packet-tag-list.h

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/*
 * Copyright (c) 2006 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 PACKET_TAG_LIST_H
#define PACKET_TAG_LIST_H
 
#include "ns3/type-id.h"
 
#include <ostream>
#include <stdint.h>
 
namespace ns3
{
 
class Tag;
 
class PacketTagList
{
  public:
    struct TagData
    {
        TagData* next;   
        uint32_t count;  
        TypeId tid;      
        uint32_t size;   
        uint8_t data[1]; 
    };
 
    inline PacketTagList();
    inline PacketTagList(const PacketTagList& o);
    inline PacketTagList& operator=(const PacketTagList& o);
    inline ~PacketTagList();
 
    void Add(const Tag& tag) const;
    bool Remove(Tag& tag);
    bool Replace(Tag& tag);
    bool Peek(Tag& tag) const;
    inline void RemoveAll();
    const PacketTagList::TagData* Head() const;
    uint32_t GetSerializedSize() const;
    uint32_t Serialize(uint32_t* buffer, uint32_t maxSize) const;
    uint32_t Deserialize(const uint32_t* buffer, uint32_t size);
 
  private:
    static TagData* CreateTagData(size_t dataSize);
 
    typedef bool (PacketTagList::*COWWriter)(Tag& tag,
                                             bool preMerge,
                                             TagData* cur,
                                             TagData** prevNext);
    bool COWTraverse(Tag& tag, PacketTagList::COWWriter Writer);
    bool RemoveWriter(Tag& tag, bool preMerge, TagData* cur, TagData** prevNext);
    bool ReplaceWriter(Tag& tag, bool preMerge, TagData* cur, TagData** prevNext);
 
    TagData* m_next;
};
 
} // namespace ns3
 
/****************************************************
 *  Implementation of inline methods for performance
 ****************************************************/
 
namespace ns3
{
 
PacketTagList::PacketTagList()
    : m_next()
{
}
 
PacketTagList::PacketTagList(const PacketTagList& o)
    : m_next(o.m_next)
{
    if (m_next != nullptr)
    {
        m_next->count++;
    }
}
 
PacketTagList&
PacketTagList::operator=(const PacketTagList& o)
{
    // self assignment
    if (m_next == o.m_next)
    {
        return *this;
    }
    RemoveAll();
    m_next = o.m_next;
    if (m_next != nullptr)
    {
        m_next->count++;
    }
    return *this;
}
 
PacketTagList::~PacketTagList()
{
    RemoveAll();
}
 
void
PacketTagList::RemoveAll()
{
    TagData* prev = nullptr;
    for (TagData* cur = m_next; cur != nullptr; cur = cur->next)
    {
        cur->count--;
        if (cur->count > 0)
        {
            break;
        }
        if (prev != nullptr)
        {
            prev->~TagData();
            std::free(prev);
        }
        prev = cur;
    }
    if (prev != nullptr)
    {
        prev->~TagData();
        std::free(prev);
    }
    m_next = nullptr;
}
 
} // namespace ns3
 
#endif /* PACKET_TAG_LIST_H */