1 /* <!-- copyright */
2 /*
3 * aria2 - The high speed download utility
4 *
5 * Copyright (C) 2006 Tatsuhiro Tsujikawa
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 *
21 * In addition, as a special exception, the copyright holders give
22 * permission to link the code of portions of this program with the
23 * OpenSSL library under certain conditions as described in each
24 * individual source file, and distribute linked combinations
25 * including the two.
26 * You must obey the GNU General Public License in all respects
27 * for all of the code used other than OpenSSL. If you modify
28 * file(s) with this exception, you may extend this exception to your
29 * version of the file(s), but you are not obligated to do so. If you
30 * do not wish to do so, delete this exception statement from your
31 * version. If you delete this exception statement from all source
32 * files in the program, then also delete it here.
33 */
34 /* copyright --> */
35 #include "RarestPieceSelector.h"
36
37 #include <limits>
38 #include <algorithm>
39
40 #include "PieceStatMan.h"
41 #include "bitfield.h"
42
43 namespace aria2 {
44
RarestPieceSelector(const std::shared_ptr<PieceStatMan> & pieceStatMan)45 RarestPieceSelector::RarestPieceSelector(
46 const std::shared_ptr<PieceStatMan>& pieceStatMan)
47 : pieceStatMan_(pieceStatMan)
48 {
49 }
50
select(size_t & index,const unsigned char * bitfield,size_t nbits) const51 bool RarestPieceSelector::select(size_t& index, const unsigned char* bitfield,
52 size_t nbits) const
53 {
54 const std::vector<size_t>& order = pieceStatMan_->getOrder();
55 const std::vector<int>& counts = pieceStatMan_->getCounts();
56 int min = std::numeric_limits<int>::max();
57 size_t bestIdx = nbits;
58 for (size_t i = 0; i < nbits; ++i) {
59 size_t idx = order[i];
60 if (bitfield::test(bitfield, nbits, idx) && counts[idx] < min) {
61 min = counts[idx];
62 bestIdx = idx;
63 }
64 }
65 if (bestIdx == nbits) {
66 return false;
67 }
68 else {
69 index = bestIdx;
70 return true;
71 }
72 }
73
74 } // namespace aria2
75