Initial project commit

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

@@ -0,0 +1,36 @@
+package com.eveningoutpost.dexdrip.ImportedLibraries.dexcom;
+
+import java.util.Arrays;
+
+// 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 ReadPacket {
+    private int command;
+    private byte[] data;
+    private byte[] crc_calc;
+    private byte[] crc;
+    private int OFFSET_CMD = 3;
+    private int OFFSET_DATA = 4;
+    private int CRC_LEN = 2;
+
+    public ReadPacket(byte[] readPacket) {
+        this.command = readPacket[OFFSET_CMD];
+        this.data = Arrays.copyOfRange(readPacket, OFFSET_DATA, readPacket.length - CRC_LEN);
+        this.crc = Arrays.copyOfRange(readPacket, readPacket.length - CRC_LEN, readPacket.length);
+        this.crc_calc=CRC16.calculate(readPacket, 0, readPacket.length - 2);
+        if (!Arrays.equals(this.crc, this.crc_calc)) {
+            throw new CRCFailRuntimeException("CRC check failed: " + Utils.bytesToHex(this.crc) + " vs " + Utils.bytesToHex(this.crc_calc));
+        }
+    }
+
+    public int getCommand() {
+        return command;
+    }
+
+    public byte[] getData() {
+        return data;
+    }
+}