFb/0JMK@qB4^F!,R<AKZ&-DfTqBG%G>uD.RTpAKYo'+CT/5+Cei#DII?(E,9)oF*2M7/c",
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],
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["", ""],
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["\0", "!!"],
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["\0\0", "!!!"],
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["\0\0\0", "!!!!"],
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//special Adobe and btoa test cases - 4 bytes equal to 0 should become a "z"
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["\0\0\0\0", "z"],
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["\0\0\0\0\0", "z!!"],
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[" ", "+<VdL"],
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],
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btoa: [
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["test", "FCfN8"],
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["ascii85", "@<5pmBfIs"],
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["Hello world!", "87cURD]j7BEbo80"],
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//wikipedia example
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[
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"Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.",
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"9jqo^BlbD-BleB1DJ+*+F(f,q/0JhKF<GL>Cj@.4Gp$d7F!,L7@<6@)/0JDEF<G%<+EV:2F!,O<DJ+*.@<*K0@<6L(Df-\\0Ec5e;DffZ(EZee.Bl.9pF\"AGXBPCsi+DGm>@3BB/F*&OCAfu2/AKYi(DIb:@FD,*)+C]U=@3BN#EcYf8ATD3s@q?d$AftVqCh[NqF<G:8+EV:.+Cf>-FD5W8ARlolDIal(DId<j@<?3r@:F%a+D58'ATD4$Bl@l3De:,-DJs`8ARoFb/0JMK@qB4^F!,R<AKZ&-DfTqBG%G>uD.RTpAKYo'+CT/5+Cei#DII?(E,9)oF*2M7/c",
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],
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["", ""],
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["\0", "!!"],
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["\0\0", "!!!"],
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["\0\0\0", "!!!!"],
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//special Adobe and btoa test cases - 4 bytes equal to 0 should become a "z"
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["\0\0\0\0", "z"],
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["\0\0\0\0\0", "z!!"],
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//special btoa test case - 4 spaces should become "y"
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[" ", "y"],
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],
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"RFC 1924": [
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["test", "bY*jN"],
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["ascii85", "VRK_?X*e|"],
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["Hello world!", "NM&qnZy<MXa%^NF"],
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//wikipedia example
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[
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"Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.",
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"O<`^zX>%ZCX>)XGZfA9Ab7*B`EFf-gbRchTY<VDJc_3(Mb0BhMVRLV8EFfZabRc4RAarPHb0BkRZfA9DVR9gFVRLh7Z*CxFa&K)QZ**v7av))DX>DO_b1WctXlY|;AZc?TVIXXEb95kYW*~HEWgu;7Ze%PVbZB98AYyqSVIXj2a&u*NWpZI|V`U(3W*}r`Y-wj`bRcPNAarPDAY*TCbZKsNWn>^>Ze$>7Ze(R<VRUI{VPb4$AZKN6WpZJ3X>V>IZ)PBCZf|#NWn^b%EFfigV`XJzb0BnRWgv5CZ*p`Xc4cT~ZDnp_Wgu^6AYpEKAY);2ZeeU7aBO8^b9HiME&",
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],
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["", ""],
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["\0", "00"],
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["\0\0", "000"],
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["\0\0\0", "0000"],
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["\0\0\0\0", "00000"],
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["\0\0\0\0\0", "0000000"],
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[" ", "ARr(h"],
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],
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Z85: [
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["test", "By/Jn"],
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["ascii85", "vrk{)x/E%"],
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["Hello world!", "nm=QNzY<mxA+]nf"],
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//wikipedia example
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[
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"Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.",
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"o<}]Zx(+zcx(!xgzFa9aB7/b}efF?GBrCHty<vdjC{3^mB0bHmvrlv8efFzABrC4raARphB0bKrzFa9dvr9GfvrlH7z/cXfA=k!qz//V7AV!!dx(do{B1wCTxLy%&azC)tvixxeB95Kyw/#hewGU&7zE+pvBzb98ayYQsvixJ2A=U/nwPzi%v}u^3w/$R}y?WJ}BrCpnaARpday/tcBzkSnwN(](zE:(7zE^r<vrui@vpB4:azkn6wPzj3x(v(iz!pbczF%-nwN]B+efFIGv}xjZB0bNrwGV5cz/P}xC4Ct#zdNP{wGU]6ayPekay!&2zEEu7Abo8]B9hIme=",
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],
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["", ""],
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["\0", "00"],
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["\0\0", "000"],
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["\0\0\0", "0000"],
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["\0\0\0\0", "00000"],
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["\0\0\0\0\0", "0000000"],
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[" ", "arR^H"],
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],
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};
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const testCasesDelimeter: TestCases = {
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Adobe: [
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["test", "<~FCfN8~>"],
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["ascii85", "<~@<5pmBfIs~>"],
