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Extract checksum implementations into separate class CheckSums

This commit is contained in:
cpfeiffer 2015-08-17 22:43:42 +02:00
parent 9dc945a406
commit e6a0c35f73
4 changed files with 43 additions and 37 deletions
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15
app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/miband/MiBandFWHelper.java
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@ -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;
}
}

24
app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/miband/UserInfo.java
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@ -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);
}
}

3
app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java
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@ -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;

38
app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/CheckSums.java Normal file
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@ -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;
}
}