From 093d912e9a872f575a8575d39e20cfefb2818f9c Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Thu, 10 Apr 2008 10:03:23 +0000
Subject: [PATCH] receive buffer optimization. added receive_buffer_size and
 used_receive_buffer to peer_info. changed plugin api to make use of new
 disk_buffer_holder type

---
 Jamfile                                    |   1 +
 docs/building.html                         |  13 ++
 docs/libtorrent_plugins.html               |  91 ++++++----
 docs/libtorrent_plugins.rst                |  24 ++-
 docs/manual.html                           |   5 +
 docs/manual.rst                            |   6 +
 examples/client_test.cpp                   |   5 +-
 include/Makefile.am                        |   1 +
 include/libtorrent/aux_/session_impl.hpp   |   2 +
 include/libtorrent/bt_peer_connection.hpp  |   2 +-
 include/libtorrent/buffer.hpp              |   5 +
 include/libtorrent/disk_buffer_holder.hpp  |  59 ++++++
 include/libtorrent/disk_io_thread.hpp      |   4 +
 include/libtorrent/extensions.hpp          |   3 +-
 include/libtorrent/peer_connection.hpp     |  19 +-
 include/libtorrent/peer_info.hpp           |   3 +
 include/libtorrent/storage.hpp             |   3 +-
 include/libtorrent/web_peer_connection.hpp |   2 +-
 src/Makefile.am                            |   2 +-
 src/bt_peer_connection.cpp                 |  57 ++++--
 src/disk_buffer_holder.cpp                 |  50 +++++
 src/disk_io_thread.cpp                     |  12 ++
 src/peer_connection.cpp                    | 202 +++++++++++++++++++--
 src/session_impl.cpp                       |   5 +
 src/storage.cpp                            |  13 +-
 25 files changed, 503 insertions(+), 86 deletions(-)
 create mode 100644 include/libtorrent/disk_buffer_holder.hpp
 create mode 100644 src/disk_buffer_holder.cpp

