big change to improve piece picker. Better end-game mode. More options on which pieces to pick.

include/libtorrent/peer_connection.hpp

@@ -151,7 +151,7 @@ namespace libtorrent
 		policy::peer* peer_info_struct() const
 		{ return m_peer_info; }
 
-		enum peer_speed_t { slow, medium, fast };
+		enum peer_speed_t { slow = 1, medium, fast };
 		peer_speed_t peer_speed();
 
 		void send_allowed_set();
@@ -187,6 +187,8 @@ namespace libtorrent
 		bool on_parole() const
 		{ return peer_info_struct() && peer_info_struct()->on_parole; }
 
+		int picker_options() const;
+
 		void prefer_whole_pieces(int num)
 		{ m_prefer_whole_pieces = num; }
 

include/libtorrent/piece_picker.hpp

@@ -88,6 +88,14 @@ namespace libtorrent
 	{
 	public:
 
+		enum
+		{
+			// the number of priority levels
+			priority_levels = 8,
+			// priority factor
+			prio_factor = priority_levels - 4
+		};
+
 		struct block_info
 		{
 			block_info(): peer(0), num_peers(0), state(state_none) {}
@@ -110,6 +118,20 @@ namespace libtorrent
 		enum piece_state_t
 		{ none, slow, medium, fast };
 
+		enum options_t
+		{
+			// pick rarest first 
+			rarest_first = 1,
+			// pick the most common first, or the last pieces if sequential
+			reverse = 2,
+			// only pick pieces exclusively requested from this peer
+			on_parole = 4,
+			// always pick partial pieces before any other piece
+			prioritize_partials = 8,
+			// pick pieces in sequential order
+			sequential = 16
+		};
+
 		struct downloading_piece
 		{
 			downloading_piece(): finished(0), writing(0), requested(0) {}
@@ -133,9 +155,6 @@ namespace libtorrent
 
 		void get_availability(std::vector<int>& avail) const;
 
-		void sequential_download(bool sd);
-		bool sequential_download() const { return m_sequential_download >= 0; }
-
 		// increases the peer count for the given piece
 		// (is used when a HAVE message is received)
 		void inc_refcount(int index);
@@ -161,6 +180,9 @@ namespace libtorrent
 		void we_have(int index);
 		void we_dont_have(int index);
 
+		int cursor() const { return m_cursor; }
+		int reverse_cursor() const { return m_reverse_cursor; }
+
 		// sets all pieces to dont-have
 		void init(int blocks_per_piece, int total_num_blocks);
 		int num_pieces() const { return int(m_piece_map.size()); }
@@ -202,11 +224,9 @@ namespace libtorrent
 		// The last argument is the policy::peer pointer for the peer that
 		// we'll download from.
 		void pick_pieces(bitfield const& pieces
-			, std::vector<piece_block>& interesting_blocks
+			, std::vector<piece_block>& interesting_blocks, int num_blocks
-			, int num_pieces, int prefer_whole_pieces
+			, int prefer_whole_pieces, void* peer, piece_state_t speed
-			, void* peer, piece_state_t speed
+			, int options, std::vector<int> const& suggested_pieces) const;
-			, bool rarest_first, bool on_parole
-			, std::vector<int> const& suggested_pieces) const;
 
 		// picks blocks from each of the pieces in the piece_list
 		// vector that is also in the piece bitmask. The blocks
@@ -214,20 +234,23 @@ namespace libtorrent
 		// added to backup_blocks. num blocks is the number of
 		// blocks to be picked. Blocks are not picked from pieces
 		// that are being downloaded
-		int add_blocks(std::vector<int> const& piece_list
+		int add_blocks(int piece, bitfield const& pieces
-			, bitfield const& pieces
-			, std::vector<piece_block>& interesting_blocks
-			, int num_blocks, int prefer_whole_pieces
-			, void* peer, std::vector<int> const& ignore) const;
-
-		// picks blocks only from downloading pieces
-		int add_blocks_downloading(
-			bitfield const& pieces
 			, std::vector<piece_block>& interesting_blocks
 			, std::vector<piece_block>& backup_blocks
+			, std::vector<piece_block>& backup_blocks2
+			, int num_blocks, int prefer_whole_pieces
+			, void* peer, std::vector<int> const& ignore
+			, piece_state_t speed, int options) const;
+
+		// picks blocks only from downloading pieces
+		int add_blocks_downloading(downloading_piece const& dp
+			, bitfield const& pieces
+			, std::vector<piece_block>& interesting_blocks
+			, std::vector<piece_block>& backup_blocks
+			, std::vector<piece_block>& backup_blocks2
 			, int num_blocks, int prefer_whole_pieces
 			, void* peer, piece_state_t speed
-			, bool on_parole) const;
+			, int options) const;
 
 		// clears the peer pointer in all downloading pieces with this
 		// peer pointer
@@ -291,6 +314,8 @@ namespace libtorrent
 		void check_invariant(const torrent* t = 0) const;
 		void verify_pick(std::vector<piece_block> const& picked
 			, bitfield const& bits) const;
+#endif
+#if defined TORRENT_PICKER_LOG || !defined NDEBUG
 		void print_pieces() const;
 #endif
 
@@ -313,6 +338,7 @@ namespace libtorrent
 		friend struct piece_pos;
 
 		bool can_pick(int piece, bitfield const& bitmask) const;
+		bool is_piece_free(int piece, bitfield const& bitmask) const;
 		std::pair<int, int> expand_piece(int piece, int whole_pieces
 			, bitfield const& have) const;
 
@@ -354,7 +380,7 @@ namespace libtorrent
 				// the priority value that means the piece is filtered
 				filter_priority = 0,
 				// the max number the peer count can hold
-				max_peer_count = 0x3ff
+				max_peer_count = 0x3ff,
 			};
 			
 			bool have() const { return index == we_have_index; }
@@ -364,20 +390,41 @@ namespace libtorrent
 			bool filtered() const { return piece_priority == filter_priority; }
 			void filtered(bool f) { piece_priority = f ? filter_priority : 0; }
 			
+			//  prio 7 is always top priority
+			//  prio 0 is always -1 (don't pick)
+			//  downloading pieces are always on an even prio_factor priority
+			//
+			//  availability x, downloading
+			//   |   availability x, prio 3; availability 2x, prio 6
+			//   |   |   availability x, prio 2; availability 2x, prio 5
+			//   |   |   |   availability x, prio 1; availability 2x, prio 4
+			//   |   |   |   |
+			// +---+---+---+---+
+			// | 0 | 1 | 2 | 3 |
+			// +---+---+---+---+
+
 			int priority(piece_picker const* picker) const
 			{
-				if (downloading || filtered()
+				// filtered pieces (prio = 0), pieces we have or pieces with
-					|| have() || peer_count + picker->m_seeds == 0)
+				// availability = 0 should not be present in the piece list
+				// returning -1 indicates that they shouldn't.
+				if (filtered() || have() || peer_count + picker->m_seeds == 0)
 					return -1;
 
-				// priority 5, 6 and 7 disregards availability of the piece
+				// prio 7 disregards availability
-				if (piece_priority > 4) return 7 - piece_priority;
+				if (piece_priority == priority_levels - 1) return 1 - downloading;
 
-				// pieces we are currently downloading have high priority
+				// prio 4,5,6 halves the availability of a piece
-				int prio = peer_count * 4;
+				int availability = peer_count;
-//				if (prio >= picker->m_prio_limit * 6) prio = picker->m_prio_limit * 6;
+				int priority = piece_priority;
+				if (piece_priority >= priority_levels / 2)
+				{
+					availability /= 2;
+					priority -= (priority_levels - 2) / 2;
+				}
 
