From 821c20eba83ca3ba4a128bf313f089095467732e Mon Sep 17 00:00:00 2001
From: Samuel Walker <swalker@piwalker.net>
Date: Fri, 23 May 2025 16:37:55 -0600
Subject: [PATCH] file based save states, and improved file structure

---
 include/cart.h  |  2 ++
 include/state.h |  5 ++++-
 lib/cart.c      | 19 +++++++++++++++++--
 lib/emu.c       |  9 +++++++++
 lib/state.c     | 41 +++++++++++++++++++++++++++++++++++++++++
 lib/ui.c        |  6 ++----
 6 files changed, 75 insertions(+), 7 deletions(-)

diff --git a/include/cart.h b/include/cart.h
index bc5342c..245c30f 100644
--- a/include/cart.h
+++ b/include/cart.h
@@ -63,6 +63,8 @@ bool cart_load(char *cart);
 
 rom_header *get_rom_header();
 
+cart_context *cart_get_context();
+
 u8 cart_read(u16 address);
 void cart_write(u16 address, u8 value);
 
diff --git a/include/state.h b/include/state.h
index b5e1401..8563877 100644
--- a/include/state.h
+++ b/include/state.h
@@ -22,4 +22,7 @@ typedef struct {
 } save_state;
 
 void state_save(save_state*);
-void state_load(const save_state*);
\ No newline at end of file
+void state_load(const save_state*);
+
+void state_save_file(u8 slot);
+void state_load_file(u8 slot);
\ No newline at end of file
diff --git a/lib/cart.c b/lib/cart.c
index c20dcbe..12c46d2 100644
--- a/lib/cart.c
+++ b/lib/cart.c
@@ -1,6 +1,7 @@
 #include <cart.h>
 #include <common.h>
 #include <string.h>
+#include <windows.h>
 
 static cart_context ctx;
 
@@ -372,8 +373,11 @@ void cart_write(u16 address, u8 value){
 }
 
 bool cart_battery_load(){
+    char *filename = strrchr(ctx.filename, '\\');
+    filename++;
     char fn[1048];
-    sprintf(fn, "%s.battery", ctx.filename);
+    char *profile = getenv("USERPROFILE");
+    sprintf(fn, "%s/Documents/gbemu/saves/%s.battery", profile, filename);
     FILE *fp = fopen(fn, "rb");
 
     if(!fp) {
@@ -386,8 +390,11 @@ bool cart_battery_load(){
 }
 
 bool cart_battery_save(){
+    char *filename = strrchr(ctx.filename, '\\');
+    filename++;
     char fn[1048];
-    sprintf(fn, "%s.battery", ctx.filename);
+    char *profile = getenv("USERPROFILE");
+    sprintf(fn, "%s/Documents/gbemu/saves/%s.battery", profile, filename);
     FILE *fp = fopen(fn, "wb");
 
     if(!fp) {
@@ -432,6 +439,10 @@ void cart_load_state(const cart_state* state){
         ctx.ram_bank = ctx.ram_banks[0];
     }
 
+    if(ctx.battery) {
+        cart_battery_load();
+    }
+
 }
 
 void cart_save_state(cart_state* state){
@@ -448,4 +459,8 @@ void cart_save_state(cart_state* state){
             memcpy((&state->ram_banks[i]), ctx.ram_banks[i], 0x2000);
         }
     }
+}
+
+cart_context *cart_get_context(){
+    return &ctx;
 }
\ No newline at end of file
diff --git a/lib/emu.c b/lib/emu.c
index bf4d592..2176c14 100644
--- a/lib/emu.c
+++ b/lib/emu.c
@@ -87,6 +87,15 @@ int emu_run(int argc, char **argv) {
         printf("Failed to load ROM file: %s\n", argv[1]);
         return -2;
     }
+
+    char fn[1048];
+    char *profile = getenv("USERPROFILE");
+    sprintf(fn, "%s\\Documents\\gbemu", profile);
+    CreateDirectory(fn, NULL);
+    sprintf(fn, "%s\\Documents\\gbemu\\saves", profile);
+    CreateDirectory(fn, NULL);
+    sprintf(fn, "%s\\Documents\\gbemu\\states", profile);
+    CreateDirectory(fn, NULL);
 	
     printf("Cart loaded..\n");
     ctx.app_path = argv[0];
diff --git a/lib/state.c b/lib/state.c
index 7adeed6..c396f5d 100644
--- a/lib/state.c
+++ b/lib/state.c
@@ -1,4 +1,5 @@
 #include <state.h>
+#include <windows.h>
 
 void state_save(save_state* state) {
     printf("Saving state\n");
@@ -24,4 +25,44 @@ void state_load(const save_state* state) {
     audio_load_state(&state->audio);
     gamepad_load_state(&state->ctlr);
     cart_load_state(&state->cart);
+}
+
+void state_save_file(u8 slot) {
+    save_state* state = malloc(sizeof(*state));
+    state_save(state);
+    char *filename = strrchr(cart_get_context()->filename, '\\');
+    filename++;
+    char fn[1048];
+    char *profile = getenv("USERPROFILE");
+    sprintf(fn, "%s/Documents/gbemu/states/%s", profile, filename);
+    CreateDirectory(fn, NULL);
+    sprintf(fn, "%s/Documents/gbemu/states/%s/%d.state", profile, filename, slot);
+    FILE *fp = fopen(fn, "wb");
+
+    if(!fp) {
+        fprintf(stderr, "unable to save state %d\n", slot);
+        return;
+    }
+
+    fwrite(state, sizeof(*state), 1, fp);
+    fclose(fp);
+}
+
+void state_load_file(u8 slot) {
+    save_state* state = malloc(sizeof(*state));
+    char *filename = strrchr(cart_get_context()->filename, '\\');
+    filename++;
+    char fn[1048];
+    char *profile = getenv("USERPROFILE");
+    sprintf(fn, "%s/Documents/gbemu/states/%s/%d.state", profile, filename, slot);
+    FILE *fp = fopen(fn, "rb");
+
+    if(!fp) {
+        printf("Save slot %d doesnt exist.\n", slot);
+        return;
+    }
+
+    fread(state, sizeof(*state), 1, fp);
+    fclose(fp);
+    state_load(state);
 }
\ No newline at end of file
diff --git a/lib/ui.c b/lib/ui.c
index 5254870..ad477ae 100644
--- a/lib/ui.c
+++ b/lib/ui.c
@@ -25,12 +25,10 @@ SDL_Renderer *sdlDebugRenderer;
 SDL_Texture *sdlDebugTexture;
 SDL_Surface *debugScreen;
 TTF_Font *sans;
-save_state *state;
 
 static int scale = 4;
 
 void ui_init(){
-    state = malloc(sizeof(*state));
     SDL_Init(SDL_INIT_VIDEO);
     printf("SDL INIT\n");
     TTF_Init();
@@ -344,13 +342,13 @@ void ui_on_key(bool down, u32 key_code) {
     }
     if(key_code == SDLK_s && down == true) {
         emu_stop();
-        state_save(state);
+        state_save_file(0);
         emu_start();
     }
     if(key_code == SDLK_l && down == true) {
         emu_stop();
         emu_reset();
-        state_load(state);
+        state_load_file(0);
         emu_start();
     }
     switch(key_code){