How to perform bitwise operations on bitsets of different sizes?

Question

Is there a way of performing bitwise operations on two std::bitsets of different sizes?

Something similar to this:

    std::bitset<8> payload { 0b1010'0010 };
    std::bitset<10> segment { 0b00'0000'0000 };
    segment |= payload;

For the above example, I basically want to transfer all the 8 bits of payload to the lower bits of segment. What other options do I have if this cannot be done? Should I write a for loop that uses the subscript operator[] to transfer the bits one by one?

Answer 1

Convert the narrower to the wider one then you can use |=:

#include <iostream>
#include <bitset>

int main() {
    std::bitset<8> payload { 0b1010'0010 };
    std::bitset<10> segment { 0b00'0000'0000 };
    
    std::bitset<10> x(payload.to_ullong());
    segment |= x;
    std::cout << segment;
}

For wider ones you can use to_string and the constructor creating the bitset from a string.