-				return prio + (4 - piece_priority);
+				if (downloading) return availability * prio_factor;
+				return availability * prio_factor + (priority_levels / 2) - priority;
 			}
 
 			bool operator!=(piece_pos p) const
@@ -467,11 +514,14 @@ namespace libtorrent
 		// the number of pieces we have
 		int m_num_have;
 
-		// -1 means sequential download is not active.
+		// we have all pieces in the range [0, m_cursor)
-		// >= 0 means that pieces are requested in sequential order
+		// m_cursor is the first piece we don't have
-		// and this variable is the next piece to request.
+		int m_cursor;
-		// in that case m_pieces is cleared and not used.
+
-		int m_sequential_download;
+		// we have all pieces in the range [m_reverse_cursor, end)
+		// m_reverse_cursor is the first piece where we also have
+		// all the subsequent pieces
+		int m_reverse_cursor;
 
 		// if this is set to true, it means update_pieces()
 		// has to be called before accessing m_pieces.

include/libtorrent/session_settings.hpp

@@ -141,6 +141,7 @@ namespace libtorrent
 			, auto_scrape_min_interval(300)
 			, max_peerlist_size(8000)
 			, min_announce_interval(5 * 60)
+			, prioritize_partial_pieces(false)
 		{}
 
 		// this is the user agent that will be sent to the tracker
@@ -436,6 +437,10 @@ namespace libtorrent
 		// that is lower than this, will be clamped to this
 		// value. It's specified in seconds
 		int min_announce_interval;
+
+		// if true, partial pieces are picked before pieces
+		// that are more rare
+		bool prioritize_partial_pieces;
 	};
 
 #ifndef TORRENT_DISABLE_DHT

src/peer_connection.cpp

@@ -572,6 +572,50 @@ namespace libtorrent
 #endif
 	}
 
+	int peer_connection::picker_options() const
+	{
+		int ret = 0; 
+		boost::shared_ptr<torrent> t = m_torrent.lock();
+		TORRENT_ASSERT(t);
+		if (!t) return 0;
+
+		if (t->is_sequential_download())
+		{
+			ret |= piece_picker::sequential;
+		}
+		else if (t->num_have() < t->settings().initial_picker_threshold)
+		{
+			// if we have fewer pieces than a certain threshols
+			// don't pick rare pieces, just pick random ones,
+			// and prioritize finishing them
+			ret |= piece_picker::prioritize_partials;
+		}
+		else
+		{
+			ret |= piece_picker::rarest_first;
+		}
+
+		if (m_snubbed)
+		{
+			// snubbed peers should request
+			// the common pieces first, just to make
+			// it more likely for all snubbed peers to
+			// request blocks from the same piece
+			ret |= piece_picker::reverse;
+		}
+
+		if (t->settings().prioritize_partial_pieces)
+			ret |= piece_picker::prioritize_partials;
+
+		if (on_parole()) ret |= piece_picker::on_parole
+			| piece_picker::prioritize_partials;
+
+		// only one of rarest_first, common_first and sequential can be set.
+		TORRENT_ASSERT(bool(ret & piece_picker::rarest_first)
+			+ bool(ret & piece_picker::sequential) <= 1);
+		return ret;
+	}
+
 	void peer_connection::fast_reconnect(bool r)
 	{
 		if (!peer_info_struct() || peer_info_struct()->fast_reconnects > 1)
@@ -1724,9 +1768,12 @@ namespace libtorrent
 		bool multi = picker.num_peers(block_finished) > 1;
 		picker.mark_as_writing(block_finished, peer_info_struct());
 
+		TORRENT_ASSERT(picker.num_peers(block_finished) == 0);
 		// if we requested this block from other peers, cancel it now
 		if (multi) t->cancel_block(block_finished);
 
+		TORRENT_ASSERT(picker.num_peers(block_finished) == 0);
+
 #if !defined NDEBUG && !defined TORRENT_DISABLE_INVARIANT_CHECKS
 		t->check_invariant();
 #endif
@@ -1777,6 +1824,7 @@ namespace libtorrent
 
 		TORRENT_ASSERT(p.piece == j.piece);
 		TORRENT_ASSERT(p.start == j.offset);
+		TORRENT_ASSERT(picker.num_peers(block_finished) == 0);
 		picker.mark_as_finished(block_finished, peer_info_struct());
 		if (t->alerts().should_post<block_finished_alert>())
 		{
@@ -3899,7 +3947,7 @@ namespace libtorrent
 			m_speed = medium;
 		else if (download_rate < torrent_download_rate / 15 && m_speed == fast)
 			m_speed = medium;
-		else if (download_rate < torrent_download_rate / 63 && m_speed == medium)
+		else
 			m_speed = slow;
 
 		return m_speed;

src/policy.cpp

@@ -200,8 +200,6 @@ namespace libtorrent
 
 		int prefer_whole_pieces = c.prefer_whole_pieces();
 
-		bool rarest_first = t.num_have() >= t.settings().initial_picker_threshold;
-
 		if (prefer_whole_pieces == 0)
 		{
 			prefer_whole_pieces = c.statistics().download_payload_rate()
@@ -250,7 +248,7 @@ namespace libtorrent
 
 			p.pick_pieces(mask, interesting_pieces
 				, num_requests, prefer_whole_pieces, c.peer_info_struct()
-				, state, rarest_first, c.on_parole(), suggested);
+				, state, c.picker_options(), suggested);
 		}
 		else
 		{
@@ -264,7 +262,7 @@ namespace libtorrent
 			// then use this mode.
 			p.pick_pieces(bits, interesting_pieces
 				, num_requests, prefer_whole_pieces, c.peer_info_struct()
-				, state, rarest_first, c.on_parole(), suggested);
+				, state, c.picker_options(), suggested);
 		}
 
 #ifdef TORRENT_VERBOSE_LOGGING
@@ -303,10 +301,6 @@ namespace libtorrent
 
 		if (busy_pieces.empty() || num_requests <= 0)
 		{
-			// in this case, we could not find any blocks
-			// that was free. If we couldn't find any busy
-			// blocks as well, we cannot download anything
-			// more from this peer.
 			return;
 		}
 

src/torrent.cpp

@@ -754,10 +754,14 @@ namespace libtorrent
 
 		m_progress = j.piece / float(torrent_file().num_pieces());
 
+		m_picker->check_invariant();
+
 		TORRENT_ASSERT(m_picker);
 		if (j.offset >= 0 && !m_picker->have_piece(j.offset))
 			m_picker->we_have(j.offset);
 
+		m_picker->check_invariant();
+
 		// we're not done checking yet
 		// this handler will be called repeatedly until
 		// we're done, or encounter a failure
@@ -3298,9 +3302,6 @@ namespace libtorrent
 		
 		if (!is_seed())
 		{
-			if (m_sequential_download)
-				picker().sequential_download(m_sequential_download);
-
 			// if we just finished checking and we're not a seed, we are
 			// likely to be unpaused
 			if (m_ses.m_auto_manage_time_scaler > 1)
@@ -3549,13 +3550,7 @@ namespace libtorrent
 #endif
 
 	void torrent::set_sequential_download(bool sd)
-	{
+	{ m_sequential_download = sd; }
-		m_sequential_download = sd;
-		if (has_picker())
-		{
-			picker().sequential_download(sd);
-		}
-	}
 
 	void torrent::set_queue_position(int p)
 	{

test/test_piece_picker.cpp

@@ -71,6 +71,14 @@ boost::shared_ptr<piece_picker> setup_picker(
 	boost::shared_ptr<piece_picker> p(new piece_picker);
 	p->init(blocks_per_piece, num_pieces * blocks_per_piece);
 
