/*
 * Copyright (c) 2007 INRIA
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
 */

#ifndef ADDRESS_H
#define ADDRESS_H

#include "tag-buffer.h"

#include "ns3/attribute-helper.h"
#include "ns3/attribute.h"

#include <ostream>
#include <stdint.h>

namespace ns3
{

/**
 * \ingroup network
 * \defgroup address Address
 *
 * Network Address abstractions, including MAC, IPv4 and IPv6.
 */
/**
 * \ingroup address
 * \brief a polymophic address class
 *
 * This class is very similar in design and spirit to the BSD sockaddr
 * structure: they are both used to hold multiple types of addresses
 * together with the type of the address.
 *
 * A new address class defined by a user needs to:
 *   - allocate a type id with Address::Register
 *   - provide a method to convert his new address to an Address
 *     instance. This method is typically a member method named ConvertTo:
 *     Address MyAddress::ConvertTo () const;
 *   - provide a method to convert an Address instance back to
 *     an instance of his new address type. This method is typically
 *     a static member method of his address class named ConvertFrom:
 *     static MyAddress MyAddress::ConvertFrom (const Address &address);
 *   - the ConvertFrom method is expected to check that the type of the
 *     input Address instance is compatible with its own type.
 *
 * Typical code to create a new class type looks like:
 * \code
 * // this class represents addresses which are 2 bytes long.
 * class MyAddress
 * {
 * public:
 *   Address ConvertTo () const;
 *   static MyAddress ConvertFrom ();
 * private:
 *   static uint8_t GetType ();
 * };
 *
 * Address MyAddress::ConvertTo () const
 * {
 *   return Address (GetType (), m_buffer, 2);
 * }
 * MyAddress MyAddress::ConvertFrom (const Address &address)
 * {
 *   MyAddress ad;
 *   NS_ASSERT (address.CheckCompatible (GetType (), 2));
 *   address.CopyTo (ad.m_buffer, 2);
 *   return ad;
 * }
 * uint8_t MyAddress::GetType ()
 * {
 *   static uint8_t type = Address::Register ();
 *   return type;
 * }
 * \endcode
 *
 * To convert a specific Address T (e.g., Ipv6Address) to and from an Address type,
 * a class must implement three public functions:
 * \code
 * static T ConvertFrom(const Address& address);
 * Address ConvertTo() const;
 * operator Address() const;
 * \endcode
 *
 * \see attribute_Address
 */
class Address
{
  public:
    /**
     * The maximum size of a byte buffer which
     * can be stored in an Address instance.
     */
    static constexpr uint32_t MAX_SIZE{20};

    /**
     * Create an invalid address
     */
    Address();
    /**
     * \brief Create an address from a type and a buffer.
     *
     * This constructor is typically invoked from the conversion
     * functions of various address types when they have to
     * convert themselves to an Address instance.
     *
     * \param type the type of the Address to create
     * \param buffer a pointer to a buffer of bytes which hold
     *        a serialized representation of the address in network
     *        byte order.
     * \param len the length of the buffer.
     */
    Address(uint8_t type, const uint8_t* buffer, uint8_t len);
    /**
     * \brief Create an address from another address.
     * \param address the address to copy
     */
    Address(const Address& address);
    /**
     * \brief Basic assignment operator.
     * \param address the address to copy
     * \returns the address
     */
    Address& operator=(const Address& address);

