Add support for blocking SRAM writes :)

config.def.h

@@ -212,6 +212,10 @@ static const unsigned autosave_interval = 0;
 // When being client over netplay, use keybinds for player 1 rather than player 2.
 static const bool netplay_client_swap_input = true;
 
+// On save state load, block SRAM from being overwritten.
+// This could potentially lead to buggy games.
+static const bool block_sram_overwrite = false;
+
 
 ////////////////////
 // Keybinds, Joypad

file.c

@@ -425,7 +425,74 @@ bool load_state(const char *path)
    else
    {
       SSNES_LOG("State size: %d bytes.\n", (int)size);
+
+      uint8_t *block_buf[2] = {NULL, NULL};
+      int block_type[2] = {-1, -1};
+      unsigned block_size[2] = {0};
+
+      if (g_settings.block_sram_overwrite)
+      {
+         SSNES_LOG("Blocking SRAM overwrite!\n");
+         switch (g_extern.game_type)
+         {
+            case SSNES_CART_NORMAL:
+               block_type[0] = SNES_MEMORY_CARTRIDGE_RAM;
+               block_type[1] = SNES_MEMORY_CARTRIDGE_RTC;
+               break;
+
+            case SSNES_CART_BSX:
+            case SSNES_CART_BSX_SLOTTED:
+               block_type[0] = SNES_MEMORY_BSX_RAM;
+               block_type[1] = SNES_MEMORY_BSX_PRAM;
+               break;
+
+            case SSNES_CART_SUFAMI:
+               block_type[0] = SNES_MEMORY_SUFAMI_TURBO_A_RAM;
+               block_type[1] = SNES_MEMORY_SUFAMI_TURBO_B_RAM;
+               break;
+
+            case SSNES_CART_SGB:
+               block_type[0] = SNES_MEMORY_GAME_BOY_RAM;
+               block_type[1] = SNES_MEMORY_GAME_BOY_RTC;
+               break;
+         }
+      }
+
+      for (unsigned i = 0; i < 2; i++)
+         if (block_type[i] != -1)
+            block_size[i] = psnes_get_memory_size(block_type[i]);
+
+      for (unsigned i = 0; i < 2; i++)
+         if (block_size[i])
+            block_buf[i] = malloc(block_size[i]);
+
+      // Backup current SRAM which is overwritten by unserialize.
+      for (unsigned i = 0; i < 2; i++)
+      {
+         if (block_buf[i])
+         {
+            const uint8_t *ptr = psnes_get_memory_data(block_type[i]);
+            if (ptr)
+               memcpy(block_buf[i], ptr, block_size[i]);
+         }
+      }
+
       psnes_unserialize(buf, size);
+
+      // Flush back :D
+      for (unsigned i = 0; i < 2; i++)
+      {
+         if (block_buf[i])
+         {
+            uint8_t *ptr = psnes_get_memory_data(block_type[i]);
+            if (ptr)
+               memcpy(ptr, block_buf[i], block_size[i]);
+         }
+      }
+
+      for (unsigned i = 0; i < 2; i++)
+         if (block_buf[i])
+            free(block_buf[i]);
    }
 
    free(buf);

general.h

@@ -148,6 +148,8 @@ struct settings
 
    bool pause_nonactive;
    unsigned autosave_interval;
+
+   bool block_sram_overwrite;
 };
 
 enum ssnes_game_type

settings.c

@@ -171,6 +171,8 @@ static void set_defaults(void)
    g_settings.pause_nonactive = pause_nonactive;
    g_settings.autosave_interval = autosave_interval;
 
+   g_settings.block_sram_overwrite = block_sram_overwrite;
+
    assert(sizeof(g_settings.input.binds[0]) >= sizeof(snes_keybinds_1));
    assert(sizeof(g_settings.input.binds[1]) >= sizeof(snes_keybinds_rest));
    memcpy(g_settings.input.binds[0], snes_keybinds_1, sizeof(snes_keybinds_1));
@@ -418,6 +420,8 @@ static void parse_config_file(void)
    CONFIG_GET_STRING(cheat_database, "cheat_database_path");
    CONFIG_GET_STRING(cheat_settings_path, "cheat_settings_path");
 
+   CONFIG_GET_BOOL(block_sram_overwrite, "block_sram_overwrite");
+
    if (!g_extern.has_set_save_path && config_get_array(conf, "savefile_directory", tmp_str, sizeof(tmp_str)))
    {
       if (path_is_directory(tmp_str))

ssnes.cfg

@@ -316,3 +316,7 @@
 
 # Records video after CPU video filter.
 # video_post_filter_record = false
+
+# Block SRAM from being overwritten when loading save states.
+# Might potentially lead to buggy games.
+# block_sram_overwrite = false