fix some PVS studio warnings

examples/connection_tester.cpp

@@ -681,7 +681,7 @@ struct peer_conn
 			if (corruption_counter == 0)
 			{
 				corruption_counter = 1000;
-				memset(write_buffer, 0, 10);
+				std::memset(write_buffer, 0, 10);
 			}
 		}
 		char* ptr = write_buf_proto;
@@ -1009,7 +1009,7 @@ int main(int argc, char* argv[])
 					, torrent_name, std::strerror(errno));
 				return 1;
 			}
-			size_t ret = fwrite(&buf[0], 1, buf.size(), f);
+			size_t ret = fwrite(buf.data(), 1, buf.size(), f);
 			if (ret != buf.size())
 			{
 				std::fprintf(stderr, "write returned: %d (expected %d)\n", int(ret), int(buf.size()));

include/libtorrent/bitfield.hpp

@@ -247,13 +247,13 @@ namespace libtorrent {
 		void set_all() noexcept
 		{
 			if (size() == 0) return;
-			std::memset(buf(), 0xff, std::size_t(num_words() * 4));
+			std::memset(buf(), 0xff, std::size_t(num_words()) * 4);
 			clear_trailing_bits();
 		}
 		void clear_all() noexcept
 		{
 			if (size() == 0) return;
-			std::memset(buf(), 0x00, std::size_t(num_words() * 4));
+			std::memset(buf(), 0x00, std::size_t(num_words()) * 4);
 		}
 
 		// make the bitfield empty, of zero size.

include/libtorrent/packet_pool.hpp

@@ -113,7 +113,7 @@ namespace libtorrent {
 	{
 		packet* p = static_cast<packet*>(std::malloc(sizeof(packet) + aux::numeric_cast<std::uint16_t>(size)));
 		if (p == nullptr) aux::throw_ex<std::bad_alloc>();
-		new (p) packet();
+		p = new (p) packet();
 		p->allocated = aux::numeric_cast<std::uint16_t>(size);
 		return packet_ptr(p);
 	}

src/http_connection.cpp

@@ -384,11 +384,11 @@ void http_connection::start(std::string const& hostname, int port
 		}
 		else
 #endif
+		m_hostname = hostname;
 		if (ps && ps->proxy_hostnames
 			&& (ps->type == settings_pack::socks5
 				|| ps->type == settings_pack::socks5_pw))
 		{
-			m_hostname = hostname;
 			m_port = std::uint16_t(port);
 			m_endpoints.emplace_back(address(), m_port);
 			connect();
@@ -400,7 +400,6 @@ void http_connection::start(std::string const& hostname, int port
 				, std::bind(&http_connection::on_resolve
 				, me, _1, _2));
 		}
-		m_hostname = hostname;
 		m_port = std::uint16_t(port);
 	}
 }

src/peer_connection.cpp

@@ -4085,7 +4085,7 @@ namespace libtorrent {
 		if (m_connecting)
 		{
 			m_counters.inc_stats_counter(counters::num_peers_half_open, -1);
-			if (t) t->dec_num_connecting(m_peer_info);
+			if (t && m_peer_info) t->dec_num_connecting(m_peer_info);
 			m_connecting = false;
 		}
 

src/stack_allocator.cpp

@@ -71,7 +71,7 @@ namespace aux {
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wformat-nonliteral"
 #endif
-			int const ret = std::vsnprintf(m_storage.data() + pos, static_cast<std::size_t>(len + 1), fmt, args);
+			int const ret = std::vsnprintf(m_storage.data() + pos, static_cast<std::size_t>(len) + 1, fmt, args);
 #ifdef __clang__
 #pragma clang diagnostic pop
 #endif

src/upnp.cpp

@@ -1284,7 +1284,7 @@ void upnp::on_upnp_get_ip_address_response(error_code const& e
 #ifndef TORRENT_DISABLE_LOGGING
 	if (s.error_code != -1)
 	{
-		log("error while getting external IP address, code: %u", s.error_code);
+		log("error while getting external IP address, code: %d", s.error_code);
 	}
 #endif
 
@@ -1386,8 +1386,7 @@ void upnp::on_upnp_map_response(error_code const& e
 	if (s.error_code != -1)
 	{
 #ifndef TORRENT_DISABLE_LOGGING
-		log("error while adding port map, code: %u"
-			, s.error_code);
+		log("error while adding port map, code: %d", s.error_code);
 #endif
 	}