+	for (int i = 0; i < num_pieces; ++i)
+	{
+		const int avail = availability[i] - '0';
+		assert(avail >= 0);
+		
+		for (int j = 0; j < avail; ++j) p->inc_refcount(i);
+	}
+
 	bitfield have = string2vec(have_str);
 
 	for (int i = 0; i < num_pieces; ++i)
@@ -86,25 +94,24 @@ boost::shared_ptr<piece_picker> setup_picker(
 			blocks = partial[i] - 'a' + 10;
 
 		int counter = 0;
-		if (blocks & 1)
+		for (int j = 0; j < 4; ++j)
 		{
+			TEST_CHECK(!p->is_finished(piece_block(i, j)));
+			if ((blocks & (1 << j)) == 0) continue;
 			++counter;
-			p->mark_as_finished(piece_block(i, 0), 0);
+			bool ret = p->mark_as_downloading(piece_block(i, j), 0, piece_picker::slow);
-		}
+			TEST_CHECK(ret == true);
-		if (blocks & 2)
+			TEST_CHECK(p->is_requested(piece_block(i, j)) == bool(blocks & (1 << j)));
-		{
+			p->mark_as_writing(piece_block(i, j), 0);
-			++counter;
+			TEST_CHECK(!p->is_finished(piece_block(i, j)));
-			p->mark_as_finished(piece_block(i, 1), 0);
+			// trying to mark a block as requested after it has been completed
-		}
+			// should fail (return false)
-		if (blocks & 4)
+			ret = p->mark_as_downloading(piece_block(i, j), 0, piece_picker::slow);
-		{
+			TEST_CHECK(ret == false);
-			++counter;
+			p->mark_as_finished(piece_block(i, j), 0);
-			p->mark_as_finished(piece_block(i, 2), 0);
+
-		}
+			TEST_CHECK(p->is_downloaded(piece_block(i, j)) == bool(blocks & (1 << j)));
-		if (blocks & 8)
+			TEST_CHECK(p->is_finished(piece_block(i, j)) == bool(blocks & (1 << j)));
-		{
-			++counter;
-			p->mark_as_finished(piece_block(i, 3), 0);
 		}
 
 		piece_picker::downloading_piece st;
@@ -114,6 +121,9 @@ boost::shared_ptr<piece_picker> setup_picker(
 		TEST_CHECK(st.index == i);
 
 		TEST_CHECK(st.finished == counter);
+		TEST_CHECK(st.finished + st.requested + st.writing == counter);
+
+		TEST_CHECK(p->is_piece_finished(i) == (counter == 4));
 	}
 
 	for (int i = 0; i < num_pieces; ++i)
@@ -134,14 +144,6 @@ boost::shared_ptr<piece_picker> setup_picker(
 			TEST_CHECK(p->is_finished(piece_block(i, j)));
 	}
 
-	for (int i = 0; i < num_pieces; ++i)
-	{
-		const int avail = availability[i] - '0';
-		assert(avail >= 0);
-		
-		for (int j = 0; j < avail; ++j) p->inc_refcount(i);
-	}
-
 	std::vector<int> availability_vec;
 	p->get_availability(availability_vec);
 	for (int i = 0; i < num_pieces; ++i)
@@ -158,20 +160,25 @@ boost::shared_ptr<piece_picker> setup_picker(
 }
 
 bool verify_pick(boost::shared_ptr<piece_picker> p
-	, std::vector<piece_block> const& picked)
+	, std::vector<piece_block> const& picked, bool allow_multi_blocks = false)
 {
 #ifndef NDEBUG
 	p->check_invariant();
 #endif
+	if (!allow_multi_blocks)
+	{
 		for (std::vector<piece_block>::const_iterator i = picked.begin()
 			, end(picked.end()); i != end; ++i)
 		{
 			if (p->num_peers(*i) > 0) return false;
 		}
+	}
 
 	// make sure there are no duplicated
 	std::set<piece_block> blocks;
-	std::copy(picked.begin(), picked.end(), std::insert_iterator<std::set<piece_block> >(blocks, blocks.end()));
+	std::copy(picked.begin(), picked.end()
+		, std::insert_iterator<std::set<piece_block> >(blocks, blocks.end()));
+	std::cerr << " verify: " << picked.size() << " " << blocks.size() << std::endl;
 	return picked.size() == blocks.size();
 }
 
@@ -189,60 +196,182 @@ void print_title(char const* name)
 	std::cerr << "==== " << name << " ====\n";
 }
 
-int test_pick(boost::shared_ptr<piece_picker> const& p)
+std::vector<piece_block> pick_pieces(boost::shared_ptr<piece_picker> const& p, char const* availability
+	, int num_blocks, int prefer_whole_pieces, void* peer_struct, piece_picker::piece_state_t state
+	, int options, std::vector<int> const& suggested_pieces)
 {
 	std::vector<piece_block> picked;
-	const std::vector<int> empty_vector;
+	p->pick_pieces(string2vec(availability), picked, num_blocks, prefer_whole_pieces, peer_struct
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
+		, state, options, suggested_pieces);
 	print_pick(picked);
 	TEST_CHECK(verify_pick(p, picked));
-	TEST_CHECK(int(picked.size()) == 1);
+	return picked;
+}
+
+int test_pick(boost::shared_ptr<piece_picker> const& p, int options = piece_picker::rarest_first)
+{
+	const std::vector<int> empty_vector;
+	std::vector<piece_block> picked = pick_pieces(p, "*******", 1, 0, 0
+		, piece_picker::fast, options, empty_vector);
+	if (picked.empty()) return -1;
 	return picked[0].piece_index;
 }
 
