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/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* 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
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "RarestPieceSelector.h"
#include <cassert>
#include <algorithm>
#include "PieceStatMan.h"
namespace aria2 {
RarestPieceSelector::RarestPieceSelector
(const SharedHandle<PieceStatMan>& pieceStatMan):pieceStatMan_(pieceStatMan) {}
class FindRarestPiece
{
private:
const unsigned char* misbitfield_;
size_t numbits_;
public:
FindRarestPiece(const unsigned char* misbitfield, size_t numbits):
misbitfield_(misbitfield), numbits_(numbits) {}
bool operator()(const size_t& index)
{
assert(index < numbits_);
unsigned char mask = (128 >> (index%8));
return misbitfield_[index/8]&mask;
}
};
bool RarestPieceSelector::select
(size_t& index, const unsigned char* bitfield, size_t nbits) const
{
const std::vector<size_t>& pieceIndexes =
pieceStatMan_->getRarerPieceIndexes();
std::vector<size_t>::const_iterator i =
std::find_if(pieceIndexes.begin(), pieceIndexes.end(),
FindRarestPiece(bitfield, nbits));
if(i == pieceIndexes.end()) {
return false;
} else {
index = *i;
return true;
}
}
} // namespace aria2
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