ESM: Ported all Hash and Checksum operations

src/core/operations/Fletcher32Checksum.mjs

@@ -0,0 +1,48 @@
+/**
+ * @author n1474335 [n1474335@gmail.com]
+ * @copyright Crown Copyright 2016
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import Utils from "../Utils";
+
+/**
+ * Fletcher-32 Checksum operation
+ */
+class Fletcher32Checksum extends Operation {
+
+    /**
+     * Fletcher32Checksum constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Fletcher-32 Checksum";
+        this.module = "Hashing";
+        this.description = "The Fletcher checksum is an algorithm for computing a position-dependent checksum devised by John Gould Fletcher at Lawrence Livermore Labs in the late 1970s.<br><br>The objective of the Fletcher checksum was to provide error-detection properties approaching those of a cyclic redundancy check but with the lower computational effort associated with summation techniques.";
+        this.inputType = "byteArray";
+        this.outputType = "string";
+        this.args = [];
+    }
+
+    /**
+     * @param {byteArray} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        let a = 0,
+            b = 0;
+
+        for (let i = 0; i < input.length; i++) {
+            a = (a + input[i]) % 0xffff;
+            b = (b + a) % 0xffff;
+        }
+
+        return Utils.hex(((b << 16) | a) >>> 0, 8);
+    }
+
+}
+
+export default Fletcher32Checksum;