Add CRC module to calculate crc 16 for image validation.

dist/crc16.js

@@ -0,0 +1,65 @@
+/* @license
+ *
+ * CRC-CCITT (0xFFFF) library.
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+ // https://github.com/umdjs/umd
+(function(global, factory) {
+
+    if (typeof exports === 'object') {
+        // CommonJS (Node)
+        module.exports = factory();
+    } else if (typeof define === 'function' && define.amd) {
+        // AMD
+        define(factory);
+    } else {
+        // Browser global (with support for web workers)
+        global.crc16 = factory();
+    }
+
+}(this, function() {
+    'use strict';
+
+    /**
+     * Copied from Nordic's command line tool nrf.exe.
+     * https://github.com/NordicSemiconductor/pc-nrfutil/blob/master/nordicsemi/dfu/crc16.py
+     */
+    return function (binaryData) {
+        var crc = 0xFFFF;
+        var view = new Uint8Array(binaryData);
+        
+        var i;
+        
+        for (i = 0; i < view.byteLength; i++) {
+            crc = (crc >> 8 & 0x00FF) | (crc << 8 & 0xFF00);
+            crc ^= view[i];
+            crc ^= (crc & 0x00FF) >> 4;
+            crc ^= (crc << 8) << 4;
+            crc ^= ((crc & 0x00FF) << 4) << 1;
+        }
+        
+        return (crc & 0xFFFF);
+    };
+}));