Initial project commit

lib/nightscout/com/eveningoutpost/dexdrip/ImportedLibraries/dexcom/CRC16.java

@@ -0,0 +1,20 @@
+package com.eveningoutpost.dexdrip.ImportedLibraries.dexcom;
+
+// This code and this particular library are from the NightScout android uploader
+// Check them out here: https://github.com/nightscout/android-uploader
+// Some of this code may have been modified for use in this project
+
+public class CRC16 {
+    public static byte[] calculate(byte[] buff, int start, int end) {
+        int crcShort = 0;
+        for (int i = start; i < end; i++) {
+            crcShort = ((crcShort  >>> 8) | (crcShort  << 8) )& 0xffff;
+            crcShort ^= (buff[i] & 0xff);
+            crcShort ^= ((crcShort & 0xff) >> 4);
+            crcShort ^= (crcShort << 12) & 0xffff;
+            crcShort ^= ((crcShort & 0xFF) << 5) & 0xffff;
+        }
+        crcShort &= 0xffff;
+        return new byte[] {(byte) (crcShort & 0xff), (byte) ((crcShort >> 8) & 0xff)};
+    }
+}