NetPlay save data synchronization

This adds the functionality of sending the host's save data (raw memory
cards, as well as GCI files and Wii saves with a matching GameID) to
all other clients. The data is compressed using LZO1X to greatly reduce
its size while keeping compression/decompression fast. Save
synchronization is enabled by default, and toggleable with a checkbox
in the NetPlay dialog.

On clicking start, if the option is enabled, game boot will be delayed
until all players have received the save data sent by the host. If any
player fails to receive it properly, boot will be cancelled to prevent
desyncs.

Source/Core/Common/CMakeLists.txt

@@ -36,6 +36,7 @@ add_library(common
   QoSSession.cpp
   Random.cpp
   SDCardUtil.cpp
+  SFMLHelper.cpp
   SettingsHandler.cpp
   StringUtil.cpp
   SymbolDB.cpp

Source/Core/Common/Common.vcxproj

@@ -147,6 +147,7 @@
     <ClInclude Include="Result.h" />
     <ClInclude Include="ScopeGuard.h" />
     <ClInclude Include="SDCardUtil.h" />
+    <ClInclude Include="SFMLHelper.h" />
     <ClInclude Include="Semaphore.h" />
     <ClInclude Include="SettingsHandler.h" />
     <ClInclude Include="SPSCQueue.h" />
@@ -210,6 +211,7 @@
     <ClCompile Include="QoSSession.cpp" />
     <ClCompile Include="Random.cpp" />
     <ClCompile Include="SDCardUtil.cpp" />
+    <ClCompile Include="SFMLHelper.cpp" />
     <ClCompile Include="SettingsHandler.cpp" />
     <ClCompile Include="StringUtil.cpp" />
     <ClCompile Include="SymbolDB.cpp" />

Source/Core/Common/Common.vcxproj.filters

@@ -68,6 +68,7 @@
     <ClInclude Include="Result.h" />
     <ClInclude Include="ScopeGuard.h" />
     <ClInclude Include="SDCardUtil.h" />
+    <ClInclude Include="SFMLHelper.h" />
     <ClInclude Include="SettingsHandler.h" />
     <ClInclude Include="SPSCQueue.h" />
     <ClInclude Include="StringUtil.h" />
@@ -299,6 +300,7 @@
     <ClCompile Include="Profiler.cpp" />
     <ClCompile Include="Random.cpp" />
     <ClCompile Include="SDCardUtil.cpp" />
+    <ClCompile Include="SFMLHelper.cpp" />
     <ClCompile Include="SettingsHandler.cpp" />
     <ClCompile Include="StringUtil.cpp" />
     <ClCompile Include="SymbolDB.cpp" />

Source/Core/Common/CommonPaths.h

@@ -109,6 +109,7 @@
 #define GC_SRAM "SRAM.raw"
 #define GC_MEMCARDA "MemoryCardA"
 #define GC_MEMCARDB "MemoryCardB"
+#define GC_MEMCARD_NETPLAY "NetPlayTemp"
 
 #define WII_STATE "state.dat"
 

Source/Core/Common/SFMLHelper.cpp

@@ -0,0 +1,38 @@
+// Copyright 2018 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include "Common/SFMLHelper.h"
+
+#include <SFML/Network/Packet.hpp>
+
+namespace Common
+{
+// This only exists as a helper for BigEndianValue
+u16 PacketReadU16(sf::Packet& packet)
+{
+  u16 tmp;
+  packet >> tmp;
+  return tmp;
+}
+
+// This only exists as a helper for BigEndianValue
+u32 PacketReadU32(sf::Packet& packet)
+{
+  u32 tmp;
+  packet >> tmp;
+  return tmp;
+}
+
+u64 PacketReadU64(sf::Packet& packet)
+{
+  u32 low, high;
+  packet >> low >> high;
+  return low | (static_cast<u64>(high) << 32);
+}
+
+void PacketWriteU64(sf::Packet& packet, const u64 value)
+{
+  packet << static_cast<u32>(value) << static_cast<u32>(value >> 32);
+}
+}  // namespace Common

Source/Core/Common/SFMLHelper.h

@@ -0,0 +1,23 @@
+// Copyright 2018 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "Common/CommonTypes.h"
+
+namespace sf
+{
+class Packet;
+}
+
+namespace Common
+{
+template <typename value_type>
+struct BigEndianValue;
+
+u16 PacketReadU16(sf::Packet& packet);
+u32 PacketReadU32(sf::Packet& packet);
+u64 PacketReadU64(sf::Packet& packet);
+void PacketWriteU64(sf::Packet& packet, u64 value);
+}  // namespace Common