Adding logic to decide which pieces are to be downloaded vs those tha…

…t are not based on config (hardcoded 64megs).

README.markdown

@@ -3,6 +3,15 @@
 Oxen is a hybrid torrent client that aims to allow peers with small ammounts
 of disk space the ability to positively impact a peer group.
 
+# Status
+
+So far you can ...
+
+ * Start the application and monitor a directory for new torrents.
+ * Add new torrents to the system
+ * Set a max memory usage value (defaulting to 64 megs)
+ * Download up to that max and seed any pieces known
+
 # USAGE
 
     $ ./oxen --directory /tmp/torrents/

src/Config.hpp

@@ -7,7 +7,7 @@ namespace oxen {
 
 class Config {
 	public:
-		Config() : directory_("/tmp") { }
+		Config() : directory_("/tmp"), maxMemory_(64) { }
 		~Config() { }
 
 		void directory(std::string directory) {
@@ -16,9 +16,11 @@ class Config {
 		std::string directory() {
 			return directory_;
 		}
+		int maxMemory() { return maxMemory_; }
 
 	private:
 		std::string directory_;
+		int maxMemory_;
 };
 
 }

src/Core.cpp

@@ -47,13 +47,15 @@ void Core::run() {
 		if (ti_->size() > index) {
 			for (int i = index; i < ti_->size(); i++) {
 				libtorrent::torrent_info *t = ti_->at(i);
-				calculatePiecePriority(t);
+#if 1
 				libtorrent::add_torrent_params parms;
 				parms.save_path = savePath;
 				parms.ti = t;
 				parms.auto_managed = true;
 				parms.storage = libtorrent::temp_storage_constructor;
-				session_->add_torrent(parms);
+				libtorrent::torrent_handle handle = session_->add_torrent(parms);
+				calculatePiecePriority(t, handle);
+#endif
 			}
 			index = ti_->size();
 		}
@@ -66,12 +68,30 @@ libtorrent::session* Core::session() {
 	return session_;
 }
 
-void Core::calculatePiecePriority(libtorrent::torrent_info * /* torrent */) {
+void Core::calculatePiecePriority(libtorrent::torrent_info *torrent, libtorrent::torrent_handle handle) {
 	/* Given the total size of the torrent and number of pieces, determine
 	 * which pieces should be marked as priority 0 (don't download) and
 	 * which should be marked 4 (normal). This should take into account
 	 * the availability of a piece, time that the piece has been seeded
 	 * and some sort of fuzzy ratio approximation. */
+	cout << "torrent has " << torrent->num_pieces() << " pieces." << endl;
+	cout << "each piece is " << torrent->piece_length() << " long." << endl;
+	cout << "total size is " << torrent->total_size() << " long." << endl;
+
+	int maxMem = config_->maxMemory() * 1048576;
+	cout << "given that maxMemory is " << config_->maxMemory() << " megs (" << maxMem << ") ..." << endl;
+	if (maxMem > torrent->total_size()) {
+		cout << "we can seed all pieces at once." << endl;
+	} else {
+		cout << "we can seed " << (maxMem / torrent->piece_length()) << " pieces at once." << endl; 
+		int pieceCount = (maxMem / torrent->piece_length());
+		for (int i = 0; i < pieceCount; i++) {
+			handle.piece_priority(i, 7);
+		}
+		for (int i = pieceCount; i < torrent->num_pieces(); i++) {
+			handle.piece_priority(i, 0);
+		}
+	}
 }
 
 

src/Core.hpp

@@ -27,7 +27,7 @@ class Core {
 		libtorrent::session *session_;
 
 		void run();
-		void calculatePiecePriority(libtorrent::torrent_info *torrent);
+		void calculatePiecePriority(libtorrent::torrent_info *torrent, libtorrent::torrent_handle handle);
 };
 
 }