libretro: implement save/load state.

Signed-off-by: Andrea Odetti <mariofutire@gmail.com>

source/frontends/libretro/CMakeLists.txt

@@ -11,9 +11,11 @@ set(SOURCE_FILES
   retroregistry.cpp
   retroframe.cpp
   diskcontrol.cpp
+  serialisation.cpp
   )
 
 set(HEADER_FILES
+  libretro-common/include/libretro.h
   environment.h
   rdirectsound.h
   game.h
@@ -25,7 +27,7 @@ set(HEADER_FILES
   retroregistry.h
   retroframe.h
   diskcontrol.h
-  libretro-common/include/libretro.h
+  serialisation.h
   )
 
 add_library(applewin_libretro SHARED

source/frontends/libretro/libretro.cpp

@@ -19,6 +19,7 @@
 #include "frontends/libretro/joypad.h"
 #include "frontends/libretro/analog.h"
 #include "frontends/libretro/mouse.h"
+#include "frontends/libretro/serialisation.h"
 
 namespace
 {
@@ -362,19 +363,22 @@ bool retro_load_game_special(unsigned type, const struct retro_game_info *info,
 size_t retro_serialize_size(void)
 {
   ra2::log_cb(RETRO_LOG_INFO, "RA2: %s\n", __FUNCTION__);
-  return 0;
+  const size_t size = ra2::RetroSerialisation::getSize();
+  // we cannot guarantee exact file size, so we allow for a small grace buffer
+  const size_t buffer = 4096;
+  return size + buffer;
 }
 
 bool retro_serialize(void *data, size_t size)
 {
   ra2::log_cb(RETRO_LOG_INFO, "RA2: %s\n", __FUNCTION__);
-  return false;
+  return ra2::RetroSerialisation::serialise(static_cast<char *>(data), size);
 }
 
 bool retro_unserialize(const void *data, size_t size)
 {
   ra2::log_cb(RETRO_LOG_INFO, "RA2: %s\n", __FUNCTION__);
-  return false;
+  return ra2::RetroSerialisation::deserialise(static_cast<const char *>(data), size);
 }
 
 void retro_cheat_reset(void)

source/frontends/libretro/serialisation.cpp

@@ -0,0 +1,136 @@
+#include "StdAfx.h"
+#include "SaveState.h"
+
+#include "frontends/libretro/serialisation.h"
+#include "frontends/libretro/environment.h"
+
+#include <cstdio>
+#include <fstream>
+
+namespace
+{
+  class AutoFile
+  {
+  public:
+    AutoFile();
+    ~AutoFile();
+
+    std::string getFilename() const;  // only if true
+
+    operator bool() const;
+  protected:
+    const char * myFilename;
+  };
+
+  AutoFile::AutoFile()
+  {
+    // massive race condition, but without changes to AW, little can we do here
+    myFilename = std::tmpnam(nullptr);
+  }
+
+  AutoFile::~AutoFile()
+  {
+    std::remove(myFilename);
+  }
+
+  AutoFile::operator bool() const
+  {
+    return myFilename;
+  }
+
+  std::string AutoFile::getFilename() const
+  {
+    return myFilename;
+  }
+
+  void saveToFile(const std::string & filename)  // cannot be null!
+  {
+    Snapshot_SetFilename(filename);
+    Snapshot_SaveState();
+  }
+
+}
+
+namespace ra2
+{
+
+  size_t RetroSerialisation::getSize()
+  {
+    AutoFile autoFile;
+    if (!autoFile)
+    {
+      return 0;
+    }
+
+    const std::string filename = autoFile.getFilename();
+    saveToFile(filename);
+    std::ifstream ifs(filename, std::ios::binary | std::ios::ate);
+
+    const std::ifstream::pos_type fileSize = ifs.tellg();
+    return sizeof(uint32_t) + fileSize;
+  }
+
+  bool RetroSerialisation::serialise(char * data, size_t size)
+  {
+    AutoFile autoFile;
+    if (!autoFile)
+    {
+      return 0;
+    }
+
+    const std::string filename = autoFile.getFilename();
+    saveToFile(filename);
+    std::ifstream ifs(filename, std::ios::binary | std::ios::ate);
+
+    const std::ifstream::pos_type fileSize = ifs.tellg();
+    if (sizeof(uint32_t) + fileSize > size)
+    {
+      return false;
+    }
+    else
+    {
+      uint32_t * sizePtr = reinterpret_cast<uint32_t *>(data);
+      *sizePtr = fileSize;
+
+      char * dataPtr = data + sizeof(uint32_t);
+
+      ifs.seekg(0, std::ios::beg);
+      ifs.read(dataPtr, fileSize);
+
+      return true;
+    }
+  }
+
+  bool RetroSerialisation::deserialise(const char * data, size_t size)
+  {
+    AutoFile autoFile;
+    if (!autoFile)
+    {
+      return false;
+    }
+
+    const uint32_t * sizePtr = reinterpret_cast<const uint32_t *>(data);
+    const size_t fileSize = *sizePtr;
+
+    if (sizeof(uint32_t) + fileSize > size)
+    {
+      return false;
+    }
+    else
+    {
+      const char * dataPtr = data + sizeof(uint32_t);
+
+      const std::string filename = autoFile.getFilename();
+      // do not remove the {} scope below!
+      {
+        std::ofstream ofs(filename, std::ios::binary);
+        ofs.write(dataPtr, fileSize);
+      }
+
+      Snapshot_SetFilename(filename);
+      Snapshot_LoadState();
+      return true;
+    }
+  }
+
+}

source/frontends/libretro/serialisation.h

@@ -0,0 +1,14 @@
+#include <cstddef>
+
+namespace ra2
+{
+
+  class RetroSerialisation
+  {
+  public:
+    static size_t getSize();
+    static bool serialise(char * data, size_t size);
+    static bool deserialise(const char * data, size_t size);
+  };
+
+}