From a380aa83f091c43849f7db5cc3361ddc8f3f0bd9 Mon Sep 17 00:00:00 2001
From: wheremyfoodat <44909372+wheremyfoodat@users.noreply.github.com>
Date: Sun, 3 Sep 2023 11:04:54 +0300
Subject: [PATCH] Add 3DSX RomFS reads via NCCH archive

---
 include/fs/archive_ncch.hpp       |  3 ++-
 include/fs/archive_self_ncch.hpp  |  2 +-
 src/core/fs/archive_ncch.cpp      | 13 +++++++------
 src/core/fs/archive_self_ncch.cpp |  1 +
 src/emulator.cpp                  |  4 ++++
 5 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/include/fs/archive_ncch.hpp b/include/fs/archive_ncch.hpp
index 275bcd20..de19cbe5 100644
--- a/include/fs/archive_ncch.hpp
+++ b/include/fs/archive_ncch.hpp
@@ -18,7 +18,8 @@ public:
 	// Returns whether the cart has a RomFS
 	bool hasRomFS() {
 		auto cxi = mem.getCXI();
-		return (cxi != nullptr && cxi->hasRomFS());
+		auto hb3dsx = mem.get3DSX();
+		return (cxi != nullptr && cxi->hasRomFS()) || (hb3dsx != nullptr && hb3dsx->hasRomFs());
 	}
 
 	// Returns whether the cart has an ExeFS (All executable carts should have an ExeFS. This is just here to be safe)
diff --git a/include/fs/archive_self_ncch.hpp b/include/fs/archive_self_ncch.hpp
index aefb210a..ed882a7d 100644
--- a/include/fs/archive_self_ncch.hpp
+++ b/include/fs/archive_self_ncch.hpp
@@ -19,7 +19,7 @@ public:
 	bool hasRomFS() {
 		auto cxi = mem.getCXI();
 		auto hb3dsx = mem.get3DSX();
-		return (cxi != nullptr && cxi->hasRomFS()) | (hb3dsx != nullptr && hb3dsx->hasRomFs());
+		return (cxi != nullptr && cxi->hasRomFS()) || (hb3dsx != nullptr && hb3dsx->hasRomFs());
 	}
 
 	// Returns whether the cart has an ExeFS (All executable carts should have an ExeFS. This is just here to be safe)
diff --git a/src/core/fs/archive_ncch.cpp b/src/core/fs/archive_ncch.cpp
index 6684ccf4..5a808ade 100644
--- a/src/core/fs/archive_ncch.cpp
+++ b/src/core/fs/archive_ncch.cpp
@@ -131,20 +131,20 @@ std::optional<u32> NCCHArchive::readFile(FileSession* file, u64 offset, u32 size
 	}
 
 	auto cxi = mem.getCXI();
-	IOFile& ioFile = mem.CXIFile;
+	auto hb3dsx = mem.get3DSX();
 
-	NCCH::FSInfo fsInfo;
+	// If isCXI is true then we've loaded a CXI/3DS file, else it's 3DSX
+	bool isCXI = cxi != nullptr;
 
 	// Seek to file offset depending on if we're reading from RomFS, ExeFS, etc
 	switch (type) {
 		case PathType::RomFS: {
-			const u64 romFSSize = cxi->romFS.size;
-			const u64 romFSOffset = cxi->romFS.offset;
+			const u64 romFSSize = isCXI ? cxi->romFS.size : hb3dsx->romFSSize;
+			const u64 romFSOffset = isCXI ? cxi->romFS.offset : hb3dsx->romFSOffset;
 			if ((offset >> 32) || (offset >= romFSSize) || (offset + size >= romFSSize)) {
 				Helpers::panic("Tried to read from NCCH with too big of an offset");
 			}
 
-			fsInfo = cxi->romFS;
 			offset += 0x1000;
 			break;
 		}
@@ -154,7 +154,8 @@ std::optional<u32> NCCHArchive::readFile(FileSession* file, u64 offset, u32 size
 	}
 
 	std::unique_ptr<u8[]> data(new u8[size]);
-	auto [success, bytesRead] = cxi->readFromFile(ioFile, fsInfo, &data[0], offset, size);
+	auto [success, bytesRead] =
+		isCXI ? cxi->readFromFile(mem.CXIFile, cxi->romFS, &data[0], offset, size) : hb3dsx->readRomFSBytes(&data[0], offset, size);
 
 	if (!success) {
 		Helpers::panic("Failed to read from NCCH archive");
diff --git a/src/core/fs/archive_self_ncch.cpp b/src/core/fs/archive_self_ncch.cpp
index d4750a18..9b572f96 100644
--- a/src/core/fs/archive_self_ncch.cpp
+++ b/src/core/fs/archive_self_ncch.cpp
@@ -125,6 +125,7 @@ std::optional<u32> SelfNCCHArchive::readFile(FileSession* file, u64 offset, u32
 		data.resize(size);
 		std::tie(success, bytesRead) = cxi->readFromFile(ioFile, fsInfo, &data[0], offset, size);
 	}
+
 	else if (auto hb3dsx = mem.get3DSX(); hb3dsx != nullptr) {
 		switch (type) {
 			case PathType::RomFS: {
diff --git a/src/emulator.cpp b/src/emulator.cpp
index dff335f5..2f8c81cc 100644
--- a/src/emulator.cpp
+++ b/src/emulator.cpp
@@ -426,6 +426,10 @@ bool Emulator::loadROM(const std::filesystem::path& path) {
 		reset(ReloadOption::NoReload);
 	}
 
+	// Reset whatever state needs to be reset before loading a new ROM
+	memory.loadedCXI = std::nullopt;
+	memory.loaded3DSX = std::nullopt;
+
 	// Get path for saving files (AppData on Windows, /home/user/.local/share/ApplcationName on Linux, etc)
 	// Inside that path, we be use a game-specific folder as well. Eg if we were loading a ROM called PenguinDemo.3ds, the savedata would be in
 	// %APPDATA%/Alber/PenguinDemo/SaveData on Windows, and so on. We do this because games save data in their own filesystem on the cart