128 lines
4.1 KiB
C++
128 lines
4.1 KiB
C++
/*
|
|
|
|
Copyright (c) 2016, Arvid Norberg
|
|
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 author 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.
|
|
|
|
*/
|
|
|
|
#ifndef TORRENT_SUGGEST_PIECE_HPP_INCLUDE
|
|
#define TORRENT_SUGGEST_PIECE_HPP_INCLUDE
|
|
|
|
#include <vector>
|
|
#include <algorithm>
|
|
|
|
#include "libtorrent/bitfield.hpp"
|
|
#include "libtorrent/sliding_average.hpp"
|
|
|
|
namespace libtorrent { namespace aux {
|
|
|
|
|
|
struct suggest_piece
|
|
{
|
|
// pick at most n piece indices that are _not_ in p (which represents
|
|
// pieces the peer has already sent a suggest for) nor in bits (which are
|
|
// pieces the peer already has, and should not be suggested)
|
|
int get_pieces(std::vector<piece_index_t>& p
|
|
, typed_bitfield<piece_index_t> const& bits
|
|
, int n)
|
|
{
|
|
if (m_priority_pieces.empty()) return 0;
|
|
|
|
int ret = 0;
|
|
|
|
// the highest priority pieces are at the end of m_priority_pieces.
|
|
// is we add any piece to the result (p), the farther back the better.
|
|
// the prioritization in p is the same, which means we have to first push
|
|
// back and then reverse the items we put there.
|
|
for (int i = int(m_priority_pieces.size()) - 1; i >= 0; --i)
|
|
{
|
|
piece_index_t const piece = m_priority_pieces[i];
|
|
if (bits.get_bit(piece)) continue;
|
|
if (std::any_of(p.begin(), p.end() - ret
|
|
, [piece](piece_index_t pi) { return pi == piece; }))
|
|
continue;
|
|
|
|
p.push_back(piece);
|
|
++ret;
|
|
--n;
|
|
if (n == 0) break;
|
|
}
|
|
|
|
// this it to maintain a strict priority order of pieces. The farther
|
|
// back, the higher priority
|
|
std::reverse(p.end() - ret, p.end());
|
|
|
|
return ret;
|
|
}
|
|
|
|
void add_piece(piece_index_t const index, int const availability
|
|
, int const max_queue_size)
|
|
{
|
|
// keep a running average of the availability of pieces, and filter
|
|
// anything above average.
|
|
int const mean = m_availability.mean();
|
|
m_availability.add_sample(availability);
|
|
|
|
if (availability > mean) return;
|
|
|
|
auto const it = std::find(m_priority_pieces.begin()
|
|
, m_priority_pieces.end(), index);
|
|
|
|
if (it != m_priority_pieces.end())
|
|
{
|
|
// increase the priority of this piece by moving it to the front
|
|
// of the queue
|
|
m_priority_pieces.erase(it);
|
|
}
|
|
|
|
if (int(m_priority_pieces.size()) >= max_queue_size)
|
|
{
|
|
int const to_remove = int(m_priority_pieces.size()) - max_queue_size + 1;
|
|
m_priority_pieces.erase(m_priority_pieces.begin()
|
|
, m_priority_pieces.begin() + to_remove);
|
|
}
|
|
|
|
m_priority_pieces.push_back(index);
|
|
}
|
|
|
|
private:
|
|
|
|
// these are pieces that would be good candidates for suggesting
|
|
// to a peer. They represent low availability pieces that we recently
|
|
// read from disk (and are likely in our read cache).
|
|
// pieces closer to the end were inserted into the cache more recently and
|
|
// have higher priority
|
|
std::vector<piece_index_t> m_priority_pieces;
|
|
|
|
sliding_average<30> m_availability;
|
|
};
|
|
|
|
}}
|
|
|
|
#endif
|