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