diff --git a/Jamfile b/Jamfile
index b75598b44..b2031a51f 100755
--- a/Jamfile
+++ b/Jamfile
@@ -244,6 +244,7 @@ SOURCES =
 	alert
 	assert
 	connection_queue
+	disk_buffer_holder
 	entry
 	escape_string
 	gzip
diff --git a/docs/building.html b/docs/building.html
index 68d6a9613..f430b09b1 100644
--- a/docs/building.html
+++ b/docs/building.html
@@ -285,6 +285,16 @@ used.</li>
 </ul>
 </td>
 </tr>
+<tr><td><tt class="docutils literal"><span class="pre">pool-allocators</span></tt></td>
+<td><ul class="first last simple">
+<li><tt class="docutils literal"><span class="pre">on</span></tt> - default, uses pool allocators for send
+buffers.</li>
+<li><tt class="docutils literal"><span class="pre">off</span></tt> - uses <tt class="docutils literal"><span class="pre">malloc()</span></tt> and <tt class="docutils literal"><span class="pre">free()</span></tt>
+instead. Might be useful to debug buffer issues
+with tools like electric fence or libgmalloc.</li>
+</ul>
+</td>
+</tr>
 <tr><td><tt class="docutils literal"><span class="pre">link</span></tt></td>
 <td><ul class="first last simple">
 <li><tt class="docutils literal"><span class="pre">static</span></tt> - builds libtorrent as a static
@@ -576,6 +586,9 @@ GCC) both little-endian and big-endian versions
 will be built and the correct code will be
 chosen at run-time.</td>
 </tr>
+<tr><td><tt class="docutils literal"><span class="pre">TORRENT_DISABLE_POOL_ALLOCATOR</span></tt></td>
+<td>Disables use of <tt class="docutils literal"><span class="pre">boost::pool&lt;&gt;</span></tt>.</td>
+</tr>
 <tr><td><tt class="docutils literal"><span class="pre">TORRENT_LINKING_SHARED</span></tt></td>
 <td>If this is defined when including the
 libtorrent headers, the classes and functions
diff --git a/docs/libtorrent_plugins.html b/docs/libtorrent_plugins.html
index 90a367ecc..682b7e450 100644
--- a/docs/libtorrent_plugins.html
+++ b/docs/libtorrent_plugins.html
@@ -16,28 +16,29 @@
 <col class="docinfo-content" />
 <tbody valign="top">
 <tr><th class="docinfo-name">Author:</th>
-<td>Arvid Norberg, <a class="last reference" href="mailto:arvid&#64;rasterbar.com">arvid&#64;rasterbar.com</a></td></tr>
+<td>Arvid Norberg, <a class="last reference external" href="mailto:arvid&#64;rasterbar.com">arvid&#64;rasterbar.com</a></td></tr>
 </tbody>
 </table>
-<div class="section">
-<h1><a id="libtorrent-plugins" name="libtorrent-plugins">libtorrent plugins</a></h1>
-<div class="contents topic" id="table-of-contents">
-<p class="topic-title first"><a id="contents" name="contents">Contents</a></p>
+<div class="section" id="libtorrent-plugins">
+<h1>libtorrent plugins</h1>
+<div class="contents topic" id="contents">
+<p class="topic-title first">Contents</p>
 <ul class="simple">
-<li><a class="reference" href="#libtorrent-plugins" id="id1" name="id1">libtorrent plugins</a><ul>
-<li><a class="reference" href="#a-word-of-caution" id="id2" name="id2">a word of caution</a></li>
+<li><a class="reference internal" href="#libtorrent-plugins" id="id1">libtorrent plugins</a><ul>
+<li><a class="reference internal" href="#a-word-of-caution" id="id2">a word of caution</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#plugin-interface" id="id3" name="id3">plugin interface</a></li>
-<li><a class="reference" href="#torrent-plugin" id="id4" name="id4">torrent_plugin</a><ul>
-<li><a class="reference" href="#new-connection" id="id5" name="id5">new_connection()</a></li>
-<li><a class="reference" href="#on-piece-pass-on-piece-fail" id="id6" name="id6">on_piece_pass() on_piece_fail()</a></li>
-<li><a class="reference" href="#tick" id="id7" name="id7">tick()</a></li>
-<li><a class="reference" href="#on-pause-on-resume" id="id8" name="id8">on_pause() on_resume()</a></li>
-<li><a class="reference" href="#on-files-checked" id="id9" name="id9">on_files_checked()</a></li>
+<li><a class="reference internal" href="#plugin-interface" id="id3">plugin interface</a></li>
+<li><a class="reference internal" href="#torrent-plugin" id="id4">torrent_plugin</a><ul>
+<li><a class="reference internal" href="#new-connection" id="id5">new_connection()</a></li>
+<li><a class="reference internal" href="#on-piece-pass-on-piece-fail" id="id6">on_piece_pass() on_piece_fail()</a></li>
+<li><a class="reference internal" href="#tick" id="id7">tick()</a></li>
+<li><a class="reference internal" href="#on-pause-on-resume" id="id8">on_pause() on_resume()</a></li>
+<li><a class="reference internal" href="#on-files-checked" id="id9">on_files_checked()</a></li>
 </ul>
 </li>
-<li><a class="reference" href="#peer-plugin" id="id10" name="id10">peer_plugin</a></li>
+<li><a class="reference internal" href="#peer-plugin" id="id10">peer_plugin</a></li>
+<li><a class="reference internal" href="#disk-buffer-holder" id="id11">disk_buffer_holder</a></li>
 </ul>
 </div>
 <p>libtorrent has a plugin interface for implementing extensions to the protocol.
@@ -47,13 +48,13 @@ to fit a particular (closed) network.</p>
 <p>In short, the plugin interface makes it possible to:</p>
 <ul class="simple">
 <li>register extension messages (sent in the extension handshake), see
-<a class="reference" href="extension_protocol.html">extensions</a>.</li>
+<a class="reference external" href="extension_protocol.html">extensions</a>.</li>
 <li>add data and parse data from the extension handshake.</li>
 <li>send extension messages and standard bittorrent messages.</li>
 <li>override or block the handling of standard bittorrent messages.</li>
 </ul>
-<div class="section">
-<h2><a id="a-word-of-caution" name="a-word-of-caution">a word of caution</a></h2>
+<div class="section" id="a-word-of-caution">
+<h2>a word of caution</h2>
 <p>Writing your own plugin is a very easy way to introduce serious bugs such as
 dead locks and race conditions. Since a plugin has access to internal
 structures it is also quite easy to sabotage libtorrent's operation.</p>
@@ -64,12 +65,12 @@ thread, you cannot use any of the member functions on the internal structures
 in libtorrent, since those require the mutex to be locked. Futhermore, you would
 also need to have a mutex on your own shared data within the plugin, to make
 sure it is not accessed at the same time from the libtorrent thread (through a
-callback). See <a class="reference" href="http://www.boost.org/doc/html/mutex.html">boost thread's mutex</a>. If you need to send out a message from
+callback). See <a class="reference external" href="http://www.boost.org/doc/html/mutex.html">boost thread's mutex</a>. If you need to send out a message from
 another thread, use an internal queue, and do the actual sending in <tt class="docutils literal"><span class="pre">tick()</span></tt>.</p>
 </div>
 </div>
-<div class="section">
-<h1><a id="plugin-interface" name="plugin-interface">plugin interface</a></h1>
+<div class="section" id="plugin-interface">
+<h1>plugin interface</h1>
 <p>The plugin interface consists of two base classes that the plugin may
 implement. These are called <tt class="docutils literal"><span class="pre">torrent_plugin</span></tt> and <tt class="docutils literal"><span class="pre">peer_plugin</span></tt>. They are
 both found in the <tt class="docutils literal"><span class="pre">&lt;libtorrent/extensions.hpp&gt;</span></tt> header.</p>
@@ -92,8 +93,8 @@ for this torrent. If it is a valid pointer (to a class inheriting
 <tt class="docutils literal"><span class="pre">torrent_plugin</span></tt>), it will be associated with this torrent and callbacks
 will be made on torrent events.</p>
 </div>
-<div class="section">
-<h1><a id="torrent-plugin" name="torrent-plugin">torrent_plugin</a></h1>
+<div class="section" id="torrent-plugin">
+<h1>torrent_plugin</h1>
 <p>The synopsis for <tt class="docutils literal"><span class="pre">torrent_plugin</span></tt> follows:</p>
 <pre class="literal-block">
 struct torrent_plugin
@@ -115,8 +116,8 @@ struct torrent_plugin
 <p>This is the base class for a torrent_plugin. Your derived class is (if added
 as an extension) instantiated for each torrent in the session. The callback
 hook functions are defined as follows.</p>
-<div class="section">
-<h2><a id="new-connection" name="new-connection">new_connection()</a></h2>
+<div class="section" id="new-connection">
+<h2>new_connection()</h2>
 <pre class="literal-block">
 boost::shared_ptr&lt;peer_plugin&gt; new_connection(peer_connection*);
 </pre>
@@ -133,8 +134,8 @@ held by the torrent object. So, it is generally a good idea to not keep a
 use <tt class="docutils literal"><span class="pre">weak_ptr</span></tt>.</p>
 <p>If this function throws an exception, the connection will be closed.</p>
 </div>
-<div class="section">
-<h2><a id="on-piece-pass-on-piece-fail" name="on-piece-pass-on-piece-fail">on_piece_pass() on_piece_fail()</a></h2>
+<div class="section" id="on-piece-pass-on-piece-fail">
+<h2>on_piece_pass() on_piece_fail()</h2>
 <pre class="literal-block">
 void on_piece_pass(int index);
 void on_piece_failed(int index);
@@ -144,16 +145,16 @@ check, respectively. The <tt class="docutils literal"><span class="pre">index</s
 It is possible to access the list of peers that participated in sending the
 piece through the <tt class="docutils literal"><span class="pre">torrent</span></tt> and the <tt class="docutils literal"><span class="pre">piece_picker</span></tt>.</p>
 </div>
-<div class="section">
-<h2><a id="tick" name="tick">tick()</a></h2>
+<div class="section" id="tick">
+<h2>tick()</h2>
 <pre class="literal-block">
 void tick();
 </pre>
 <p>This hook is called approximately once per second. It is a way of making it
 easy for plugins to do timed events, for sending messages or whatever.</p>
 </div>
-<div class="section">
-<h2><a id="on-pause-on-resume" name="on-pause-on-resume">on_pause() on_resume()</a></h2>
+<div class="section" id="on-pause-on-resume">
+<h2>on_pause() on_resume()</h2>
 <pre class="literal-block">
 bool on_pause();
 bool on_resume();
@@ -169,8 +170,8 @@ handler it will recurse back into your handler, so in order to invoke the
 standard handler, you have to keep your own state on whether you want standard
 behavior or overridden behavior.</p>
 </div>
-<div class="section">
-<h2><a id="on-files-checked" name="on-files-checked">on_files_checked()</a></h2>
+<div class="section" id="on-files-checked">
+<h2>on_files_checked()</h2>
 <pre class="literal-block">
 void on_files_checked();
 </pre>
@@ -180,8 +181,8 @@ checked. If there are no files to check, this function is called immediately.</p
 can start downloading.</p>
 </div>
 </div>
-<div class="section">
-<h1><a id="peer-plugin" name="peer-plugin">peer_plugin</a></h1>
+<div class="section" id="peer-plugin">
+<h1>peer_plugin</h1>
 <pre class="literal-block">
 struct peer_plugin
 {
@@ -201,7 +202,7 @@ struct peer_plugin
         virtual bool on_have_none();
         virtual bool on_allowed_fast(int index);
         virtual bool on_request(peer_request const&amp; req);
-        virtual bool on_piece(peer_request const&amp; piece, char const* data);
+        virtual bool on_piece(peer_request const&amp; piece, disk_buffer_holder&amp; buffer);
         virtual bool on_cancel(peer_request const&amp; req);
         virtual bool on_reject(peer_request const&amp; req);
         virtual bool on_suggest(int index);
@@ -218,6 +219,24 @@ struct peer_plugin
 };
 </pre>
 </div>
+<div class="section" id="disk-buffer-holder">
+<h1>disk_buffer_holder</h1>
+<pre class="literal-block">
+struct disk_buffer_holder
+{
+        disk_buffer_holder(aux::session_impl&amp; s, char* b);
+        ~disk_buffer_holder();
+        char* release();
+        char* buffer();
+};
+</pre>
+<p>The disk buffer holder acts like a <tt class="docutils literal"><span class="pre">scoped_ptr</span></tt> that frees a disk buffer
+when it's destructed, unless it's released. <tt class="docutils literal"><span class="pre">release</span></tt> returns the disk
+buffer and transferres ownership and responsibility to free it to the caller.</p>
+<p>A disk buffer is freed by passing it to <tt class="docutils literal"><span class="pre">session_impl::free_disk_buffer()</span></tt>.</p>
+<p><tt class="docutils literal"><span class="pre">buffer()</span></tt> returns the pointer without transferring responsibility. If
+this buffer has been released, <tt class="docutils literal"><span class="pre">buffer()</span></tt> will return 0.</p>
+</div>
 </div>
 </body>
 </html>
diff --git a/docs/libtorrent_plugins.rst b/docs/libtorrent_plugins.rst
index 839f3917b..42d018f0a 100644
--- a/docs/libtorrent_plugins.rst
+++ b/docs/libtorrent_plugins.rst
@@ -200,7 +200,7 @@ peer_plugin
 		virtual bool on_have_none();
 		virtual bool on_allowed_fast(int index);
 		virtual bool on_request(peer_request const& req);
-		virtual bool on_piece(peer_request const& piece, char const* data);
+		virtual bool on_piece(peer_request const& piece, disk_buffer_holder& buffer);
 		virtual bool on_cancel(peer_request const& req);
 		virtual bool on_reject(peer_request const& req);
 		virtual bool on_suggest(int index);
@@ -216,3 +216,25 @@ peer_plugin
 		virtual bool write_request(peer_request const& r);
 	};
 