 int test_main()
 {
 
+	int tmp1;
+	int tmp2;
+	int tmp3;
 	tcp::endpoint endp;
+	piece_picker::downloading_piece st;
 	policy::peer peer_struct(endp, policy::peer::connectable, 0);
 	std::vector<piece_block> picked;
 	boost::shared_ptr<piece_picker> p;
 	const std::vector<int> empty_vector;
+	int options = piece_picker::rarest_first;
+
+// ========================================================
+
+	// test abort_download
+	print_title("test abort_download");
+	p = setup_picker("1111111", "       ", "7110000", ""); 
+	picked = pick_pieces(p, "*******", blocks_per_piece, 0, 0, piece_picker::fast
+		, options, empty_vector);
+	TEST_CHECK(p->is_requested(piece_block(0, 0)) == false);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(0,0)) != picked.end());
+
+	p->abort_download(piece_block(piece_block(0,0)));
+	picked = pick_pieces(p, "*******", blocks_per_piece, 0, 0, piece_picker::fast
+		, options, empty_vector);
+	TEST_CHECK(p->is_requested(piece_block(0, 0)) == false);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(0,0)) != picked.end());
+
+	p->mark_as_downloading(piece_block(0,0), &tmp1, piece_picker::fast);
+	picked = pick_pieces(p, "*******", blocks_per_piece, 0, 0, piece_picker::fast
+		, options, empty_vector);
+	TEST_CHECK(p->is_requested(piece_block(0, 0)) == true);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(0,0)) == picked.end());
+
+	p->abort_download(piece_block(0,0));
+	picked = pick_pieces(p, "*******", blocks_per_piece, 0, 0, piece_picker::fast
+		, options, empty_vector);
+	TEST_CHECK(p->is_requested(piece_block(0, 0)) == false);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(0,0)) != picked.end());
+
+	p->mark_as_downloading(piece_block(0,0), &tmp1, piece_picker::fast);
+	p->mark_as_downloading(piece_block(0,1), &tmp1, piece_picker::fast);
+	p->abort_download(piece_block(0,0));
+	picked = pick_pieces(p, "*******", blocks_per_piece, 0, 0, piece_picker::fast
+		, options, empty_vector);
+	TEST_CHECK(p->is_requested(piece_block(0, 0)) == false);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(0,0)) != picked.end());
+
+	p->mark_as_downloading(piece_block(0,0), &tmp1, piece_picker::fast);
+	p->mark_as_writing(piece_block(0,0), &tmp1);
+	p->write_failed(piece_block(0,0));
+	picked = pick_pieces(p, "*******", blocks_per_piece, 0, 0, piece_picker::fast
+		, options, empty_vector);
+	TEST_CHECK(p->is_requested(piece_block(0, 0)) == false);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(0,0)) != picked.end());
+
+	p->mark_as_downloading(piece_block(0,0), &tmp1, piece_picker::fast);
+	p->mark_as_writing(piece_block(0,0), &tmp1);
+	p->mark_as_finished(piece_block(0,0), &tmp1);
+	p->abort_download(piece_block(0,0));
+	picked = pick_pieces(p, "*******", blocks_per_piece, 0, 0, piece_picker::fast
+		, options, empty_vector);
+	TEST_CHECK(p->is_requested(piece_block(0, 0)) == false);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(0,0)) == picked.end());
+
+	p = setup_picker("1111111", "       ", "7110000", ""); 
+	p->mark_as_downloading(piece_block(0,0), &tmp1, piece_picker::fast);
+	p->mark_as_finished(piece_block(0,1), 0);
+	p->piece_info(0, st);
+	TEST_CHECK(st.requested == 1);
+	TEST_CHECK(st.finished == 1);
+	TEST_CHECK(st.state == piece_picker::fast);
+	p->abort_download(piece_block(0,0));
+	p->piece_info(0, st);
+	TEST_CHECK(st.requested == 0);
+	TEST_CHECK(st.finished == 1);
+	TEST_CHECK(st.state == piece_picker::none);
+	picked = pick_pieces(p, "*******", blocks_per_piece, 0, 0, piece_picker::fast
+		, options, empty_vector);
+	TEST_CHECK(p->is_requested(piece_block(0, 0)) == false);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(0,0)) != picked.end());
+
+// ========================================================
 
 	// make sure the block that is picked is from piece 1, since it
 	// it is the piece with the lowest availability
 	print_title("test pick lowest availability");
 	p = setup_picker("2223333", "* * *  ", "", "");
-	picked.clear();
+	TEST_CHECK(test_pick(p) == 1);
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
+	
-	TEST_CHECK(verify_pick(p, picked));
+// ========================================================
-	TEST_CHECK(int(picked.size()) > 0);
+
-	TEST_CHECK(picked.front().piece_index == 1);
+	// make sure pieces with equal priority and availability
+	// are picked at random
+	print_title("test random pick at same priority");
+	std::map<int, int> random_prio_pieces;
+	for (int i = 0; i < 100; ++i)
+	{
+		p = setup_picker("1111112", "       ", "", "");
+		++random_prio_pieces[test_pick(p)];
+	}
+	TEST_CHECK(random_prio_pieces.size() == 6);
+	for (std::map<int, int>::iterator i = random_prio_pieces.begin()
+		, end(random_prio_pieces.end()); i != end; ++i)
+		std::cout << i->first << ": " << i->second << " ";
+	std::cout << std::endl;
 
 // ========================================================
 
 	// make sure the block that is picked is from piece 5, since it
 	// has the highest priority among the available pieces
 	print_title("test pick highest priority");
-	p = setup_picker("1111111", "* * *  ", "1111122", "");
+	p = setup_picker("1111111", "* * *  ", "1111121", "");
-	picked.clear();
+	TEST_CHECK(test_pick(p) == 5);
-	p->pick_pieces(string2vec("****** "), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
+
-	TEST_CHECK(verify_pick(p, picked));
+// ========================================================
-	TEST_CHECK(int(picked.size()) > 0);
+
-	TEST_CHECK(picked.front().piece_index == 5);
+	print_title("test reverse rarest first");
+	p = setup_picker("4179253", "       ", "", "");
+	picked = pick_pieces(p, "*******", 7 * blocks_per_piece, 0, &peer_struct, piece_picker::fast
+		, piece_picker::rarest_first | piece_picker::reverse, empty_vector);
+	int expected_common_pieces[] = {3, 2, 5, 0, 6, 4, 1};
+	for (int i = 0; i < int(picked.size()); ++i)
+		TEST_CHECK(picked[i] == piece_block(expected_common_pieces[i / blocks_per_piece], i % blocks_per_piece));
+
+	// piece 3 should be prioritized since it's a partial
+	p = setup_picker("1122111", "       ", "3333333", "   1   ");
+	TEST_CHECK(test_pick(p, piece_picker::rarest_first | piece_picker::reverse) == 3);
 
 // ========================================================
 
 	// make sure the 4 blocks are picked from the same piece if
-	// whole pieces are preferred. The only whole piece is 1.
+	// whole pieces are preferred. Priority and availability is more
+	// important. Piece 1 has the lowest availability even though
+	// it is not a whole piece
 	print_title("test pick whole pieces");
-	p = setup_picker("1111111", "       ", "1111111", "1023460");
+	p = setup_picker("2212222", "       ", "1111111", "1023460");
-	picked.clear();
+	picked = pick_pieces(p, "****** ", 1, 1, &peer_struct, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("****** "), picked, 1, 1, &peer_struct, piece_picker::fast, true, true, empty_vector);
+	TEST_CHECK(int(picked.size()) == 3);
-	TEST_CHECK(verify_pick(p, picked));
-	TEST_CHECK(int(picked.size()) >= blocks_per_piece);
 	for (int i = 0; i < blocks_per_piece && i < int(picked.size()); ++i)
-		TEST_CHECK(picked[i].piece_index == 1);
+		TEST_CHECK(picked[i].piece_index == 2);
+
+	p = setup_picker("1111111", "       ", "1111111", "");
+	picked = pick_pieces(p, "****** ", 1, 1, &peer_struct, piece_picker::fast, options, empty_vector);
+	TEST_CHECK(int(picked.size()) == blocks_per_piece);
+	for (int i = 0; i < blocks_per_piece && i < int(picked.size()); ++i)
+		TEST_CHECK(picked[i].block_index == i);
+
+	p = setup_picker("2221222", "       ", "", "");
+	picked = pick_pieces(p, "*******", 1, 7, &peer_struct, piece_picker::fast, options, empty_vector);
+	TEST_CHECK(int(picked.size()) == 7 *  blocks_per_piece);
+	for (int i = 0; i < int(picked.size()); ++i)
+		TEST_CHECK(picked[i] == piece_block(i / blocks_per_piece, i % blocks_per_piece));
 
