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Merged
merged 4 commits into from
Nov 9, 2022
Merged

Create CRC16.java #3733

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e65c8f6
Create CRC16.java
rnzit Oct 29, 2022
0c0e027
Merge branch 'master' into master
rnzit Nov 1, 2022
76a50ec
Merge branch 'master' into master
rnzit Nov 8, 2022
7395b47
Create CRC16Test.java
rnzit Nov 8, 2022
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29 changes: 29 additions & 0 deletions src/main/java/com/thealgorithms/others/CRC16.java
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package com.thealgorithms.others;

/**
* Generates a crc16 checksum for a given string
*/
public class CRC16 {

public static void main(String[] args) {
System.out.println(crc16("Hello World!"));
}

public static String crc16(String message) {
int crc = 0xFFFF; // initial value
int polynomial = 0x1021; // 0001 0000 0010 0001 (0, 5, 12)
byte[] bytes = message.getBytes();

for (byte b : bytes) {
for (int i = 0; i < 8; i++) {
boolean bit = ((b >> (7 - i) & 1) == 1);
boolean c15 = ((crc >> 15 & 1) == 1);
crc <<= 1;
if (c15 ^ bit)
crc ^= polynomial;
}
}
crc &= 0xffff;
return Integer.toHexString(crc).toUpperCase();
}
}
23 changes: 23 additions & 0 deletions src/test/java/com/thealgorithms/others/CRC16Test.java
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package com.thealgorithms.others;

import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;

class CRC16Test {

CRC16 crc = new CRC16();

@Test
void testCRC16() {
// given
String textToCRC16 = "hacktoberfest!";

// when
String resultCRC16 = crc.crc16(textToCRC16); // Algorithm CRC16-CCITT-FALSE

// then
assertEquals("10FC", resultCRC16);
}

}