Merge branch 'PenguinGeorge-ascii85-new'

This commit is contained in:
n1474335 2018-08-23 22:05:44 +01:00
commit 4c2d612bdd
4 changed files with 245 additions and 0 deletions

View File

@ -25,6 +25,8 @@
"From Base32",
"To Base58",
"From Base58",
"To Base85",
"From Base85",
"To Base",
"From Base",
"To BCD",

45
src/core/lib/Base85.mjs Normal file
View File

@ -0,0 +1,45 @@
/**
* Base85 resources.
*
* @author PenguinGeorge [george@penguingeorge.com]
* @copyright Crown Copyright 2018
* @license Apache-2.0
*/
/**
* Base85 alphabet options.
*/
export const ALPHABET_OPTIONS = [
{
name: "Standard",
value: "!-u",
},
{
name: "Z85 (ZeroMQ)",
value: "0-9a-zA-Z.#\\-:+=^!/*?&<>()[]{}@%$#",
},
{
name: "IPv6",
value: "0-9A-Za-z!#$%&()*+\\-;<=>?@^_`{|~}",
}
];
/**
* Returns the name of the alphabet, when given the alphabet.
*
* @param {string} alphabet
* @returns {string}
*/
export function alphabetName(alphabet) {
alphabet = alphabet.replace("'", "&apos;");
alphabet = alphabet.replace("\"", "&quot;");
alphabet = alphabet.replace("\\", "&bsol;");
let name;
ALPHABET_OPTIONS.forEach(function(a) {
if (escape(alphabet) === escape(a.value)) name = a.name;
});
return name;
}

View File

@ -0,0 +1,105 @@
/**
* @author PenguinGeorge [george@penguingeorge.com]
* @copyright Crown Copyright 2018
* @license Apache-2.0
*/
import Operation from "../Operation";
import OperationError from "../errors/OperationError";
import Utils from "../Utils";
import {alphabetName, ALPHABET_OPTIONS} from "../lib/Base85";
/**
* From Base85 operation
*/
class FromBase85 extends Operation {
/**
* From Base85 constructor
*/
constructor() {
super();
this.name = "From Base85";
this.module = "Default";
this.description = "Base85 (also called Ascii85) is a notation for encoding arbitrary byte data. It is usually more efficient that Base64.<br><br>This operation decodes data from an ASCII string (with an alphabet of your choosing, presets included).<br><br>e.g. <code>BOu!rD]j7BEbo7</code> becomes <code>hello world</code><br><br>Base85 is commonly used in Adobe's PostScript and PDF file formats.";
this.infoURL = "https://wikipedia.org/wiki/Ascii85";
this.inputType = "string";
this.outputType = "byteArray";
this.args = [
{
name: "Alphabet",
type: "editableOption",
value: ALPHABET_OPTIONS
},
];
}
/**
* @param {string} input
* @param {Object[]} args
* @returns {byteArray}
*/
run(input, args) {
const alphabet = Utils.expandAlphRange(args[0]).join(""),
encoding = alphabetName(alphabet),
result = [];
if (alphabet.length !== 85 ||
[].unique.call(alphabet).length !== 85) {
throw new OperationError("Alphabet must be of length 85");
}
if (input.length === 0) return [];
const matches = input.match(/<~(.+?)~>/);
if (matches !== null) input = matches[1];
let i = 0;
let block, blockBytes;
while (i < input.length) {
if (encoding === "Standard" && input[i] === "z") {
result.push(0, 0, 0, 0);
i++;
} else {
let digits = [];
digits = input
.substr(i, 5)
.split("")
.map((chr, idx) => {
const digit = alphabet.indexOf(chr);
if (digit < 0 || digit > 84) {
throw `Invalid character '${chr}' at index ${idx}`;
}
return digit;
});
block =
digits[0] * 52200625 +
digits[1] * 614125 +
(i + 2 < input.length ? digits[2] : 84) * 7225 +
(i + 3 < input.length ? digits[3] : 84) * 85 +
(i + 4 < input.length ? digits[4] : 84);
blockBytes = [
(block >> 24) & 0xff,
(block >> 16) & 0xff,
(block >> 8) & 0xff,
block & 0xff
];
if (input.length < i + 5) {
blockBytes.splice(input.length - (i + 5), 5);
}
result.push.apply(result, blockBytes);
i += 5;
}
}
return result;
}
}
export default FromBase85;

View File

@ -0,0 +1,93 @@
/**
* @author PenguinGeorge [george@penguingeorge.com]
* @copyright Crown Copyright 2018
* @license Apache-2.0
*/
import Operation from "../Operation";
import OperationError from "../errors/OperationError";
import Utils from "../Utils";
import {alphabetName, ALPHABET_OPTIONS} from "../lib/Base85";
/**
* To Base85 operation
*/
class ToBase85 extends Operation {
/**
* To Base85 constructor
*/
constructor() {
super();
this.name = "To Base85";
this.module = "Default";
this.description = "Base85 (also called Ascii85) is a notation for encoding arbitrary byte data. It is usually more efficient that Base64.<br><br>This operation encodes data in an ASCII string (with an alphabet of your choosing, presets included).<br><br>e.g. <code>hello world</code> becomes <code>BOu!rD]j7BEbo7</code><br><br>Base85 is commonly used in Adobe's PostScript and PDF file formats.<br><br><strong>Options</strong><br><u>Alphabet</u><ul><li>Standard - The standard alphabet, referred to as Ascii85</li><li>Z85 (ZeroMQ) - A string-safe variant of Base85, which avoids quote marks and backslash characters</li><li>IPv6 - A variant of Base85 suitable for encoding IPv6 addresses (RFC 1924)</li></ul><u>Include delimiter</u><br>Adds a '<~' and '~>' delimiter to the start and end of the data. This is standard for Adobe's implementation of Base85.";
this.infoURL = "https://wikipedia.org/wiki/Ascii85";
this.inputType = "byteArray";
this.outputType = "string";
this.args = [
{
name: "Alphabet",
type: "editableOption",
value: ALPHABET_OPTIONS
},
{
name: "Include delimeter",
type: "boolean",
value: false
}
];
}
/**
* @param {byteArray} input
* @param {Object[]} args
* @returns {string}
*/
run(input, args) {
const alphabet = Utils.expandAlphRange(args[0]).join(""),
encoding = alphabetName(alphabet),
includeDelim = args[1];
let result = "";
if (alphabet.length !== 85 ||
[].unique.call(alphabet).length !== 85) {
throw new OperationError("Error: Alphabet must be of length 85");
}
if (input.length === 0) return "";
let block;
for (let i = 0; i < input.length; i += 4) {
block = (
((input[i]) << 24) +
((input[i + 1] || 0) << 16) +
((input[i + 2] || 0) << 8) +
((input[i + 3] || 0))
) >>> 0;
if (encoding !== "Standard" || block > 0) {
let digits = [];
for (let j = 0; j < 5; j++) {
digits.push(block % 85);
block = Math.floor(block / 85);
}
digits = digits.reverse();
if (input.length < i + 4) {
digits.splice(input.length - (i + 4), 4);
}
result += digits.map(digit => alphabet[digit]).join("");
} else {
result += (encoding === "Standard") ? "z" : null;
}
}
return includeDelim ? `<~${result}~>` : result;
}
}
export default ToBase85;