From 630e3a591a89b24a268be772a209de33d8a07824 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Sat, 7 Sep 2024 21:12:19 -0700
Subject: [PATCH] GBA SIO: Add support for side data in save states

---
 include/mgba/gba/interface.h          |  3 +++
 include/mgba/internal/gba/serialize.h |  1 +
 src/gba/core.c                        | 37 ++++++++++++++++++++++++++-
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/include/mgba/gba/interface.h b/include/mgba/gba/interface.h
index 3d52e7743..cba586632 100644
--- a/include/mgba/gba/interface.h
+++ b/include/mgba/gba/interface.h
@@ -113,6 +113,9 @@ struct GBASIODriver {
 	void (*reset)(struct GBASIODriver* driver);
 	bool (*load)(struct GBASIODriver* driver);
 	bool (*unload)(struct GBASIODriver* driver);
+	uint32_t (*driverId)(const struct GBASIODriver* renderer);
+	bool (*loadState)(struct GBASIODriver* renderer, const void* state, size_t size);
+	void (*saveState)(struct GBASIODriver* renderer, void** state, size_t* size);
 	void (*setMode)(struct GBASIODriver* driver, enum GBASIOMode mode);
 	bool (*handlesMode)(struct GBASIODriver* driver, enum GBASIOMode mode);
 	int (*connectedDevices)(struct GBASIODriver* driver);
diff --git a/include/mgba/internal/gba/serialize.h b/include/mgba/internal/gba/serialize.h
index c824e85aa..8b1823a17 100644
--- a/include/mgba/internal/gba/serialize.h
+++ b/include/mgba/internal/gba/serialize.h
@@ -287,6 +287,7 @@ DECL_BITS(GBASerializedMiscFlags, KeyIRQKeys, 4, 11);
 
 enum {
 	GBA_SUBSYSTEM_VIDEO_RENDERER = 0,
+	GBA_SUBSYSTEM_SIO_DRIVER = 1,
 	GBA_SUBSYSTEM_MAX,
 };
 
diff --git a/src/gba/core.c b/src/gba/core.c
index a6939406e..00f5ccf97 100644
--- a/src/gba/core.c
+++ b/src/gba/core.c
@@ -842,7 +842,21 @@ static bool _GBACoreLoadExtraState(struct mCore* core, const struct mStateExtdat
 			if (type == gba->video.renderer->rendererId(gba->video.renderer)) {
 				ok = gba->video.renderer->loadState(gba->video.renderer,
 				                                    (void*) ((uintptr_t) item.data + sizeof(uint32_t)),
-				                                    item.size - sizeof(type));
+				                                    item.size - sizeof(type)) && ok;
+			}
+		} else if (item.data) {
+			ok = false;
+		}
+	}
+	if (gba->sio.activeDriver && gba->sio.activeDriver->driverId && gba->sio.activeDriver->loadState &&
+	    mStateExtdataGet(extdata, EXTDATA_SUBSYSTEM_START + GBA_SUBSYSTEM_SIO_DRIVER, &item)) {
+		if ((uint32_t) item.size > sizeof(uint32_t)) {
+			uint32_t type;
+			LOAD_32(type, 0, item.data);
+			if (type == gba->sio.activeDriver->driverId(gba->sio.activeDriver)) {
+				ok = gba->sio.activeDriver->loadState(gba->sio.activeDriver,
+				                                    (void*) ((uintptr_t) item.data + sizeof(uint32_t)),
+				                                    item.size - sizeof(type)) && ok;
 			}
 		} else if (item.data) {
 			ok = false;
@@ -868,6 +882,27 @@ static bool _GBACoreSaveExtraState(struct mCore* core, struct mStateExtdata* ext
 	}
 	if (buffer) {
 		free(buffer);
+		buffer = NULL;
+	}
+	size = 0;
+
+	if (gba->sio.activeDriver && gba->sio.activeDriver->driverId && gba->sio.activeDriver->saveState) {
+		gba->sio.activeDriver->saveState(gba->sio.activeDriver, &buffer, &size);
+		if (size > 0 && buffer) {
+			struct mStateExtdataItem item;
+			item.size = size + sizeof(uint32_t);
+			item.data = malloc(item.size);
+			item.clean = free;
+			uint32_t type = gba->sio.activeDriver->driverId(gba->sio.activeDriver);
+			STORE_32(type, 0, item.data);
+			memcpy((void*) ((uintptr_t) item.data + sizeof(uint32_t)), buffer, size);
+			mStateExtdataPut(extdata, EXTDATA_SUBSYSTEM_START + GBA_SUBSYSTEM_SIO_DRIVER, &item);
+		}
+		if (buffer) {
+			free(buffer);
+			buffer = NULL;
+		}
+		size = 0;
 	}
 
 	return true;