Hamming distance calculation

HammingDistance.cpp

typedef unsigned long int   hash_t; 
 
#include <iostream>
#include <bitset>
 #include <iostream>
#include <bitset>
#include <climits>
#include "HashDistance.h"

int popcnt(const hash_t& val) noexcept
{
    int ret;
    __asm__ ("popcnt %1, %1" : "=r" (ret) : "0" (val));
    return ret;
}

constexpr  size_t hashsize()
{
    return CHAR_BIT * sizeof(hash_t);
}

int HashDistance::distance(const hash_t &x, const hash_t &y) const
{
    auto z = x ^ y;
    auto p = popcnt(z);

    if(debug)
    {
        std::cout<<"size  : " << std::dec << hashsize() << std::endl;
        std::cout<<"x val : " << std::bitset<hashsize()>(x) << std::endl;
        std::cout<<"y val : " << std::bitset<hashsize()>(y) << std::endl;
        std::cout<<"z val : " << std::bitset<hashsize()>(z) << std::endl;
        std::cout<<"pop   : " << p << std::endl;
    }

    return p;
}