+disk_buffer_holder
+==================
+
+::
+
+	struct disk_buffer_holder
+	{
+		disk_buffer_holder(aux::session_impl& s, char* b);
+		~disk_buffer_holder();
+		char* release();
+		char* buffer();
+	};
+
+The disk buffer holder acts like a ``scoped_ptr`` that frees a disk buffer
+when it's destructed, unless it's released. ``release`` returns the disk
+buffer and transferres ownership and responsibility to free it to the caller.
+
+A disk buffer is freed by passing it to ``session_impl::free_disk_buffer()``.
+
+``buffer()`` returns the pointer without transferring responsibility. If
+this buffer has been released, ``buffer()`` will return 0.
+
diff --git a/docs/manual.html b/docs/manual.html
index 298398c27..6dde7a9be 100644
--- a/docs/manual.html
+++ b/docs/manual.html
@@ -2429,6 +2429,9 @@ struct peer_info
         int send_buffer_size;
         int used_send_buffer;
 
+        int receive_buffer_size;
+        int used_receive_buffer;
+
         int num_hashfails;
 
         char country[2];
@@ -2633,6 +2636,8 @@ receive. -1 means it's unlimited.</p>
 to this peer and since any transfer occurred with this peer, respectively.</p>
 <p><tt class="docutils literal"><span class="pre">send_buffer_size</span></tt> and <tt class="docutils literal"><span class="pre">used_send_buffer</span></tt> is the number of bytes allocated
 and used for the peer's send buffer, respectively.</p>
+<p><tt class="docutils literal"><span class="pre">receive_buffer_size</span></tt> and <tt class="docutils literal"><span class="pre">used_receive_buffer</span></tt> are the number of bytes
+allocated and used as receive buffer, respectively.</p>
 <p><tt class="docutils literal"><span class="pre">num_hashfails</span></tt> is the number of pieces this peer has participated in
 sending us that turned out to fail the hash check.</p>
 <p><tt class="docutils literal"><span class="pre">country</span></tt> is the two letter <a class="reference external" href="http://www.iso.org/iso/en/prods-services/iso3166ma/02iso-3166-code-lists/list-en1.html">ISO 3166 country code</a> for the country the peer
diff --git a/docs/manual.rst b/docs/manual.rst
index 2f1daab57..889ae7944 100644
--- a/docs/manual.rst
+++ b/docs/manual.rst
@@ -2423,6 +2423,9 @@ It contains the following fields::
 		int send_buffer_size;
 		int used_send_buffer;
 
+		int receive_buffer_size;
+		int used_receive_buffer;
+
 		int num_hashfails;
 
 		char country[2];
@@ -2605,6 +2608,9 @@ to this peer and since any transfer occurred with this peer, respectively.
 ``send_buffer_size`` and ``used_send_buffer`` is the number of bytes allocated
 and used for the peer's send buffer, respectively.
 
+``receive_buffer_size`` and ``used_receive_buffer`` are the number of bytes
+allocated and used as receive buffer, respectively.
+
 ``num_hashfails`` is the number of pieces this peer has participated in
 sending us that turned out to fail the hash check.
 
diff --git a/examples/client_test.cpp b/examples/client_test.cpp
index 4cfe92297..5960645e8 100644
--- a/examples/client_test.cpp
+++ b/examples/client_test.cpp
@@ -348,7 +348,7 @@ void print_peer_info(std::ostream& out, std::vector<libtorrent::peer_info> const
 #endif
 	out << "down     (total | peak   )  up      (total | peak   ) sent-req recv flags        source ";
 	if (print_fails) out << "fail hshf ";
-	if (print_send_bufs) out << "sndb            quota ";
+	if (print_send_bufs) out << "sndb            quota rcvb            ";
 	if (print_timers) out << "inactive wait ";
 	out << "disk   rtt ";
 	if (print_block) out << "block-progress ";
@@ -427,7 +427,8 @@ void print_peer_info(std::ostream& out, std::vector<libtorrent::peer_info> const
 		if (print_send_bufs)
 		{
 			out << to_string(i->used_send_buffer, 6) << " ("<< add_suffix(i->send_buffer_size) << ") "
-				<< to_string(i->send_quota, 5) << " ";
+				<< to_string(i->send_quota, 5) << " "
+				<< to_string(i->used_receive_buffer, 6) << " ("<< add_suffix(i->receive_buffer_size) << ") ";
 		}
 		if (print_timers)
 		{
diff --git a/include/Makefile.am b/include/Makefile.am
index b3a10a4ef..2a789a2e3 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -10,6 +10,7 @@ libtorrent/buffer.hpp \
 libtorrent/connection_queue.hpp \
 libtorrent/config.hpp \
 libtorrent/debug.hpp \
+libtorrent/disk_buffer_holder.hpp \
 libtorrent/disk_io_thread.hpp \
 libtorrent/entry.hpp \
 libtorrent/enum_net.hpp \
diff --git a/include/libtorrent/aux_/session_impl.hpp b/include/libtorrent/aux_/session_impl.hpp
index 9894a7b94..3664e0e3a 100644
--- a/include/libtorrent/aux_/session_impl.hpp
+++ b/include/libtorrent/aux_/session_impl.hpp
@@ -334,6 +334,8 @@ namespace libtorrent
 
