Extract checksum implementations into separate class CheckSums

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/miband/MiBandFWHelper.java

@@ -67,19 +67,4 @@ public class MiBandFWHelper {
         }
         return false;
     }
-
-    //thanks http://stackoverflow.com/questions/13209364/convert-c-crc16-to-java-crc16
-    public int getCRC16(byte[] seq) {
-        int crc = 0xFFFF;
-
-        for (int j = 0; j < seq.length; j++) {
-            crc = ((crc >>> 8) | (crc << 8)) & 0xffff;
-            crc ^= (seq[j] & 0xff);//byte to int, trunc sign
-            crc ^= ((crc & 0xff) >> 4);
-            crc ^= (crc << 12) & 0xffff;
-            crc ^= ((crc & 0xFF) << 5) & 0xffff;
-        }
-        crc &= 0xffff;
-        return crc;
-    }
 }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/miband/UserInfo.java

@@ -1,5 +1,7 @@
 package nodomain.freeyourgadget.gadgetbridge.devices.miband;
 
+import nodomain.freeyourgadget.gadgetbridge.util.CheckSums;
+
 /**
  * Created by UgoRaffaele on 30/01/2015.
  */
@@ -76,7 +78,7 @@ public class UserInfo {
         byte[] crcSequence = new byte[19];
         System.arraycopy(sequence, 0, crcSequence, 0, crcSequence.length);
 
-        sequence[19] = (byte) ((getCRC8(crcSequence) ^ Integer.parseInt(address.substring(address.length() - 2), 16)) & 0xff);
+        sequence[19] = (byte) ((CheckSums.getCRC8(crcSequence) ^ Integer.parseInt(address.substring(address.length() - 2), 16)) & 0xff);
 
         this.data = sequence;
     }
@@ -109,24 +111,4 @@ public class UserInfo {
     public byte[] getData() {
         return this.data;
     }
-
-    protected int getCRC8(byte[] seq) {
-        int len = seq.length;
-        int i = 0;
-        byte crc = 0x00;
-
-        while (len-- > 0) {
-            byte extract = seq[i++];
-            for (byte tempI = 8; tempI != 0; tempI--) {
-                byte sum = (byte) ((crc & 0xff) ^ (extract & 0xff));
-                sum = (byte) ((sum & 0xff) & 0x01);
-                crc = (byte) ((crc & 0xff) >>> 1);
-                if (sum != 0) {
-                    crc = (byte) ((crc & 0xff) ^ 0x8c);
-                }
-                extract = (byte) ((extract & 0xff) >>> 1);
-            }
-        }
-        return (crc & 0xff);
-    }
 }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java

@@ -40,6 +40,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.AbortTransactio
 import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceBusyAction;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceStateAction;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetProgressAction;
+import nodomain.freeyourgadget.gadgetbridge.util.CheckSums;
 import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 
@@ -602,7 +603,7 @@ public class MiBandSupport extends AbstractBTLEDeviceSupport {
 
             int newFwVersion = mFwHelper.getFirmwareVersion();
             int oldFwVersion = mDeviceInfo.getFirmwareVersion();
-            int checksum = (Integer.decode("0x" + mMacOctets[4]) << 8 | Integer.decode("0x" + mMacOctets[5])) ^ mFwHelper.getCRC16(mFwHelper.getFw());
+            int checksum = (Integer.decode("0x" + mMacOctets[4]) << 8 | Integer.decode("0x" + mMacOctets[5])) ^ CheckSums.getCRC16(mFwHelper.getFw());
 
             if (sendFirmwareInfo(oldFwVersion, newFwVersion, mFwHelper.getFw().length, checksum)) {
                 firmwareInfoSent = true;

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/CheckSums.java

@@ -0,0 +1,38 @@
+package nodomain.freeyourgadget.gadgetbridge.util;
+
+public class CheckSums {
+    public static int getCRC8(byte[] seq) {
+        int len = seq.length;
+        int i = 0;
+        byte crc = 0x00;
+
+        while (len-- > 0) {
+            byte extract = seq[i++];
+            for (byte tempI = 8; tempI != 0; tempI--) {
+                byte sum = (byte) ((crc & 0xff) ^ (extract & 0xff));
+                sum = (byte) ((sum & 0xff) & 0x01);
+                crc = (byte) ((crc & 0xff) >>> 1);
+                if (sum != 0) {
+                    crc = (byte) ((crc & 0xff) ^ 0x8c);
+                }
+                extract = (byte) ((extract & 0xff) >>> 1);
+            }
+        }
+        return (crc & 0xff);
+    }
+
+    //thanks http://stackoverflow.com/questions/13209364/convert-c-crc16-to-java-crc16
+    public static int getCRC16(byte[] seq) {
+        int crc = 0xFFFF;
+
+        for (int j = 0; j < seq.length; j++) {
+            crc = ((crc >>> 8) | (crc << 8)) & 0xffff;
+            crc ^= (seq[j] & 0xff);//byte to int, trunc sign
+            crc ^= ((crc & 0xff) >> 4);
+            crc ^= (crc << 12) & 0xffff;
+            crc ^= ((crc & 0xFF) << 5) & 0xffff;
+        }
+        crc &= 0xffff;
+        return crc;
+    }
+}