diff --git a/docs/manual.html b/docs/manual.html
index 90779cbb9..c067d9c72 100755
--- a/docs/manual.html
+++ b/docs/manual.html
@@ -712,14 +712,15 @@ struct peer_info
         address ip;
         float up_speed;
         float down_speed;
-        unsigned int total_download;
-        unsigned int total_upload;
+        size_type total_download;
+        size_type total_upload;
         peer_id id;
         std::vector<bool> pieces;
         int upload_limit;
         int upload_ceiling;
 
-        int load_balancing;
+        size_type load_balancing;
+
         int download_queue_length;
         int upload_queue_length;
 
diff --git a/docs/manual.rst b/docs/manual.rst
index 40f4378c4..1b6ff9715 100755
--- a/docs/manual.rst
+++ b/docs/manual.rst
@@ -718,14 +718,15 @@ fields::
 		address ip;
 		float up_speed;
 		float down_speed;
-		unsigned int total_download;
-		unsigned int total_upload;
+		size_type total_download;
+		size_type total_upload;
 		peer_id id;
 		std::vector<bool> pieces;
 		int upload_limit;
 		int upload_ceiling;
 
-		int load_balancing;
+		size_type load_balancing;
+
 		int download_queue_length;
 		int upload_queue_length;
 
diff --git a/examples/client_test.cpp b/examples/client_test.cpp
index 6da01d645..159e89b67 100755
--- a/examples/client_test.cpp
+++ b/examples/client_test.cpp
@@ -35,11 +35,19 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <iterator>
 #include <exception>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/format.hpp>
 #include <boost/date_time/posix_time/posix_time.hpp>
 #include <boost/filesystem/fstream.hpp>
 #include <boost/bind.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/entry.hpp"
 #include "libtorrent/bencode.hpp"
 #include "libtorrent/session.hpp"
@@ -261,7 +269,7 @@ int main(int argc, char* argv[])
 				handles.push_back(ses.add_torrent(t, save_path, resume_data));
 				handles.back().set_max_connections(60);
 				handles.back().set_max_uploads(-1);
-				handles.back().set_ratio(1.02);
+				handles.back().set_ratio(1.02f);
 			}
 			catch (std::exception& e)
 			{
@@ -342,9 +350,9 @@ int main(int argc, char* argv[])
 				i->get_peer_info(peers);
 				float down = s.download_rate;
 				float up = s.upload_rate;
-				int total_down = s.total_download;
-				int total_up = s.total_upload;
-				int num_peers = peers.size();
+				size_type total_down = s.total_download;
+				size_type total_up = s.total_upload;
+				int num_peers = (int)peers.size();
 
 				out.precision(4);
 				out.width(5);
diff --git a/include/libtorrent/alert.hpp b/include/libtorrent/alert.hpp
index 5a265a081..3fec24a19 100755
--- a/include/libtorrent/alert.hpp
+++ b/include/libtorrent/alert.hpp
@@ -30,8 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
-#ifndef TORRENT_ERROR_HPP_INCLUDED
-#define TORRENT_ERROR_HPP_INCLUDED
+#ifndef TORRENT_ALERT_HPP_INCLUDED
+#define TORRENT_ALERT_HPP_INCLUDED
 
 #include <memory>
 #include <queue>
@@ -39,6 +39,10 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <cassert>
 #include <typeinfo>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/thread/mutex.hpp>
 
 #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
@@ -47,6 +51,11 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <boost/preprocessor/repetition/enum_shifted_params.hpp>
 #include <boost/date_time/posix_time/posix_time.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+
 namespace libtorrent {
 
 	class alert
@@ -158,5 +167,5 @@ namespace libtorrent {
 
 } // namespace libtorrent
 
-#endif // TORRENT_ERROR_HPP_INCLUDED
+#endif // TORRENT_ALERT_HPP_INCLUDED
 
diff --git a/include/libtorrent/bencode.hpp b/include/libtorrent/bencode.hpp
index 03b5afb73..0f1700d5b 100755
--- a/include/libtorrent/bencode.hpp
+++ b/include/libtorrent/bencode.hpp
@@ -64,8 +64,17 @@ POSSIBILITY OF SUCH DAMAGE.
 
 
 #include <cstdlib>
+
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/lexical_cast.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/entry.hpp"
 
 #if defined(_MSC_VER)
diff --git a/include/libtorrent/debug.hpp b/include/libtorrent/debug.hpp
index 79c3b1c9a..11ef9192b 100755
--- a/include/libtorrent/debug.hpp
+++ b/include/libtorrent/debug.hpp
@@ -36,8 +36,16 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <string>
 #include <fstream>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/lexical_cast.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 namespace libtorrent
 {
 
diff --git a/include/libtorrent/file.hpp b/include/libtorrent/file.hpp
index 4fd823e6f..1953c97e9 100755
--- a/include/libtorrent/file.hpp
+++ b/include/libtorrent/file.hpp
@@ -36,9 +36,17 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <memory>
 #include <stdexcept>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/noncopyable.hpp>
 #include <boost/filesystem/path.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/size_type.hpp"
 
 namespace libtorrent
diff --git a/include/libtorrent/invariant_check.hpp b/include/libtorrent/invariant_check.hpp
new file mode 100755
index 000000000..2c119d7ca
--- /dev/null
+++ b/include/libtorrent/invariant_check.hpp
@@ -0,0 +1,77 @@
+// Copyright Daniel Wallin 2004. Use, modification and distribution is
+// subject to the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef TORRENT_INVARIANT_ACCESS_HPP_INCLUDED
+#define TORRENT_INVARIANT_ACCESS_HPP_INCLUDED
+
+#include <iostream>
+#include <cassert>
+
+namespace libtorrent
+{
+
+	class invariant_access
+	{
+	public:
+		template<class T>
+		static void check_invariant(T const& self)
+		{
+			self.check_invariant();
+		}
+	};
+
+	template<class T>
+	void check_invariant(T const& x)
+	{
+		invariant_access::check_invariant(x);
+	}
+
+	struct invariant_checker {};
+
+	template<class T>
+	struct invariant_checker_impl : invariant_checker
+	{
+		invariant_checker_impl(T const& self_)
+			: self(self_)
+		{
+			try
+			{
+				check_invariant(self);
+			}
+			catch (...)
+			{
+				assert(false);
+			}
+		}
+
+		~invariant_checker_impl()
+		{
+			try
+			{
+				check_invariant(self);
+			}
+			catch (...)
+			{
+				assert(false);
+			}
+		}
+
+		T const& self;
+	};
+
+	template<class T>
+	invariant_checker_impl<T> make_invariant_checker(T const& x)
+	{
+		return invariant_checker_impl<T>(x);
+	}
+}
+
+#ifndef NDEBUG
+#define INVARIANT_CHECK \
+	invariant_checker const& _invariant_check = make_invariant_checker(*this)
+#else
+#define INVARIANT_CHECK do {} while (false)
+#endif
+
+#endif // TORRENT_INVARIANT_ACCESS_HPP_INCLUDED
diff --git a/include/libtorrent/peer_connection.hpp b/include/libtorrent/peer_connection.hpp
index 0283e43a5..3bf7a6c9b 100755
--- a/include/libtorrent/peer_connection.hpp
+++ b/include/libtorrent/peer_connection.hpp
@@ -39,6 +39,10 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <deque>
 #include <string>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/smart_ptr.hpp>
 #include <boost/noncopyable.hpp>
 #include <boost/array.hpp>
@@ -46,6 +50,10 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <boost/optional.hpp>
 #include <boost/cstdint.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/socket.hpp"
 #include "libtorrent/peer_id.hpp"
 #include "libtorrent/storage.hpp"
@@ -196,6 +204,7 @@ namespace libtorrent
 
 	class peer_connection: public boost::noncopyable
 	{
+	friend class invariant_access;
 	public:
 
 		// this is the constructor where the we are teh active part. The peer_conenction
@@ -304,10 +313,10 @@ namespace libtorrent
 		// quota is unlimited.
 		int send_quota_left() const { return m_send_quota_left; }
 
-		int total_free_upload() const
+		size_type total_free_upload() const
 		{ return m_free_upload; }
 
-		void add_free_upload(int free_upload)
+		void add_free_upload(size_type free_upload)
 		{ m_free_upload += free_upload; }
 
 		// returns the send quota assigned to this
@@ -332,7 +341,7 @@ namespace libtorrent
 		int send_quota_limit() const
 		{ return m_send_quota_limit; }
 
-		int share_diff() const;
+		size_type share_diff() const;
 
 		bool support_extensions() const
 		{ return m_supports_extensions; }
@@ -388,6 +397,8 @@ namespace libtorrent
 
 	private:
 
+		void check_invariant() const;
+
 		bool dispatch_message(int received);
 		void send_buffer_updated();
 
@@ -429,8 +440,8 @@ namespace libtorrent
 
 		const static message_handler m_message_handler[num_supported_messages];
 
-		std::size_t m_packet_size;
-		std::size_t m_recv_pos;
+		int m_packet_size;
+		int m_recv_pos;
 		std::vector<char> m_recv_buffer;
 
 		// this is the buffer where data that is
@@ -542,7 +553,7 @@ namespace libtorrent
 		// this will be negative on a peer from which
 		// we get free download, and positive on peers
 		// that we give the free upload, to keep the balance.
-		int m_free_upload;
+		size_type m_free_upload;
 
 		// this is used to limit upload bandwidth.
 		// it is reset to the allowed number of
diff --git a/include/libtorrent/peer_info.hpp b/include/libtorrent/peer_info.hpp
index 2ee91732d..fa340a866 100755
--- a/include/libtorrent/peer_info.hpp
+++ b/include/libtorrent/peer_info.hpp
@@ -34,8 +34,10 @@ POSSIBILITY OF SUCH DAMAGE.
 #define TORRENT_PEER_INFO_HPP_INCLUDED
 
 #include <vector>
+
 #include "libtorrent/socket.hpp"
 #include "libtorrent/peer_id.hpp"
+#include "libtorrent/size_type.hpp"
 
 namespace libtorrent
 {
@@ -54,14 +56,14 @@ namespace libtorrent
 		address ip;
 		float up_speed;
 		float down_speed;
-		unsigned int total_download;
-		unsigned int total_upload;
+		size_type total_download;
+		size_type total_upload;
 		peer_id id;
 		std::vector<bool> pieces;
 		int upload_limit; // from peer_connection
 		int upload_ceiling; // from the global upload limiter
 
-		int load_balancing;
+		size_type load_balancing;
 
 		// this is the number of requests
 		// we have sent to this peer
diff --git a/include/libtorrent/piece_picker.hpp b/include/libtorrent/piece_picker.hpp
index e9a079208..a6526fb04 100755
--- a/include/libtorrent/piece_picker.hpp
+++ b/include/libtorrent/piece_picker.hpp
@@ -37,8 +37,16 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <bitset>
 #include <cassert>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/optional.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/peer_id.hpp"
 #include "libtorrent/socket.hpp"
 
diff --git a/include/libtorrent/policy.hpp b/include/libtorrent/policy.hpp
index d5786e7fe..1037070bd 100755
--- a/include/libtorrent/policy.hpp
+++ b/include/libtorrent/policy.hpp
@@ -36,8 +36,16 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <algorithm>
 #include <vector>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/date_time/posix_time/posix_time.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/peer.hpp"
 #include "libtorrent/piece_picker.hpp"
 #include "libtorrent/socket.hpp"
@@ -202,7 +210,7 @@ namespace libtorrent
 
