From d7c23fa92ef3b5829a2bd6ad137367b4e94b1678 Mon Sep 17 00:00:00 2001
From: harry <hrosen2016@gmail.com>
Date: Sat, 4 Mar 2023 16:34:21 -0500
Subject: [PATCH] FCEU state recorder in work.

---
 src/emufile.h |   4 +-
 src/fceu.cpp  |   9 +++
 src/state.cpp | 161 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/state.h   |   6 ++
 4 files changed, 178 insertions(+), 2 deletions(-)

diff --git a/src/emufile.h b/src/emufile.h
index 0bd65c3d..623f6c21 100644
--- a/src/emufile.h
+++ b/src/emufile.h
@@ -179,10 +179,10 @@ public:
 		va_start(argptr, format);
 		vsprintf(tempbuf,format,argptr);
 
-        fwrite(tempbuf,amt);
+		fwrite(tempbuf,amt);
 		delete[] tempbuf;
 
-        va_end(argptr);
+		va_end(argptr);
 		return amt;
 	};
 
diff --git a/src/fceu.cpp b/src/fceu.cpp
index 49f5c750..ce870582 100644
--- a/src/fceu.cpp
+++ b/src/fceu.cpp
@@ -208,6 +208,8 @@ static void FCEU_CloseGame(void)
 
 		GameInterface(GI_CLOSE);
 
+		FCEU_StateRecorderStop();
+
 		FCEUI_StopMovie();
 
 		ResetExState(0, 0);
@@ -592,6 +594,12 @@ FCEUGI *FCEUI_LoadGameVirtual(const char *name, int OverwriteVidMode, bool silen
 	}
 
 	FCEU_fclose(fp);
+
+	if ( FCEU_StateRecorderIsEnabled() )
+	{
+		FCEU_StateRecorderStart();
+	}
+
 	return GameInfo;
 }
 
@@ -793,6 +801,7 @@ void FCEUI_Emulate(uint8 **pXBuf, int32 **SoundBuf, int32 *SoundBufSize, int ski
 
 	AutoFire();
 	UpdateAutosave();
+	FCEU_StateRecorderUpdate();
 
