libudt-dev 4.11+dfsg1-1ubuntu1 / usr / include / udt / cache.h

/*****************************************************************************
Copyright (c) 2001 - 2011, The Board of Trustees of the University of Illinois.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the
  above copyright notice, this list of conditions
  and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

* Neither the name of the University of Illinois
  nor the names of its contributors may be used to
  endorse or promote products derived from this
  software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*****************************************************************************/

/*****************************************************************************
written by
   Yunhong Gu, last updated 01/27/2011
*****************************************************************************/

#ifndef __UDT_CACHE_H__
#define __UDT_CACHE_H__

#include <list>
#include <vector>

#include "common.h"
#include "udt.h"

class CCacheItem
{
public:
   virtual ~CCacheItem() {}

public:
   virtual CCacheItem& operator=(const CCacheItem&) = 0;

   // The "==" operator SHOULD only compare key values.
   virtual bool operator==(const CCacheItem&) = 0;

      // Functionality:
      //    get a deep copy clone of the current item
      // Parameters:
      //    None.
      // Returned value:
      //    Pointer to the new item, or NULL if failed.

   virtual CCacheItem* clone() = 0;

      // Functionality:
      //    get a random key value between 0 and MAX_INT to be used for the hash in cache
      // Parameters:
      //    None.
      // Returned value:
      //    A random hash key.

   virtual int getKey() = 0;

   // If there is any shared resources between the cache item and its clone,
   // the shared resource should be released by this function.
   virtual void release() {}
};

template<typename T> class CCache
{
public:
   CCache(int size = 1024):
   m_iMaxSize(size),
   m_iHashSize(size * 3),
   m_iCurrSize(0)
   {
      m_vHashPtr.resize(m_iHashSize);
      CGuard::createMutex(m_Lock);
   }

   ~CCache()
   {
      clear();
      CGuard::releaseMutex(m_Lock);
   }

public:
      // Functionality:
      //    find the matching item in the cache.
      // Parameters:
      //    0) [in/out] data: storage for the retrieved item; initially it must carry the key information
      // Returned value:
      //    0 if found a match, otherwise -1.

   int lookup(T* data)
   {
      CGuard cacheguard(m_Lock);

      int key = data->getKey();
      if (key < 0)
         return -1;
      if (key >= m_iMaxSize)
         key %= m_iHashSize;

      const ItemPtrList& item_list = m_vHashPtr[key];
      for (typename ItemPtrList::const_iterator i = item_list.begin(); i != item_list.end(); ++ i)
      {
         if (*data == ***i)
         {
            // copy the cached info
            *data = ***i;
            return 0;
         }
      }

      return -1;
   }

      // Functionality:
      //    update an item in the cache, or insert one if it doesn't exist; oldest item may be removed
      // Parameters:
      //    0) [in] data: the new item to updated/inserted to the cache
      // Returned value:
      //    0 if success, otherwise -1.

   int update(T* data)
   {
      CGuard cacheguard(m_Lock);

      int key = data->getKey();
      if (key < 0)
         return -1;
      if (key >= m_iMaxSize)
         key %= m_iHashSize;

      T* curr = NULL;

      ItemPtrList& item_list = m_vHashPtr[key];
      for (typename ItemPtrList::iterator i = item_list.begin(); i != item_list.end(); ++ i)
      {
         if (*data == ***i)
         {
            // update the existing entry with the new value
            ***i = *data;
            curr = **i;

            // remove the current entry
            m_StorageList.erase(*i);
            item_list.erase(i);

            // re-insert to the front
            m_StorageList.push_front(curr);
            item_list.push_front(m_StorageList.begin());

            return 0;
         }
      }

      // create new entry and insert to front
      curr = data->clone();
      m_StorageList.push_front(curr);
      item_list.push_front(m_StorageList.begin());

      ++ m_iCurrSize;
      if (m_iCurrSize >= m_iMaxSize)
      {
         // Cache overflow, remove oldest entry.
         T* last_data = m_StorageList.back();
         int last_key = last_data->getKey() % m_iHashSize;

         item_list = m_vHashPtr[last_key];
         for (typename ItemPtrList::iterator i = item_list.begin(); i != item_list.end(); ++ i)
         {
            if (*last_data == ***i)
            {
               item_list.erase(i);
               break;
            }
         }

         last_data->release();
         delete last_data;
         m_StorageList.pop_back();
         -- m_iCurrSize;
      }

      return 0;
   }

      // Functionality:
      //    Specify the cache size (i.e., max number of items).
      // Parameters:
      //    0) [in] size: max cache size.
      // Returned value:
      //    None.

   void setSizeLimit(int size)
   {
      m_iMaxSize = size;
      m_iHashSize = size * 3;
      m_vHashPtr.resize(m_iHashSize);
   }

      // Functionality:
      //    Clear all entries in the cache, restore to initialization state.
      // Parameters:
      //    None.
      // Returned value:
      //    None.

   void clear()
   {
      for (typename std::list<T*>::iterator i = m_StorageList.begin(); i != m_StorageList.end(); ++ i)
      {
         (*i)->release();
         delete *i;
      }
      m_StorageList.clear();
      for (typename std::vector<ItemPtrList>::iterator i = m_vHashPtr.begin(); i != m_vHashPtr.end(); ++ i)
         i->clear();
      m_iCurrSize = 0;
   }

private:
   std::list<T*> m_StorageList;
   typedef typename std::list<T*>::iterator ItemPtr;
   typedef std::list<ItemPtr> ItemPtrList;
   std::vector<ItemPtrList> m_vHashPtr;

   int m_iMaxSize;
   int m_iHashSize;
   int m_iCurrSize;

   pthread_mutex_t m_Lock;

private:
   CCache(const CCache&);
   CCache& operator=(const CCache&);
};


class CInfoBlock
{
public:
   uint32_t m_piIP[4];		// IP address, machine read only, not human readable format
   int m_iIPversion;		// IP version
   uint64_t m_ullTimeStamp;	// last update time
   int m_iRTT;			// RTT
   int m_iBandwidth;		// estimated bandwidth
   int m_iLossRate;		// average loss rate
   int m_iReorderDistance;	// packet reordering distance
   double m_dInterval;		// inter-packet time, congestion control
   double m_dCWnd;		// congestion window size, congestion control

public:
   virtual ~CInfoBlock() {}
   virtual CInfoBlock& operator=(const CInfoBlock& obj);
   virtual bool operator==(const CInfoBlock& obj);
   virtual CInfoBlock* clone();
   virtual int getKey();
   virtual void release() {}

public:

      // Functionality:
      //    convert sockaddr structure to an integer array
      // Parameters:
      //    0) [in] addr: network address
      //    1) [in] ver: IP version
      //    2) [out] ip: the result machine readable IP address in integer array
      // Returned value:
      //    None.

   static void convert(const sockaddr* addr, int ver, uint32_t ip[]);
};


#endif