    /**
     * \returns true if this address is invalid, false otherwise.
     *
     * An address is invalid if and only if it was created
     * through the default constructor and it was never
     * re-initialized.
     */
    bool IsInvalid() const;
    /**
     * \brief Get the length of the underlying address.
     * \returns the length of the underlying address.
     */
    uint8_t GetLength() const;
    /**
     * \brief Copy the address bytes into a buffer.
     * \param buffer buffer to copy the address bytes to.
     * \returns the number of bytes copied.
     */
    uint32_t CopyTo(uint8_t buffer[MAX_SIZE]) const;
    /**
     * \param buffer buffer to copy the whole address data structure to
     * \param len the size of the buffer
     * \returns the number of bytes copied.
     *
     * Copies the type to buffer[0], the length of the address internal buffer
     * to buffer[1] and copies the internal buffer starting at buffer[2].  len
     * must be at least the size of the internal buffer plus a byte for the type
     * and a byte for the length.
     */
    uint32_t CopyAllTo(uint8_t* buffer, uint8_t len) const;
    /**
     * \param buffer pointer to a buffer of bytes which contain
     *        a serialized representation of the address in network
     *        byte order.
     * \param len length of buffer
     * \returns the number of bytes copied.
     *
     * Copy the address bytes from buffer into to the internal buffer of this
     * address instance.
     */
    uint32_t CopyFrom(const uint8_t* buffer, uint8_t len);
    /**
     * \param buffer pointer to a buffer of bytes which contain
     *        a copy of all the members of this Address class.
     * \param len the length of the buffer
     * \returns the number of bytes copied.
     *
     * The inverse of CopyAllTo().
     *
     * \see CopyAllTo
     */
    uint32_t CopyAllFrom(const uint8_t* buffer, uint8_t len);
    /**
     * \param type a type id as returned by Address::Register
     * \param len the length associated to this type id.
     *
     * \returns true if the type of the address stored internally
     * is compatible with the requested type, false otherwise.
     */
    bool CheckCompatible(uint8_t type, uint8_t len) const;
    /**
     * \param type a type id as returned by Address::Register
     * \returns true if the type of the address stored internally
     * is compatible with the requested type, false otherwise.
     *
     * This method checks that the types are _exactly_ equal.
     * This method is really used only by the PacketSocketAddress
     * and there is little point in using it otherwise so,
     * you have been warned: DO NOT USE THIS METHOD.
     */
    bool IsMatchingType(uint8_t type) const;
    /**
     * Allocate a new type id for a new type of address.
     * \returns a new type id.
     */
    static uint8_t Register();
    /**
     * Get the number of bytes needed to serialize the underlying Address
     * Typically, this is GetLength () + 2
     *
     * \returns the number of bytes required for an Address in serialized form
     */
    uint32_t GetSerializedSize() const;
    /**
     * Serialize this address in host byte order to a byte buffer
     *
     * \param buffer output buffer that gets written with this Address
     */
    void Serialize(TagBuffer buffer) const;
    /**
     * \param buffer buffer to read address from
     *
     * The input address buffer is expected to be in host byte order format.
     */
    void Deserialize(TagBuffer buffer);

  private:
    /**
     * \brief Equal to operator.
     *
     * \param a the first operand
     * \param b the first operand
     * \returns true if the operands are equal
     */
    friend bool operator==(const Address& a, const Address& b);

    /**
     * \brief Not equal to operator.
     *
     * \param a the first operand
     * \param b the first operand
     * \returns true if the operands are not equal
     */
    friend bool operator!=(const Address& a, const Address& b);

    /**
     * \brief Less than operator.
     *
     * \param a the first operand
     * \param b the first operand
     * \returns true if the operand a is less than operand b
     */
    friend bool operator<(const Address& a, const Address& b);

    /**
     * \brief Stream insertion operator.
     *
     * \param os the stream
     * \param address the address
     * \returns a reference to the stream
     */
    friend std::ostream& operator<<(std::ostream& os, const Address& address);

    /**
     * \brief Stream extraction operator.
     *
     * \param is the stream
     * \param address the address
     * \returns a reference to the stream
     */
    friend std::istream& operator>>(std::istream& is, Address& address);

    uint8_t m_type;           //!< Type of the address
    uint8_t m_len;            //!< Length of the address
    uint8_t m_data[MAX_SIZE]; //!< The address value
};

ATTRIBUTE_HELPER_HEADER(Address);

bool operator==(const Address& a, const Address& b);
bool operator!=(const Address& a, const Address& b);
bool operator<(const Address& a, const Address& b);
std::ostream& operator<<(std::ostream& os, const Address& address);
std::istream& operator>>(std::istream& is, Address& address);

} // namespace ns3

#endif /* ADDRESS_H */