 // ========================================================
 
@@ -259,22 +388,23 @@ int test_main()
 	// make sure filtered pieces are ignored
 	print_title("test filtered pieces");
 	p = setup_picker("1111111", "       ", "0010000", "");
-	picked.clear();
+	TEST_CHECK(test_pick(p, piece_picker::rarest_first) == 2);
-	p->pick_pieces(string2vec("*** ** "), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
+	TEST_CHECK(test_pick(p, piece_picker::rarest_first | piece_picker::reverse) == 2);
-	TEST_CHECK(verify_pick(p, picked));
+	TEST_CHECK(test_pick(p, piece_picker::sequential) == 2);
-	TEST_CHECK(int(picked.size()) > 0);
+	TEST_CHECK(test_pick(p, piece_picker::sequential | piece_picker::reverse) == 2);
-	TEST_CHECK(picked.front().piece_index == 2);
 
 // ========================================================
 	
 	// make sure we_dont_have works
 	print_title("test we_dont_have");
 	p = setup_picker("1111111", "*******", "0100000", "");
-	picked.clear();
+	TEST_CHECK(p->have_piece(1));
+	TEST_CHECK(p->have_piece(2));
 	p->we_dont_have(1);
 	p->we_dont_have(2);
-	p->pick_pieces(string2vec("*** ** "), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
+	TEST_CHECK(!p->have_piece(1));
-	TEST_CHECK(verify_pick(p, picked));
+	TEST_CHECK(!p->have_piece(2));
+	picked = pick_pieces(p, "*** ** ", 1, 0, 0, piece_picker::fast, options, empty_vector);
 	TEST_CHECK(int(picked.size()) > 0);
 	TEST_CHECK(picked.front().piece_index == 1);
 
@@ -309,76 +439,122 @@ int test_main()
 	
 	// make sure requested blocks aren't picked
 	print_title("test don't pick requested blocks");
-	p = setup_picker("1234567", "       ", "", "");
+	p = setup_picker("1111111", "       ", "", "");
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) > 0);
-	TEST_CHECK(picked.front().piece_index == 0);
 	piece_block first = picked.front();
 	p->mark_as_downloading(picked.front(), &peer_struct, piece_picker::fast);
 	TEST_CHECK(p->num_peers(picked.front()) == 1);
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) > 0);
 	TEST_CHECK(picked.front() != first);
-	TEST_CHECK(picked.front().piece_index == 0);
 
 // ========================================================
-/*
+
-	// test sequenced download
+	// make sure downloading pieces have higher priority
+	print_title("test downloading piece priority");
+	p = setup_picker("1111111", "       ", "", "");
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
+	TEST_CHECK(int(picked.size()) > 0);
+	first = picked.front();
+	p->mark_as_downloading(picked.front(), &peer_struct, piece_picker::fast);
+	TEST_CHECK(p->num_peers(picked.front()) == 1);
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
+	TEST_CHECK(int(picked.size()) > 0);
+	TEST_CHECK(picked.front() != first);
+	TEST_CHECK(picked.front().piece_index == first.piece_index);
+
+// ========================================================
+
+	// make sure downloading pieces closer to completion have higher priority
+	// piece 3 has only 1 block from being completed, and should be picked
+	print_title("test downloading piece order");
+	p = setup_picker("1111111", "       ", "", "013700f");
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast
+		, options | piece_picker::prioritize_partials, empty_vector);
+	TEST_CHECK(int(picked.size()) > 0);
+	TEST_CHECK(picked.front() == piece_block(3, 3));
+
+// ========================================================
+
+	// test sequential download
+	print_title("test sequential download");
 	p = setup_picker("7654321", "       ", "", "");
-	picked.clear();
+	picked = pick_pieces(p, "*******", 7 * blocks_per_piece, 0, 0, piece_picker::fast
-	p->set_sequenced_download_threshold(3);
+		, piece_picker::sequential, empty_vector);
-	p->pick_pieces(string2vec("*****  "), picked, 5 * blocks_per_piece, false, 0, piece_picker::fast, true, false, empty_vector);
+	TEST_CHECK(int(picked.size()) == 7 * blocks_per_piece);
-	print_pick(picked);
+	for (int i = 0; i < int(picked.size()); ++i)
-	TEST_CHECK(verify_pick(p, picked));
+		TEST_CHECK(picked[i] == piece_block(i / blocks_per_piece, i % blocks_per_piece));
-	TEST_CHECK(int(picked.size()) == 5 * blocks_per_piece);
-	for (int i = 0; i < 5 * blocks_per_piece && i < int(picked.size()); ++i)
-		TEST_CHECK(picked[i].piece_index == i / blocks_per_piece);
 
-	picked.clear();
+// ========================================================
-	p->set_sequenced_download_threshold(4);
-	p->pick_pieces(string2vec("****   "), picked, 5 * blocks_per_piece, false, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
-	TEST_CHECK(int(picked.size()) == 4 * blocks_per_piece);
-	for (int i = 0; i < 4 * blocks_per_piece && i < int(picked.size()); ++i)
-		TEST_CHECK(picked[i].piece_index == i / blocks_per_piece);
 
-	picked.clear();
+	// test reverse sequential download
-	p->set_sequenced_download_threshold(2);
+	print_title("test reverse sequential download");
-	p->pick_pieces(string2vec("****** "), picked, 6 * blocks_per_piece, false, 0, piece_picker::fast, true, false, empty_vector);
+	p = setup_picker("7654321", "       ", "", "");
-	print_pick(picked);
+	picked = pick_pieces(p, "*******", 7 * blocks_per_piece, 0, 0, piece_picker::fast
-	TEST_CHECK(verify_pick(p, picked));
+		, piece_picker::sequential | piece_picker::reverse, empty_vector);
-	TEST_CHECK(int(picked.size()) == 6 * blocks_per_piece);
+	TEST_CHECK(int(picked.size()) == 7 * blocks_per_piece);
-	for (int i = 0; i < 6 * blocks_per_piece && i < int(picked.size()); ++i)
+	for (int i = 0; i < int(picked.size()); ++i)
-		TEST_CHECK(picked[i].piece_index == i / blocks_per_piece);
+		TEST_CHECK(picked[i] == piece_block(6 - (i / blocks_per_piece), i % blocks_per_piece));
 
-	picked.clear();
+// ========================================================
+
+	// test cursors
+	print_title("test cursors");
+	p = setup_picker("7654321", "       ", "", "");
+	TEST_CHECK(p->cursor() == 0);
+	TEST_CHECK(p->reverse_cursor() == 7);
+	p->we_have(1);
+	TEST_CHECK(p->cursor() == 0);
+	TEST_CHECK(p->reverse_cursor() == 7);
+	p->we_have(0);
+	TEST_CHECK(p->cursor() == 2);
+	TEST_CHECK(p->reverse_cursor() == 7);
+	p->we_have(5);
+	TEST_CHECK(p->cursor() == 2);
+	TEST_CHECK(p->reverse_cursor() == 7);
+	p->we_have(6);
+	TEST_CHECK(p->cursor() == 2);
+	TEST_CHECK(p->reverse_cursor() == 5);
+	p->we_have(4);
+	p->we_have(3);
+	p->we_have(2);
+	TEST_CHECK(p->cursor() == 7);
+	TEST_CHECK(p->reverse_cursor() == 0);
+	p->we_dont_have(3);
+	TEST_CHECK(p->cursor() == 3);
+	TEST_CHECK(p->reverse_cursor() == 4);
+
+	p = setup_picker("7654321", "       ", "", "");
+	TEST_CHECK(p->cursor() == 0);
+	TEST_CHECK(p->reverse_cursor() == 7);
+	p->set_piece_priority(1, 0);
+	TEST_CHECK(p->cursor() == 0);
+	TEST_CHECK(p->reverse_cursor() == 7);
 	p->set_piece_priority(0, 0);
-	p->pick_pieces(string2vec("****** "), picked, 6 * blocks_per_piece, false, 0, piece_picker::fast, true, false, empty_vector);
+	TEST_CHECK(p->cursor() == 2);
-	print_pick(picked);
+	TEST_CHECK(p->reverse_cursor() == 7);
-	TEST_CHECK(verify_pick(p, picked));
+	p->set_piece_priority(5, 0);
-	TEST_CHECK(int(picked.size()) == 5 * blocks_per_piece);
+	TEST_CHECK(p->cursor() == 2);
-	for (int i = 0; i < 5 * blocks_per_piece && i < int(picked.size()); ++i)
+	TEST_CHECK(p->reverse_cursor() == 7);
-		TEST_CHECK(picked[i].piece_index == i / blocks_per_piece + 1);
+	p->set_piece_priority(6, 0);
+	TEST_CHECK(p->cursor() == 2);
+	TEST_CHECK(p->reverse_cursor() == 5);
+	p->set_piece_priority(4, 0);
+	p->set_piece_priority(3, 0);
+	p->set_piece_priority(2, 0);
+	TEST_CHECK(p->cursor() == 7);
+	TEST_CHECK(p->reverse_cursor() == 0);
+	p->set_piece_priority(3, 1);
+	TEST_CHECK(p->cursor() == 3);
+	TEST_CHECK(p->reverse_cursor() == 4);
+
 
