283 lines
8.7 KiB
C++
Executable File
283 lines
8.7 KiB
C++
Executable File
/*
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Copyright (c) 2003, Arvid Norberg
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TORRENT_PIECE_PICKER_HPP_INCLUDED
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#define TORRENT_PIECE_PICKER_HPP_INCLUDED
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#include <algorithm>
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#include <vector>
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#include <bitset>
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#include <cassert>
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#ifdef _MSC_VER
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#pragma warning(push, 1)
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#endif
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#include <boost/optional.hpp>
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#ifdef _MSC_VER
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#pragma warning(pop)
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#endif
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#include "libtorrent/peer_id.hpp"
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#include "libtorrent/socket.hpp"
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namespace libtorrent
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{
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class torrent;
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class address;
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class peer_connection;
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struct piece_block
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{
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piece_block(int p_index, int b_index)
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: piece_index(p_index)
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, block_index(b_index)
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{}
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int piece_index;
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int block_index;
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bool operator==(const piece_block& b) const
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{ return piece_index == b.piece_index && block_index == b.block_index; }
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bool operator!=(const piece_block& b) const
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{ return piece_index != b.piece_index || block_index != b.block_index; }
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};
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class piece_picker
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{
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public:
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enum { max_blocks_per_piece = 256 };
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struct block_info
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{
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block_info(): num_downloads(0) {}
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// the peer this block was requested or
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// downloaded from
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address peer;
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// the number of times this block has been downloaded
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int num_downloads;
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};
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struct downloading_piece
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{
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int index;
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// each bit represents a block in the piece
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// set to one if the block has been requested
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std::bitset<max_blocks_per_piece> requested_blocks;
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// the bit is set to one if the block has been acquired
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std::bitset<max_blocks_per_piece> finished_blocks;
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// info about each block
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block_info info[max_blocks_per_piece];
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// TODO: If the hash test fails on the
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// piece, redownload one block from another peer
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// then the first time, and check the hash again.
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// also maintain a counter how many times a piece-hash
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// has been confirmed. Download blocks that hasn't
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// been confirmed (since they are most probably the
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// invalid blocks)
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};
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piece_picker(int blocks_per_piece,
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int total_num_blocks);
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// this is called before any other method is called
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// after the local files has been checked.
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// the vector tells which pieces we already have
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// and which we don't have.
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void files_checked(
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const std::vector<bool>& pieces
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, const std::vector<downloading_piece>& unfinished);
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// increases the peer count for the given piece
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// (is used when a HAVE or BITFIELD message is received)
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void inc_refcount(int index);
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// decreases the peer count for the given piece
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// (used when a peer disconnects)
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void dec_refcount(int index);
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// This indicates that we just received this piece
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// it means that the refcounter will indicate that
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// we are not interested in this piece anymore
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// (i.e. we don't have to maintain a refcount)
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void we_have(int index);
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// pieces should be the vector that represents the pieces a
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// client has. It returns a list of all pieces that this client
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// has and that are interesting to download. It returns them in
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// priority order. It doesn't care about the download flag.
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// The user of this function must lookup if any piece is
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// marked as being downloaded. If the user of this function
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// decides to download a piece, it must mark it as being downloaded
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// itself, by using the mark_as_downloading() member function.
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// THIS IS DONE BY THE peer_connection::request_piece() MEMBER FUNCTION!
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void pick_pieces(const std::vector<bool>& pieces,
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std::vector<piece_block>& interesting_blocks,
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int num_pieces) const;
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// returns true if any client is currently downloading this
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// piece-block, or if it's queued for downloading by some client
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// or if it already has been successfully downlloaded
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bool is_downloading(piece_block block) const;
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bool is_finished(piece_block block) const;
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// marks this piece-block as queued for downloading
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void mark_as_downloading(piece_block block, const address& peer);
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void mark_as_finished(piece_block block, const address& peer);
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// if a piece had a hash-failure, it must be restured and
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// made available for redownloading
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void restore_piece(int index);
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// clears the given piece's download flag
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// this means that this piece-block can be picked again
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void abort_download(piece_block block);
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bool is_piece_finished(int index) const;
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// returns the number of blocks there is in the goven piece
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int blocks_in_piece(int index) const;
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// the number of downloaded blocks that hasn't passed
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// the hash-check yet
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int unverified_blocks() const;
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void get_downloaders(std::vector<address>& d, int index) const;
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const std::vector<downloading_piece>& get_download_queue() const
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{ return m_downloads; }
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boost::optional<address> get_downloader(piece_block block) const;
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#ifndef NDEBUG
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// used in debug mode
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void integrity_check(const torrent* t = 0) const;
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#endif
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// functor that compares indices on downloading_pieces
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struct has_index
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{
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has_index(int i): index(i) { assert(i >= 0); }
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bool operator()(const downloading_piece& p) const
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{ return p.index == index; }
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int index;
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};
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int blocks_in_last_piece() const
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{ return m_blocks_in_last_piece; }
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private:
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struct piece_pos
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{
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piece_pos() {}
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piece_pos(int peer_count_, int index_)
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: peer_count(peer_count_)
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, downloading(0)
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, index(index_)
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{
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assert(peer_count_ >= 0);
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assert(index_ >= 0);
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}
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// selects which vector to look in
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unsigned peer_count : 7;
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// is 1 if the piece is marked as being downloaded
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unsigned downloading : 1;
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// index in to the piece_info vector
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unsigned index : 24;
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bool operator!=(piece_pos p)
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{ return index != p.index || peer_count != p.peer_count; }
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bool operator==(piece_pos p)
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{ return index == p.index && peer_count == p.peer_count; }
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};
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void move(bool downloading, int vec_index, int elem_index);
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void remove(bool downloading, int vec_index, int elem_index);
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int add_interesting_blocks(const std::vector<int>& piece_list,
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const std::vector<bool>& pieces,
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std::vector<piece_block>& interesting_pieces,
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int num_blocks) const;
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// this vector contains all pieces we don't have.
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// in the first entry (index 0) is a vector of all pieces
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// that no peer have, the vector at index 1 contains
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// all pieces that exactly one peer have, index 2 contains
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// all pieces exactly two peers have and so on.
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std::vector<std::vector<int> > m_piece_info;
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// this vector has the same structure as m_piece_info
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// but only contains pieces we are currently downloading
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// they have higher priority than pieces we aren't downloading
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// during piece picking
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std::vector<std::vector<int> > m_downloading_piece_info;
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// this maps indices to number of peers that has this piece and
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// index into the m_piece_info vectors.
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// 0xffffff means that we have the piece, so it doesn't
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// exist in the piece_info buckets
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std::vector<piece_pos> m_piece_map;
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// each piece that's currently being downloaded
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// has an entry in this list with block allocations.
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// i.e. it says wich parts of the piece that
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// is being downloaded
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std::vector<downloading_piece> m_downloads;
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int m_blocks_per_piece;
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int m_blocks_in_last_piece;
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};
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inline int piece_picker::blocks_in_piece(int index) const
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{
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assert(index >= 0);
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assert(index < (int)m_piece_map.size());
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if (index+1 == (int)m_piece_map.size())
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return m_blocks_in_last_piece;
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else
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return m_blocks_per_piece;
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}
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}
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#endif // TORRENT_PIECE_PICKER_HPP_INCLUDED
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