 		// free download we have got that hasn't
 		// been distributed yet.
-		int m_available_free_upload;
+		size_type m_available_free_upload;
 
 		// if there is a connection limit,
 		// we disconnect one peer every minute in hope of
diff --git a/include/libtorrent/session.hpp b/include/libtorrent/session.hpp
index cb3466f02..a7406ef06 100755
--- a/include/libtorrent/session.hpp
+++ b/include/libtorrent/session.hpp
@@ -40,11 +40,19 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <list>
 #include <deque>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/limits.hpp>
 #include <boost/tuple/tuple.hpp>
 #include <boost/filesystem/path.hpp>
 #include <boost/thread.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/torrent.hpp"
 #include "libtorrent/entry.hpp"
@@ -145,6 +153,7 @@ namespace libtorrent
 		// thread started to run the main downloader loop
 		struct session_impl: boost::noncopyable
 		{
+			friend class invariant_access;
 			typedef std::map<boost::shared_ptr<socket>, boost::shared_ptr<peer_connection> > connection_map;
 
 			session_impl(int listen_port, const fingerprint& cl_fprint);
@@ -208,7 +217,7 @@ namespace libtorrent
 			void purge_connections();
 
 #ifndef NDEBUG
-			void assert_invariant(const char *place);
+			void check_invariant(const char *place = 0);
 			boost::shared_ptr<logger> create_log(std::string name);
 			boost::shared_ptr<logger> m_logger;
 #endif
diff --git a/include/libtorrent/size_type.hpp b/include/libtorrent/size_type.hpp
index 3050b46a3..f636475be 100755
--- a/include/libtorrent/size_type.hpp
+++ b/include/libtorrent/size_type.hpp
@@ -33,8 +33,16 @@ POSSIBILITY OF SUCH DAMAGE.
 #ifndef TORRENT_SIZE_TYPE_HPP_INCLUDED
 #define TORRENT_SIZE_TYPE_HPP_INCLUDED
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/cstdint.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 namespace libtorrent
 {
 #if defined(_MSC_VER) && _MSC_VER < 1300
diff --git a/include/libtorrent/socket.hpp b/include/libtorrent/socket.hpp
index 4d1529634..c85f64724 100755
--- a/include/libtorrent/socket.hpp
+++ b/include/libtorrent/socket.hpp
@@ -33,10 +33,19 @@ POSSIBILITY OF SUCH DAMAGE.
 #ifndef TORRENT_SOCKET_HPP_INCLUDED
 #define TORRENT_SOCKET_HPP_INCLUDED
 
-#include <boost/smart_ptr.hpp>
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
+#include <boost/shared_ptr.hpp>
 #include <boost/function.hpp>
 #include <boost/noncopyable.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+
 #include <vector>
 #include <exception>
 #include <string>
diff --git a/include/libtorrent/stat.hpp b/include/libtorrent/stat.hpp
index dbbb9e9ed..5852a20bc 100755
--- a/include/libtorrent/stat.hpp
+++ b/include/libtorrent/stat.hpp
@@ -38,12 +38,14 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <assert.h>
 
 #include "libtorrent/size_type.hpp"
+#include "libtorrent/invariant_check.hpp"
 
 namespace libtorrent
 {
 
 	class stat
 	{
+	friend class invariant_access;
 	enum { history = 10 };
 	public:
 
@@ -67,6 +69,8 @@ namespace libtorrent
 
 		void operator+=(const stat& s)
 		{
+			INVARIANT_CHECK;
+
 			m_downloaded_payload += s.m_downloaded_payload;
 			m_total_download_payload += s.m_downloaded_payload;
 			m_downloaded_protocol += s.m_downloaded_protocol;
@@ -80,22 +84,26 @@ namespace libtorrent
 
 		void received_bytes(int bytes_payload, int bytes_protocol)
 		{
+			INVARIANT_CHECK;
+
 			assert(bytes_payload >= 0);
 			assert(bytes_protocol >= 0);
+
 			m_downloaded_payload += bytes_payload;
 			m_total_download_payload += bytes_payload;
-
 			m_downloaded_protocol += bytes_protocol;
 			m_total_download_protocol += bytes_protocol;
 		}
 
 		void sent_bytes(int bytes_payload, int bytes_protocol)
 		{
+			INVARIANT_CHECK;
+
 			assert(bytes_payload >= 0);
 			assert(bytes_protocol >= 0);
+
 			m_uploaded_payload += bytes_payload;
 			m_total_upload_payload += bytes_payload;
-
 			m_uploaded_protocol += bytes_protocol;
 			m_total_upload_protocol += bytes_protocol;
 		}
@@ -119,7 +127,7 @@ namespace libtorrent
 	private:
 
 #ifndef NDEBUG
-		void check_invariant()
+		void check_invariant() const
 		{
 			assert(m_mean_upload_per_second >= 0);
 			assert(m_mean_download_per_second >= 0);
@@ -159,12 +167,12 @@ namespace libtorrent
 		size_type m_total_upload_protocol;
 
 		// peak mean download/upload rates
-		int m_peak_downloaded_per_second;
-		int m_peak_uploaded_per_second;
+		float m_peak_downloaded_per_second;
+		float m_peak_uploaded_per_second;
 
 		// current mean download/upload rates
-		int m_mean_download_per_second;
-		int m_mean_upload_per_second;
+		float m_mean_download_per_second;
+		float m_mean_upload_per_second;
 	};
 
 }
diff --git a/include/libtorrent/storage.hpp b/include/libtorrent/storage.hpp
index 2e8758159..166654b55 100755
--- a/include/libtorrent/storage.hpp
+++ b/include/libtorrent/storage.hpp
@@ -36,10 +36,19 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <vector>
 #include <bitset>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/limits.hpp>
 #include <boost/filesystem/path.hpp>
 #include <boost/thread.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+
 #include "libtorrent/torrent_info.hpp"
 #include "libtorrent/opaque_value_ptr.hpp"
 
@@ -78,11 +87,14 @@ namespace libtorrent
 
 		void swap(storage&);
 
-		size_type read(char* buf, int slot, size_type offset, size_type size);
-		void write(const char* buf, int slot, size_type offset, size_type size);
+		// may throw file_error if storage for slot does not exist
+		size_type read(char* buf, int slot, int offset, int size);
+
+		// may throw file_error if storage for slot hasn't been allocated
+		void write(const char* buf, int slot, int offset, int size);
 
 	private:
-		struct impl;
+		class impl;
 		opaque_value_ptr<impl> m_pimpl;
 	};
 
@@ -110,8 +122,17 @@ namespace libtorrent
 			, const std::bitset<256>& bitmask);
 		int slot_for_piece(int piece_index) const;
 
-		size_type read(char* buf, int piece_index, size_type offset, size_type size);
-		void write(const char* buf, int piece_index, size_type offset, size_type size);
+		size_type read(
+			char* buf
+			, int piece_index
+			, int offset
+			, int size);
+
+		void write(
+			const char* buf
+			, int piece_index
+			, int offset
+			, int size);
 
 		const boost::filesystem::path& save_path() const;
 
@@ -122,7 +143,7 @@ namespace libtorrent
 		void export_piece_map(std::vector<int>& pieces) const;
 
 	private:
-		struct impl;
+		class impl;
 		std::auto_ptr<impl> m_pimpl;
 	};
 
diff --git a/include/libtorrent/torrent.hpp b/include/libtorrent/torrent.hpp
index aa0fac812..e7e5014ef 100755
--- a/include/libtorrent/torrent.hpp
+++ b/include/libtorrent/torrent.hpp
@@ -39,10 +39,18 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <list>
 #include <iostream>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/limits.hpp>
 #include <boost/filesystem/path.hpp>
 #include <boost/date_time/posix_time/posix_time.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/entry.hpp"
 #include "libtorrent/torrent_info.hpp"
@@ -151,7 +159,7 @@ namespace libtorrent
 		}
 
 		// the number of peers that belong to this torrent
-		int num_peers() const { return m_connections.size(); }
+		int num_peers() const { return (int)m_connections.size(); }
 
 		// returns true if this torrent has a connection
 		// to a peer with the given peer_id
diff --git a/include/libtorrent/torrent_handle.hpp b/include/libtorrent/torrent_handle.hpp
index b30388980..8e754c8dd 100755
--- a/include/libtorrent/torrent_handle.hpp
+++ b/include/libtorrent/torrent_handle.hpp
@@ -34,8 +34,17 @@ POSSIBILITY OF SUCH DAMAGE.
 #define TORRENT_TORRENT_HANDLE_HPP_INCLUDED
 
 #include <vector>
+
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/date_time/posix_time/posix_time.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/peer_id.hpp"
 #include "libtorrent/peer_info.hpp"
 #include "libtorrent/piece_picker.hpp"
diff --git a/include/libtorrent/torrent_info.hpp b/include/libtorrent/torrent_info.hpp
index eb7bc8f6f..327f54f19 100755
--- a/include/libtorrent/torrent_info.hpp
+++ b/include/libtorrent/torrent_info.hpp
@@ -36,8 +36,17 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <string>
 #include <vector>
+
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/date_time/posix_time/posix_time.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/entry.hpp"
 #include "libtorrent/socket.hpp"
 #include "libtorrent/peer_id.hpp"
@@ -106,7 +115,7 @@ namespace libtorrent
 		reverse_file_iterator rbegin_files() const { return m_files.rbegin(); }
 		reverse_file_iterator rend_files() const { return m_files.rend(); }
 
-		std::size_t num_files() const { return m_files.size(); }
+		int num_files() const { return (int)m_files.size(); }
 		const file_entry& file_at(int index) const { assert(index >= 0 && index < (int)m_files.size()); return m_files[index]; }
 
 		const std::vector<announce_entry>& trackers() const { return m_urls; }
@@ -116,8 +125,8 @@ namespace libtorrent
 		// the begining) and return the new index to the tracker.
 		int prioritize_tracker(int index);
 
-		size_type total_size() const { assert(m_total_size>=0); return m_total_size; }
-		size_type piece_length() const { assert(m_piece_length>0); return m_piece_length; }
+		size_type total_size() const { return m_total_size; }
+		int piece_length() const { return m_piece_length; }
 		int num_pieces() const { return (int)m_piece_hash.size(); }
 		const sha1_hash& info_hash() const { return m_info_hash; }
 		const std::string& name() const { return m_name; }
@@ -125,12 +134,13 @@ namespace libtorrent
 
 		void convert_file_names();
 
-		size_type piece_size(int index) const
+		int piece_size(int index) const
 		{
 			assert(index >= 0 && index < num_pieces());
 			if (index == num_pieces()-1)
 			{
-				size_type s = total_size() - (size_type)(num_pieces() - 1)*piece_length();
+				int s = static_cast<int>(total_size()
+					- (size_type)(num_pieces() - 1) * piece_length());
 				assert(s > 0);
 				assert(s <= piece_length());
 				return s;
@@ -141,7 +151,8 @@ namespace libtorrent
 
 		const sha1_hash& hash_for_piece(int index) const
 		{
-			assert(index >= 0 && index < (int)m_piece_hash.size());
+			assert(index >= 0);
+			assert(index < (int)m_piece_hash.size());
 			return m_piece_hash[index];
 		}
 
