How to Extract Individual Bits from a Byte in Go?

Getting Bits from Bytes in Go

To extract the individual bits from a byte in Go, there are several approaches to consider.

Visual Representation:

For a visual representation of the bits, you can use fmt.Sprintf("b", ...) to print the byte in binary format.

Bitwise Operations:

However, if you need to use the bits for operations like calculating the Hamming distance, you'll need to use bitwise operators.

To retrieve the nth bit of a byte, bitwise AND the byte with a mask that has the nth bit set to 1 and the rest to 0 (i.e., a power of 2). For instance, to find the 1st bit of the byte 13 (00001101), mask it with 1 (00000001). If the result of the bitwise AND is equal to the mask, the nth bit is 1.

Example Code:

<code class="go">fmt.Print(13 & 1) // Output: 1 (1st bit)
fmt.Print(13 & 2) // Output: 0 (2nd bit)
fmt.Print(13 & 4) // Output: 4 (3rd bit)
fmt.Print(13 & 8) // Output: 8 (4th bit)</code>

Hamming Distance Calculation:

To calculate the Hamming distance between two bytes, use the bitwise AND operation to compare the corresponding bits. If the resulting bit is 1, it indicates that the bits are different, and you increment the distance count.

<code class="go">diff := 0
mask := byte(1 << uint(j))
if (b1 & mask) != (b2 & mask) {
    diff++
}</code>

Function for Hamming Distance:

Here's an example function for calculating the Hamming distance between two arrays of bytes:

<code class="go">func hamming(a, b []byte) (int, error) {
    ...
    for j := 0; j < 8; j++ {
        mask := byte(1 << uint(j))
        if (b1 & mask) != (b2 & mask) {
            diff++
        }
    }
    ...
}</code>

This function compares the bits of corresponding bytes in the arrays and increments the distance count for each dissimilar bit.

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