Updated Base85 operations for latest CyberChef version

src/core/operations/FromBase85.mjs

@@ -0,0 +1,104 @@
+/**
+ * @author PenguinGeorge [george@penguingeorge.com]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import OperationError from "../errors/OperationError";
+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 (similar to Base64) 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 = args[0] || ALPHABET_OPTIONS[0].value,
+            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;