diff --git a/core-java-modules/core-java-security-2/pom.xml b/core-java-modules/core-java-security-2/pom.xml index 9315ab4af2..5db3b67c04 100644 --- a/core-java-modules/core-java-security-2/pom.xml +++ b/core-java-modules/core-java-security-2/pom.xml @@ -17,6 +17,7 @@ + commons-codec commons-codec @@ -36,6 +37,15 @@ ${assertj-core.version} test + + + + javax.xml.bind + jaxb-api + 2.3.1 + + + @@ -46,4 +56,5 @@ 3.10.0 + diff --git a/core-java-modules/core-java-security-2/src/main/java/com/baeldung/checksums/ChecksumUtils.java b/core-java-modules/core-java-security-2/src/main/java/com/baeldung/checksums/ChecksumUtils.java new file mode 100644 index 0000000000..d214a0f757 --- /dev/null +++ b/core-java-modules/core-java-security-2/src/main/java/com/baeldung/checksums/ChecksumUtils.java @@ -0,0 +1,23 @@ +package com.baeldung.checksums; + +import java.io.IOException; +import java.io.InputStream; +import java.util.zip.CRC32; +import java.util.zip.CheckedInputStream; +import java.util.zip.Checksum; + +public class ChecksumUtils { + + public static long getChecksumCRC32(byte[] bytes) { + Checksum crc32 = new CRC32(); + crc32.update(bytes, 0, bytes.length); + return crc32.getValue(); + } + + public static long getChecksumCRC32(InputStream stream, int bufferSize) throws IOException { + CheckedInputStream checkedInputStream = new CheckedInputStream(stream, new CRC32()); + byte[] buffer = new byte[bufferSize]; + while (checkedInputStream.read(buffer, 0, buffer.length) >= 0) {} + return checkedInputStream.getChecksum().getValue(); + } +} diff --git a/core-java-modules/core-java-security-2/src/test/java/com/baeldung/checksums/ChecksumUtilsUnitTest.java b/core-java-modules/core-java-security-2/src/test/java/com/baeldung/checksums/ChecksumUtilsUnitTest.java new file mode 100644 index 0000000000..f5366917f6 --- /dev/null +++ b/core-java-modules/core-java-security-2/src/test/java/com/baeldung/checksums/ChecksumUtilsUnitTest.java @@ -0,0 +1,51 @@ +package com.baeldung.checksums; + + +import org.junit.Before; +import org.junit.Test; + +import java.io.ByteArrayInputStream; +import java.io.IOException; +import java.io.InputStream; + +import static org.junit.jupiter.api.Assertions.*; + +class ChecksumUtilsUnitTest { + + byte[] arr; + + @Before + void setUp() { + arr = new byte[]{0,10,21,20,35,40,120,56,72,22}; + } + + @Test + void givenByteArray_whenChecksumCreated_checkCorrect() { + + long checksum = ChecksumUtils.getChecksumCRC32(arr); + + assertEquals(3915397664L, checksum); + } + + @Test + void givenTwoDifferentStrings_whenChecksumCreated_checkCollision() { + + String plumless = "plumless"; + String buckeroo = "buckeroo"; + + long plumlessChecksum = ChecksumUtils.getChecksumCRC32(plumless.getBytes()); + long buckerooChecksum = ChecksumUtils.getChecksumCRC32(buckeroo.getBytes()); + + assertEquals(plumlessChecksum, buckerooChecksum); + } + + @Test + void givenInputString_whenChecksumCreated_checkCorrect() throws IOException { + + InputStream inputStream = new ByteArrayInputStream(arr); + long checksum = ChecksumUtils.getChecksumCRC32(inputStream, 10); + + assertEquals(3915397664L, checksum); + + } +} \ No newline at end of file