/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file is part of zmqpp.
 * Copyright (c) 2011-2015 Contributors as noted in the AUTHORS file.
 */

/**
 * \file
 *
 * \date   10 Aug 2011
 * \author Ben Gray (\@benjamg)
 */

#ifndef ZMQPP_INET_HPP_
#define ZMQPP_INET_HPP_

#include <utility>
#include <cassert>
#include <cstdint>

/** \todo cross-platform version of including headers. */
// We get htons and htonl from here
#ifdef _WIN32
#include <WinSock2.h>
#else
#include <netinet/in.h>
#endif

#include "compatibility.hpp"

namespace zmqpp
{

/*!
 * \brief Possible byte order types.
 *
 * An enumeration of all the known order types, all two of them.
 * There is also an entry for unknown which is just used as a default.
 */
ZMQPP_COMPARABLE_ENUM order {
	big_endian,   /*!< byte order is big endian */
	little_endian /*!< byte order is little endian */
};

/*!
 * Common code for the 64bit versions of htons/htons and ntohs/ntohl
 *
 * As htons and ntohs (or htonl and ntohs) always just do the same thing, ie
 * swap bytes if the host order differs from network order or otherwise don't
 * do anything, it seemed silly to type the code twice.
 *
 * \note This code assumes network order is always big endian. Which it is.
 * \note The host endian is only checked once and afterwards assumed to remain
 *       the same.
 *
 * \param value_to_check unsigned 64 bit integer to swap
 * \return swapped (or not) unsigned 64 bit integer
 */
inline uint64_t swap_if_needed(uint64_t const value_to_check)
{
	static order host_order = (htonl(42) == 42) ? order::big_endian : order::little_endian;

	if (order::big_endian == host_order)
	{
		return value_to_check;
	}

	union {
		uint64_t integer;
		uint8_t bytes[8];
	} value { value_to_check };

	std::swap(value.bytes[0], value.bytes[7]);
	std::swap(value.bytes[1], value.bytes[6]);
	std::swap(value.bytes[2], value.bytes[5]);
	std::swap(value.bytes[3], value.bytes[4]);

	return value.integer;
}

/*!
 * 64 bit version of the htons/htonl
 *
 * I've used the name htonll to try and keep with the htonl naming scheme.
 * We do not define this function if the macro `htonll` exists.
 *
 * \param hostlonglong unsigned 64 bit host order integer
 * \return unsigned 64 bit network order integer
 */
#ifndef htonll
inline uint64_t htonll(uint64_t const hostlonglong)
{
	return zmqpp::swap_if_needed(hostlonglong);
}
#endif

/*!
 * 64 bit version of the ntohs/ntohl
 *
 * I've used the name htonll to try and keep with the htonl naming scheme.
 * We do not define this function if the macro `ntohll` exists.
 *
 * \param networklonglong unsigned 64 bit network order integer
 * \return unsigned 64 bit host order integer
 */
#ifndef ntohll
inline uint64_t ntohll(uint64_t const networklonglong)
{
	return zmqpp::swap_if_needed(networklonglong);
}
#endif

/*!
 * floating point version of the htons/htonl
 *
 * \param value host order floating point
 * \returns network order floating point
 */
inline float htonf(float value)
{
	assert(sizeof(float) == sizeof(uint32_t));

	uint32_t temp;
	memcpy(&temp, &value, sizeof(uint32_t));
	temp = htonl( temp );
	memcpy(&value, &temp, sizeof(uint32_t));

	return value;
}

/*!
 * floating point version of the ntohs/ntohl
 *
 * \param value network order float
 * \returns host order float
 */
inline float ntohf(float value)
{
	assert(sizeof(float) == sizeof(uint32_t));

	uint32_t temp;
	memcpy(&temp, &value, sizeof(uint32_t));
	temp = ntohl( temp );
	memcpy(&value, &temp, sizeof(uint32_t));

	return value;
}

/*!
 * double precision floating point version of the htons/htonl
 *
 * \param value host order double precision floating point
 * \returns network order double precision floating point
 */
inline double htond(double value)
{
	assert(sizeof(double) == sizeof(uint64_t));

	uint64_t temp;
	memcpy(&temp, &value, sizeof(uint64_t));
	temp = htonll(temp);
	memcpy(&value, &temp, sizeof(uint64_t));

	return value;
}

/*!
 * double precision floating point version of the ntohs/ntohl
 *
 * \param value network order double precision floating point
 * \returns host order double precision floating point
 */
inline double ntohd(double value)
{
	assert(sizeof(double) == sizeof(uint64_t));

	uint64_t temp;
	memcpy(&temp, &value, sizeof(uint64_t));
	temp = ntohll(temp);
	memcpy(&value, &temp, sizeof(uint64_t));

	return value;
}

}

#endif /* INET_HPP_ */