Only store the GBA ROM header in save states

Also fix some potential crashes due to SRAM
state not being cleared correctly on state load.

1 files changed, 31 insertions, 9 deletions

diff --git a/src/GBACart.cpp b/src/GBACart.cpp
index f6bed86..7753482 100644
--- a/src/GBACart.cpp
+++ b/src/GBACart.cpp
@@ -110,8 +110,11 @@ void DoSavestate(Savestate* file)
     }

     else

     {

-        // no save data, nothing left to do

+        // no save data, clear the current state

         SRAMType = SaveType::S_NULL;

+        if (SRAMFile) fclose(SRAMFile);

+        SRAM = NULL;

+        SRAMFile = NULL;

         return;

     }

 

@@ -541,21 +544,40 @@ void DoSavestate(Savestate* file)
     // first we need to reload the cart itself,

     // since unlike with DS, it's not loaded in advance

 

-    u32 oldlen = CartROMSize;

-

     file->Var32(&CartROMSize);

     if (!CartROMSize) return; // no GBA cartridge state? nothing to do here.

 

-    if (CartROMSize != oldlen) // loading a differently-sized cartridge

+    u32 oldCRC = CartCRC;

+    file->Var32(&CartCRC);

+    if (CartCRC != oldCRC)

     {

-        if (oldlen) delete[] CartROM;

+        // delete and reallocate ROM so that it is zero-padded to its full length

+        if (CartROM) delete[] CartROM;

         CartROM = new u8[CartROMSize];

-    }

 

-    // why yes, let's save the whole GBA cart in the state

-    // TODO: let's maybe not?

+        // clear the SRAM file handle; writes will not be committed

+        if (GBACart_SRAM::SRAMFile)

+        {

+            fclose(GBACart_SRAM::SRAMFile);

+            GBACart_SRAM::SRAMFile = NULL;

+        }

+    }

 

-    file->VarArray(CartROM, CartROMSize);

+    // only save/load the cartridge header

+    //

+    // GBA connectivity on DS mainly involves identifying the title currently

+    // inserted, reading save data, and issuing commands intercepted here

+    // (e.g. solar sensor signals). we don't know of any case where GBA ROM is

+    // read directly from DS software. therefore, it is more practical, both

+    // from the development and user experience perspectives, to avoid dealing

+    // with file dependencies, and store a small portion of ROM data that should

+    // satisfy the needs of all known software that reads from the GBA slot.

+    //

+    // note: in case of a state load, only the cartridge header is restored, but

+    // the rest of the ROM data is only cleared (zero-initialized) if the CRC

+    // differs. Therefore, loading the GBA cartridge associated with the save state

+    // in advance will maintain access to the full ROM contents.

+    file->VarArray(CartROM, 192);

 

     CartInserted = true; // known, because CartROMSize > 0

     file->Var32(&CartCRC);