@@ -159,7 +170,7 @@ namespace libtorrent
 		std::vector<announce_entry> m_urls;
 
 		// the length of one piece
-		size_type m_piece_length;
+		int m_piece_length;
 
 		// the sha-1 hashes of each piece
 		std::vector<sha1_hash> m_piece_hash;
diff --git a/src/identify_client.cpp b/src/identify_client.cpp
index 113979c4e..9f79c9468 100755
--- a/src/identify_client.cpp
+++ b/src/identify_client.cpp
@@ -30,9 +30,18 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
-#include <boost/optional.hpp>
 #include <cctype>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
+#include <boost/optional.hpp>
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/identify_client.hpp"
 #include "libtorrent/fingerprint.hpp"
 
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 9bd7cf7e8..29528148e 100755
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -41,6 +41,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/entry.hpp"
 #include "libtorrent/bencode.hpp"
 #include "libtorrent/alert_types.hpp"
+#include "libtorrent/invariant_check.hpp"
 
 #if defined(_MSC_VER)
 #define for if (false) {} else for
@@ -82,8 +83,8 @@ namespace libtorrent
 		, m_timeout(120)
 		, m_packet_size(1)
 		, m_recv_pos(0)
-		, m_last_receive(boost::gregorian::date(std::time(0)))
-		, m_last_sent(boost::gregorian::date(std::time(0)))
+		, m_last_receive(boost::posix_time::second_clock::local_time())
+		, m_last_sent(boost::posix_time::second_clock::local_time())
 		, m_selector(sel)
 		, m_socket(s)
 		, m_torrent(t)
@@ -102,10 +103,12 @@ namespace libtorrent
 		, m_send_quota_limit(100)
 		, m_trust_points(0)
 		, m_num_invalid_requests(0)
-		, m_last_piece(boost::gregorian::date(std::time(0)))
+		, m_last_piece(boost::posix_time::second_clock::local_time())
 		, m_last_piece_time(boost::posix_time::seconds(0))
 		, m_disconnecting(false)
 	{
+		INVARIANT_CHECK;
+
 		assert(!m_socket->is_blocking());
 		assert(m_torrent != 0);
 
@@ -141,8 +144,8 @@ namespace libtorrent
 		, m_timeout(120)
 		, m_packet_size(1)
 		, m_recv_pos(0)
-		, m_last_receive(boost::gregorian::date(std::time(0)))
-		, m_last_sent(boost::gregorian::date(std::time(0)))
+		, m_last_receive(boost::posix_time::second_clock::local_time())
+		, m_last_sent(boost::posix_time::second_clock::local_time())
 		, m_selector(sel)
 		, m_socket(s)
 		, m_torrent(0)
@@ -162,10 +165,12 @@ namespace libtorrent
 		, m_send_quota_limit(100)
 		, m_trust_points(0)
 		, m_num_invalid_requests(0)
-		, m_last_piece(boost::gregorian::date(std::time(0)))
+		, m_last_piece(boost::posix_time::second_clock::local_time())
 		, m_last_piece_time(boost::posix_time::seconds(0))
 		, m_disconnecting(false)
 	{
+		INVARIANT_CHECK;
+
 		assert(!m_socket->is_blocking());
 
 		std::fill(m_peer_id.begin(), m_peer_id.end(), 0);
@@ -200,6 +205,8 @@ namespace libtorrent
 
 	void peer_connection::set_send_quota(int num_bytes)
 	{
+		INVARIANT_CHECK;
+
 		assert(num_bytes <= m_send_quota_limit || m_send_quota_limit == -1);
 		if (num_bytes > m_send_quota_limit && m_send_quota_limit!=-1) num_bytes = m_send_quota_limit;
 
@@ -210,6 +217,8 @@ namespace libtorrent
 
 	void peer_connection::send_handshake()
 	{
+		INVARIANT_CHECK;
+
 		assert(m_send_buffer.size() == 0);
 
 		// add handshake to the send buffer
@@ -312,6 +321,8 @@ namespace libtorrent
 
 	void peer_connection::on_choke(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size != 1)
 			throw protocol_error("'choke' message size != 1");
 		m_statistics.received_bytes(0, received);
@@ -343,6 +354,8 @@ namespace libtorrent
 
 	void peer_connection::on_unchoke(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size != 1)
 			throw protocol_error("'unchoke' message size != 1");
 		m_statistics.received_bytes(0, received);
@@ -361,6 +374,8 @@ namespace libtorrent
 
 	void peer_connection::on_interested(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size != 1)
 			throw protocol_error("'interested' message size != 1");
 		m_statistics.received_bytes(0, received);
@@ -379,6 +394,8 @@ namespace libtorrent
 
 	void peer_connection::on_not_interested(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size != 1)
 			throw protocol_error("'not interested' message size != 1");
 		m_statistics.received_bytes(0, received);
@@ -400,6 +417,8 @@ namespace libtorrent
 
 	void peer_connection::on_have(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size != 5)
 			throw protocol_error("'have' message size != 5");
 		m_statistics.received_bytes(0, received);
@@ -408,7 +427,7 @@ namespace libtorrent
 		const char* ptr = &m_recv_buffer[1];
 		int index = detail::read_int32(ptr);
 		// if we got an invalid message, abort
-		if (index >= m_have_piece.size() || index < 0)
+		if (index >= (int)m_have_piece.size() || index < 0)
 			throw protocol_error("have message with higher index than the number of pieces");
 
 #ifndef NDEBUG
@@ -442,6 +461,8 @@ namespace libtorrent
 
 	void peer_connection::on_bitfield(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size - 1 != (m_have_piece.size() + 7) / 8)
 			throw protocol_error("bitfield with invalid size");
 		m_statistics.received_bytes(0, received);
@@ -452,9 +473,9 @@ namespace libtorrent
 #endif
 		// build a vector of all pieces
 		std::vector<int> piece_list;
-		for (std::size_t i = 0; i < m_have_piece.size(); ++i)
+		for (int i = 0; i < (int)m_have_piece.size(); ++i)
 		{
-			bool have = m_recv_buffer[1 + (i>>3)] & (1 << (7 - (i&7)));
+			bool have = (m_recv_buffer[1 + (i>>3)] & (1 << (7 - (i&7)))) != 0;
 			if (have && !m_have_piece[i])
 			{
 				m_have_piece[i] = true;
@@ -507,6 +528,8 @@ namespace libtorrent
 
 	void peer_connection::on_request(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size != 13)
 			throw protocol_error("'request' message size != 13");
 		m_statistics.received_bytes(0, received);
@@ -572,6 +595,8 @@ namespace libtorrent
 
 	void peer_connection::on_piece(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_recv_pos - received <= 9)
 		{
 			m_last_piece = boost::posix_time::second_clock::local_time();
@@ -717,6 +742,8 @@ namespace libtorrent
 
 	void peer_connection::on_cancel(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size != 13)
 			throw protocol_error("'cancel' message size != 13");
 		m_statistics.received_bytes(0, received);
@@ -752,6 +779,8 @@ namespace libtorrent
 
 	void peer_connection::on_extension_list(int received)
 	{
+		INVARIANT_CHECK;
+
 		if (m_packet_size > 100 * 1024)
 		{
 			// too big extension message, abort
@@ -771,7 +800,7 @@ namespace libtorrent
 					extensions.find(extension_names[i]);
 				if (f != extensions.end())
 				{
-					m_extension_messages[i] = f->second.integer();
+					m_extension_messages[i] = (int)f->second.integer();
 				}
 			}
 #ifndef NDEBUG
@@ -784,11 +813,11 @@ namespace libtorrent
 			}
 #endif
 		}
-		catch(invalid_encoding& e)
+		catch(invalid_encoding&)
 		{
 			throw protocol_error("'extensions' packet contains invalid bencoding");
 		}
-		catch(type_error& e)
+		catch(type_error&)
 		{
 			throw protocol_error("'extensions' packet contains incorrect types");
 		}
@@ -800,6 +829,8 @@ namespace libtorrent
 
 	void peer_connection::on_extended(int received)
 	{
+		INVARIANT_CHECK;
+
 		m_statistics.received_bytes(0, received);
 		if (m_packet_size < 5)
 			throw protocol_error("'extended' message smaller than 5 bytes");
@@ -837,11 +868,11 @@ namespace libtorrent
 					}
 
 				}
-				catch (invalid_encoding& e)
+				catch (invalid_encoding&)
 				{
 					throw protocol_error("invalid bencoding in CHAT message");
 				}
-				catch (type_error& e)
+				catch (type_error&)
 				{
 					throw protocol_error("invalid types in bencoded CHAT message");
 				}
@@ -873,6 +904,8 @@ namespace libtorrent
 
 	bool peer_connection::dispatch_message(int received)
 	{
+		INVARIANT_CHECK;
+
 		assert(m_recv_pos >= received);
 		assert(m_recv_pos > 0);
 		assert(m_torrent);
@@ -898,6 +931,8 @@ namespace libtorrent
 
 	void peer_connection::send_cancel(piece_block block)
 	{
+		INVARIANT_CHECK;
+
 		assert(block.piece_index >= 0);
 		assert(block.piece_index < m_torrent->torrent_file().num_pieces());
 		assert(m_torrent->picker().is_downloading(block));
@@ -944,6 +979,8 @@ namespace libtorrent
 
 	void peer_connection::send_request(piece_block block)
 	{
+		INVARIANT_CHECK;
+
 		assert(block.piece_index >= 0);
 		assert(block.piece_index < m_torrent->torrent_file().num_pieces());
 		assert(!m_torrent->picker().is_downloading(block));
@@ -995,6 +1032,8 @@ namespace libtorrent
 
 	void peer_connection::send_chat_message(const std::string& msg)
 	{
+		INVARIANT_CHECK;
+
 		assert(msg.length() <= 1 * 1024);
 		if (m_extension_messages[extended_chat_message] == -1) return;
 
@@ -1005,7 +1044,7 @@ namespace libtorrent
 		bencode(std::back_inserter(message), e);
 		std::back_insert_iterator<std::vector<char> > ptr(m_send_buffer);
 
-		detail::write_uint32(1 + 4 + message.size(), ptr);
+		detail::write_uint32(1 + 4 + (int)message.size(), ptr);
 		detail::write_uint8(msg_extended, ptr);
 		detail::write_int32(m_extension_messages[extended_chat_message], ptr);
 		std::copy(message.begin(), message.end(), ptr);
@@ -1014,17 +1053,21 @@ namespace libtorrent
 
 	void peer_connection::send_bitfield()
 	{
+		INVARIANT_CHECK;
+
 	#ifndef NDEBUG
 		(*m_logger) << " ==> BITFIELD\n";
 	#endif
-		const int packet_size = (m_have_piece.size() + 7) / 8 + 5;
-		const int old_size = m_send_buffer.size();
+		const int packet_size = ((int)m_have_piece.size() + 7) / 8 + 5;
+		const int old_size = (int)m_send_buffer.size();
 		m_send_buffer.resize(old_size + packet_size);
+
 		char* ptr = &m_send_buffer[old_size];
 		detail::write_int32(packet_size - 4, ptr);
-		m_send_buffer[old_size+4] = msg_bitfield;
-		std::fill(m_send_buffer.begin()+old_size+5, m_send_buffer.end(), 0);
-		for (std::size_t i = 0; i < m_have_piece.size(); ++i)
+		detail::write_uint8(msg_bitfield, ptr);
+
+		std::fill(m_send_buffer.begin() + old_size + 5, m_send_buffer.end(), 0);
+		for (int i = 0; i < (int)m_have_piece.size(); ++i)
 		{
 			if (m_torrent->have_piece(i))
 				m_send_buffer[old_size + 5 + (i>>3)] |= 1 << (7 - (i&7));
@@ -1034,6 +1077,8 @@ namespace libtorrent
 
 	void peer_connection::send_extensions()
 	{
+		INVARIANT_CHECK;
+
 	#ifndef NDEBUG
 		(*m_logger) << " ==> EXTENSIONS\n";
 	#endif
@@ -1047,7 +1092,7 @@ namespace libtorrent
 		}
 
