source: routing/net.h @ f0b96ba

#ifndef NET_H
#define NET_H

#include <cstdlib>
#include <iostream>
#include <string>

class Net {
    // A network. It has a mask and an address.  The mask is the mask size in
    // consecutive bits: net= 10.0.0.0 mask =8 means 0xa000000000 network and
    // 0xff000000 mask.  Masked bits are always 0 in net.
    protected:
        int net;    // Network 
        int mask;   // Mask
        // Clear the net to the mask.
        void normalize() { net &= 0xffffffff & (0xffffffff << (32 - mask)); }
    public:
        Net(const Net& n) : net(n.net), mask(n.mask) { normalize(); }
        // m is the number of consecutive 1 bits in the mask.
        Net(int n, int m) : net(n), mask(m) { normalize(); }

        // Parse a string of the form n.n.n.n/m
        Net(const std::string& s) : net(0), mask(0) {
            std::string::size_type mi = s.find("/");

            if ( mi != std::string::npos ) mask = atoi(s.substr(mi+1).c_str());
            else mask = 32;

            std::string::size_type p = 0;
            for (int i = 24; i >= 0; i -= 8 ) {
                int x = atoi(s.substr(p).c_str());
                net |= (x) << i;
                
                if ( (p = s.find(".", p)) != std::string::npos) p++;
            }
            normalize();
        }

        // Accessors
        int get_net() const { return net; }
        void set_net(int n) { net = n; normalize(); }
        int get_mask() const { return mask; }
        void set_mask(int m) { mask = m; normalize(); }

        // Output in n.n.n.n/m format.
        std::ostream& print(std::ostream& f) const {
            f << ( (net & 0xff000000) >> 24) << ".";
            f << ( (net & 0x00ff0000) >> 16) << ".";
            f << ( (net & 0x0000ff00) >>  8) << ".";
            f << ( (net & 0x000000ff));
            f << "/" << mask;
            return f;
        }

        // True if the given net is inside this net using this net's mask
        bool inside(const Net& n) const {
            Net tn = Net(net, n.mask);
            return (tn.net ^ n.net) == 0;
        }

        // Standard operators
        bool operator==(const Net& n) const {
            return net == n.net && mask == n.mask;
        }

        bool operator<(const Net& n) const {
            return mask < n.mask || ( (mask == n.mask) && (net < n.net));
        }
};

// Convenient << defintion for output
inline std::ostream& operator<<(std::ostream& f, const Net& n) {
    return n.print(f);
}

// A Net specialized to have a 32 bit mask and print without the /
class Host : public Net {
    public:
        Host(const Host& h) : Net(h) { }
        Host(int h) : Net(h, 32) { }
        Host(const std::string& s) : Net(s) { }

        std::ostream& print(std::ostream& f) const {
            f << ( (net & 0xff000000) >> 24) << ".";
            f << ( (net & 0x00ff0000) >> 16) << ".";
            f << ( (net & 0x0000ff00) >>  8) << ".";
            f << ( (net & 0x000000ff));
            return f;
        }
};

// Convenient << defintion for output
inline std::ostream& operator<<(std::ostream& f, const Host& n) { 
    return n.print(f);
}

#endif