 #ifdef _S9XLUA_H
 	FCEU_LuaFrameBoundary();
diff --git a/src/state.cpp b/src/state.cpp
index 0ef771e8..cdce4ad8 100644
--- a/src/state.cpp
+++ b/src/state.cpp
@@ -1179,3 +1179,164 @@ void RedoLoadState()
 	redoLS = false;		//Flag that RedoLoadState can not be run again
 	undoLS = true;		//Flag that LoadBackup can be run again
 }
+
+//-----------------------------------------------------------------------------------------------------
+//-----------------------------------------------------------------------------------------------------
+//----------- Save State History ----------------
+//-----------------------------------------------------------------------------------------------------
+//-----------------------------------------------------------------------------------------------------
+class StateRecorder
+{
+	public:
+		StateRecorder(void)
+		{
+			size_t ringBufSize = 60;
+
+			for (size_t i=0; i<ringBufSize; i++)
+			{
+				EMUFILE_MEMORY *em = new EMUFILE_MEMORY( 0x10000 );
+
+				ringBuf.push_back(em);
+			}
+			ringStart = ringHead = ringTail = 0;
+			frameCounter = 0;
+			framesPerSnap = 3 * 60;
+			compressionLevel = Z_NO_COMPRESSION;
+		}
+
+		~StateRecorder(void)
+		{
+			for (size_t i=0; i<ringBuf.size(); i++)
+			{
+				delete ringBuf[i];
+			}
+			ringBuf.clear();
+		}
+
+		void update(void)
+		{
+			unsigned int curFrame = static_cast<unsigned int>(currFrameCounter);
+
+			if (curFrame != frameCounter)
+			{
+				frameCounter = curFrame;
+
+				if ( (frameCounter % framesPerSnap) == 0 )
+				{
+					int ringBufSize = static_cast<int>( ringBuf.size() );
+
+					EMUFILE_MEMORY *em = ringBuf[ ringHead ];
+
+					em->set_len(0);
+
+					FCEUSS_SaveMS( em, compressionLevel );
+
+					//printf("Frame:%u  Save:%i  Size:%zu  Total:%zukB \n", frameCounter, ringHead, em->size(), dataSize() / 1024 );
+
+					ringHead = (ringHead + 1) % ringBufSize;
+
+					if (ringStart == ringHead)
+					{	// Buffer Overrun
+						ringStart = (ringHead + 1) % ringBufSize;
+					}
+				}
+			}
+		}
+
+		int loadState( int numSnapsFromLatest )
+		{
+			int ringBufSize = static_cast<int>( ringBuf.size() );
+
+			if (numSnapsFromLatest < 0)
+			{
+				numSnapsFromLatest = 0;
+			}
+			numSnapsFromLatest = numSnapsFromLatest % ringBufSize;
+
+			int snapIdx = ringHead - numSnapsFromLatest - 1;
+
+			if (snapIdx < 0)
+			{
+				snapIdx = snapIdx + ringBufSize;
+			}
+
+			EMUFILE_MEMORY *em = ringBuf[ snapIdx ];
+
+			FCEUSS_LoadFP( em, SSLOADPARAM_NOBACKUP );
+
+			return 0;
+		}
+
+		int numSnapsSaved(void)
+		{
+			int numSnaps = ringHead - ringStart;
+
+			if (numSnaps < 0)
+			{
+				numSnaps = numSnaps + static_cast<int>( ringBuf.size() );
+			}
+			return numSnaps;
+		}
+
+		size_t  dataSize(void)
+		{
+			return ringBuf.size() * ringBuf[0]->size();
+		}
+
+		static bool enabled;
+	private:
+
+		void doSnap(void)
+		{
+
+		}
+
+		std::vector <EMUFILE_MEMORY*> ringBuf;
+		int  ringHead;
+		int  ringTail;
+		int  ringStart;
+		int  compressionLevel;
+		unsigned int frameCounter;
+		unsigned int framesPerSnap;
+
+};
+
+static StateRecorder *stateRecorder = nullptr;
+bool StateRecorder::enabled = false;
+
+int FCEU_StateRecorderStart(void)
+{
+	if (stateRecorder == nullptr)
+	{
+		stateRecorder = new StateRecorder();
+	}
+	return stateRecorder == nullptr;
+}
+
+int FCEU_StateRecorderStop(void)
+{
+	if (stateRecorder != nullptr)
+	{
+		delete stateRecorder; stateRecorder = nullptr;
+	}
+	return stateRecorder != nullptr;
+}
+
+int FCEU_StateRecorderUpdate(void)
+{
+	if (stateRecorder != nullptr)
+	{
+		stateRecorder->update();
+	}
+	return 0;
+}
+
+bool FCEU_StateRecorderIsEnabled(void)
+{
+	return StateRecorder::enabled;
+}
+
+bool FCEU_StateRecorderRunning(void)
+{
+	return stateRecorder != nullptr;
+}
diff --git a/src/state.h b/src/state.h
index 4157dc9e..3899a7aa 100644
--- a/src/state.h
+++ b/src/state.h
@@ -78,3 +78,9 @@ extern bool backupSavestates;		 //Whether or not to make backups, true by defaul
 bool CheckBackupSaveStateExist();	 //Checks if backupsavestate exists
 
 extern bool compressSavestates;		//Whether or not to compress non-movie savestates (by default, yes)
+
+int FCEU_StateRecorderStart(void);
+int FCEU_StateRecorderStop(void);
+int FCEU_StateRecorderUpdate(void);
+bool FCEU_StateRecorderRunning(void);
+bool FCEU_StateRecorderIsEnabled(void);