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!1129 ByteUtil

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Merge pull request !1129 from Faker/v6-dev
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Looly 2023-12-12 11:21:38 +00:00 committed by Gitee
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38
hutool-core/src/main/java/org/dromara/hutool/core/util/ByteUtil.java
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@ -14,11 +14,14 @@ package org.dromara.hutool.core.util;
import org.dromara.hutool.core.io.buffer.FastByteBuffer;
import org.dromara.hutool.core.math.NumberUtil;
import org.dromara.hutool.core.text.StrUtil;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.DoubleAdder;
@ -629,4 +632,39 @@ public class ByteUtil {
}
return buffer.toArrayZeroCopyIfPossible();
}
/**
* 统计byte中位数为1的个数
*
* @param buf 无符号bytes
* @return 为 1 的个数
*/
public static int bitCount(final byte[] buf) {
int sum = 0;
for (byte b : buf) {
sum += Integer.bitCount((b & 0xFF));
}
return sum;
}
/**
* 统计无符号bytes转为bit位数为1的索引集合
*
* @param bytes 无符号bytes
* @return 位数为1的索引集合
*/
public static List<Integer> toUnsignedBitIndex(final byte[] bytes) {
List<Integer> idxList = new LinkedList<>();
StringBuilder sb = new StringBuilder();
for (byte b : bytes) {
sb.append(StrUtil.padPre(Integer.toBinaryString((b & 0xFF)), 8, "0"));
}
final String bitStr = sb.toString();
for (int i = 0; i < bitStr.length(); i++) {
if (bitStr.charAt(i) == '1') {
idxList.add(i);
}
}
return idxList;
}
}

17
hutool-core/src/test/java/org/dromara/hutool/core/util/ByteUtilTest.java
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@ -12,11 +12,13 @@
package org.dromara.hutool.core.util;
import org.dromara.hutool.core.lang.Console;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.List;
public class ByteUtilTest {
@Test
@ -191,4 +193,19 @@ public class ByteUtilTest {
aShort = wrap.getShort();
Assertions.assertEquals(a, aShort);
}
@Test
public void toUnsignedBitIndex() {
byte[] bytes = {0, 13, -64, -31, 101, 88, 47, -64};
List<Integer> list = ByteUtil.toUnsignedBitIndex(bytes);
Console.log(list);
}
@Test
public void bitCount() {
byte[] bytes = {0, 13, -64, -31, 101, 88, 47, -64};
int count = ByteUtil.bitCount(bytes);
Console.log(count);
Assertions.assertEquals(count, ByteUtil.toUnsignedBitIndex(bytes).size());
}
}