From 05d4b706b46c010df06f075d90c4127944cef8cf Mon Sep 17 00:00:00 2001
From: modeco80 <lily.modeco80@protonmail.ch>
Date: Sun, 12 Jan 2025 16:37:44 -0500
Subject: [PATCH] libeuropa/io: Refactor PakWriter for pakv5 sector alignment
 support

This really could be classed a "fix", since adding support for it when reading broke writing. Now we do the right thing.

This makes sector-alignment a no-op when writing other archive versions. I might make it an error to specify -s with a non-JSF package version.
---
 include/europa/io/PakFile.hpp        | 12 ++++++++--
 src/libeuropa/io/PakWriter.cpp       | 36 ++++++++++++++++++++--------
 src/tools/eupak/main.cpp             |  2 +-
 src/tools/eupak/tasks/CreateTask.cpp |  2 +-
 4 files changed, 38 insertions(+), 14 deletions(-)

diff --git a/include/europa/io/PakFile.hpp b/include/europa/io/PakFile.hpp
index 361b772..ef8c012 100644
--- a/include/europa/io/PakFile.hpp
+++ b/include/europa/io/PakFile.hpp
@@ -93,7 +93,7 @@ namespace europa::io {
 			toc = value;
 		}
 
-		void InitAs(structs::PakVersion version) {
+		void InitAs(structs::PakVersion version, bool aligned) {
 			switch(version) {
 				case structs::PakVersion::Ver3:
 					toc = structs::PakHeader_V3::TocEntry {};
@@ -102,7 +102,10 @@ namespace europa::io {
 					toc = structs::PakHeader_V4::TocEntry {};
 					break;
 				case structs::PakVersion::Ver5:
-					toc = structs::PakHeader_V5::TocEntry {};
+					if(aligned)
+						toc = structs::PakHeader_V5::TocEntry_SectorAligned {};
+					else
+						toc = structs::PakHeader_V5::TocEntry {};
 					break;
 				default:
 					throw std::invalid_argument("Invalid PAK version to initalize TOC entry");
@@ -147,6 +150,11 @@ namespace europa::io {
 			return std::get<T>(toc);
 		}
 
+		template <class T>
+		[[nodiscard]] T& GetTOCEntry() {
+			return std::get<T>(toc);
+		}
+
 		std::uint32_t GetCreationUnixTime() const {
 			std::uint32_t time {};
 
diff --git a/src/libeuropa/io/PakWriter.cpp b/src/libeuropa/io/PakWriter.cpp
index cb5e57d..384d28f 100644
--- a/src/libeuropa/io/PakWriter.cpp
+++ b/src/libeuropa/io/PakWriter.cpp
@@ -64,15 +64,21 @@ namespace europa::io {
 		// Leave space for the header
 		os.seekp(sizeof(THeader), std::ostream::beg);
 
-		// Version 5 paks seem to have an additional bit of reserved data
-		// (which is all zeros.)
-		if(THeader::VERSION == structs::PakVersion::Ver5) {
-			os.seekp(6, std::ostream::cur);
+		if constexpr(THeader::VERSION == structs::PakVersion::Ver5) {
+			if(sectorAlignment == SectorAlignment::Align) {
+				pakHeader.sectorAlignment = util::kCDSectorSize;
+				pakHeader.sectorAlignedFlag = 1;
+			} else {
+				pakHeader.sectorAlignment = 0;
+				pakHeader.sectorAlignedFlag = 0;
+			}
 		}
 
-		// Align the first file to start on the next sector boundary.
-		if(sectorAlignment == SectorAlignment::Align)
-			os.seekp(util::AlignBy(static_cast<std::size_t>(os.tellp()), util::kCDSectorSize), std::istream::beg);
+		if constexpr(THeader::VERSION == structs::PakVersion::Ver5) {
+			// Align the first file to start on the next sector boundary.
+			if(sectorAlignment == SectorAlignment::Align)
+				os.seekp(util::AlignBy(static_cast<std::size_t>(os.tellp()), util::kCDSectorSize), std::istream::beg);
+		}
 
 		// Write all the file data
 		for(auto& [filename, file] : sortedFiles) {
@@ -84,6 +90,14 @@ namespace europa::io {
 				tocEntry.offset = os.tellp();
 			});
 
+			// For sector alignment.
+			if constexpr(THeader::VERSION == structs::PakVersion::Ver5) {
+				if(sectorAlignment == SectorAlignment::Align) {
+					auto& toc = file.GetTOCEntry<structs::PakHeader_V5::TocEntry_SectorAligned>();
+					toc.startLBA = (os.tellp() / util::kCDSectorSize);
+				}
+			}
+
 			auto& fileData = file.GetData();
 
 			// Visit the file data sum type and do the right operation
@@ -109,9 +123,11 @@ namespace europa::io {
 			});
 			// clang-format on
 
-			// Align to the next sector boundary.
-			if(sectorAlignment == SectorAlignment::Align)
-				os.seekp(util::AlignBy(static_cast<std::size_t>(os.tellp()), util::kCDSectorSize), std::istream::beg);
+			if constexpr(THeader::VERSION == structs::PakVersion::Ver5) {
+				// Align to the next sector boundary.
+				if(sectorAlignment == SectorAlignment::Align)
+					os.seekp(util::AlignBy(static_cast<std::size_t>(os.tellp()), util::kCDSectorSize), std::istream::beg);
+			}
 
 			sink.OnEvent({ PakProgressReportSink::FileEvent::EventCode::FileWriteEnd,
 						   filename });
diff --git a/src/tools/eupak/main.cpp b/src/tools/eupak/main.cpp
index 4b4d877..9a36aba 100644
--- a/src/tools/eupak/main.cpp
+++ b/src/tools/eupak/main.cpp
@@ -61,7 +61,7 @@ int main(int argc, char** argv) {
 	.metavar("VERSION");
 
 	createParser.add_argument("-s", "--sector-aligned")
-	.help(R"(Aligns all files in this new package to CD-ROM sector boundaries.)")
+	.help(R"(Aligns all files in this new package to CD-ROM sector boundaries. Only valid for -V jedistarfighter.)")
 	.flag();
 
 	createParser.add_argument("output")
diff --git a/src/tools/eupak/tasks/CreateTask.cpp b/src/tools/eupak/tasks/CreateTask.cpp
index 8f33f89..37b4dd1 100644
--- a/src/tools/eupak/tasks/CreateTask.cpp
+++ b/src/tools/eupak/tasks/CreateTask.cpp
@@ -130,7 +130,7 @@ namespace eupak::tasks {
 			eio::PakFile file;
 			eio::PakFile::DataType pakData = eio::PakFileData::InitAsPath(ent.path());
 
-			file.InitAs(args.pakVersion);
+			file.InitAs(args.pakVersion, args.sectorAligned);
 
 			// Add data
 			file.SetData(std::move(pakData));