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["Hello world!", "<~87cURD]j7BEbo80~>"],
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//wikipedia example
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[
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"Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.",
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"<~9jqo^BlbD-BleB1DJ+*+F(f,q/0JhKF<GL>Cj@.4Gp$d7F!,L7@<6@)/0JDEF<G%<+EV:2F!,O<DJ+*.@<*K0@<6L(Df-\\0Ec5e;DffZ(EZee.Bl.9pF\"AGXBPCsi+DGm>@3BB/F*&OCAfu2/AKYi(DIb:@FD,*)+C]U=@3BN#EcYf8ATD3s@q?d$AftVqCh[NqF<G:8+EV:.+Cf>-FD5W8ARlolDIal(DId<j@<?3r@:F%a+D58'ATD4$Bl@l3De:,-DJs`8ARoFb/0JMK@qB4^F!,R<AKZ&-DfTqBG%G>uD.RTpAKYo'+CT/5+Cei#DII?(E,9)oF*2M7/c~>",
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],
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["", "<~~>"],
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["\0", "<~!!~>"],
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["\0\0", "<~!!!~>"],
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["\0\0\0", "<~!!!!~>"],
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//special Adobe and btoa test cases - 4 bytes equal to 0 should become a "z"
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["\0\0\0\0", "<~z~>"],
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["\0\0\0\0\0", "<~z!!~>"],
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[" ", "<~+<VdL~>"],
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],
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btoa: [
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["test", "xbtoa Begin\nFCfN8\nxbtoa End"],
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["ascii85", "xbtoa Begin\n@<5pmBfIs\nxbtoa End"],
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["Hello world!", "xbtoa Begin\n87cURD]j7BEbo80\nxbtoa End"],
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//wikipedia example
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[
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"Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, that by a perseverance of delight in the continued and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.",
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"xbtoa Begin\n9jqo^BlbD-BleB1DJ+*+F(f,q/0JhKF<GL>Cj@.4Gp$d7F!,L7@<6@)/0JDEF<G%<+EV:2F!,O<DJ+*.@<*K0@<6L(Df-\\0Ec5e;DffZ(EZee.Bl.9pF\"AGXBPCsi+DGm>@3BB/F*&OCAfu2/AKYi(DIb:@FD,*)+C]U=@3BN#EcYf8ATD3s@q?d$AftVqCh[NqF<G:8+EV:.+Cf>-FD5W8ARlolDIal(DId<j@<?3r@:F%a+D58'ATD4$Bl@l3De:,-DJs`8ARoFb/0JMK@qB4^F!,R<AKZ&-DfTqBG%G>uD.RTpAKYo'+CT/5+Cei#DII?(E,9)oF*2M7/c\nxbtoa End",
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],
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["", "xbtoa Begin\n\nxbtoa End"],
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["\0", "xbtoa Begin\n!!\nxbtoa End"],
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["\0\0", "xbtoa Begin\n!!!\nxbtoa End"],
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["\0\0\0", "xbtoa Begin\n!!!!\nxbtoa End"],
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//special Adobe and btoa test cases - 4 bytes equal to 0 should become a "z"
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["\0\0\0\0", "xbtoa Begin\nz\nxbtoa End"],
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["\0\0\0\0\0", "xbtoa Begin\nz!!\nxbtoa End"],
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//special btoa test case - 4 spaces should become "y"
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[" ", "xbtoa Begin\ny\nxbtoa End"],
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],
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};
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for (const [standard, tests] of Object.entries(testCasesNoDelimeter)) {
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if (tests === undefined) continue;
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Deno.test({
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name: `[encoding/ascii85] encode ${standard}`,
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fn(): void {
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for (const [bin, b85] of tests) {
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assertEquals(
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encode(utf8encoder.encode(bin), {
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standard: standard as Ascii85Standard,
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}),
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b85
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);
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}
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},
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});
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||||
|
||||
Deno.test({
|
||||
name: `[encoding/ascii85] decode ${standard}`,
|
||||
fn(): void {
|
||||
for (const [bin, b85] of tests) {
|
||||
assertEquals(
|
||||
decode(b85, { standard: standard as Ascii85Standard }),
|
||||
utf8encoder.encode(bin)
|
||||
);
|
||||
}
|
||||
},
|
||||
});
|
||||
}
|
||||
for (const [standard, tests] of Object.entries(testCasesDelimeter)) {
|
||||
if (tests === undefined) continue;
|
||||
Deno.test({
|
||||
name: `[encoding/ascii85] encode ${standard} with delimeter`,
|
||||
fn(): void {
|
||||
for (const [bin, b85] of tests) {
|
||||
assertEquals(
|
||||
encode(utf8encoder.encode(bin), {
|
||||
standard: standard as Ascii85Standard,
|
||||
delimiter: true,
|
||||
}),
|
||||
b85
|
||||
);
|
||||
}
|
||||
},
|
||||
});
|
||||
|
||||
Deno.test({
|
||||
name: `[encoding/ascii85] decode ${standard} with delimeter`,
|
||||
fn(): void {
|
||||
for (const [bin, b85] of tests) {
|
||||
assertEquals(
|
||||
decode(b85, {
|
||||
standard: standard as Ascii85Standard,
|
||||
delimiter: true,
|
||||
}),
|
||||
utf8encoder.encode(bin)
|
||||
);
|
||||
}
|
||||
},
|
||||
});
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user