java byte 循环左移 循环右移 rotateLeft rotateRight

java byte 循环左移 循环右移 rotateLeft rotateRight

1.概念。

　　循环左移：

　　　　eg1：byte in = (byte) 0x01;【0000 0001】则循环左移2位后变为【0000 0100】

　　　　eg2: btye in = (byte)0x90;[1001 0000],则循环左移2位变为[0100 0010]

　　循环右移：

　　　　eg3：byte in = (byte)0x01;[0000 0001]则循环右移2位后变为[0100 0000]

　　　　eg4：byte in = (byte)0x90;[1001 0000]则循环右移2位后变为[0010 0100]

2.示例。

public class DataConvertUtil {
    /**
     * 循环左移
     * @param sourceByte 待左移动的值
     * @param n 左移动的为数
     * @return
     */
    public static byte rotateLeft(byte sourceByte, int n) {
        // 去除高位的1
        int temp = sourceByte & 0xFF;
        return (byte) ((temp << n) | (temp >>> (8 - n)));
    }
    /**
     * 循环右移
     * @param sourceByte
     * @param n
     * @return
     */
    public static byte rotateRight(byte sourceByte, int n) {
        // 去除高位的1
        int temp = sourceByte & 0xFF;
        return (byte) ((temp >>> n) | (temp << (8 - n)));
    }
    /**
     * 循环左移
     * @param sourceBytes
     * @param n
     * @return
     */
    public static byte[] rotateLeft(byte[] sourceBytes, int n) {
        byte[] out = new byte[sourceBytes.length];
        for (int i = 0; i < sourceBytes.length; i++) {
            out[i] = rotateLeft(sourceBytes[i], n);
        }
        return out;
    }
    
    public static byte[] rotateRight(byte[] sourceBytes, int n) {
        byte[] out = new byte[sourceBytes.length];
        for (int i = 0; i < sourceBytes.length; i++) {
            out[i] = rotateRight(sourceBytes[i], n);
        }
        return out;
    }
}

3.一个简单的测试类

import static org.junit.Assert.*;

import org.junit.Test;

public class DataConvertUtilTest {

    @Test
    public void test() {
        System.out.println("originByte" 
                + "|" + "BinaryOrig"
                + "|" + "outByte"
                + "|" + "BinaryOut"
                + "|" + "outLength");
        byte[] sourceBytes = new byte[]{(byte)(0x01),(byte)(0x03),5,(byte)(0x07),(byte)(0x0f)
                ,(byte)(0x1f),(byte)(0x3F),(byte)(0x7F),(byte)(0xFF),(byte)(0xF0),(byte)(0xC0)
                };
        byte[] out = DataConvertUtil.rotateRight(sourceBytes, 2);
        for (int i = 0; i < out.length; i++) {
            System.out.println("rright"
                    + "|" + sourceBytes[i] 
                    + "|" + Integer.toBinaryString(sourceBytes[i])
                    + "|" + Byte.toString(out[i])
                    + "|" + Integer.toBinaryString(out[i])
                    + "|" + Integer.toBinaryString(out[i]).length()
                    + "|" + Integer.toBinaryString(out[i]).indexOf('0'));
        }
        System.out.println();
        out = DataConvertUtil.rotateLeft(sourceBytes, 2);
        for (int i = 0; i < out.length; i++) {
            System.out.println("rleft"
                    + "|" + sourceBytes[i] 
                    + "|" + Integer.toBinaryString(sourceBytes[i])
                    + "|" + Byte.toString(out[i])
                    + "|" + Integer.toBinaryString(out[i])
                    + "|" + Integer.toBinaryString(out[i]).length()
                    + "|" + Integer.toBinaryString(out[i]).indexOf('0'));
        }
    }

}