How do you extract individual bits from a byte in Golang?

Extracting Bits from a Byte in Golang

Many tasks, such as calculating the Hamming distance between bytes, require access to individual bits within the byte. However, the built-in Golang packages do not provide a direct function for this purpose.

Visual Representation vs. Bitwise Operations

One approach is to use fmt.Sprintf("b", ...) to print a binary representation of the byte, as suggested by several answers online. However, this approach merely provides a visual representation of the bits, making it unsuitable for operations like bitwise comparisons.

Bit Masking for Retrieving Bits

To perform bitwise operations, we can utilize the bitwise AND operator (&) along with masking. For instance, to obtain the n^th bit of a byte (where n starts from 1), we create a mask m where only the n^th bit is set to 1. This mask can be obtained as m = 2**(n-1). By bitwise ANDing the byte with the mask, we can determine if the n^th bit is set:

if (b & m) != 0 {
    // nth bit is set to 1
}

Sample Code

The following code demonstrates the use of bit masking to extract bits from a byte and calculate the Hamming distance:

<code class="go">package main

import "fmt"

func hamming(a, b []byte) (int, error) {
    if len(a) != len(b) {
        return 0, errors.New("a, b are not the same length")
    }

    diff := 0
    for i := 0; i </code>

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