-	picked.clear();
-	p->set_piece_priority(0, 1);
-	p->pick_pieces(string2vec("****** "), picked, 6 * blocks_per_piece, false, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
-	TEST_CHECK(int(picked.size()) == 6 * blocks_per_piece);
-	for (int i = 0; i < 6 * blocks_per_piece && i < int(picked.size()); ++i)
-		TEST_CHECK(picked[i].piece_index == i / blocks_per_piece);
-*/
 // ========================================================
 
 	// test piece priorities
 	print_title("test piece priorities");
-	p = setup_picker("5555555", "       ", "3214576", "");
+	p = setup_picker("5555555", "       ", "7654321", "");
 	TEST_CHECK(p->num_filtered() == 0);
 	TEST_CHECK(p->num_have_filtered() == 0);
 	p->set_piece_priority(0, 0);
@@ -389,25 +565,34 @@ int test_main()
 	TEST_CHECK(p->num_filtered() == 0);
 	TEST_CHECK(p->num_have_filtered() == 1);
 	
-	picked.clear();
+	p->we_dont_have(0);
-	p->pick_pieces(string2vec("*******"), picked, 6 * blocks_per_piece, false, 0, piece_picker::fast, true, false, empty_vector);
+	p->set_piece_priority(0, 7);
-	print_pick(picked);
+
-	TEST_CHECK(verify_pick(p, picked));
+	picked = pick_pieces(p, "*******", 7 * blocks_per_piece, 0, 0
-	TEST_CHECK(int(picked.size()) == 6 * blocks_per_piece);
+		, piece_picker::fast, options, empty_vector);
-	TEST_CHECK(picked[0 * blocks_per_piece].piece_index == 5);
+	TEST_CHECK(int(picked.size()) == 7 * blocks_per_piece);
-	// priority 5 and 6 is currently the same
+
-	TEST_CHECK(picked[1 * blocks_per_piece].piece_index == 6 || picked[1 * blocks_per_piece].piece_index == 4);
+	for (int i = 0; i < int(picked.size()); ++i)
-	TEST_CHECK(picked[2 * blocks_per_piece].piece_index == 6 || picked[2 * blocks_per_piece].piece_index == 4);
+		TEST_CHECK(picked[i] == piece_block(i / blocks_per_piece, i % blocks_per_piece));
-	TEST_CHECK(picked[3 * blocks_per_piece].piece_index == 3);
+	
-	TEST_CHECK(picked[4 * blocks_per_piece].piece_index == 1);
+	// test changing priority on a piece we have
-	TEST_CHECK(picked[5 * blocks_per_piece].piece_index == 2);
+	p->we_have(0);
+	p->set_piece_priority(0, 0);
+	p->set_piece_priority(0, 1);
+	p->set_piece_priority(0, 0);
 
 	std::vector<int> prios;
 	p->piece_priorities(prios);
 	TEST_CHECK(prios.size() == 7);
-	int prio_comp[] = {0, 2, 1, 4, 5, 7, 6};
+	int prio_comp[] = {0, 6, 5, 4, 3, 2, 1};
 	TEST_CHECK(std::equal(prios.begin(), prios.end(), prio_comp));
 	
+	std::vector<bool> filter;
+	p->filtered_pieces(filter);
+	TEST_CHECK(prios.size() == 7);
+	bool filter_comp[] = {true, false, false, false, false, false, false};
+	TEST_CHECK(std::equal(filter.begin(), filter.end(), filter_comp));
+
 // ========================================================
 
 	// test restore_piece
@@ -418,18 +603,12 @@ int test_main()
 	p->mark_as_finished(piece_block(0,2), 0);
 	p->mark_as_finished(piece_block(0,3), 0);
 
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= 1);
 	TEST_CHECK(picked.front().piece_index == 1);
 
 	p->restore_piece(0);	
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= 1);
 	TEST_CHECK(picked.front().piece_index == 0);
 
@@ -439,46 +618,128 @@ int test_main()
 	p->mark_as_finished(piece_block(0,3), 0);
 	p->set_piece_priority(0, 0);
 
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= 1);
 	TEST_CHECK(picked.front().piece_index == 1);
 
 	p->restore_piece(0);	
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= 1);
 	TEST_CHECK(picked.front().piece_index == 1);
 
 	p->set_piece_priority(0, 1);
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 0, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, false, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= 1);
 	TEST_CHECK(picked.front().piece_index == 0);
 
 // ========================================================
 
-	// test non-rarest-first mode
+	// test random mode
-	print_title("test not rarest first");
+	print_title("test random pick");
-	p = setup_picker("1234567", "* * *  ", "1111122", "");
+	p = setup_picker("1234567", "       ", "1111122", "");
-	picked.clear();
+	std::set<int> random_pieces;
-	p->pick_pieces(string2vec("****** "), picked, 5 * blocks_per_piece, false, 0, piece_picker::fast, false, false, empty_vector);
+	for (int i = 0; i < 100; ++i)
-	print_pick(picked);
+		random_pieces.insert(test_pick(p, 0));
-	TEST_CHECK(verify_pick(p, picked));
+	TEST_CHECK(random_pieces.size() == 7);
-	TEST_CHECK(int(picked.size()) == 3 * blocks_per_piece);
 
