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ktorrent/libktorrent/torrent/chunkselector.cpp

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/***************************************************************************
* Copyright (C) 2005 by Joris Guisson *
* joris.guisson@gmail.com *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* 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., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#include <stdlib.h>
#include <vector>
#include <algorithm>
#include <util/log.h>
#include <util/bitset.h>
#include "chunkcounter.h"
#include "chunkselector.h"
#include "chunkmanager.h"
#include "downloader.h"
#include "peerdownloader.h"
#include "globals.h"
#include "peer.h"
#include "peermanager.h"
namespace bt
{
struct RareCmp
{
ChunkManager & cman;
ChunkCounter & cc;
bool warmup;
RareCmp(ChunkManager & cman,ChunkCounter & cc,bool warmup) : cman(cman),cc(cc),warmup(warmup) {}
bool operator()(Uint32 a,Uint32 b)
{
// do some sanity checks
if (a >= cman.getNumChunks() || b >= cman.getNumChunks())
return false;
// the sorting is done on two criteria, priority and rareness
Priority pa = cman.getChunk(a)->getPriority();
Priority pb = cman.getChunk(b)->getPriority();
if (pa == pb)
return normalCmp(a,b); // if both have same priority compare on rareness
else if (pa > pb) // pa has priority over pb, so select pa
return true;
else // pb has priority over pa, so select pb
return false;
}
bool normalCmp(Uint32 a,Uint32 b)
{
// during warmup mode choose most common chunks
if (!warmup)
return cc.get(a) < cc.get(b);
else
return cc.get(a) > cc.get(b);
}
};
ChunkSelector::ChunkSelector(ChunkManager & cman,Downloader & downer,PeerManager & pman)
: cman(cman),downer(downer),pman(pman)
{
std::vector<Uint32> tmp;
for (Uint32 i = 0;i < cman.getNumChunks();i++)
{
if (!cman.getBitSet().get(i))
{
tmp.push_back(i);
}
}
std::random_shuffle(tmp.begin(),tmp.end());
// std::list does not support random_shuffle so we use a vector as a temporary storage
// for the random_shuffle
chunks.insert(chunks.begin(),tmp.begin(),tmp.end());
sort_timer.update();
}
ChunkSelector::~ChunkSelector()
{}
bool ChunkSelector::select(PeerDownloader* pd,Uint32 & chunk)
{
const BitSet & bs = cman.getBitSet();
// sort the chunks every 2 seconds
if (sort_timer.getElapsedSinceUpdate() > 2000)
{
bool warmup = cman.getNumChunks() - cman.chunksLeft() <= 4;
// dataChecked(bs);
chunks.sort(RareCmp(cman,pman.getChunkCounter(),warmup));
sort_timer.update();
}
std::list<Uint32>::iterator itr = chunks.begin();
while (itr != chunks.end())
{
Uint32 i = *itr;
Chunk* c = cman.getChunk(*itr);
// if we have the chunk remove it from the list
if (bs.get(i))
{
std::list<Uint32>::iterator tmp = itr;
itr++;
chunks.erase(tmp);
}
else
{
// pd has to have the selected chunk and it needs to be not excluded
if (pd->hasChunk(i) && !downer.areWeDownloading(i) &&
!c->isExcluded() && !c->isExcludedForDownloading())
{
// we have a chunk
chunk = i;
return true;
}
itr++;
}
}
return false;
}
void ChunkSelector::dataChecked(const BitSet & ok_chunks)
{
for (Uint32 i = 0;i < ok_chunks.getNumBits();i++)
{
bool in_chunks = std::find(chunks.begin(),chunks.end(),i) != chunks.end();
if (in_chunks && ok_chunks.get(i))
{
// if we have the chunk, remove it from the chunks list
chunks.remove(i);
}
else if (!in_chunks && !ok_chunks.get(i))
{
// if we don't have the chunk, add it to the list if it wasn't allrready in there
chunks.push_back(i);
}
}
}
void ChunkSelector::reincluded(Uint32 from, Uint32 to)
{
// lets do a safety check first
if (from >= cman.getNumChunks() || to >= cman.getNumChunks())
{
Out(SYS_DIO|LOG_NOTICE) << "Internal error in chunkselector" << endl;
return;
}
for (Uint32 i = from;i <= to;i++)
{
bool in_chunks = std::find(chunks.begin(),chunks.end(),i) != chunks.end();
if (!in_chunks && cman.getChunk(i)->getStatus() != Chunk::ON_DISK)
{
// Out(SYS_DIO|LOG_DEBUG) << "ChunkSelector::reIncluded " << i << endl;
chunks.push_back(i);
}
}
}
void ChunkSelector::reinsert(Uint32 chunk)
{
bool in_chunks = std::find(chunks.begin(),chunks.end(),chunk) != chunks.end();
if (!in_chunks)
chunks.push_back(chunk);
}
}