 		// make room for message size
-		const int msg_size_pos = m_send_buffer.size();
+		const int msg_size_pos = (int)m_send_buffer.size();
 		m_send_buffer.resize(msg_size_pos + 4);
 
 		m_send_buffer.push_back(msg_extension_list);
@@ -1056,13 +1101,15 @@ namespace libtorrent
 
 		// write the length of the message
 		char* ptr = &m_send_buffer[msg_size_pos];
-		detail::write_int32(m_send_buffer.size() - msg_size_pos - 4, ptr);
+		detail::write_int32((int)m_send_buffer.size() - msg_size_pos - 4, ptr);
 
 		send_buffer_updated();
 	}
 
 	void peer_connection::send_choke()
 	{
+		INVARIANT_CHECK;
+
 		if (m_choked) return;
 		char msg[] = {0,0,0,1,msg_choke};
 		m_send_buffer.insert(m_send_buffer.end(), msg, msg+sizeof(msg));
@@ -1077,6 +1124,8 @@ namespace libtorrent
 
 	void peer_connection::send_unchoke()
 	{
+		INVARIANT_CHECK;
+
 		if (!m_choked) return;
 		char msg[] = {0,0,0,1,msg_unchoke};
 		m_send_buffer.insert(m_send_buffer.end(), msg, msg+sizeof(msg));
@@ -1089,6 +1138,8 @@ namespace libtorrent
 
 	void peer_connection::send_interested()
 	{
+		INVARIANT_CHECK;
+
 		if (m_interesting) return;
 		char msg[] = {0,0,0,1,msg_interested};
 		m_send_buffer.insert(m_send_buffer.end(), msg, msg+sizeof(msg));
@@ -1101,6 +1152,8 @@ namespace libtorrent
 
 	void peer_connection::send_not_interested()
 	{
+		INVARIANT_CHECK;
+
 		if (!m_interesting) return;
 		char msg[] = {0,0,0,1,msg_not_interested};
 		m_send_buffer.insert(m_send_buffer.end(), msg, msg+sizeof(msg));
@@ -1113,6 +1166,8 @@ namespace libtorrent
 
 	void peer_connection::send_have(int index)
 	{
+		INVARIANT_CHECK;
+
 		// optimization, don't send have messages
 		// to peers that already have the piece
 		if (m_have_piece[index]) return;
@@ -1128,7 +1183,7 @@ namespace libtorrent
 		send_buffer_updated();
 	}
 
-	int peer_connection::share_diff() const
+	size_type peer_connection::share_diff() const
 	{
 		float ratio = m_torrent->ratio();
 
@@ -1137,12 +1192,14 @@ namespace libtorrent
 		if (ratio == 0.f) return std::numeric_limits<int>::max();
 
 		return m_free_upload
-			+ static_cast<int>(m_statistics.total_payload_download() * ratio)
+			+ static_cast<size_type>(m_statistics.total_payload_download() * ratio)
 			- m_statistics.total_payload_upload();
 	}
 
 	void peer_connection::second_tick()
 	{
+		INVARIANT_CHECK;
+
 		m_statistics.second_tick();
 		m_send_quota_left = m_send_quota;
 		if (m_send_quota > 0) send_buffer_updated();
@@ -1154,7 +1211,7 @@ namespace libtorrent
 		// maintain the share ratio given by m_ratio
 		// with all peers.
 
-		int diff = share_diff();
+		size_type diff = share_diff();
 
 		enum { block_limit=2 }; // how many blocks difference is considered unfair
 
@@ -1200,6 +1257,8 @@ namespace libtorrent
 	// throws exception when the client should be disconnected
 	void peer_connection::receive_data()
 	{
+		INVARIANT_CHECK;
+
 		assert(!m_socket->is_blocking());
 		assert(m_packet_size > 0);
 		assert(m_socket->is_readable());
@@ -1466,6 +1525,8 @@ namespace libtorrent
 	// throws exception when the client should be disconnected
 	void peer_connection::send_data()
 	{
+		INVARIANT_CHECK;
+
 		assert(m_socket->is_writable());
 		assert(has_data());
 
@@ -1475,19 +1536,22 @@ namespace libtorrent
 		// requested block. Have a limit of how much of the requested
 		// block is actually read at a time.
 		while (!m_requests.empty()
-			&& (m_send_buffer.size() < m_torrent->block_size())
+			&& ((int)m_send_buffer.size() < m_torrent->block_size())
 			&& !m_choked)
 		{
 			peer_request& r = m_requests.front();
 			
-			assert(r.piece >= 0 && r.piece < m_have_piece.size() && m_torrent && m_torrent->have_piece(r.piece));
+			assert(r.piece >= 0);
+			assert(r.piece < (int)m_have_piece.size());
+			assert(m_torrent != 0);
+			assert(m_torrent->have_piece(r.piece));
 			assert(r.start + r.length <= m_torrent->torrent_file().piece_size(r.piece));
 			assert(r.length > 0 && r.start >= 0);
 
 #ifndef NDEBUG
 //			assert(m_torrent->verify_piece(r.piece) && "internal error");
 #endif
-			const int send_buffer_offset = m_send_buffer.size();
+			const int send_buffer_offset = (int)m_send_buffer.size();
 			const int packet_size = 4 + 5 + 4 + r.length;
 			m_send_buffer.resize(send_buffer_offset + packet_size);
 			char* ptr = &m_send_buffer[send_buffer_offset];
@@ -1539,7 +1603,7 @@ namespace libtorrent
 		if (!m_send_buffer.empty())
 		{
 
-			int amount_to_send = m_send_buffer.size();
+			int amount_to_send = (int)m_send_buffer.size();
 			assert(m_send_quota_left != 0);
 			if (m_send_quota_left > 0)
 				amount_to_send = std::min(m_send_quota_left, amount_to_send);
@@ -1615,22 +1679,19 @@ namespace libtorrent
 
 		assert(m_added_to_selector);
 		send_buffer_updated();
-/*
-	#ifndef NDEBUG
-		if (has_data())
-		{
-			if (m_socket->is_writable())
-			{
-				std::cout << "ERROR, not good\n";
-			}
-		}
-	#endif
-*/
 	}
 
+#ifndef NDEBUG
+	void peer_connection::check_invariant() const
+	{
+		assert(has_data() == m_selector.is_writability_monitored(m_socket));
+	}
+#endif
 
 	void peer_connection::keep_alive()
 	{
+		INVARIANT_CHECK;
+
 		boost::posix_time::time_duration d;
 		d = boost::posix_time::second_clock::local_time() - m_last_sent;
 		if (d.seconds() < m_timeout / 2) return;
diff --git a/src/piece_picker.cpp b/src/piece_picker.cpp
index f1a4174c1..6cace6408 100755
--- a/src/piece_picker.cpp
+++ b/src/piece_picker.cpp
@@ -87,7 +87,7 @@ namespace libtorrent
 			++i)
 		{
 			if (*i) continue;
-			int index = i - pieces.begin();
+			int index = static_cast<int>(i - pieces.begin());
 			piece_list.push_back(index);
 		}
 	
@@ -100,14 +100,14 @@ namespace libtorrent
 			++i)
 		{
 			int index = *i;
-			assert(index < m_piece_map.size());
+			assert(index < (int)m_piece_map.size());
 			assert(m_piece_map[index].index  == 0xffffff);
 
 			int peer_count = m_piece_map[index].peer_count;
 			assert(peer_count == 0);
 			assert(m_piece_info.size() == 2);
 
-			m_piece_map[index].index = m_piece_info[peer_count].size();
+			m_piece_map[index].index = (int)m_piece_info[peer_count].size();
 			m_piece_info[peer_count].push_back(index);
 		}
 
@@ -147,7 +147,7 @@ namespace libtorrent
 			i != m_piece_map.end();
 			++i)
 		{
-			int index = i - m_piece_map.begin();
+			int index = static_cast<int>(i - m_piece_map.begin());
 
 			if (t != 0)
 			{
@@ -249,8 +249,8 @@ namespace libtorrent
 	{
 		std::vector<std::vector<int> >& src_vec = (downloading)?m_downloading_piece_info:m_piece_info;
 
-		assert(src_vec.size() > peer_count);
-		assert(src_vec[peer_count].size() > elem_index);
+		assert((int)src_vec.size() > peer_count);
+		assert((int)src_vec[peer_count].size() > elem_index);
 
 		int index = src_vec[peer_count][elem_index];
 		// update the piece_map
@@ -266,7 +266,7 @@ namespace libtorrent
 			assert(dst_vec.size() > p.peer_count);
 		}
 
-		p.index = dst_vec[p.peer_count].size();
+		p.index = (int)dst_vec[p.peer_count].size();
 		dst_vec[p.peer_count].push_back(index);
 		assert(p.index < dst_vec[p.peer_count].size());
 		assert(dst_vec[p.peer_count][p.index] == index);
@@ -279,7 +279,7 @@ namespace libtorrent
 			// update the entry we moved from the back
 			m_piece_map[replace_index].index = elem_index;
 
-			assert(src_vec[peer_count].size() > elem_index);
+			assert((int)src_vec[peer_count].size() > elem_index);
 			assert(m_piece_map[replace_index].peer_count == peer_count);
 			assert(m_piece_map[replace_index].index == elem_index);
 			assert(src_vec[peer_count][elem_index] == replace_index);
@@ -297,8 +297,8 @@ namespace libtorrent
 	{
 		std::vector<std::vector<int> >& src_vec = (downloading)?m_downloading_piece_info:m_piece_info;
 
-		assert(src_vec.size() > peer_count);
-		assert(src_vec[peer_count].size() > elem_index);
+		assert((int)src_vec.size() > peer_count);
+		assert((int)src_vec[peer_count].size() > elem_index);
 
 		int index = src_vec[peer_count][elem_index];
 		m_piece_map[index].index = 0xffffff;
@@ -318,7 +318,7 @@ namespace libtorrent
 		// preserving order
 		index = src_vec[peer_count][elem_index] = src_vec[peer_count].back();
 		// update the entry we moved from the back
-		if (src_vec[peer_count].size() > elem_index+1)
+		if ((int)src_vec[peer_count].size() > elem_index+1)
 			m_piece_map[index].index = elem_index;
 		src_vec[peer_count].pop_back();
 