-	for (int i = 0; i < 4 * blocks_per_piece && i < int(picked.size()); ++i)
+	random_pieces.clear();
+	for (int i = 0; i < 7; ++i)
 	{
-		TEST_CHECK(picked[i].piece_index != 0);
+		int piece = test_pick(p, 0);
-		TEST_CHECK(picked[i].piece_index != 2);
+		p->we_have(piece);
-		TEST_CHECK(picked[i].piece_index != 4);
+		random_pieces.insert(piece);
 	}
+	TEST_CHECK(random_pieces.size() == 7);
+
+// ========================================================
+
+	// make sure that blocks from a slow piece are picked
+	// by a fast peer if there are no other options
+	print_title("test downloading piece affinity");
+	p = setup_picker("1111111", "       ", "", "");
+	p->mark_as_downloading(piece_block(2,2), &tmp1, piece_picker::slow);
+	picked = pick_pieces(p, "*******", 7 * blocks_per_piece - 1, 0, &tmp2
+		, piece_picker::fast, options, empty_vector);
+	TEST_CHECK(picked.size() == 7 * blocks_per_piece - 1);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(2,2)) == picked.end());
+	// piece 2 sould be the last one (least matching piece to pick)
+	TEST_CHECK(picked[7 * blocks_per_piece - 2].piece_index == 2);
+	TEST_CHECK(picked[7 * blocks_per_piece - 3].piece_index == 2);
+	TEST_CHECK(picked[7 * blocks_per_piece - 4].piece_index == 2);
+
+	// test the affinity of pieces with the same speed state
+	p = setup_picker("1111111", "       ", "", "");
+	p->mark_as_downloading(piece_block(3,2), &tmp1, piece_picker::slow);
+	p->mark_as_downloading(piece_block(2,2), &tmp1, piece_picker::medium);
+	p->mark_as_downloading(piece_block(4,2), &tmp1, piece_picker::fast);
+	picked = pick_pieces(p, "*******", 2 * blocks_per_piece, 0, 0
+		, piece_picker::fast, piece_picker::prioritize_partials, empty_vector);
+	TEST_CHECK(picked.size() == 2 * blocks_per_piece);
+	TEST_CHECK(picked[0].piece_index == 4);
+	TEST_CHECK(picked[blocks_per_piece - 1].piece_index == 2);
+	TEST_CHECK(picked[2 * blocks_per_piece - 2].piece_index == 3);
+
+// ========================================================
+
+	// make sure the piece picker will pick pieces that
+	// are already requested from other peers if it has to
+	print_title("test picking downloading blocks");
+	p = setup_picker("1111111", "       ", "", "");
+	p->mark_as_downloading(piece_block(2,2), &tmp1, piece_picker::fast);
+	p->mark_as_downloading(piece_block(1,2), &tmp1, piece_picker::slow);
+
+	picked.clear();
+	p->pick_pieces(string2vec("*******"), picked, 7 * blocks_per_piece, 0, 0
+		, piece_picker::fast, piece_picker::prioritize_partials, empty_vector);
+	TEST_CHECK(verify_pick(p, picked, true));
+	print_pick(picked);
+	TEST_CHECK(picked.size() == 7 * blocks_per_piece);
+
+	picked.clear();
+	p->pick_pieces(string2vec("*******"), picked, 7 * blocks_per_piece, 0, 0
+		, piece_picker::fast, piece_picker::prioritize_partials
+		| piece_picker::rarest_first, empty_vector);
+	TEST_CHECK(verify_pick(p, picked, true));
+	print_pick(picked);
+	TEST_CHECK(picked.size() == 7 * blocks_per_piece);
+
+	picked.clear();
+	p->pick_pieces(string2vec("*******"), picked, 7 * blocks_per_piece, 0, 0
+		, piece_picker::fast, piece_picker::rarest_first, empty_vector);
+	TEST_CHECK(verify_pick(p, picked, true));
+	print_pick(picked);
+	TEST_CHECK(picked.size() == 7 * blocks_per_piece);
+
+// ========================================================
+	
+	// test clear_peer
+	print_title("test clear_peer");
+	p = setup_picker("1123333", "       ", "", "");
+	p->mark_as_downloading(piece_block(0, 0), &tmp1, piece_picker::slow);
+	p->mark_as_downloading(piece_block(0, 1), &tmp2, piece_picker::slow);
+	p->mark_as_downloading(piece_block(0, 2), &tmp3, piece_picker::slow);
+	p->mark_as_downloading(piece_block(1, 1), &tmp1, piece_picker::slow);
+	p->mark_as_downloading(piece_block(2, 1), &tmp2, piece_picker::slow);
+	p->mark_as_downloading(piece_block(3, 1), &tmp3, piece_picker::slow);
+
+	std::vector<void*> dls;
+	void* expected_dls1[] = {&tmp1, &tmp2, &tmp3, 0};
+	void* expected_dls2[] = {0, &tmp1, 0, 0};
+	void* expected_dls3[] = {0, &tmp2, 0, 0};
+	void* expected_dls4[] = {0, &tmp3, 0, 0};
+	void* expected_dls5[] = {&tmp1, 0, &tmp3, 0};
+	p->get_downloaders(dls, 0);
+	TEST_CHECK(std::equal(dls.begin(), dls.end(), expected_dls1));
+	p->get_downloaders(dls, 1);
+	TEST_CHECK(std::equal(dls.begin(), dls.end(), expected_dls2));
+	p->get_downloaders(dls, 2);
+	TEST_CHECK(std::equal(dls.begin(), dls.end(), expected_dls3));
+	p->get_downloaders(dls, 3);
+	TEST_CHECK(std::equal(dls.begin(), dls.end(), expected_dls4));
+
+	p->clear_peer(&tmp2);
+	p->get_downloaders(dls, 0);
+	TEST_CHECK(std::equal(dls.begin(), dls.end(), expected_dls5));
 
 // ========================================================
 	
@@ -505,7 +766,7 @@ int test_main()
 
 // ========================================================
 	
-	// test have_all and have_none with sequential download
+	// test have_all and have_none
 	print_title("test have_all and have_none with sequential download");
 	p = setup_picker("0123333", "*      ", "", "");
 	dc = p->distributed_copies();
@@ -515,17 +776,6 @@ int test_main()
 	dc = p->distributed_copies();
 	std::cout << "distributed copies: " << dc << std::endl;
 	TEST_CHECK(fabs(dc - (2.f + 5.f / 7.f)) < 0.01f);
-	p->sequential_download(true);
-	p->dec_refcount_all();
-	dc = p->distributed_copies();
-	std::cout << "distributed copies: " << dc << std::endl;
-	TEST_CHECK(fabs(dc - (1.f + 5.f / 7.f)) < 0.01f);
-	p->inc_refcount(0);
-	p->dec_refcount_all();
-	dc = p->distributed_copies();
-	std::cout << "distributed copies: " << dc << std::endl;
-	TEST_CHECK(fabs(dc - (0.f + 6.f / 7.f)) < 0.01f);
-	p->inc_refcount(1);
 	TEST_CHECK(test_pick(p) == 1);
 
 // ========================================================
@@ -546,40 +796,15 @@ int test_main()
 	p->dec_refcount(5);
 	p->inc_refcount(5);
 	
-	p->inc_refcount(0);
+	bitfield bits(7);
-	p->dec_refcount(4);
+	bits.clear_all();
+	bits.set_bit(0);
+	p->inc_refcount(bits);
+	bits.clear_all();
+	bits.set_bit(4);
+	p->dec_refcount(bits);
 	TEST_CHECK(test_pick(p) == 0);
 
-// ========================================================
-/*	
-	// test have_all and have_none, with a sequenced download threshold
-	p = setup_picker("1233333", "*      ", "", "");
-	p->set_sequenced_download_threshold(3);
-	p->inc_refcount_all();
-	dc = p->distributed_copies();
-	TEST_CHECK(fabs(dc - (3.f + 5.f / 7.f)) < 0.01f);
-	p->dec_refcount_all();
-	dc = p->distributed_copies();
-	TEST_CHECK(fabs(dc - (2.f + 5.f / 7.f)) < 0.01f);
-	p->dec_refcount(2);
-	dc = p->distributed_copies();
-	TEST_CHECK(fabs(dc - (2.f + 4.f / 7.f)) < 0.01f);
-	p->mark_as_downloading(piece_block(1,0), &peer_struct, piece_picker::fast);
-	p->mark_as_downloading(piece_block(1,1), &peer_struct, piece_picker::fast);
-	p->we_have(1);
-	dc = p->distributed_copies();
-	TEST_CHECK(fabs(dc - (2.f + 5.f / 7.f)) < 0.01f);
-	picked.clear();
-	// make sure it won't pick the piece we just got
-	p->pick_pieces(string2vec(" * ****"), picked, 100, false, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
-	TEST_CHECK(int(picked.size()) >= 4 * blocks_per_piece);
-	TEST_CHECK(picked[0 * blocks_per_piece].piece_index == 3);
-	TEST_CHECK(picked[1 * blocks_per_piece].piece_index == 4);
-	TEST_CHECK(picked[2 * blocks_per_piece].piece_index == 5);
-	TEST_CHECK(picked[3 * blocks_per_piece].piece_index == 6);
-*/	
 // ========================================================
 	
