added in-ram savestates (#2252)

Author: eadmaster

core/input/gamepad.h

@@ -52,6 +52,8 @@ enum DreamcastKey
 	EMU_BTN_SAVESTATE,
 	EMU_BTN_NEXTSLOT,
 	EMU_BTN_PREVSLOT,
+	EMU_BTN_LOADSTATE_RAM,
+	EMU_BTN_SAVESTATE_RAM,
 	EMU_BTN_BYPASS_KB,
 	EMU_BTN_SCREENSHOT,
 	EMU_BTN_SRVMODE,		// used internally by virtual gamepad

core/input/gamepad_device.cpp

@@ -110,6 +110,14 @@ bool GamepadDevice::handleButtonInput(int port, DreamcastKey key, bool pressed)
 			if (pressed)
 				gui_cycleSaveStateSlot(-1);
 			break;
+		case EMU_BTN_LOADSTATE_RAM:
+			if (pressed)
+				gui_loadState(true);
+			break;
+		case EMU_BTN_SAVESTATE_RAM:
+			if (pressed)
+				gui_saveState(false, true);
+			break;
 		case EMU_BTN_SCREENSHOT:
 			if (pressed)
 				gui_takeScreenshot();

core/input/mapping.cpp

@@ -64,6 +64,8 @@ button_list[] =
 	{ EMU_BTN_SAVESTATE, "emulator", "btn_quick_save" },
 	{ EMU_BTN_NEXTSLOT, "emulator", "btn_next_slot" },
 	{ EMU_BTN_PREVSLOT, "emulator", "btn_prev_slot" },
+	{ EMU_BTN_LOADSTATE_RAM, "emulator", "btn_jump_state_ram" },
+	{ EMU_BTN_SAVESTATE_RAM, "emulator", "btn_quick_save_ram" },
 	{ EMU_BTN_BYPASS_KB, "emulator", "btn_bypass_kb" },
 	{ EMU_BTN_SCREENSHOT, "emulator", "btn_screenshot" },
 };

core/nullDC.cpp

@@ -27,6 +27,22 @@
 static std::string lastStateFile;
 static time_t lastStateTime;
 
+#if defined(__ANDROID__)
+    #include <android/api-level.h>
+    // fmemopen was added in Marshmallow (API 23)
+    #if __ANDROID_API__ >= 23
+        #define HAS_FMEMOPEN
+    #endif
+#elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || defined(__GLIBC__)
+    // Standard POSIX platforms usually have fmemopen
+    #define HAS_FMEMOPEN
+#endif
+
+#ifdef HAS_FMEMOPEN
+const u32 QUICKSAVE_DEFAULT_SIZE = 32 * 1024 * 1024; // 32 MB
+static u8 quicksave_buf[QUICKSAVE_DEFAULT_SIZE] = {0};
+#endif
+
 struct SavestateHeader
 {
 	void init()
@@ -182,8 +198,23 @@ void dc_savestate(int index, const u8 *pngData, u32 pngSize)
 	ser = Serializer(data, ser.size());
 	dc_serialize(ser);
 
-	std::string filename = hostfs::getSavestatePath(index, true);
-	FILE *f = nowide::fopen(filename.c_str(), "wb");
+	FILE *f = nullptr;
+	std::string filename = "";
+#ifdef HAS_FMEMOPEN
+	if (index == -2)
+	{
+		// in-ram savestate
+		filename = "RAM";
+		f = fmemopen(quicksave_buf, QUICKSAVE_DEFAULT_SIZE, "wb");
+	}
+	else
+#endif
+	{
+		// regular file savestate
+		filename = hostfs::getSavestatePath(index, true);
+		f = nowide::fopen(filename.c_str(), "wb");
+	}
+	
 	if (f == nullptr)
 	{
 		WARN_LOG(SAVESTATE, "Failed to save state - could not open %s for writing", filename.c_str());
@@ -235,8 +266,23 @@ void dc_loadstate(int index)
 		return;
 	u32 total_size = 0;
 