@@ -327,7 +327,7 @@ namespace libtorrent
 	void piece_picker::restore_piece(int index)
 	{
 		assert(index >= 0);
-		assert(index < m_piece_map.size());
+		assert(index < (int)m_piece_map.size());
 
 		assert(m_piece_map[index].downloading == 1);
 
@@ -349,7 +349,7 @@ namespace libtorrent
 	void piece_picker::inc_refcount(int i)
 	{
 		assert(i >= 0);
-		assert(i < m_piece_map.size());
+		assert(i < (int)m_piece_map.size());
 
 		int peer_count = m_piece_map[i].peer_count;
 		int index = m_piece_map[i].index;
@@ -371,7 +371,7 @@ namespace libtorrent
 	void piece_picker::dec_refcount(int i)
 	{
 		assert(i >= 0);
-		assert(i < m_piece_map.size());
+		assert(i < (int)m_piece_map.size());
 
 		int peer_count = m_piece_map[i].peer_count;
 		int index = m_piece_map[i].index;
@@ -385,7 +385,7 @@ namespace libtorrent
 
 	void piece_picker::we_have(int index)
 	{
-		assert(index < m_piece_map.size());
+		assert(index < (int)m_piece_map.size());
 		int info_index = m_piece_map[index].index;
 		int peer_count = m_piece_map[index].peer_count;
 
@@ -448,7 +448,7 @@ namespace libtorrent
 			i != piece_list.end();
 			++i)
 		{
-			assert(*i < m_piece_map.size());
+			assert(*i < (int)m_piece_map.size());
 			// if the peer doesn't have the piece
 			// skip it
 			if (!pieces[*i]) continue;
@@ -496,14 +496,14 @@ namespace libtorrent
 
 	bool piece_picker::is_piece_finished(int index) const
 	{
-		assert(index < m_piece_map.size());
+		assert(index < (int)m_piece_map.size());
 		assert(index >= 0);
 
 		if (m_piece_map[index].downloading == 0) return false;
 		std::vector<downloading_piece>::const_iterator i
 			= std::find_if(m_downloads.begin(), m_downloads.end(), has_index(index));
 		assert(i != m_downloads.end());
-		assert(i->finished_blocks.count() <= m_blocks_per_piece);
+		assert((int)i->finished_blocks.count() <= m_blocks_per_piece);
 		int max_blocks = blocks_in_piece(index);
 		if (i->finished_blocks.count() != max_blocks) return false;
 
@@ -513,7 +513,7 @@ namespace libtorrent
 
 	bool piece_picker::is_downloading(piece_block block) const
 	{
-		assert(block.piece_index < m_piece_map.size());
+		assert(block.piece_index < (int)m_piece_map.size());
 		assert(block.block_index < max_blocks_per_piece);
 
 		if (m_piece_map[block.piece_index].downloading == 0) return false;
@@ -529,7 +529,7 @@ namespace libtorrent
 
 	bool piece_picker::is_finished(piece_block block) const
 	{
-		assert(block.piece_index < m_piece_map.size());
+		assert(block.piece_index < (int)m_piece_map.size());
 		assert(block.block_index < max_blocks_per_piece);
 
 		if (m_piece_map[block.piece_index].index == 0xffffff) return true;
@@ -546,7 +546,7 @@ namespace libtorrent
 #ifndef NDEBUG
 //		integrity_check();
 #endif
-		assert(block.piece_index < m_piece_map.size());
+		assert(block.piece_index < (int)m_piece_map.size());
 		assert(block.block_index < blocks_in_piece(block.piece_index));
 
 		piece_pos& p = m_piece_map[block.piece_index];
@@ -580,7 +580,7 @@ namespace libtorrent
 #ifndef NDEBUG
 //		integrity_check();
 #endif
-		assert(block.piece_index < m_piece_map.size());
+		assert(block.piece_index < (int)m_piece_map.size());
 		assert(block.block_index < blocks_in_piece(block.piece_index));
 
 		piece_pos& p = m_piece_map[block.piece_index];
@@ -675,7 +675,7 @@ namespace libtorrent
 //		integrity_check();
 #endif
 
-		assert(block.piece_index < m_piece_map.size());
+		assert(block.piece_index < (int)m_piece_map.size());
 		assert(block.block_index < max_blocks_per_piece);
 
 		if (m_piece_map[block.piece_index].downloading == 0)
@@ -716,7 +716,7 @@ namespace libtorrent
 			i != m_downloads.end();
 			++i)
 		{
-			counter += i->finished_blocks.count();
+			counter += (int)i->finished_blocks.count();
 		}
 		return counter;
 	}
diff --git a/src/policy.cpp b/src/policy.cpp
index c4ff608e9..622bf6714 100755
--- a/src/policy.cpp
+++ b/src/policy.cpp
@@ -32,8 +32,16 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <iostream>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/date_time/posix_time/posix_time.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/policy.hpp"
 #include "libtorrent/torrent.hpp"
 #include "libtorrent/socket.hpp"
@@ -99,7 +107,7 @@ namespace
 
 		assert(desired_queue_size >= min_request_queue);
 
-		int num_requests = desired_queue_size - c.download_queue().size();
+		int num_requests = desired_queue_size - (int)c.download_queue().size();
 
 		// if our request queue is already full, we
 		// don't have to make any new requests yet
@@ -187,18 +195,18 @@ namespace
 	}
 
 
-	int collect_free_download(
+	size_type collect_free_download(
 		torrent::peer_iterator start
 		, torrent::peer_iterator end)
 	{
-		int accumulator = 0;
+		size_type accumulator = 0;
 		for (torrent::peer_iterator i = start; i != end; ++i)
 		{
 			// if the peer is interested in us, it means it may
 			// want to trade it's surplus uploads for downloads itself
 			// (and we should consider it free). If the share diff is
 			// negative, there's no free download to get from this peer.
-			int diff = i->second->share_diff();
+			size_type diff = i->second->share_diff();
 			if (i->second->is_peer_interested() || diff <= 0)
 				continue;
 
@@ -214,14 +222,14 @@ namespace
 
 	// returns the amount of free upload left after
 	// it has been distributed to the peers
-	int distribute_free_upload(
+	size_type distribute_free_upload(
 		torrent::peer_iterator start
 		, torrent::peer_iterator end
-		, int free_upload)
+		, size_type free_upload)
 	{
 		if (free_upload <= 0) return free_upload;
 		int num_peers = 0;
-		int total_diff = 0;
+		size_type total_diff = 0;
 		for (torrent::peer_iterator i = start; i != end; ++i)
 		{
 			total_diff += i->second->share_diff();
@@ -230,7 +238,7 @@ namespace
 		}
 
 		if (num_peers == 0) return free_upload;
-		int upload_share;
+		size_type upload_share;
 		if (total_diff >= 0)
 		{
 			upload_share = std::min(free_upload, total_diff) / num_peers;
@@ -295,7 +303,7 @@ namespace libtorrent
 	policy::peer* policy::find_choke_candidate()
 	{
 		peer* worst_peer = 0;
-		int min_weight = std::numeric_limits<int>::max();
+		size_type min_weight = std::numeric_limits<int>::max();
 
 		// TODO: make this selection better
 
@@ -311,10 +319,10 @@ namespace libtorrent
 			if (!c->is_peer_interested())
 				return &(*i);
 
-			int diff = i->total_download()
+			size_type diff = i->total_download()
 				- i->total_upload();
 
-			int weight = static_cast<int>(c->statistics().download_rate() * 10.f)
+			size_type weight = static_cast<int>(c->statistics().download_rate() * 10.f)
 				+ diff
 				+ (c->has_peer_choked()?-10:10)*1024;
 
@@ -367,11 +375,10 @@ namespace libtorrent
 	policy::peer* policy::find_disconnect_candidate()
 	{
 		peer *disconnect_peer = 0;
-		double slowest_transfer_rate=std::numeric_limits<double>::max();
+		double slowest_transfer_rate = std::numeric_limits<double>::max();
 
-		bool is_seed=m_torrent->is_seed();
-
-		boost::posix_time::ptime local_time=boost::posix_time::second_clock::local_time();
+		boost::posix_time::ptime local_time
+			= boost::posix_time::second_clock::local_time();
 
 		for (std::vector<peer>::iterator i = m_peers.begin();
 			i != m_peers.end();
@@ -383,24 +390,24 @@ namespace libtorrent
 			if(c->is_disconnecting())
 				continue;
 
-			double transferred_amount;
+			double transferred_amount
+				= (double)c->statistics().total_payload_download();
 
-			if(is_seed)
-				transferred_amount=c->statistics().total_payload_download();
-			else
-				transferred_amount=c->statistics().total_payload_download();
+			boost::posix_time::time_duration connected_time
+				= local_time - i->connected;
 
-			boost::posix_time::time_duration connected_time = local_time - i->connected;
+			double connected_time_in_seconds
+				= connected_time.seconds()
+				+ connected_time.minutes()*60.0
+				+ connected_time.hours()*60.0*60.0;
 
-
-			double connected_time_in_seconds=connected_time.seconds() + connected_time.minutes()*60.0 + connected_time.hours()*60.0*60.0;
-
-			double transfer_rate=transferred_amount/(connected_time_in_seconds+1);
+			double transfer_rate
+				= transferred_amount / (connected_time_in_seconds+1);
 
 			if (transfer_rate <= slowest_transfer_rate)
 			{
-				slowest_transfer_rate=transfer_rate;
-				disconnect_peer=&*i;
+				slowest_transfer_rate = transfer_rate;
+				disconnect_peer = &(*i);
 			}
 		}
 		return disconnect_peer;
@@ -410,7 +417,7 @@ namespace libtorrent
 	{
 		boost::posix_time::ptime local_time=boost::posix_time::second_clock::local_time();
 		boost::posix_time::ptime ptime(local_time);
-		policy::peer *candidate=0;
+		policy::peer* candidate  =0;
 
 		for (std::vector<peer>::iterator i = m_peers.begin();
 			i != m_peers.end();
@@ -422,12 +429,13 @@ namespace libtorrent
 
 			assert(i->connected <= local_time);
 
-			boost::posix_time::ptime next_connect=i->connected + boost::posix_time::seconds(10*60);
+			boost::posix_time::ptime next_connect
+				= i->connected + boost::posix_time::seconds(10 * 60);
 
 			if (next_connect <= ptime)
 			{
-				ptime=next_connect;
-				candidate=&*i;
+				ptime = next_connect;
+				candidate = &(*i);
 			}
 		}
 		
@@ -557,7 +565,7 @@ namespace libtorrent
 				peer_connection* c = i->connection;
 				if (c == 0) continue;
 
-				int diff = i->connection->share_diff();
+				size_type diff = i->connection->share_diff();
 				if (diff < -free_upload_amount
 					&& !c->is_choked())
 				{
@@ -796,7 +804,7 @@ namespace libtorrent
 		if (m_torrent->ratio() != 0.f)
 		{
 			assert(c.share_diff() < std::numeric_limits<int>::max());
-			int diff = c.share_diff();
+			size_type diff = c.share_diff();
 			if (diff > 0 && c.is_seed())
 			{
 				// the peer is a seed and has sent
diff --git a/src/session.cpp b/src/session.cpp
index a92d7f12e..8ee64cace 100755
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -40,12 +40,20 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <cctype>
 #include <algorithm>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/lexical_cast.hpp>
 #include <boost/filesystem/convenience.hpp>
 #include <boost/filesystem/exception.hpp>
 #include <boost/limits.hpp>
 #include <boost/bind.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/peer_id.hpp"
 #include "libtorrent/torrent_info.hpp"
 #include "libtorrent/url_handler.hpp"
@@ -56,6 +64,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/fingerprint.hpp"
 #include "libtorrent/entry.hpp"
 #include "libtorrent/alert_types.hpp"
+#include "libtorrent/invariant_check.hpp"
 