 			std::pair<char*, int> allocate_buffer(int size);
 			void free_buffer(char* buf, int size);
+
+			char* allocate_disk_buffer();
 			void free_disk_buffer(char* buf);
 
 			void set_external_address(address const& ip);
diff --git a/include/libtorrent/bt_peer_connection.hpp b/include/libtorrent/bt_peer_connection.hpp
index db46ff99a..4ef15631a 100755
--- a/include/libtorrent/bt_peer_connection.hpp
+++ b/include/libtorrent/bt_peer_connection.hpp
@@ -210,7 +210,7 @@ namespace libtorrent
 		void write_cancel(peer_request const& r);
 		void write_bitfield(std::vector<bool> const& bitfield);
 		void write_have(int index);
-		void write_piece(peer_request const& r, char* buffer);
+		void write_piece(peer_request const& r, disk_buffer_holder& buffer);
 		void write_handshake();
 #ifndef TORRENT_DISABLE_EXTENSIONS
 		void write_extensions();
diff --git a/include/libtorrent/buffer.hpp b/include/libtorrent/buffer.hpp
index a823a7677..425a6a634 100644
--- a/include/libtorrent/buffer.hpp
+++ b/include/libtorrent/buffer.hpp
@@ -44,6 +44,11 @@ class buffer
 public:
 	struct interval
 	{
+	   interval()
+		  : begin(0)
+		  , end(0)
+		{}
+
 	   interval(char* begin, char* end)
 		  : begin(begin)
 		  , end(end)
diff --git a/include/libtorrent/disk_buffer_holder.hpp b/include/libtorrent/disk_buffer_holder.hpp
new file mode 100644
index 000000000..65da342a3
--- /dev/null
+++ b/include/libtorrent/disk_buffer_holder.hpp
@@ -0,0 +1,59 @@
+/*
+
+Copyright (c) 2008, Arvid Norberg
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in
+      the documentation and/or other materials provided with the distribution.
+    * Neither the name of the author nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#ifndef TORRENT_DISK_BUFFER_HOLDER_HPP_INCLUDED
+#define TORRENT_DISK_BUFFER_HOLDER_HPP_INCLUDED
+
+#include "libtorrent/config.hpp"
+
+namespace libtorrent
+{
+
+	namespace aux { class session_impl; }
+
+	struct TORRENT_EXPORT disk_buffer_holder
+	{
+		disk_buffer_holder(aux::session_impl& ses, char* buf)
+			: m_ses(ses), m_buf(buf) {}
+		~disk_buffer_holder();
+		char* release();
+		char* buffer() const { return m_buf; }
+	private:
+		aux::session_impl& m_ses;
+		char* m_buf;
+	};
+
+
+}
+
+#endif
+
diff --git a/include/libtorrent/disk_io_thread.hpp b/include/libtorrent/disk_io_thread.hpp
index ff974b210..a5345f43e 100644
--- a/include/libtorrent/disk_io_thread.hpp
+++ b/include/libtorrent/disk_io_thread.hpp
@@ -174,6 +174,10 @@ namespace libtorrent
 
 		void operator()();
 
+#ifndef NDEBUG
+		bool is_disk_buffer(char* buffer) const;
+#endif
+
 		char* allocate_buffer();
 		void free_buffer(char* buf);
 
diff --git a/include/libtorrent/extensions.hpp b/include/libtorrent/extensions.hpp
index fd48588e1..8046d307d 100644
--- a/include/libtorrent/extensions.hpp
+++ b/include/libtorrent/extensions.hpp
@@ -56,6 +56,7 @@ namespace libtorrent
 	struct peer_request;
 	class peer_connection;
 	class entry;
+	struct disk_buffer_holder;
 
 	struct TORRENT_EXPORT torrent_plugin
 	{
@@ -143,7 +144,7 @@ namespace libtorrent
 		virtual bool on_request(peer_request const& req)
 		{ return false; }
 
-		virtual bool on_piece(peer_request const& piece, char const* data)
+		virtual bool on_piece(peer_request const& piece, disk_buffer_holder& data)
 		{ return false; }
 
 		virtual bool on_cancel(peer_request const& req)
diff --git a/include/libtorrent/peer_connection.hpp b/include/libtorrent/peer_connection.hpp
index 4d3942c98..07fe96d4c 100755
--- a/include/libtorrent/peer_connection.hpp
+++ b/include/libtorrent/peer_connection.hpp
@@ -75,6 +75,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/intrusive_ptr_base.hpp"
 #include "libtorrent/assert.hpp"
 #include "libtorrent/chained_buffer.hpp"
+#include "libtorrent/disk_buffer_holder.hpp"
 
 namespace libtorrent
 {
@@ -321,6 +322,7 @@ namespace libtorrent
 		void incoming_have(int piece_index);
 		void incoming_bitfield(std::vector<bool> const& bitfield);
 		void incoming_request(peer_request const& r);
+		void incoming_piece(peer_request const& p, disk_buffer_holder& data);
 		void incoming_piece(peer_request const& p, char const* data);
 		void incoming_piece_fragment();
 		void incoming_cancel(peer_request const& r);
@@ -439,7 +441,7 @@ namespace libtorrent
 		virtual void write_cancel(peer_request const& r) = 0;
 		virtual void write_have(int index) = 0;
 		virtual void write_keepalive() = 0;
-		virtual void write_piece(peer_request const& r, char* buffer) = 0;
+		virtual void write_piece(peer_request const& r, disk_buffer_holder& buffer) = 0;
 		
 		virtual void write_reject_request(peer_request const& r) = 0;
 		virtual void write_allow_fast(int piece) = 0;
@@ -455,10 +457,14 @@ namespace libtorrent
 #ifndef TORRENT_DISABLE_ENCRYPTION
 		buffer::interval wr_recv_buffer()
 		{
+			TORRENT_ASSERT(m_disk_recv_buffer == 0);
+			TORRENT_ASSERT(m_disk_recv_buffer_size == 0);
 			if (m_recv_buffer.empty()) return buffer::interval(0,0);
 			return buffer::interval(&m_recv_buffer[0]
 				, &m_recv_buffer[0] + m_recv_pos);
 		}
+
+		std::pair<buffer::interval, buffer::interval> wr_recv_buffers(int bytes);
 #endif
 		
 		buffer::const_interval receive_buffer() const
@@ -468,8 +474,10 @@ namespace libtorrent
 				, &m_recv_buffer[0] + m_recv_pos);
 		}
 
+		bool allocate_disk_receive_buffer(int disk_buffer_size);
+		char* release_disk_receive_buffer();
+		bool has_disk_receive_buffer() const { return m_disk_recv_buffer; }
 		void cut_receive_buffer(int size, int packet_size);
-
 		void reset_recv_buffer(int packet_size);
 
 		void setup_receive();
@@ -555,6 +563,13 @@ namespace libtorrent
 		int m_recv_pos;
 		buffer m_recv_buffer;
 