 	// test unverified_blocks, marking blocks and get_downloader
@@ -592,7 +817,6 @@ int test_main()
 	TEST_CHECK(p->get_downloader(piece_block(4, 3)) == 0);
 	p->mark_as_downloading(piece_block(4, 3), &peer_struct, piece_picker::fast);
 	TEST_CHECK(p->get_downloader(piece_block(4, 3)) == &peer_struct);
-	piece_picker::downloading_piece st;
 	p->piece_info(4, st);
 	TEST_CHECK(st.requested == 1);
 	TEST_CHECK(st.writing == 0);
@@ -625,10 +849,7 @@ int test_main()
 	// test prefer_whole_pieces
 	print_title("test prefer whole pieces");
 	p = setup_picker("1111111", "       ", "", "");
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 3, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, 3, 0, piece_picker::fast, true, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= 3 * blocks_per_piece);
 	piece_block b = picked.front();
 	for (int i = 1; i < int(picked.size()); ++i)
@@ -638,10 +859,7 @@ int test_main()
 		b = picked[i];
 	}
 
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 3, 0, piece_picker::fast, options, empty_vector);
-	p->pick_pieces(string2vec("*******"), picked, 1, 3, 0, piece_picker::fast, false, false, empty_vector);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= 3 * blocks_per_piece);
 	b = picked.front();
 	for (int i = 1; i < int(picked.size()); ++i)
@@ -651,34 +869,36 @@ int test_main()
 		b = picked[i];
 	}
 
+	// make sure pieces that don't match the 'whole pieces' requirement
+	// are picked if there's no other choice
+	p = setup_picker("1111111", "       ", "", "");
+	p->mark_as_downloading(piece_block(2,2), &tmp1, piece_picker::fast);
+	picked = pick_pieces(p, "*******", 7 * blocks_per_piece - 1, 1, 0
+		, piece_picker::fast, options, empty_vector);
+	TEST_CHECK(picked.size() == 7 * blocks_per_piece - 1);
+	TEST_CHECK(std::find(picked.begin(), picked.end(), piece_block(2,2)) == picked.end());
+
+//#error test picking with partial pieces and other peers present so that both backup_pieces and backup_pieces2 are used
+	
 // ========================================================
 
 	// test parole mode
 	print_title("test parole mode");
 	p = setup_picker("3333133", "       ", "", "");
 	p->mark_as_finished(piece_block(0, 0), 0);
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 1, 0, piece_picker::fast
-	p->pick_pieces(string2vec("*******"), picked, 1, 1, 0, piece_picker::fast, true, true, empty_vector);
+		, options | piece_picker::on_parole | piece_picker::prioritize_partials, empty_vector);
-	print_pick(picked);
+	TEST_CHECK(int(picked.size()) == blocks_per_piece - 1);
-	TEST_CHECK(verify_pick(p, picked));
-	TEST_CHECK(int(picked.size()) >= blocks_per_piece - 1);
 	for (int i = 1; i < int(picked.size()); ++i)
-	{
+		TEST_CHECK(picked[i] == piece_block(0, i + 1));
-		TEST_CHECK(picked[i].piece_index == 0);
-		TEST_CHECK(picked[i].block_index == i + 1);
-	}
 
 	//	make sure that the partial piece is not picked by a
 	// peer that is has not downloaded/requested the other blocks
-	picked.clear();
+	picked = pick_pieces(p, "*******", 1, 1, &peer_struct, piece_picker::fast
-	p->pick_pieces(string2vec("*******"), picked, 1, 1, &peer_struct, piece_picker::fast, true, true, empty_vector);
+		, options | piece_picker::on_parole | piece_picker::prioritize_partials, empty_vector);
-	print_pick(picked);
+	TEST_CHECK(int(picked.size()) == blocks_per_piece);
-	TEST_CHECK(int(picked.size()) >= blocks_per_piece);
 	for (int i = 1; i < int(picked.size()); ++i)
-	{
+		TEST_CHECK(picked[i] == piece_block(4, i));
-		TEST_CHECK(picked[i].piece_index == 4);
-		TEST_CHECK(picked[i].block_index == i);
-	}
 
 // ========================================================
 
@@ -688,53 +908,29 @@ int test_main()
 	int v[] = {1, 5};
 	std::vector<int> suggested_pieces(v, v + 2);
 	
-	picked.clear();
+	picked = pick_pieces(p, "****************", 1, 1, 0, piece_picker::fast, options, suggested_pieces);
-	p->pick_pieces(string2vec("****************"), picked, 1, 1, 0, piece_picker::fast, true, true, suggested_pieces);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= blocks_per_piece);
 	for (int i = 1; i < int(picked.size()); ++i)
-	{
+		TEST_CHECK(picked[i] == piece_block(1, i));
-		TEST_CHECK(picked[i].piece_index == 1);
-		TEST_CHECK(picked[i].block_index == i);
-	}
 	p->set_piece_priority(0, 0);
 	p->set_piece_priority(1, 0);
 	p->set_piece_priority(2, 0);
 	p->set_piece_priority(3, 0);
 
-	picked.clear();
+	picked = pick_pieces(p, "****************", 1, 1, 0, piece_picker::fast, options, suggested_pieces);
-	p->pick_pieces(string2vec("****************"), picked, 1, 1, 0, piece_picker::fast, true, true, suggested_pieces);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= blocks_per_piece);
 	for (int i = 1; i < int(picked.size()); ++i)
-	{
+		TEST_CHECK(picked[i] == piece_block(5, i));
-		TEST_CHECK(picked[i].piece_index == 5);
-		TEST_CHECK(picked[i].block_index == i);
-	}
 
 	p = setup_picker("1111222233334444", "****            ", "", "");
-	picked.clear();
+	picked = pick_pieces(p, "****************", 1, 1, 0, piece_picker::fast, options, suggested_pieces);
-	p->pick_pieces(string2vec("****************"), picked, 1, 1, 0, piece_picker::fast, true, true, suggested_pieces);
-	print_pick(picked);
-	TEST_CHECK(verify_pick(p, picked));
 	TEST_CHECK(int(picked.size()) >= blocks_per_piece);
 	for (int i = 1; i < int(picked.size()); ++i)
-	{
+		TEST_CHECK(picked[i] == piece_block(5, i));
-		TEST_CHECK(picked[i].piece_index == 5);
-		TEST_CHECK(picked[i].block_index == i);
-	}
 	
 // MISSING TESTS:
-// 2. inc_ref() from 0 to 1 while sequenced download threshold is 1
+// 1. abort_download
-// 4. filtered_pieces
+// 2. write_failed
-// 5. clear peer
-// 6. pick_pieces with prefer whole pieces
-// 7. is_requested
-// 8. is_downloaded
-// 9. get_downloaders
-// 10. abort_download
 
 /*