 #if defined(_MSC_VER) && _MSC_VER < 1300
 namespace std
@@ -208,7 +217,7 @@ namespace
 					// Rounds upwards to avoid trying to give 0 bandwidth to someone
 					// (may get caught in an endless loop otherwise)
 					
-					int num_peers_left_to_share_quota = peer_info.size() - i;
+					int num_peers_left_to_share_quota = (int)peer_info.size() - i;
 					int try_to_give_to_this_peer
 						= (quota_left_to_distribute + num_peers_left_to_share_quota - 1)
 						/ num_peers_left_to_share_quota;
@@ -359,7 +368,7 @@ namespace libtorrent
 
 			// ---- generate a peer id ----
 
-			std::srand(std::time(0));
+			std::srand((unsigned int)std::time(0));
 
 			std::string print = cl_fprint.to_string();
 			assert(print.length() == 8);
@@ -438,7 +447,7 @@ namespace libtorrent
 			{
 
 #ifndef NDEBUG
-				assert_invariant("loops_per_second++");
+				check_invariant("loops_per_second++");
 				loops_per_second++;
 #endif
 
@@ -479,7 +488,7 @@ namespace libtorrent
 				}
 
 #ifndef NDEBUG
-				assert_invariant("before SEND SOCKETS");
+				check_invariant("before SEND SOCKETS");
 #endif
 
 				// ************************
@@ -527,7 +536,7 @@ namespace libtorrent
 				purge_connections();
 
 #ifndef NDEBUG
-				assert_invariant("after SEND SOCKETS");
+				check_invariant("after SEND SOCKETS");
 #endif
 				// ************************
 				// RECEIVE SOCKETS
@@ -591,7 +600,7 @@ namespace libtorrent
 				}
 				purge_connections();
 #ifndef NDEBUG
-				assert_invariant("after RECEIVE SOCKETS");
+				check_invariant("after RECEIVE SOCKETS");
 #endif
 
 				// ************************
@@ -623,7 +632,7 @@ namespace libtorrent
 				}
 
 #ifndef NDEBUG
-				assert_invariant("after ERROR SOCKETS");
+				check_invariant("after ERROR SOCKETS");
 #endif
 
 				boost::posix_time::time_duration d = boost::posix_time::second_clock::local_time() - timer;
@@ -751,7 +760,7 @@ namespace libtorrent
 #endif
 
 #ifndef NDEBUG
-		void session_impl::assert_invariant(const char *place)
+		void session_impl::check_invariant(const char *place)
 		{
 			assert(place);
 
@@ -763,7 +772,7 @@ namespace libtorrent
 				{
 					std::ofstream error_log("error.log", std::ios_base::app);
 					boost::shared_ptr<peer_connection> p = i->second;
-					error_log << "session_imple::assert_invariant()\n"
+					error_log << "session_imple::check_invariant()\n"
 						"peer_connection::has_data() != is_writability_monitored()\n";
 					error_log << "peer_connection::has_data() " << p->has_data() << "\n";
 					error_log << "peer_connection::send_quota_left " << p->send_quota_left() << "\n";
@@ -982,7 +991,9 @@ namespace libtorrent
 				i != peer_list.end();
 				++i)
 			{
-				address a(i->dict()["ip"].string(), i->dict()["port"].integer());
+				address a(
+					i->dict()["ip"].string()
+					, (unsigned short)i->dict()["port"].integer());
 				tmp_peers.push_back(a);
 			}
 
@@ -1001,14 +1012,14 @@ namespace libtorrent
 				i != slots.end();
 				++i)
 			{
-				int index = i->integer();
+				int index = (int)i->integer();
 				if (index >= info.num_pieces() || index < -2)
 					return;
 				tmp_pieces.push_back(index);
 			}
 
 
-			int num_blocks_per_piece = rd.dict()["blocks per piece"].integer();
+			int num_blocks_per_piece = (int)rd.dict()["blocks per piece"].integer();
 			if (num_blocks_per_piece != info.piece_length() / torrent_ptr->block_size())
 				return;
 
@@ -1024,7 +1035,7 @@ namespace libtorrent
 			{
 				piece_picker::downloading_piece p;
 
-				p.index = i->dict()["piece"].integer();
+				p.index = (int)i->dict()["piece"].integer();
 				if (p.index < 0 || p.index >= info.num_pieces())
 					return;
 
@@ -1055,7 +1066,7 @@ namespace libtorrent
 				}
 
 				assert(*slot_iter == p.index);
-				int slot_index = slot_iter - tmp_pieces.begin();
+				int slot_index = static_cast<int>(slot_iter - tmp_pieces.begin());
 				unsigned long adler
 					= torrent_ptr->filesystem().piece_crc(
 						slot_index
diff --git a/src/stat.cpp b/src/stat.cpp
index 1bb06b098..d3b4c19b3 100755
--- a/src/stat.cpp
+++ b/src/stat.cpp
@@ -38,11 +38,14 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <numeric>
 
 #include "libtorrent/stat.hpp"
+#include "libtorrent/invariant_check.hpp"
 
 using namespace libtorrent;
 
 void libtorrent::stat::second_tick()
 {
+	INVARIANT_CHECK;
+
 	std::copy(m_download_per_second_history,
 		m_download_per_second_history+history-1,
 		m_download_per_second_history+1);
@@ -59,11 +62,11 @@ void libtorrent::stat::second_tick()
 	m_uploaded_protocol = 0;
 
 	m_mean_download_per_second
-		= std::accumulate(m_download_per_second_history,
+		= (float)std::accumulate(m_download_per_second_history,
 		m_download_per_second_history+history, 0) / history;
 
 	m_mean_upload_per_second
-		= std::accumulate(m_upload_per_second_history,
+		= (float)std::accumulate(m_upload_per_second_history,
 		m_upload_per_second_history+history, 0) / history;
 
 	if (m_mean_download_per_second > m_peak_downloaded_per_second)
diff --git a/src/storage.cpp b/src/storage.cpp
index 5582983cc..a7cfa3e3e 100755
--- a/src/storage.cpp
+++ b/src/storage.cpp
@@ -38,25 +38,35 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <algorithm>
 #include <set>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/lexical_cast.hpp>
 #include <boost/filesystem/convenience.hpp>
 #include <boost/filesystem/fstream.hpp>
 #include <boost/thread/mutex.hpp>
 #include <boost/ref.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/storage.hpp"
 #include "libtorrent/torrent.hpp"
 #include "libtorrent/hasher.hpp"
 #include "libtorrent/session.hpp"
 #include "libtorrent/peer_id.hpp"
 #include "libtorrent/file.hpp"
+#include "libtorrent/invariant_check.hpp"
 
 #if defined(_MSC_VER)
 #define for if (false) {} else for
 #endif
 
-namespace {
-
+/*
+namespace
+{
 	struct lazy_hash
 	{
 		mutable libtorrent::sha1_hash digest;
@@ -85,10 +95,12 @@ namespace {
 	};
 
 } // namespace unnamed
+*/
 
 namespace fs = boost::filesystem;
 
-namespace {
+namespace
+{
 
 	void print_to_log(const std::string& s)
 	{
@@ -190,8 +202,9 @@ namespace libtorrent
 		int slot;
 	};
 
-	struct storage::impl : thread_safe_storage
+	class storage::impl : public thread_safe_storage
 	{
+	public:
 		impl(const torrent_info& info, const fs::path& path)
 			: thread_safe_storage(info.num_pieces())
 			, info(info)
@@ -222,10 +235,10 @@ namespace libtorrent
 	size_type storage::read(
 		char* buf
 	  , int slot
-	  , size_type offset
-  	  , size_type size)
+	  , int offset
+  	  , int size)
 	{
-		assert(buf);
+		assert(buf != 0);
 		assert(slot >= 0 && slot < m_pimpl->info.num_pieces());
 		assert(offset >= 0);
 		assert(offset < m_pimpl->info.piece_size(slot));
@@ -247,51 +260,53 @@ namespace libtorrent
 			file_offset -= file_iter->size;
 			++file_iter;
 		}
-/*
-		fs::ifstream in(
-			m_pimpl->save_path / file_iter->path / file_iter->filename
-			, std::ios_base::binary
-		);
-*/
+
 		file in(
 			m_pimpl->save_path / file_iter->path / file_iter->filename
 			, file::in);
 
 		assert(file_offset < file_iter->size);
 
-//		in.seekg(file_offset);
 		in.seek(file_offset);
+		if (in.tell() != file_offset)
+		{
+			// the file was not big enough
+			throw file_error("slot has no storage");
+		}
 
-//		assert(size_type(in.tellg()) == file_offset);
 #ifndef NDEBUG
 		size_type in_tell = in.tell();
 		assert(in_tell == file_offset);
 #endif
 
-		size_type left_to_read = size;
-		size_type slot_size = m_pimpl->info.piece_size(slot);
+		int left_to_read = size;
+		int slot_size = m_pimpl->info.piece_size(slot);
 
 		if (offset + left_to_read > slot_size)
 			left_to_read = slot_size - offset;
 
 		assert(left_to_read >= 0);
 
-		int result = left_to_read;
+		size_type result = left_to_read;
 		int buf_pos = 0;
 
 		while (left_to_read > 0)
 		{
 			int read_bytes = left_to_read;
 			if (file_offset + read_bytes > file_iter->size)
-				read_bytes = file_iter->size - file_offset;
+				read_bytes = static_cast<int>(file_iter->size - file_offset);
 
 			assert(read_bytes > 0);
 
 //			in.read(buf + buf_pos, read_bytes);
 //			int actual_read = in.gcount();
-			int actual_read = in.read(buf + buf_pos, read_bytes);
+			size_type actual_read = in.read(buf + buf_pos, read_bytes);
 
-			assert(read_bytes == actual_read);
+			if (read_bytes != actual_read)
+			{
+				// the file was not big enough
+				throw file_error("slot has no storage");
+			}
 
 			left_to_read -= read_bytes;
 			buf_pos += read_bytes;
@@ -304,9 +319,6 @@ namespace libtorrent
 				fs::path path = m_pimpl->save_path / file_iter->path / file_iter->filename;
 
 				file_offset = 0;
-//				in.close();
-//				in.clear();
-//				in.open(path, std::ios_base::binary);
 				in.open(path, file::in);
 			}
 		}
@@ -314,10 +326,15 @@ namespace libtorrent
 		return result;
 	}
 
-	void storage::write(const char* buf, int slot, size_type offset, size_type size)
+	void storage::write(
+		const char* buf
+		, int slot
+		, int offset
+		, int size)
 	{
 		assert(buf != 0);
-		assert(slot >= 0 && slot < m_pimpl->info.num_pieces());
+		assert(slot >= 0);
+		assert(slot < m_pimpl->info.num_pieces());
 		assert(offset >= 0);
 		assert(size > 0);
 