+		// if this peer is receiving a piece, this
+		// points to a disk buffer that the data is
+		// read into. This eliminates a memcopy from
+		// the receive buffer into the disk buffer
+		int m_disk_recv_buffer_size;
+		char* m_disk_recv_buffer;
+
 		chained_buffer m_send_buffer;
 
 		// the number of bytes we are currently reading
diff --git a/include/libtorrent/peer_info.hpp b/include/libtorrent/peer_info.hpp
index 2ec9742a7..fe29c5288 100755
--- a/include/libtorrent/peer_info.hpp
+++ b/include/libtorrent/peer_info.hpp
@@ -111,6 +111,9 @@ namespace libtorrent
 		// the number bytes that's actually used of the send buffer
 		int used_send_buffer;
 
+		int receive_buffer_size;
+		int used_receive_buffer;
+
 		// the number of failed hashes for this peer
 		int num_hashfails;
 
diff --git a/include/libtorrent/storage.hpp b/include/libtorrent/storage.hpp
index 7a953f210..2a3efb1b3 100755
--- a/include/libtorrent/storage.hpp
+++ b/include/libtorrent/storage.hpp
@@ -71,6 +71,7 @@ namespace libtorrent
 	class session;
 	struct file_pool;
 	struct disk_io_job;
+	struct disk_buffer_holder;
 
 	enum storage_mode_t
 	{
@@ -216,7 +217,7 @@ namespace libtorrent
 
 		void async_write(
 			peer_request const& r
-			, char const* buffer
+			, disk_buffer_holder& buffer
 			, boost::function<void(int, disk_io_job const&)> const& f);
 
 		void async_hash(int piece, boost::function<void(int, disk_io_job const&)> const& f);
diff --git a/include/libtorrent/web_peer_connection.hpp b/include/libtorrent/web_peer_connection.hpp
index 24acdd972..f9d235bbc 100755
--- a/include/libtorrent/web_peer_connection.hpp
+++ b/include/libtorrent/web_peer_connection.hpp
@@ -122,7 +122,7 @@ namespace libtorrent
 		void write_cancel(peer_request const& r)
 		{ incoming_reject_request(r); }
 		void write_have(int index) {}
-		void write_piece(peer_request const& r, char* buffer) { TORRENT_ASSERT(false); }
+		void write_piece(peer_request const& r, disk_buffer_holder& buffer) { TORRENT_ASSERT(false); }
 		void write_keepalive() {}
 		void on_connected();
 		void write_reject_request(peer_request const&) {}
diff --git a/src/Makefile.am b/src/Makefile.am
index e47774d8b..9efbc64c1 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -23,7 +23,7 @@ alert.cpp identify_client.cpp ip_filter.cpp file.cpp metadata_transfer.cpp \
 logger.cpp file_pool.cpp ut_pex.cpp lsd.cpp upnp.cpp instantiate_connection.cpp \
 socks5_stream.cpp socks4_stream.cpp http_stream.cpp connection_queue.cpp \
 disk_io_thread.cpp ut_metadata.cpp magnet_uri.cpp udp_socket.cpp smart_ban.cpp \
-http_parser.cpp gzip.cpp $(kademlia_sources)
+http_parser.cpp gzip.cpp disk_buffer_holder.cpp $(kademlia_sources)
 
 noinst_HEADERS = \
 $(top_srcdir)/include/libtorrent/alert.hpp \
diff --git a/src/bt_peer_connection.cpp b/src/bt_peer_connection.cpp
index 732f22f1b..7394406dc 100755
--- a/src/bt_peer_connection.cpp
+++ b/src/bt_peer_connection.cpp
@@ -993,6 +993,14 @@ namespace libtorrent
 		buffer::const_interval recv_buffer = receive_buffer();
 		int recv_pos = recv_buffer.end - recv_buffer.begin;
 
+		if (recv_pos == 1)
+		{
+			TORRENT_ASSERT(!has_disk_receive_buffer());
+			if (!allocate_disk_receive_buffer(packet_size() - 9))
+				return;
+		}
+		TORRENT_ASSERT(has_disk_receive_buffer());
+
 		// classify the received data as protocol chatter
 		// or data payload for the statistics
 		if (recv_pos <= 9)
@@ -1021,7 +1029,8 @@ namespace libtorrent
 		p.start = detail::read_int32(ptr);
 		p.length = packet_size() - 9;
 
-		incoming_piece(p, recv_buffer.begin + 9);
+		disk_buffer_holder holder(m_ses, release_disk_receive_buffer());
+		incoming_piece(p, holder);
 	}
 
 	// -----------------------------
@@ -1322,6 +1331,7 @@ namespace libtorrent
 
 		buffer::const_interval recv_buffer = receive_buffer();
 
+		TORRENT_ASSERT(recv_buffer.left() >= 1);
 		int packet_type = recv_buffer[0];
 		if (packet_type < 0
 			|| packet_type >= num_supported_messages
@@ -1643,7 +1653,7 @@ namespace libtorrent
 		send_buffer(msg, sizeof(msg));
 	}
 
-	void bt_peer_connection::write_piece(peer_request const& r, char* buffer)
+	void bt_peer_connection::write_piece(peer_request const& r, disk_buffer_holder& buffer)
 	{
 		INVARIANT_CHECK;
 
@@ -1661,9 +1671,10 @@ namespace libtorrent
 		detail::write_int32(r.start, ptr);
 		send_buffer(msg, sizeof(msg));
 
-		append_send_buffer(buffer, r.length
+		append_send_buffer(buffer.buffer(), r.length
 			, boost::bind(&session_impl::free_disk_buffer
 			, boost::ref(m_ses), _1));
+		buffer.release();
 
 		m_payloads.push_back(range(send_buffer_size() - r.length, r.length));
 		setup_send();
@@ -1711,8 +1722,9 @@ namespace libtorrent
 		TORRENT_ASSERT(in_handshake() || !m_rc4_encrypted || m_encrypted);
 		if (m_rc4_encrypted && m_encrypted)
 		{
-			buffer::interval wr_buf = wr_recv_buffer();
-			m_RC4_handler->decrypt((wr_buf.end - bytes_transferred), bytes_transferred);
+			std::pair<buffer::interval, buffer::interval> wr_buf = wr_recv_buffers(bytes_transferred);
+			m_RC4_handler->decrypt(wr_buf.first.begin, wr_buf.first.left());
+			if (wr_buf.second.left()) m_RC4_handler->decrypt(wr_buf.second.begin, wr_buf.second.left());
 		}
 #endif
 
@@ -1724,10 +1736,10 @@ namespace libtorrent
 		// for outgoing
 		if (m_state == read_pe_dhkey)
 		{
-			assert (!m_encrypted);
-			assert (!m_rc4_encrypted);
-			assert (packet_size() == dh_key_len);
-			assert (recv_buffer == receive_buffer());
+			TORRENT_ASSERT(!m_encrypted);
+			TORRENT_ASSERT(!m_rc4_encrypted);
+			TORRENT_ASSERT(packet_size() == dh_key_len);
+			TORRENT_ASSERT(recv_buffer == receive_buffer());
 
 			if (!packet_finished()) return;
 			
