added support for storing per-peer rate limits across reconnects

ChangeLog

@@ -89,6 +89,7 @@
 	* added support for min-interval in tracker responses
 	* only keeps one outstanding duplicate request per peer
 	  reduces waste download, specifically when streaming
+	* added support for storing per-peer rate limits across reconnects
 
 	* disabled feature to drop requests after having been skipped too many times
 	* fixed range request bug for files larger than 2 GB in web seeds

include/libtorrent/policy.hpp

@@ -50,6 +50,46 @@ namespace libtorrent
 	class torrent;
 	class peer_connection;
 
+	// this is compressed as an unsigned floating point value
+	// the top 13 bits are the mantissa and the low
+	// 3 bits is the unsigned exponent. The exponent
+	// has an implicit + 4 as well.
+	// This means that the resolution is no less than 16
+	// The actual rate is: (upload_rate >> 4) << ((upload_rate & 0xf) + 4)
+	// the resolution gets worse the higher the value is
+	// min value is 0, max value is 16775168
+	struct ufloat16
+	{
+		ufloat16() {}
+		ufloat16(int v)
+		{ *this = v; }
+		operator int()
+		{
+			return (m_val >> 3) << ((m_val & 7) + 4);
+		}
+
+		ufloat16& operator=(int v)
+		{
+			if (v > 0x1fff << (7 + 4)) m_val = 0xffff;
+			else if (v <= 0) m_val = 0;
+			else
+			{
+				int exp = 4;
+				v >>= 4;
+				while (v > 0x1fff)
+				{
+					v >>= 1;
+					++exp;
+				}
+				TORRENT_ASSERT(exp <= 7);
+				m_val = (v << 3) || (exp & 7);
+			}
+			return *this;
+		}
+	private:
+		unsigned int m_val;
+	};
+
 	enum
 	{
 		// the limits of the download queue size
@@ -118,13 +158,15 @@ namespace libtorrent
 // 18     2     2         last_connected
 // 20     16    1         addr
 // 36     2     2         port
-// 38     1     1         hashfails
-// 39     1     1         failcount, connectable, optimistically_unchoked, seed
-// 40     1     1         fast_reconnects, trust_points
-// 41     1     1         source, pe_support, is_v6_addr
-// 42     1     1         on_parole, banned, added_to_dht
-// 43     1     1         <padding>
-// 44
+// 38     2     2         upload_rate_limit
+// 40     2     2         download_rate_limit
+// 42     1     1         hashfails
+// 43     1     1         failcount, connectable, optimistically_unchoked, seed
+// 44     1     1         fast_reconnects, trust_points
+// 45     1     1         source, pe_support, is_v6_addr
+// 46     1     1         on_parole, banned, added_to_dht
+// 47     1     1         <padding>
+// 48
 		struct TORRENT_EXPORT peer
 		{
 			peer();
@@ -186,6 +228,10 @@ namespace libtorrent
 			// the port this peer is or was connected on
 			boost::uint16_t port;
 
+			// the upload and download rate limits set for this peer
+			ufloat16 upload_rate_limit;
+			ufloat16 download_rate_limit;
+
 			// the number of times this peer has been
 			// part of a piece that failed the hash check
 			boost::uint8_t hashfails;

src/policy.cpp

@@ -786,6 +786,14 @@ namespace libtorrent
 		c.set_peer_info(i);
 		TORRENT_ASSERT(i->connection == 0);
 		c.add_stat(i->prev_amount_download, i->prev_amount_upload);
+
+		// restore transfer rate limits
+		int rate_limit;
+		rate_limit = i->upload_rate_limit;
+		if (rate_limit) c.set_upload_limit(rate_limit);
+		rate_limit = i->download_rate_limit;
+		if (rate_limit) c.set_download_limit(rate_limit);
+
 		i->prev_amount_download = 0;
 		i->prev_amount_upload = 0;
 		i->connection = &c;
@@ -1195,6 +1203,11 @@ namespace libtorrent
 		TORRENT_ASSERT(p->connection == &c);
 		TORRENT_ASSERT(!is_connect_candidate(*p, m_finished));
 
+		// save transfer rate limits
+		int rate_limit;
+		p->upload_rate_limit = c.upload_limit();
+		p->download_rate_limit = c.download_limit();
+
 		p->connection = 0;
 		p->optimistically_unchoked = false;
 
@@ -1404,6 +1417,8 @@ namespace libtorrent
 		, last_connected(0)
 		, port(port)
 		, hashfails(0)
+		, upload_rate_limit(0)
+		, download_rate_limit(0)
 		, failcount(0)
 		, connectable(conn)
 		, optimistically_unchoked(false)