CODEWITHSUNDEEP
c#mathbyteconverters
Robin Simon
Robin Simon

Reputation: 45

return a specific bit as boolean from a byte value

I have a function that convert a Byte to an 8 bit address and returns the bit on the location that is specified in the parameter.

The way it's build now it works fine, but it's pretty ugly in my opinion is there a way to do this with a method in math or something in that direction, I tried looking for another approach but didn't came up with anything.

    private bool ConvertByteToBitAddres(byte byteToConvert, int bitToReturn)
    {
        bool[] address = new bool[8];
        int remaining = byteToConvert;


        if (remaining > 128)
        {
            remaining = remaining - remaining;
            address[7] = true;
        }
        if (remaining > 64 || remaining < 128)
        {
            remaining = remaining - remaining;
            address[6] = true;
        }
        if (remaining > 32)
        {
            remaining = remaining - remaining;
            address[5] = true;
        }
        if (remaining > 16)
        {
            remaining = remaining - remaining;
            address[4] = true;
        }
        if (remaining > 8)
        {
            remaining = remaining - remaining;
            address[3] = true;
        }
        if (remaining > 4)
        {
            remaining = remaining - remaining;
            address[2] = true;
        }
        if (remaining > 2)
        {
            remaining = remaining - remaining;
            address[1] = true;
        }
        if (remaining > 1)
        {
            remaining = remaining - remaining;
            address[0] = true;
        }

        if (remaining == 0)
        {
            return address[bitToReturn];
        }
        throw new Exception();
    }

Thanks in advance.

Upvotes: 3

Views: 2928

Answers (3)

Chris Dunaway
Chris Dunaway

Reputation: 11216

Another option that might be suitable is to use BitVector32:

byte b = 10;
var bv = new BitVector32(b);

for (int i = 0; i < 8; i++)
{
    Console.WriteLine($"Value of bit {i}:  {bv[1 << i]}");
}

//You could also declare consts for each bit and use that:
const int Bit0 = 1;
const int Bit1 = 2;
const int Bit2 = 4;
const int Bit3 = 8;

Console.WriteLine($"\r\nValue of bit 3:  {bv[Bit3]}");

Output:

Value of bit 0:  False
Value of bit 1:  True 
Value of bit 2:  False
Value of bit 3:  True 
Value of bit 4:  False 
Value of bit 5:  False
Value of bit 6:  False 
Value of bit 7:  False

Value of bit 3:  True

Upvotes: 0

Matt Burland
Matt Burland

Reputation: 45135

Use a bitmask.

private bool ConvertByteToBitAddres(byte byteToConvert, int bitToReturn)
{
    int mask = 1 << bitToReturn;
    return (byteToConvert & mask) == mask;
}

Upvotes: 4

Marc Gravell
Marc Gravell

Reputation: 1062600

Use bitwise operations; for example:

int mask = 1 << (bitToReturn - 1); // if "bitToReturn" is 1-based
// int mask = 1 << bitToReturn; // if "bitToReturn" is 0-based
return (byteToConvert & mask) != 0

Perhaps easier, though, is to just pass in the mask rather than bitToReturn.

Upvotes: 3

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