@@ -2232,7 +2244,7 @@ namespace libtorrent
 		
 		if (m_state == read_protocol_identifier)
 		{
-			assert (packet_size() == 20);
+			TORRENT_ASSERT(packet_size() == 20);
 
 			if (!packet_finished()) return;
 			recv_buffer = receive_buffer();
@@ -2263,14 +2275,14 @@ namespace libtorrent
  					return;
 				}
 				
-				assert ((!is_local() && m_encrypted) || is_local());
+				TORRENT_ASSERT((!is_local() && m_encrypted) || is_local());
 #endif // #ifndef TORRENT_DISABLE_ENCRYPTION
 				disconnect("incorrect protocol identifier");
 				return;
 			}
 
 #ifndef TORRENT_DISABLE_ENCRYPTION
-			assert (m_state != read_pe_dhkey);
+			TORRENT_ASSERT(m_state != read_pe_dhkey);
 
 			if (!is_local() && 
 				(m_ses.get_pe_settings().in_enc_policy == pe_settings::forced) &&
@@ -2494,7 +2506,7 @@ namespace libtorrent
 #endif
 
 			m_state = read_packet_size;
-			reset_recv_buffer(4);
+			reset_recv_buffer(5);
 			if (t->valid_metadata())
 			{
 				write_bitfield(t->pieces());
@@ -2512,11 +2524,12 @@ namespace libtorrent
 		if (m_state == read_packet_size)
 		{
 			// Make sure this is not fallen though into
-			assert (recv_buffer == receive_buffer());
+			TORRENT_ASSERT(recv_buffer == receive_buffer());
 
 			if (!t) return;
 			m_statistics.received_bytes(0, bytes_transferred);
-			if (!packet_finished()) return;
+
+			if (recv_buffer.left() < 4) return;
 
 			const char* ptr = recv_buffer.begin;
 			int packet_size = detail::read_int32(ptr);
@@ -2536,15 +2549,19 @@ namespace libtorrent
 				incoming_keepalive();
 				// keepalive message
 				m_state = read_packet_size;
-				reset_recv_buffer(4);
+				cut_receive_buffer(4, 4);
+				return;
 			}
 			else
 			{
+				if (recv_buffer.left() < 5) return;
+
 				m_state = read_packet;
-				reset_recv_buffer(packet_size);
+				cut_receive_buffer(4, packet_size);
+				bytes_transferred = 1;
+				recv_buffer = receive_buffer();
+				TORRENT_ASSERT(recv_buffer.left() == 1);
 			}
-			TORRENT_ASSERT(!packet_finished());
-			return;
 		}
 
 		if (m_state == read_packet)
@@ -2554,7 +2571,7 @@ namespace libtorrent
 			if (dispatch_message(bytes_transferred))
 			{
 				m_state = read_packet_size;
-				reset_recv_buffer(4);
+				reset_recv_buffer(5);
 			}
 			TORRENT_ASSERT(!packet_finished());
 			return;
diff --git a/src/disk_buffer_holder.cpp b/src/disk_buffer_holder.cpp
new file mode 100644
index 000000000..dc3846930
--- /dev/null
+++ b/src/disk_buffer_holder.cpp
@@ -0,0 +1,50 @@
+/*
+
+Copyright (c) 2008, Arvid Norberg
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in
+      the documentation and/or other materials provided with the distribution.
+    * Neither the name of the author nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#include "libtorrent/disk_buffer_holder.hpp"
+#include "libtorrent/aux_/session_impl.hpp"
+
+namespace libtorrent
+{
+	char* disk_buffer_holder::release()
+	{
+		char* ret = m_buf;
+		m_buf = 0;
+		return ret;
+	}
+
+	disk_buffer_holder::~disk_buffer_holder()
+	{
+		if (m_buf) m_ses.free_disk_buffer(m_buf);
+	}
+}
+
diff --git a/src/disk_io_thread.cpp b/src/disk_io_thread.cpp
index 11f86dbd4..9d7f37e88 100644
--- a/src/disk_io_thread.cpp
+++ b/src/disk_io_thread.cpp
@@ -678,6 +678,18 @@ namespace libtorrent
 		m_signal.notify_all();
 	}
 
+#ifndef NDEBUG
+	bool disk_io_thread::is_disk_buffer(char* buffer) const
+	{
+#ifdef TORRENT_DISABLE_POOL_ALLOCATOR
+		return true;
+#else
+		mutex_t::scoped_lock l(m_mutex);
+		return m_pool.is_from(buffer);
+#endif
+	}
+#endif
+
 	char* disk_io_thread::allocate_buffer()
 	{
 		mutex_t::scoped_lock l(m_mutex);
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 99a420103..44d8b91fe 100755
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -59,7 +59,6 @@ using libtorrent::aux::session_impl;
 
 namespace libtorrent
 {
-
 	// outbound connection
 	peer_connection::peer_connection(
 		session_impl& ses
@@ -81,6 +80,8 @@ namespace libtorrent
 		, m_last_unchoke(min_time())
 		, m_packet_size(0)
 		, m_recv_pos(0)
+		, m_disk_recv_buffer_size(0)
+		, m_disk_recv_buffer(0)
 		, m_reading_bytes(0)
 		, m_last_receive(time_now())
 		, m_last_sent(time_now())
@@ -167,6 +168,8 @@ namespace libtorrent
 		, m_last_unchoke(min_time())
 		, m_packet_size(0)
 		, m_recv_pos(0)
+		, m_disk_recv_buffer_size(0)
+		, m_disk_recv_buffer(0)
 		, m_reading_bytes(0)
 		, m_last_receive(time_now())
 		, m_last_sent(time_now())
@@ -451,6 +454,13 @@ namespace libtorrent
 		TORRENT_ASSERT(!m_in_constructor);
 		TORRENT_ASSERT(m_disconnecting);
 
+		if (m_disk_recv_buffer)
+		{
+			m_ses.free_disk_buffer(m_disk_recv_buffer);
+			m_disk_recv_buffer = 0;
+			m_disk_recv_buffer_size = 0;
+		}
+
 #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
 		if (m_logger)
 		{
@@ -1368,12 +1378,27 @@ namespace libtorrent
 	// -----------------------------
 
 	void peer_connection::incoming_piece(peer_request const& p, char const* data)
+	{
+		char* buffer = m_ses.allocate_disk_buffer();
+		if (buffer == 0)
+		{
+			disconnect("out of memory");
+			return;
+		}		
+		disk_buffer_holder holder(m_ses, buffer);
+		incoming_piece(p, holder);
+	}
+
+	void peer_connection::incoming_piece(peer_request const& p, disk_buffer_holder& data)
 	{
 		INVARIANT_CHECK;
 
 		boost::shared_ptr<torrent> t = m_torrent.lock();
 		TORRENT_ASSERT(t);
 
+		TORRENT_ASSERT(m_disk_recv_buffer == 0);
+		TORRENT_ASSERT(m_disk_recv_buffer_size == 0);
+
 #ifndef TORRENT_DISABLE_EXTENSIONS
 		for (extension_list_t::iterator i = m_extensions.begin()
 			, end(m_extensions.end()); i != end; ++i)
@@ -2079,7 +2104,6 @@ namespace libtorrent
 		m_last_piece = time_now();
 	}
 