@@ -360,8 +377,8 @@ namespace libtorrent
 		assert(file_offset == out_tell);
 #endif
 
-		size_type left_to_write = size;
-		size_type slot_size = m_pimpl->info.piece_size(slot);
+		int left_to_write = size;
+		int slot_size = m_pimpl->info.piece_size(slot);
 
 		if (offset + left_to_write > slot_size)
 			left_to_write = slot_size - offset;
@@ -378,7 +395,7 @@ namespace libtorrent
 			if (file_offset + write_bytes > file_iter->size)
 			{
 				assert(file_iter->size > file_offset);
-				write_bytes = file_iter->size - file_offset;
+				write_bytes = static_cast<int>(file_iter->size - file_offset);
 			}
 
 			assert(buf_pos >= 0);
@@ -422,6 +439,7 @@ namespace libtorrent
 
 	class piece_manager::impl
 	{
+	friend class invariant_access;
 	public:
 
 		impl(
@@ -442,8 +460,17 @@ namespace libtorrent
 
 		int slot_for_piece(int piece_index) const;
 
-		size_type read(char* buf, int piece_index, size_type offset, size_type size);
-		void write(const char* buf, int piece_index, size_type offset, size_type size);
+		size_type read(
+			char* buf
+			, int piece_index
+			, int offset
+			, int size);
+
+		void write(
+			const char* buf
+			, int piece_index
+			, int offset
+			, int size);
 
 		const boost::filesystem::path& save_path() const
 		{ return m_save_path; }
@@ -454,6 +481,12 @@ namespace libtorrent
 		// returns the slot currently associated with the given
 		// piece or assigns the given piece_index to a free slot
 
+		int identify_data(
+			const std::vector<char>& piece_data
+			, int current_slot
+			, std::vector<bool>& have_pieces
+			, const std::multimap<sha1_hash, int>& hash_to_piece);
+
 		int allocate_slot_for_piece(int piece_index);
 #ifndef NDEBUG
 		void check_invariant() const;
@@ -468,24 +501,28 @@ namespace libtorrent
 
 		const torrent_info& m_info;
 
-		// maps piece index to slot index. -1 means the piece
-		// doesn't exist
-		enum { has_no_slot = -3 };
-		std::vector<int> m_piece_to_slot;
 		// slots that hasn't had any file storage allocated
 		std::vector<int> m_unallocated_slots;
 		// slots that has file storage, but isn't assigned to a piece
 		std::vector<int> m_free_slots;
 
-		// index here is a slot number in the file
-		// if index>=0, the slot is assigned to this piece
-		// otherwise it can have one of these values:
+		enum
+		{
+			has_no_slot = -3 // the piece has no storage
+		};
+
+		// maps piece indices to slots. If a piece doesn't
+		// have any storage, it is set to 'has_no_slot'
+		std::vector<int> m_piece_to_slot;
+
 		enum
 		{
 			unallocated = -1, // the slot is unallocated
 			unassigned = -2   // the slot is allocated but not assigned to a piece
 		};
 
+		// maps slots to piece indices, if a slot doesn't have a piece
+		// it can either be 'unassigned' or 'unallocated'
 		std::vector<int> m_slot_to_piece;
 
 		boost::filesystem::path m_save_path;
@@ -503,6 +540,7 @@ namespace libtorrent
 		: m_storage(info, save_path)
 		, m_info(info)
 		, m_save_path(save_path)
+		, m_allocating(false)
 	{
 	}
 
@@ -644,8 +682,8 @@ namespace libtorrent
 	size_type piece_manager::impl::read(
 		char* buf
 	  , int piece_index
-	  , size_type offset
-	  , size_type size)
+	  , int offset
+	  , int size)
 	{
 		assert(buf);
 		assert(offset >= 0);
@@ -660,8 +698,8 @@ namespace libtorrent
 	size_type piece_manager::read(
 		char* buf
 	  , int piece_index
-	  , size_type offset
-	  , size_type size)
+	  , int offset
+	  , int size)
 	{
 		return m_pimpl->read(buf, piece_index, offset, size);
 	}
@@ -669,8 +707,8 @@ namespace libtorrent
 	void piece_manager::impl::write(
 		const char* buf
 	  , int piece_index
-	  , size_type offset
-	  , size_type size)
+	  , int offset
+	  , int size)
 	{
 		assert(buf);
 		assert(offset >= 0);
@@ -684,12 +722,12 @@ namespace libtorrent
 	void piece_manager::write(
 		const char* buf
 	  , int piece_index
-	  , size_type offset
-	  , size_type size)
+	  , int offset
+	  , int size)
 	{
 		m_pimpl->write(buf, piece_index, offset, size);
 	}
-
+/*
 	void piece_manager::impl::check_pieces(
 		boost::mutex& mutex
 	  , detail::piece_checker_data& data
@@ -787,7 +825,7 @@ namespace libtorrent
 			end_iter = m_info.end_files(); 
 			file_iter != end_iter;)
 		{
-			assert(current_slot>=0 && current_slot<m_info.num_pieces());
+			assert(current_slot >= 0 && current_slot < m_info.num_pieces());
 
 			// Update progress meter and check if we've been requested to abort
 			{
@@ -856,10 +894,13 @@ namespace libtorrent
 					{
 						m_unallocated_slots.push_back(current_slot);
 						++current_slot;
-						assert(current_slot <= m_info.num_pieces());
 					}
 
 					seek_into_next = pos - file_end;
+					if (current_slot >= m_info.num_pieces())
+					{
+						break;
+					}
 					bytes_to_read = m_info.piece_size(current_slot);
 					piece_offset = 0;
 				}
@@ -952,7 +993,7 @@ namespace libtorrent
 		}
 
 		// dirty "fix" for a bug when file is corrupt
-		for(int i = 0; i < (int)m_info.num_pieces(); ++i)
+		for (int i = 0; i < (int)m_info.num_pieces(); ++i)
 		{
 			if(m_piece_to_slot[i] != has_no_slot
 				&& m_piece_to_slot[i] != i
@@ -1000,6 +1041,230 @@ namespace libtorrent
 		check_invariant();
 #endif
 	}
+*/
+	int piece_manager::impl::identify_data(
+		const std::vector<char>& piece_data
+		, int current_slot
+		, std::vector<bool>& have_pieces
+		, const std::multimap<sha1_hash, int>& hash_to_piece)
+	{
+		assert(have_pieces.size() == m_info.num_pieces());
+
+		const int piece_size = m_info.piece_length();
+		const int last_piece_size = m_info.piece_size(
+			m_info.num_pieces() - 1);
+
+		assert((int)piece_data.size() >= last_piece_size);
+
+		// calculate a small digest, with the same
+		// size as the last piece. And a large digest
+		// which has the same size as a normal piece
+		hasher small_digest;
+		small_digest.update(&piece_data[0], last_piece_size);
+		hasher large_digest(small_digest);
+		large_digest.update(
+			&piece_data[last_piece_size]
+			, piece_size - last_piece_size);
+		sha1_hash large_hash = large_digest.final();
+		sha1_hash small_hash = small_digest.final();
+
+		typedef std::multimap<sha1_hash, int>::const_iterator map_iter;
+		map_iter begin1;
+		map_iter end1;
+		map_iter begin2;
+		map_iter end2;
+
+		// makes the lookups for the small digest and the large digest
+		boost::tie(begin1, end1) = hash_to_piece.equal_range(small_hash);
+		boost::tie(begin2, end2) = hash_to_piece.equal_range(large_hash);
+
+		// copy all potential piece indices into this vector
+		std::vector<int> matching_pieces;
+		for (map_iter i = begin1; i != end1; ++i)
+			matching_pieces.push_back(i->second);
+		for (map_iter i = begin2; i != end2; ++i)
+			matching_pieces.push_back(i->second);
+
+
+		// no piece matched the data in the slot
+		if (matching_pieces.empty())
+			return -1;
+
+		// ------------------------------------------
+		// CHECK IF THE PIECE IS IN ITS CORRECT PLACE
+		// ------------------------------------------
+
+		if (std::find(
+			matching_pieces.begin()
+			, matching_pieces.end()
+			, current_slot) != matching_pieces.end())
+		{
+			const int piece_index = current_slot;
+
+			if (have_pieces[piece_index])
+			{
+				// we have already found a piece with
+				// this index.
+				int other_slot = m_piece_to_slot[piece_index];
+				assert(other_slot >= 0);
+
+				// take one of the other matching pieces
+				// that hasn't already been assigned
+				std::sort(matching_pieces.begin(), matching_pieces.end());
+				int other_piece = -1;
+				for (std::vector<int>::iterator i = matching_pieces.begin();
+					i != matching_pieces.end();
+					++i)
+				{
+					if (have_pieces[*i] || *i == piece_index) continue;
+					other_piece = *i;
+					break;
+				}
+				if (other_piece >= 0)
+				{
+					assert(have_pieces[other_piece] == false);
+					have_pieces[other_piece] = true;
+					m_slot_to_piece[other_slot] = other_piece;
+					m_piece_to_slot[other_piece] = other_slot;
+				}
+				else
+				{
+					m_slot_to_piece[other_slot] = unassigned;
+					m_free_slots.push_back(other_slot);
+				}
+			}
+			
+			have_pieces[piece_index] = true;
+			return piece_index;
+		}
+
+		std::sort(matching_pieces.begin(), matching_pieces.end());
+		const int piece_index = matching_pieces.back();
+		have_pieces[piece_index] = true;
+		return piece_index;
+	}
+
+	void piece_manager::impl::check_pieces(
+		boost::mutex& mutex
+	  , detail::piece_checker_data& data
+	  , std::vector<bool>& pieces)
+	{
+		// synchronization ------------------------------------------------------
+		boost::recursive_mutex::scoped_lock lock(m_mutex);
+		// ----------------------------------------------------------------------
+
+		INVARIANT_CHECK;
+
+		m_piece_to_slot.resize(m_info.num_pieces(), has_no_slot);
+		m_slot_to_piece.resize(m_info.num_pieces(), unallocated);
+		m_free_slots.clear();
+		m_unallocated_slots.clear();
+		pieces.clear();
+		pieces.resize(m_info.num_pieces(), false);
+
+		// if we have fast-resume info
+		// use it instead of doing the actual checking
+		if (!data.piece_map.empty()
+			&& data.piece_map.size() <= m_slot_to_piece.size())
+		{
+			for (int i = 0; i < (int)data.piece_map.size(); ++i)
+			{
+				m_slot_to_piece[i] = data.piece_map[i];
+				if (data.piece_map[i] >= 0)
+				{
+					m_piece_to_slot[data.piece_map[i]] = i;
+					int found_piece = data.piece_map[i];
+
+					// if the piece is not in the unfinished list
+					// we have all of it
+					if (std::find_if(
+						data.unfinished_pieces.begin()
+						, data.unfinished_pieces.end()
+						, piece_picker::has_index(found_piece))
+						== data.unfinished_pieces.end())
+					{
+						pieces[found_piece] = true;
+					}
+				}
+				else if (data.piece_map[i] == unassigned)
+				{
+					m_free_slots.push_back(i);
+				}
+				else
+				{
+					assert(data.piece_map[i] == unallocated);
+					m_unallocated_slots.push_back(i);
+				}
+			}
+
+			for (int i = (int)data.piece_map.size(); i < (int)pieces.size(); ++i)
+			{
+				m_unallocated_slots.push_back(i);
+			}
+			return;
+		}
+
+
+
+		// do the full check
+		std::vector<char> piece_data(m_info.piece_length());
+		const int piece_size = m_info.piece_length();
+		const int last_piece_size = m_info.piece_size(
+			m_info.num_pieces() - 1);
+
+		std::multimap<sha1_hash, int> hash_to_piece;
+		// build the hash-map, that maps hashes to pieces
+		for (int i = 0; i < m_info.num_pieces(); ++i)
+		{
+			hash_to_piece.insert(std::make_pair(m_info.hash_for_piece(i), i));
+		}
+
+		for (int current_slot = 0; current_slot <  m_info.num_pieces(); ++current_slot)
+		{
+			try
+			{
+				m_storage.read(
+					&piece_data[0]
+					, current_slot
+					, 0
+					, m_info.piece_size(current_slot));
+
+				int piece_index = identify_data(
+					piece_data
+					, current_slot
+					, pieces
+					, hash_to_piece);
+
+				if (piece_index >= 0)
+				{
+					// the slot was identified as piece 'piece_index'
+					m_piece_to_slot[piece_index] = current_slot;
+					m_slot_to_piece[current_slot] = piece_index;
+				}
+				else
+				{
+					// the data in the slot was not recognized
+					// consider the slot free
+					m_slot_to_piece[current_slot] = unassigned;
+					m_free_slots.push_back(current_slot);
+				}
+			}
+			catch (file_error&)
+			{
+				// this means the slot wasn't allocated
+				m_slot_to_piece[current_slot] = unallocated;
+				m_unallocated_slots.push_back(current_slot);
+			}
+
+			// Update progress meter and check if we've been requested to abort
+			{
+				boost::mutex::scoped_lock lock(mutex);
+				data.progress = (float)current_slot / m_info.num_pieces();
+				if (data.abort)
+					return;
+			}
+		}
+	}
 
