Reverse order of boost::dynamic_bitset

Question

Is there a clean way to return the reverse ordering of a boost::dynamic_bitset object?

For example: 01001100 becomes 00110010. The simplest solution I can think of is to convert the bitset to a string, reverse the string and convert it back to a bitset, but this seems a rather slow method that nullifies the speed of bitstring operations.

Thank you in advance!

Answer 1

boost::dynamic_bitset doesn't have iterators, so a long range of comfy STL solutions like, off the top of my head, std::reverse or std::swap or their boost counterparts are not available, I reckon that a good way would be to make your own trivial reverse method:

#include <iostream>
#include <boost/dynamic_bitset.hpp>

void reverse(boost::dynamic_bitset<> &bs)
{
    for (size_t begin = 0, end = bs.size() - 1; begin < end; begin++, end--)
    {
        bool b = bs[end];
        bs[end] = bs[begin];
        bs[begin] = b;
    }
}

int main()
{
    size_t size = 8;
    boost::dynamic_bitset<> bs(size, 50);

    std::cout << "Normal:  " << bs << std::endl;
    reverse(bs);
    std::cout << "Reverse: " << bs << std::endl;
}

Output:

Normal:  00110010
Reverse: 01001100

Live demo