TODO: inv filter vectorized

#include <cstdint>
#include <cstddef>
#include <vector>

int test(size_t old_sz, std::vector<uint8_t> &_selection) {
    for (size_t i = 0; i < old_sz; i++) {
        _selection[i] = 1 - _selection[i];
    }
    return 0;
}