-
 	void peer_connection::timed_out()
 	{
 		TORRENT_ASSERT(m_connecting);
@@ -2301,10 +2325,51 @@ namespace libtorrent
 		p.remote_dl_rate = m_remote_dl_rate;
 		p.send_buffer_size = m_send_buffer.capacity();
 		p.used_send_buffer = m_send_buffer.size();
+		p.receive_buffer_size = m_recv_buffer.capacity() + m_disk_recv_buffer_size;
+		p.used_receive_buffer = m_recv_pos;
 		p.write_state = m_channel_state[upload_channel];
 		p.read_state = m_channel_state[download_channel];
 	}
 
+	// allocates a disk buffer of size 'disk_buffer_size' and replaces the
+	// end of the current receive buffer with it. i.e. the receive pos
+	// must be <= packet_size - disk_buffer_size
+	// the disk buffer can be accessed through release_disk_receive_buffer()
+	// when it is queried, the responsibility to free it is transferred
+	// to the caller
+	bool peer_connection::allocate_disk_receive_buffer(int disk_buffer_size)
+	{
+		INVARIANT_CHECK;
+		
+		TORRENT_ASSERT(m_packet_size > 0);
+		TORRENT_ASSERT(m_recv_pos <= m_packet_size - disk_buffer_size);
+		TORRENT_ASSERT(m_disk_recv_buffer == 0);
+		TORRENT_ASSERT(disk_buffer_size <= 16 * 1024);
+
+		if (disk_buffer_size > 16 * 1024)
+		{
+			disconnect("invalid piece size");
+			return false;
+		}
+
+		m_disk_recv_buffer = m_ses.allocate_disk_buffer();
+		if (m_disk_recv_buffer == 0)
+		{
+			disconnect("out of memory");
+			return false;
+		}
+		m_disk_recv_buffer_size = disk_buffer_size;
+		return true;
+	}
+
+	char* peer_connection::release_disk_receive_buffer()
+	{
+		char* ret = m_disk_recv_buffer;
+		m_disk_recv_buffer = 0;
+		m_disk_recv_buffer_size = 0;
+		return ret;
+	}
+	
 	void peer_connection::cut_receive_buffer(int size, int packet_size)
 	{
 		INVARIANT_CHECK;
@@ -2324,7 +2389,6 @@ namespace libtorrent
 #endif
 
 		m_packet_size = packet_size;
-		if (m_packet_size >= m_recv_pos) m_recv_buffer.resize(m_packet_size);
 	}
 
 	void peer_connection::second_tick(float tick_interval)
@@ -2542,9 +2606,10 @@ namespace libtorrent
 
 		m_reading_bytes -= r.length;
 
+		disk_buffer_holder buffer(m_ses, j.buffer);
+
 		if (ret != r.length || m_torrent.expired())
 		{
-			if (j.buffer) m_ses.free_disk_buffer(j.buffer);
 			boost::shared_ptr<torrent> t = m_torrent.lock();
 			if (!t)
 			{
@@ -2572,7 +2637,7 @@ namespace libtorrent
 			<< " | l: " << r.length << " ]\n";
 #endif
 
-		write_piece(r, j.buffer);
+		write_piece(r, buffer);
 		setup_send();
 	}
 
@@ -2735,11 +2800,84 @@ namespace libtorrent
 #ifdef TORRENT_VERBOSE_LOGGING
 		(*m_logger) << time_now_string() << " *** ASYNC_READ [ max: " << max_receive << " bytes ]\n";
 #endif
-		m_socket->async_read_some(asio::buffer(&m_recv_buffer[m_recv_pos]
-			, max_receive), bind(&peer_connection::on_receive_data, self(), _1, _2));
+
+		int regular_buffer_size = m_packet_size - m_disk_recv_buffer_size;
+
+		if (int(m_recv_buffer.size()) < regular_buffer_size)
+			m_recv_buffer.resize(regular_buffer_size);
+
+		if (m_disk_recv_buffer == 0 || regular_buffer_size >= m_recv_pos + max_receive)
+		{
+			// only receive into regular buffer
+			TORRENT_ASSERT(m_recv_pos + max_receive <= int(m_recv_buffer.size()));
+			m_socket->async_read_some(asio::buffer(&m_recv_buffer[m_recv_pos]
+				, max_receive), bind(&peer_connection::on_receive_data, self(), _1, _2));
+		}
+		else if (m_recv_pos >= regular_buffer_size)
+		{
+			// only receive into disk buffer
+			TORRENT_ASSERT(m_recv_pos - regular_buffer_size >= 0);
+			TORRENT_ASSERT(m_recv_pos - regular_buffer_size + max_receive <= m_disk_recv_buffer_size);
+			m_socket->async_read_some(asio::buffer(m_disk_recv_buffer + m_recv_pos - regular_buffer_size
+				, max_receive)
+				, bind(&peer_connection::on_receive_data, self(), _1, _2));
+		}
+		else
+		{
+			// receive into both regular and disk buffer
+			TORRENT_ASSERT(max_receive + m_recv_pos > regular_buffer_size);
+			TORRENT_ASSERT(m_recv_pos < regular_buffer_size);
+			TORRENT_ASSERT(max_receive - regular_buffer_size
+				+ m_recv_pos <= m_disk_recv_buffer_size);
+
+			boost::array<asio::mutable_buffer, 2> vec;
+			vec[0] = asio::buffer(&m_recv_buffer[m_recv_pos]
+				, regular_buffer_size - m_recv_pos);
+			vec[1] = asio::buffer(m_disk_recv_buffer
+				, max_receive - regular_buffer_size + m_recv_pos);
+			m_socket->async_read_some(vec, bind(&peer_connection::on_receive_data
+				, self(), _1, _2));
+		}
 		m_channel_state[download_channel] = peer_info::bw_network;
 	}
 
+#ifndef TORRENT_DISABLE_ENCRYPTION
+
+	// returns the last 'bytes' from the receive buffer
+	std::pair<buffer::interval, buffer::interval> peer_connection::wr_recv_buffers(int bytes)
+	{
+		TORRENT_ASSERT(bytes <= m_recv_pos);
+
+		std::pair<buffer::interval, buffer::interval> vec;
+		int regular_buffer_size = m_packet_size - m_disk_recv_buffer_size;
+		TORRENT_ASSERT(regular_buffer_size >= 0);
+		if (m_disk_recv_buffer == 0 || regular_buffer_size >= m_recv_pos)
+		{
+			vec.first = buffer::interval(&m_recv_buffer[0]
+				+ m_recv_pos - bytes, &m_recv_buffer[0] + m_recv_pos);
+			vec.second = buffer::interval(0,0);
+		}
+		else if (m_recv_pos - bytes >= regular_buffer_size)
+		{
+			vec.first = buffer::interval(m_disk_recv_buffer + m_recv_pos
+				- regular_buffer_size - bytes, m_disk_recv_buffer + m_recv_pos
+				- regular_buffer_size);
+			vec.second = buffer::interval(0,0);
+		}
+		else
+		{
+			TORRENT_ASSERT(m_recv_pos - bytes < regular_buffer_size);
+			TORRENT_ASSERT(m_recv_pos > regular_buffer_size);
+			vec.first = buffer::interval(&m_recv_buffer[0] + m_recv_pos - bytes
+				, &m_recv_buffer[0] + regular_buffer_size);
+			vec.second = buffer::interval(m_disk_recv_buffer
+				, m_disk_recv_buffer + m_recv_pos - regular_buffer_size);
+		}
+		TORRENT_ASSERT(vec.first.left() + vec.second.left() == bytes);
+		return vec;
+	}
+#endif
+
 	void peer_connection::reset_recv_buffer(int packet_size)
 	{
 		TORRENT_ASSERT(packet_size > 0);
@@ -2750,8 +2888,6 @@ namespace libtorrent
 		}
 		m_recv_pos = 0;
 		m_packet_size = packet_size;
-		if (int(m_recv_buffer.size()) < m_packet_size)
-			m_recv_buffer.resize(m_packet_size);
 	}
 
