add new operation CRC-16-CCITT Checksum

src/core/operations/CRC16CCITTChecksum.mjs

@@ -0,0 +1,62 @@
+/**
+ * @author mikecat
+ * @copyright Crown Copyright 2022
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import Utils from "../Utils.mjs";
+
+/**
+ * CRC-16-CCITT Checksum operation
+ */
+class CRC16CCITTChecksum extends Operation {
+
+    /**
+     * CRC16CCITTChecksum constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "CRC-16-CCITT Checksum";
+        this.module = "Crypto";
+        this.description = "Another version of CRC-16, used in XMODEM/YMODEM protocol.";
+        this.infoURL = "https://wikipedia.org/wiki/Cyclic_redundancy_check";
+        this.inputType = "ArrayBuffer";
+        this.outputType = "string";
+        this.args = [
+        ];
+
+        this.crcTable = [];
+        for (let i = 0; i < 256; i++) {
+            let value = i << 8;
+            for (let j = 0; j < 8; j++) {
+                value <<= 1;
+                if (value & 0x10000) value ^= 0x1021;
+                value &= 0xffff;
+            }
+            this.crcTable.push(value);
+        }
+    }
+
+    /**
+     * @param {ArrayBuffer} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        if (ArrayBuffer.isView(input)) {
+            input = new Uint8Array(input.buffer, input.byteOffset, input.byteLength);
+        } else {
+            input = new Uint8Array(input);
+        }
+        let crc = 0;
+        for (let i = 0; i < input.length; i++) {
+            crc = ((crc << 8) ^ this.crcTable[((crc >> 8) ^ input[i]) & 0xff]) & 0xffff;
+        }
+        return Utils.hex(crc, 4);
+    }
+
+}
+
+export default CRC16CCITTChecksum;