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BAEL-4286 How to get the value of a bit at a certain position from a byte

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515882294 2021-11-02 16:09:03 +08:00
parent 664819a5a1
commit ba638cb58a
2 changed files with 124 additions and 0 deletions
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5
core-java-modules/core-java-lang-operators-2/pom.xml
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@ -15,6 +15,11 @@
</parent>
<dependencies>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>${commons-lang3.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>

119
core-java-modules/core-java-lang-operators-2/src/test/java/com/baeldung/oroperators/GetABitFromIntegralValueUnitTest.java Normal file
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@ -0,0 +1,119 @@
package com.baeldung.oroperators;
import org.apache.commons.lang3.BitField;
import org.junit.Test;
import java.math.BigInteger;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
public class GetABitFromIntegralValueUnitTest {
@Test
public void givenAByte_whenUsingAHardCodedMask_thenGetBitValue() {
byte val1 = 0b0110_0100;
byte val2 = 0b0110_0010;
byte mask = 0b0000_0100;
boolean isSet1 = (val1 & mask) > 0;
boolean isSet2 = (val2 & mask) > 0;
assertTrue(isSet1);
assertFalse(isSet2);
}
@Test
public void givenAnIntValue_whenUsingACalculatedMask_thenGetBitValue() {
int val = 0b0110_0100;
int pos = 2;
int mask = 1 << pos;
boolean isSet = (val & mask) > 0;
assertTrue(isSet);
}
@Test
public void givenAnIntValue_whenUsingMultiPos_thenGetSameResult() {
int val = 0b0110_0100;
for (int i = 6; i < Integer.SIZE; i++) {
int pos = 1 << i | 2;
int mask = 1 << pos;
boolean isSet = (val & mask) > 0;
assertTrue(isSet);
}
}
@Test
public void givenALongValue_whenUsingACalculatedMask_thenGetBitValue() {
long val = 0b0110_0100;
int pos = 2;
long mask = 1L << pos;
boolean isSet = (val & mask) > 0;
assertTrue(isSet);
}
@Test
public void givenAnIntValue_whenUsingALeftShiftedValue_thenGetBitValue() {
int val = 0b0110_0100;
int pos = 2;
boolean isSet = ((val << ~pos) < 0);
assertTrue(isSet);
}
@Test
public void givenALongValue_whenUsingALeftShiftedValue_thenGetBitValue() {
long val = 0b0110_0100;
int pos = 2;
boolean isSet = ((val << ~pos) < 0);
assertTrue(isSet);
}
@Test
public void givenAnIntValue_whenUsingARightShiftedValue_thenGetBitValue() {
int val = 0b0110_0100;
int pos = 2;
boolean isSet = ((val >> pos) & 1) == 1;
assertTrue(isSet);
}
@Test
public void givenALongValue_whenUsingARightShiftedValue_thenGetBitValue() {
long val = 0b0110_0100;
int pos = 2;
boolean isSet = ((val >> pos) & 1) == 1;
assertTrue(isSet);
}
@Test
public void givenAnIntValue_whenUsingBigInteger_thenGetBitValue() {
int val = 0b0110_0100;
int pos = 2;
boolean isSet = BigInteger.valueOf(val).testBit(pos);
assertTrue(isSet);
}
@Test
public void givenALongValue_whenUsingBigInteger_thenGetBitValue() {
long val = 0b0110_0100;
int pos = 2;
boolean isSet = BigInteger.valueOf(val).testBit(pos);
assertTrue(isSet);
}
@Test
public void givenAnIntValue_whenUsingCommonsLang_thenGetBitValue() {
int val = 0b0110_0100;
int mask = 0b0000_1100;
BitField bitField = new BitField(mask);
boolean isSet = bitField.isSet(val);
assertTrue(isSet);
}
}