-	std::string filename = hostfs::getSavestatePath(index, false);
-	FILE *f = hostfs::storage().openFile(filename, "rb");
+	FILE *f = nullptr;
+	std::string filename = "";
+#ifdef HAS_FMEMOPEN
+	if (index == -2)
+	{
+		// in-ram savestate
+		filename = "RAM";
+		f = fmemopen(quicksave_buf, QUICKSAVE_DEFAULT_SIZE, "rb");
+	}
+	else
+#endif
+	{
+		// regular file savestate
+		filename = hostfs::getSavestatePath(index, false);
+		f = hostfs::storage().openFile(filename, "rb");
+	}
+	
 	if (f == nullptr)
 	{
 		WARN_LOG(SAVESTATE, "Failed to load state - could not open %s for reading", filename.c_str());

core/oslib/oslib.cpp

@@ -206,6 +206,8 @@ std::string getSavestatePath(int index, bool writable)
 	state_file = state_file + index_str + ".state";
 	if (index == -1)
 		state_file += ".net";
+	if (index == -2)
+		state_file += ".tmp";
 
 	static std::string lastFile;
 	static std::string lastPath;

core/ui/gui.cpp

@@ -1736,30 +1736,38 @@ void gui_error(const std::string& what) {
 	error_msg = what;
 }
 
-void gui_loadState()
+void gui_loadState(bool inRam)
 {
 	const LockGuard lock(guiMutex);
 	if (gui_state == GuiState::Closed && dc_savestateAllowed())
 	{
 		try {
 			emu.stop();
-			dc_loadstate(config::SavestateSlot);
+			if (inRam)
+				dc_loadstate(-2);  // special slot used for inRam states
+			else
+				dc_loadstate(config::SavestateSlot);
 			emu.start();
 		} catch (const FlycastException& e) {
 			gui_stop_game(e.what());
 		}
 	}
 }
 
-void gui_saveState(bool stopRestart)
+void gui_saveState(bool stopRestart, bool inRam)
 {
 	const LockGuard lock(guiMutex);
 	if ((gui_state == GuiState::Closed || !stopRestart) && dc_savestateAllowed())
 	{
 		try {
 			if (stopRestart)
 				emu.stop();
-			savestate();
+			
+			if (inRam)
+				dc_savestate(-2);
+			else
+				savestate();
+
 			if (stopRestart)
 				emu.start();
 		} catch (const FlycastException& e) {

core/ui/gui.h

@@ -48,8 +48,8 @@ void gui_stop_game(const std::string& message = "");
 void gui_start_game(const std::string& path);
 void gui_error(const std::string& what);
 void gui_setOnScreenKeyboardCallback(void (*callback)(bool show));
-void gui_loadState();
-void gui_saveState(bool stopRestart = true);
+void gui_loadState(bool inRam = false);
+void gui_saveState(bool stopRestart = true, bool inRam = false);
 void gui_cycleSaveStateSlot(int step);
 std::string gui_getCurGameBoxartUrl();
 void gui_takeScreenshot();

core/ui/settings_controls.cpp

@@ -221,6 +221,8 @@ static Mapping dcButtons[] = {
 	{ EMU_BTN_FFORWARD, Tnop("Fast-forward") },
 	{ EMU_BTN_LOADSTATE, Tnop("Load State") },
 	{ EMU_BTN_SAVESTATE, Tnop("Save State") },
+	{ EMU_BTN_LOADSTATE_RAM, Tnop("Load State in RAM") },
+	{ EMU_BTN_SAVESTATE_RAM, Tnop("Save State in RAM") },
 	{ EMU_BTN_NEXTSLOT, Tnop("Next Save State Slot") },
 	{ EMU_BTN_PREVSLOT, Tnop("Previous Save State Slot") },
 	{ EMU_BTN_BYPASS_KB, Tnop("Bypass Emulated Keyboard") },
@@ -277,6 +279,8 @@ static Mapping arcadeButtons[] = {
 	{ EMU_BTN_FFORWARD, Tnop("Fast-forward") },
 	{ EMU_BTN_LOADSTATE, Tnop("Load State") },
 	{ EMU_BTN_SAVESTATE, Tnop("Save State") },
+	{ EMU_BTN_LOADSTATE_RAM, Tnop("Load State in RAM") },
+	{ EMU_BTN_SAVESTATE_RAM, Tnop("Save State in RAM") },
 	{ EMU_BTN_NEXTSLOT, Tnop("Next Save State Slot") },
 	{ EMU_BTN_PREVSLOT, Tnop("Previous Save State Slot") },
 	{ EMU_BTN_BYPASS_KB, Tnop("Bypass Emulated Keyboard") },