From 0d65ea6050de2d47f62a8eb0148864ee6583d2fc Mon Sep 17 00:00:00 2001
From: zeromus <zeromus@users.noreply.github.com>
Date: Thu, 15 Oct 2020 16:46:16 -0400
Subject: [PATCH] add code to make a backup savestate every time a slot
 savestate is loaded. I don't need to spell out for you which users this is
 for, and why they need it.

---
 desmume/src/addons/slot1_r4.cpp |  8 -------
 desmume/src/commandline.cpp     |  3 +++
 desmume/src/path.cpp            |  2 --
 desmume/src/saves.cpp           | 37 +++++++++++++++++++++++++++++++++
 4 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/desmume/src/addons/slot1_r4.cpp b/desmume/src/addons/slot1_r4.cpp
index 48b2cc593..c4d3c53a1 100644
--- a/desmume/src/addons/slot1_r4.cpp
+++ b/desmume/src/addons/slot1_r4.cpp
@@ -44,14 +44,6 @@ public:
 		static Slot1InfoSimple info("R4", "Slot1 R4 emulation", 0x03);
 		return &info;
 	}
-
-	//called once when the emulator starts up, or when the device springs into existence
-	virtual bool init()
-	{
-		//strange to do this here but we need to make sure its done at some point
-		srand(time(NULL));
-		return true;
-	}
 	
 	virtual void connect()
 	{
diff --git a/desmume/src/commandline.cpp b/desmume/src/commandline.cpp
index 069d9fdbb..cfe87f775 100644
--- a/desmume/src/commandline.cpp
+++ b/desmume/src/commandline.cpp
@@ -230,6 +230,9 @@ ENDL
 
 bool CommandLine::parse(int argc,char **argv)
 {
+	//closest thing to a portable main() we have, I guess.
+	srand((unsigned)time(nullptr));
+
 	std::string _render3d;
 
 	int opt_help = 0;
diff --git a/desmume/src/path.cpp b/desmume/src/path.cpp
index 9646fcc38..babd51b99 100644
--- a/desmume/src/path.cpp
+++ b/desmume/src/path.cpp
@@ -411,8 +411,6 @@ void PathInfo::formatname(char *output)
 	time_t now = time(NULL);
 	tm *time_struct = localtime(&now);
 
-	srand((unsigned)now);
-
 	for (char*  p = screenshotFormat,
 		*end = p + sizeof(screenshotFormat); p < end; p++)
 	{
diff --git a/desmume/src/saves.cpp b/desmume/src/saves.cpp
index a04ba4c19..a795e48c7 100644
--- a/desmume/src/saves.cpp
+++ b/desmume/src/saves.cpp
@@ -57,6 +57,7 @@
 
 #ifdef HOST_WINDOWS
 #include "frontend/windows/main.h"
+extern char IniName[MAX_PATH];
 #endif
 
 int lastSaveState = 0;		//Keeps track of last savestate used for quick save/load functions
@@ -726,8 +727,44 @@ void loadstate_slot(int num)
 
 	path.getpathnoext(path.STATE_SLOTS, filename);
 
+	//save the state before we load the state, to give people a path for recovery in case they hit the wrong key
+	#ifdef HOST_WINDOWS
+	if(!GetPrivateProfileInt("General", "BackupSavestateSuppress", 0, IniName))
+	#endif
+	{
+		if(movieMode == MOVIEMODE_INACTIVE)
+		{
+			std::string dirname = (std::string)filename + " (backups)";
+			#ifdef HOST_WINDOWS
+			static const char PSS = '\\';
+			#else
+			static const char PSS = '/';
+			#endif
+			mkdir(dirname.c_str(),0777);
+			static unsigned seed;
+			for(;;)
+			{
+				std::string fname = dirname + PSS;
+				char mini[100];
+				sprintf(mini,"%u",seed);
+				fname += mini + (std::string)".dst";
+				FILE* f = fopen(fname.c_str(),"rb");
+				if(f)
+				{
+					seed = rand()*16000+rand();
+					fclose(f);
+					continue;
+				}
+				seed++;
+				savestate_save(fname.c_str());
+				break;
+			}
+		}
+	}
+
 	if (strlen(filename) + strlen(".dsx") + strlen("-2147483648") /* = biggest string for num */ > MAX_PATH) return;
 	sprintf(filename + strlen(filename), ".ds%d", num);
+
 	if (savestate_load(filename))
 	{
 		driver->SetLineColor(255, 255, 255);