 	void peer_connection::send_buffer(char const* buf, int size)
@@ -2861,6 +2997,7 @@ namespace libtorrent
 			return;
 		}
 
+		int max_receive = 0;
 		do
 		{
 #ifdef TORRENT_VERBOSE_LOGGING
@@ -2877,7 +3014,8 @@ namespace libtorrent
 
 			m_last_receive = time_now();
 			m_recv_pos += bytes_transferred;
-			TORRENT_ASSERT(m_recv_pos <= int(m_recv_buffer.size()));
+			TORRENT_ASSERT(m_recv_pos <= int(m_recv_buffer.size()
+				+ m_disk_recv_buffer_size));
 
 			on_receive(error, bytes_transferred);
 
@@ -2890,21 +3028,57 @@ namespace libtorrent
 				buffer(m_packet_size).swap(m_recv_buffer);
 			}
 
-			int max_receive = m_packet_size - m_recv_pos;
+			max_receive = m_packet_size - m_recv_pos;
 			int quota_left = m_bandwidth_limit[download_channel].quota_left();
 			if (!m_ignore_bandwidth_limits && max_receive > quota_left)
 				max_receive = quota_left;
 
 			if (max_receive == 0) break;
 
+			int regular_buffer_size = m_packet_size - m_disk_recv_buffer_size;
+
+			if (int(m_recv_buffer.size()) < regular_buffer_size)
+				m_recv_buffer.resize(regular_buffer_size);
+
 			asio::error_code ec;	
-			bytes_transferred = m_socket->read_some(asio::buffer(&m_recv_buffer[m_recv_pos]
-				, max_receive), ec);
+			if (m_disk_recv_buffer == 0 || regular_buffer_size >= m_recv_pos + max_receive)
+			{
+				// only receive into regular buffer
+				TORRENT_ASSERT(m_recv_pos + max_receive <= int(m_recv_buffer.size()));
+				bytes_transferred = m_socket->read_some(asio::buffer(&m_recv_buffer[m_recv_pos]
+					, max_receive), ec);
+			}
+			else if (m_recv_pos >= regular_buffer_size)
+			{
+				// only receive into disk buffer
+				TORRENT_ASSERT(m_recv_pos - regular_buffer_size >= 0);
+				TORRENT_ASSERT(m_recv_pos - regular_buffer_size + max_receive <= m_disk_recv_buffer_size);
+				bytes_transferred = m_socket->read_some(asio::buffer(m_disk_recv_buffer
+					+ m_recv_pos - regular_buffer_size, (std::min)(m_packet_size
+					- m_recv_pos, max_receive)), ec);
+			}
+			else
+			{
+				// receive into both regular and disk buffer
+				TORRENT_ASSERT(max_receive + m_recv_pos > regular_buffer_size);
+				TORRENT_ASSERT(m_recv_pos < regular_buffer_size);
+				TORRENT_ASSERT(max_receive - regular_buffer_size
+					+ m_recv_pos <= m_disk_recv_buffer_size);
+
+				boost::array<asio::mutable_buffer, 2> vec;
+				vec[0] = asio::buffer(&m_recv_buffer[m_recv_pos]
+					, regular_buffer_size - m_recv_pos);
+				vec[1] = asio::buffer(m_disk_recv_buffer
+					, (std::min)(m_disk_recv_buffer_size
+					, max_receive - regular_buffer_size + m_recv_pos));
+				bytes_transferred = m_socket->read_some(vec, ec);
+			}
 			if (ec && ec != asio::error::would_block)
 			{
 				disconnect(ec.message().c_str());
 				return;
 			}
+			if (ec == asio::error::would_block) break;
 		}
 		while (bytes_transferred > 0);
 
@@ -3109,6 +3283,8 @@ namespace libtorrent
 #ifndef NDEBUG
 	void peer_connection::check_invariant() const
 	{
+		TORRENT_ASSERT((m_disk_recv_buffer != 0) == (m_disk_recv_buffer_size > 0));
+
 		boost::shared_ptr<torrent> t = m_torrent.lock();
 		if (m_disconnecting)
 		{
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index b1463b6c3..a12d906ef 100755
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -2215,6 +2215,11 @@ namespace aux {
 	{
 		m_disk_thread.free_buffer(buf);
 	}
+
+	char* session_impl::allocate_disk_buffer()
+	{
+		return m_disk_thread.allocate_buffer();
+	}
 	
 	std::pair<char*, int> session_impl::allocate_buffer(int size)
 	{
diff --git a/src/storage.cpp b/src/storage.cpp
index 0436063a9..a56a1aba2 100755
--- a/src/storage.cpp
+++ b/src/storage.cpp
@@ -67,6 +67,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/invariant_check.hpp"
 #include "libtorrent/file_pool.hpp"
 #include "libtorrent/aux_/session_impl.hpp"
+#include "libtorrent/disk_buffer_holder.hpp"
 
 #ifndef NDEBUG
 #include <ios>
@@ -1243,10 +1244,12 @@ namespace libtorrent
 
 	void piece_manager::async_write(
 		peer_request const& r
-		, char const* buffer
+		, disk_buffer_holder& buffer
 		, boost::function<void(int, disk_io_job const&)> const& handler)
 	{
 		TORRENT_ASSERT(r.length <= 16 * 1024);
+		// the buffer needs to be allocated through the io_thread
+		TORRENT_ASSERT(m_io_thread.is_disk_buffer(buffer.buffer()));
 
 		disk_io_job j;
 		j.storage = this;
@@ -1254,13 +1257,9 @@ namespace libtorrent
 		j.piece = r.piece;
 		j.offset = r.start;
 		j.buffer_size = r.length;
-		j.buffer = m_io_thread.allocate_buffer();
-#ifndef BOOST_NO_EXCEPTIONS
-		if (j.buffer == 0) throw file_error("out of memory");
-		// TODO: return error code instead of throwing
-#endif
-		std::memcpy(j.buffer, buffer, j.buffer_size);
+		j.buffer = buffer.buffer();
 		m_io_thread.add_job(j, handler);
+		buffer.release();
 	}
 
 	void piece_manager::async_hash(int piece