 	void piece_manager::check_pieces(
 		boost::mutex& mutex
@@ -1015,9 +1280,7 @@ namespace libtorrent
 		boost::recursive_mutex::scoped_lock lock(m_mutex);
 		// ----------------------------------------------------------------------
 
-#ifndef NDEBUG
-		check_invariant();
-#endif
+		INVARIANT_CHECK;
 
 		assert(piece_index >= 0);
 	  	assert(piece_index < (int)m_piece_to_slot.size());
@@ -1029,11 +1292,6 @@ namespace libtorrent
 		{
 			assert(slot_index >= 0);
 			assert(slot_index < (int)m_slot_to_piece.size());
-
-#ifndef NDEBUG
-			check_invariant();
-#endif
-
 			return slot_index;
 		}
 
@@ -1080,7 +1338,8 @@ namespace libtorrent
 		if (slot_index != piece_index
 			&& m_slot_to_piece[piece_index] >= 0)
 		{
-#ifndef NDEBUG
+
+#if !defined(NDEBUG) && defined(TORRENT_STORAGE_DEBUG)
 			std::stringstream s;
 
 			s << "there is another piece at our slot, swapping..";
@@ -1092,15 +1351,14 @@ namespace libtorrent
 			s << "\n   piece at our slot: ";
 			s << m_slot_to_piece[piece_index];
 			s << "\n";
-#endif
-			int piece_at_our_slot = m_slot_to_piece[piece_index];
-			assert(m_piece_to_slot[piece_at_our_slot] == piece_index);
-#ifndef NDEBUG
+
 			print_to_log(s.str());
-#ifdef TORRENT_STORAGE_DEBUG
 			debug_log();
 #endif
-#endif
+
+			int piece_at_our_slot = m_slot_to_piece[piece_index];
+			assert(m_piece_to_slot[piece_at_our_slot] == piece_index);
+
 			std::swap(
 				m_slot_to_piece[piece_index]
 				, m_slot_to_piece[slot_index]);
@@ -1117,6 +1375,7 @@ namespace libtorrent
 			assert(m_piece_to_slot[piece_index] == piece_index);
 
 			slot_index = piece_index;
+
 #if !defined(NDEBUG) && defined(TORRENT_STORAGE_DEBUG)
 			debug_log();
 #endif
@@ -1124,16 +1383,12 @@ namespace libtorrent
 
 		assert(slot_index >= 0);
 	  	assert(slot_index < (int)m_slot_to_piece.size());
-
-#ifndef NDEBUG
-		check_invariant();
-#endif
 		return slot_index;
 	}
 
 	void piece_manager::impl::allocate_slots(int num_slots)
 	{
-		assert(num_slots>0);
+		assert(num_slots > 0);
 
 		{
 			boost::mutex::scoped_lock lock(m_allocating_monitor);
@@ -1148,9 +1403,7 @@ namespace libtorrent
 		boost::recursive_mutex::scoped_lock lock(m_mutex);
 		// ----------------------------------------------------------------------
 
-#ifndef NDEBUG
-		check_invariant();
-#endif
+		INVARIANT_CHECK;
 
 		namespace fs = boost::filesystem;
 		
@@ -1159,7 +1412,7 @@ namespace libtorrent
 		std::vector<int>::iterator end_iter 
 			= m_unallocated_slots.end();
 
-		const size_type piece_size = m_info.piece_length();
+		const int piece_size = m_info.piece_length();
 
 		std::vector<char> zeros(piece_size, 0);
 
@@ -1185,7 +1438,15 @@ namespace libtorrent
 			m_slot_to_piece[new_free_slot] = unassigned;
 			m_free_slots.push_back(new_free_slot);
 
-			m_storage.write(&zeros[0], pos, 0, m_info.piece_size(pos));
+			try
+			{
+				m_storage.write(&zeros[0], pos, 0, m_info.piece_size(pos));
+			}
+			catch(file_error&)
+			{
+				m_allocating = false;
+				throw;
+			}
 		}
 
 		m_unallocated_slots.erase(m_unallocated_slots.begin(), iter);
@@ -1193,10 +1454,6 @@ namespace libtorrent
 		m_allocating = false;
 
 		assert(m_free_slots.size()>0);
-		
-#ifndef NDEBUG
-		check_invariant();
-#endif
 	}
 
 	void piece_manager::allocate_slots(int num_slots)
diff --git a/src/torrent.cpp b/src/torrent.cpp
index d420735c0..cf2288640 100755
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -39,9 +39,17 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <cctype>
 #include <numeric>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/lexical_cast.hpp>
 #include <boost/filesystem/convenience.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/session.hpp"
 #include "libtorrent/torrent_info.hpp"
@@ -219,7 +227,7 @@ namespace libtorrent
 		, m_policy(new policy(this))
 		, m_ses(ses)
 		, m_picker(torrent_file.piece_length() / m_block_size,
-			(torrent_file.total_size()+m_block_size-1)/m_block_size)
+			static_cast<int>((torrent_file.total_size()+m_block_size-1)/m_block_size))
 		, m_last_working_tracker(0)
 		, m_currently_trying_tracker(0)
 		, m_time_scaler(0)
@@ -493,7 +501,7 @@ namespace libtorrent
 			i != pieces.end();
 			++i)
 		{
-			if (*i) piece_list.push_back(i - pieces.begin());
+			if (*i) piece_list.push_back(static_cast<int>(i - pieces.begin()));
 		}
 
 		std::random_shuffle(piece_list.begin(), piece_list.end());
@@ -677,7 +685,7 @@ namespace libtorrent
 		assert(piece_index >= 0);
 		assert(piece_index < m_torrent_file.num_pieces());
 
-		size_type size = m_torrent_file.piece_size(piece_index);
+		int size = m_torrent_file.piece_size(piece_index);
 		std::vector<char> buffer(size);
 		assert(size > 0);
 		m_storage.read(&buffer[0], piece_index, 0, size);
@@ -731,7 +739,7 @@ namespace libtorrent
 		st.announce_interval = boost::posix_time::seconds(m_duration);
 
 
-		st.num_peers = m_connections.size();
+		st.num_peers = (int)m_connections.size();
 
 		st.pieces = &m_have_pieces;
 
diff --git a/src/torrent_handle.cpp b/src/torrent_handle.cpp
index 17e86a919..8718ab4d6 100755
--- a/src/torrent_handle.cpp
+++ b/src/torrent_handle.cpp
@@ -40,10 +40,18 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <cctype>
 #include <algorithm>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/lexical_cast.hpp>
 #include <boost/filesystem/convenience.hpp>
 #include <boost/optional.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/peer_id.hpp"
 #include "libtorrent/torrent_info.hpp"
 #include "libtorrent/url_handler.hpp"
@@ -233,7 +241,7 @@ namespace libtorrent
 		ret.dict()["blocks per piece"] = num_blocks_per_piece;
 
 		// num unfinished pieces
-		int num_unfinished = q.size();
+		int num_unfinished = (int)q.size();
 		ret.dict()["unfinished"] = entry::list_type();
 		entry::list_type& up = ret.dict()["unfinished"].list();
 
@@ -436,8 +444,8 @@ namespace libtorrent
 
 			p.load_balancing = peer->total_free_upload();
 
-			p.download_queue_length = peer->download_queue().size();
-			p.upload_queue_length = peer->upload_queue().size();
+			p.download_queue_length = (int)peer->download_queue().size();
+			p.upload_queue_length = (int)peer->upload_queue().size();
 
 			boost::optional<piece_block_progress> ret = peer->downloading_piece();
 			if (ret)
diff --git a/src/torrent_info.cpp b/src/torrent_info.cpp
index 3bfecc255..642a1567e 100755
--- a/src/torrent_info.cpp
+++ b/src/torrent_info.cpp
@@ -38,9 +38,17 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <algorithm>
 #include <set>
 
+#ifdef _MSC_VER
+#pragma warning(push, 1)
+#endif
+
 #include <boost/lexical_cast.hpp>
 #include <boost/date_time/time.hpp>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
 #include "libtorrent/torrent_info.hpp"
 #include "libtorrent/bencode.hpp"
 #include "libtorrent/hasher.hpp"
@@ -135,7 +143,9 @@ namespace libtorrent
 		i = dict.find("creation date");
 		if (i != dict.end() && i->second.type() == entry::int_t)
 		{
-			m_creation_date = m_creation_date + boost::posix_time::seconds(i->second.integer());
+			m_creation_date
+				= m_creation_date
+				+ boost::posix_time::seconds((long)i->second.integer());
 		}
 
 		// extract comment
@@ -153,7 +163,7 @@ namespace libtorrent
 		std::vector<char> buf;
 		bencode(std::back_insert_iterator<std::vector<char> >(buf), info);
 		hasher h;
-		h.update(&buf[0], buf.size());
+		h.update(&buf[0], (int)buf.size());
 		m_info_hash = h.final();
 
 		// extract piece length
@@ -192,7 +202,7 @@ namespace libtorrent
 		// extract sha-1 hashes for all pieces
 		// we want this division to round upwards, that's why we have the
 		// extra addition
-		size_type num_pieces = (m_total_size + m_piece_length - 1) / m_piece_length;
+		int num_pieces = static_cast<int>((m_total_size + m_piece_length - 1) / m_piece_length);
 		i = info.dict().find("pieces");
 		if (i == info.dict().end()) throw invalid_torrent_file();