Is there a way to convert a byte to a boolean array in java?

Question

I am trying to write a TCP server/client program that transmits a stream of 4 bytes. Once the client receives the 4 bytes, I would then like to convert each received byte into a boolean[8]. Is there a way to do this? I can successfully transmit the 4 bytes from server to client, and the value of each byte received by the client matches the one transmitted to the server. I have pinpointed the error in the conversion method I wrote on the client side which is pasted below, I can post more code upon request if required.

SAMPLE INPUT======(-2 11111110) (-10 11110110) (-2 11111110) (-2 11111110)

ACTUAL OUTPUT====(-2 11111110) (-10 11110110) (-2 11111110) (-2 11111110)

EXPECTED OUTPUT==(-2 11111110) (-10 11110110) (-2 11111110) (-2 11111110) [Same as input]

public static boolean[] byteToBoolArr(byte x) {
    boolean[] boolArr = new boolean[8];
    boolArr[0] = ((x & 0x01) != 0);
    boolArr[1] = ((x & 0x02) != 0);
    boolArr[2] = ((x & 0x04) != 0);
    boolArr[3] = ((x & 0x08) != 0);

    boolArr[4] = ((x & 0x16) != 0);
    boolArr[5] = ((x & 0x32) != 0);
    boolArr[6] = ((x & 0x64) != 0);
    boolArr[7] = ((x & 0x128) != 0);
    return boolArr;
}

In future, it would be useful if you provided sample input, expected output and actual output. — Jon Skeet
– Jon Skeet, Commented Feb 19, 2014 at 22:33
@JonSkeet thank you for the tip, I will edit my question now and remember to supply this in the future. — trawww
– trawww, Commented Feb 19, 2014 at 22:45

rgettman · Accepted Answer · 2014-02-19 22:33:05Z

7

You are specifying hexadecimal values with 0x, but then you go ahead and use the decimal numbers anyway. 0x08 happens to be 8, but 0x16 is not 16. Try

boolArr[4] = ((x & 0x10) != 0);
boolArr[5] = ((x & 0x20) != 0);
boolArr[6] = ((x & 0x40) != 0);
boolArr[7] = ((x & 0x80) != 0);

answered Feb 19, 2014 at 22:33

rgettman

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Comments

jlxip · Accepted Answer · 2017-07-02 20:40:58Z

2

Actually, there's a much beautiful way to do it.

public static boolean[] byteToBoolArr(byte b) {
    boolean boolArr[] = new boolean[8];
    for(int i=0;i<8;i++) boolArr[i] = (b & (byte)(128 / Math.pow(2, i))) != 0;
    return boolArr;
}

edited Jul 2, 2017 at 20:40

answered Jul 2, 2017 at 20:09

jlxip

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