Ttykuu

I've recently picked up a book that gives various "modern" C++ challenges/solutions. One of the first ones I did was on modeling an IPv4 address in C++. Below is the full implementation; it's also on Github. Any suggestions? My goal is to make this as modern as possible and I'm not sure if there are some C++17 features I'm not taking advantage of.

ip_address.h

#pragma once

#include <array>
#include <string>
#include <string_view>
#include <stdint.h>

namespace ip

 /**
 * @brief Thrown when there is an invalid ip address passed via
 * string.
 */
 class invalid_format_exception : public std::exception
 
 std::string invalid_format_;
 public:
 invalid_format_exception(const std::string &invalid_format);
 char const* what() const override;
 ;

 /**
 * Class that models a IPv4 address. 
 */
 class address
 
 public:

#pragma region Type definitions
 using value_type = uint8_t;
 using reference = value_type & ;
 using pointer = value_type * ;
 using iterator = std::array<value_type, 4>::iterator;
 using const_iterator = std::array<value_type, 4>::const_iterator;
 using reverse_iterator = std::array<value_type, 4>::reverse_iterator;
 using const_reverse_iterator = std::array<value_type, 4>::const_reverse_iterator;
 using size_type = std::array<value_type, 4>::size_type;
#pragma endregion

 /**
 * @brief Create an IP address representation from the 
 * four parts of the address definition. 
 * @param first the first part of the address 
 * @param second the second part of the address
 * @param third the third part of the address.
 * @param fourth the fourth part of the address.
 * @details Example:
 * @code
 * ip::address addr(127, 0, 0, 1);
 * @endcode
 */
 address(const value_type& first, const value_type &second,
 const value_type &third, const value_type& fourth);

 /**
 * @brief Create an IP address representaiton from an
 * array.
 * @param data the data array. 
 * @details Example:
 * @code
 * ip::address addr = 127, 0, 0, 1;
 * @endcode
 */
 address(const std::array<unsigned char, 4> &data);

 /**
 * @brief Create an IP adderss representation from a 
 * unsigned 32 bit integer.
 * @param value the integer representation of an IP address.
 */
 explicit address(const uint32_t &value);

 /**
 * @brief Implicit conversion to an unsigned 32 bit integer.
 */
 uint32_t operator()() const;

 /**
 * @brief Access operator.
 * @param index the index to access. 
 */
 reference operator[](const int &index) noexcept(false);

 /**
 * @brief Const version of the access operator.
 */
 value_type operator[](const int &index) const noexcept(false);

 /**
 * @brief Prefix increment operator.
 */
 void operator++();

 /**
 * @brief Postfix increment operator.
 */
 ::ip::address& operator++(int);

 /**
 * @brief Prefix decrement operator.
 */
 void operator--();

 /**
 * @brief Prefix decrement operator.
 */
 ::ip::address& operator--(int);

 iterator begin();
 iterator end();
 const_iterator begin() const;
 const_iterator end() const;
 private:
 std::array<value_type, 4> data_;
 ;

 bool operator<(const ip::address &first, const ip::address &second);
 bool operator==(const ip::address &first, const ip::address &second);
 std::ostream& operator<<(std::ostream& output, const ip::address &address);
 address from_string(const std::string &view);
 std::string to_string(const address& address);

ip_address.cpp

#include <ip_address.h>

#include <iterator>
#include <iostream>
#include <sstream>
#include <regex>
#include <vector>
#include <string>

#pragma region Utilities
template<typename Output>
void split(const std::string &s, char delim, Output result) 
 std::stringstream ss(s);
 std::string item;
 while (std::getline(ss, item, delim)) 
 *(result++) = item;
 


std::vector<std::string> split(const std::string &s, char delim) 
 std::vector<std::string> elems;
 split(s, delim, std::back_inserter(elems));
 return elems;


#pragma endregion

ip::invalid_format_exception::invalid_format_exception(const std::string& invalid_format)
 : invalid_format_(invalid_format)



char const* ip::invalid_format_exception::what() const

 std::ostringstream oss;
 oss << "Invalid IP address format: " << invalid_format_;
 return oss.str().c_str();


ip::address::address(const value_type & first, const value_type & second, const value_type & third, const value_type & fourth)

 data_[0] = first;
 data_[1] = second;
 data_[2] = third;
 data_[3] = fourth;


ip::address::address(const std::array<unsigned char, 4>& data)

 data_ = data;


ip::address::address(const uint32_t& value)

 data_[0] = value >> 24 & 0xFF;
 data_[1] = value >> 16 & 0xFF;
 data_[2] = value >> 8 & 0xFF;
 data_[3] = value & 0xFF;


uint32_t ip::address::operator()() const
 data_[2] << 8 

ip::address::reference ip::address::operator[](const int& index)

 return data_.at(index);


ip::address::value_type ip::address::operator[](const int& index) const

 return data_.at(index);


void ip::address::operator++()

 auto location = std::find_if(data_.rbegin(), data_.rend(), [](const unsigned char& data)
 
 return data < 255;
 );

 if(location != std::rend(data_))
 
 const auto r_index = std::distance(data_.rbegin(), location);
 auto index = 4 - r_index - 1;
 data_[index]++;
 


::ip::address& ip::address::operator++(int)

 auto result(*this);
 ++(*this);
 return result;


void ip::address::operator--()

 auto location = std::find_if(data_.rbegin(), data_.rend(), [](const unsigned char& data)
 
 return data < 255;
 );

 if (location != std::rend(data_))
 
 const auto r_index = std::distance(data_.rbegin(), location);
 auto index = 4 - r_index - 1;
 data_[index]--;
 


::ip::address& ip::address::operator--(int)

 auto result(*this);
 --(*this);
 return result;


ip::address::iterator ip::address::begin()

 return data_.begin();


ip::address::const_iterator ip::address::end() const

 return data_.end();


bool ip::operator<(const ip::address& first, const ip::address& second)

 return (uint32_t)first() < (uint32_t)second();


bool ip::operator==(const ip::address& first, const ip::address& second)

 return (uint32_t)first() == (uint32_t) second();


ip::address::const_iterator ip::address::begin() const

 return data_.begin();


ip::address::iterator ip::address::end()

 return data_.end();


std::ostream& ip::operator<<(std::ostream& output, const ip::address& address)

 std::copy(address.begin(), address.end()-1, 
 std::ostream_iterator<short>(output, "."));
 output << +address[3];
 return output;


ip::address ip::from_string(const std::string &view)

 auto parts = split(view, '.');
 if (parts.size() != 4)
 
 throw invalid_format_exception(view);
 

 return 
 (ip::address::value_type)std::stoi(parts[0]),
 (ip::address::value_type)std::stoi(parts[1]),
 (ip::address::value_type)std::stoi(parts[2]),
 (ip::address::value_type)std::stoi(parts[3])
 ;


std::string ip::to_string(const address& address)

 std::ostringstream string_stream;
 string_stream << address;
 return string_stream.str();