RomFS Extraction

src/core/file_sys/romfs.cpp

@@ -0,0 +1,124 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/common_types.h"
+#include "common/swap.h"
+#include "core/file_sys/romfs.h"
+#include "core/file_sys/vfs.h"
+#include "core/file_sys/vfs_offset.h"
+#include "core/file_sys/vfs_vector.h"
+
+namespace FileSys {
+
+constexpr u32 ROMFS_ENTRY_EMPTY = 0xFFFFFFFF;
+
+struct TableLocation {
+    u64_le offset;
+    u64_le size;
+};
+static_assert(sizeof(TableLocation) == 0x10, "TableLocation has incorrect size.");
+
+struct RomFSHeader {
+    u64_le header_size;
+    TableLocation directory_hash;
+    TableLocation directory_meta;
+    TableLocation file_hash;
+    TableLocation file_meta;
+    u64_le data_offset;
+};
+static_assert(sizeof(RomFSHeader) == 0x50, "RomFSHeader has incorrect size.");
+
+struct DirectoryEntry {
+    u32_le sibling;
+    u32_le child_dir;
+    u32_le child_file;
+    u32_le hash;
+    u32_le name_length;
+};
+static_assert(sizeof(DirectoryEntry) == 0x14, "DirectoryEntry has incorrect size.");
+
+struct FileEntry {
+    u32_le parent;
+    u32_le sibling;
+    u64_le offset;
+    u64_le size;
+    u32_le hash;
+    u32_le name_length;
+};
+static_assert(sizeof(FileEntry) == 0x20, "FileEntry has incorrect size.");
+
+template <typename Entry>
+static std::pair<Entry, std::string> GetEntry(const VirtualFile& file, size_t offset) {
+    Entry entry{};
+    if (file->ReadObject(&entry, offset) != sizeof(Entry))
+        return {};
+    std::string string(entry.name_length, '\0');
+    if (file->ReadArray(&string[0], string.size(), offset + sizeof(Entry)) != string.size())
+        return {};
+    return {entry, string};
+}
+
+void ProcessFile(VirtualFile file, size_t file_offset, size_t data_offset, u32 this_file_offset,
+                 std::shared_ptr<VectorVfsDirectory> parent) {
+    while (true) {
+        auto entry = GetEntry<FileEntry>(file, file_offset + this_file_offset);
+
+        parent->AddFile(std::make_shared<OffsetVfsFile>(
+            file, entry.first.size, entry.first.offset + data_offset, entry.second, parent));
+
+        if (entry.first.sibling == ROMFS_ENTRY_EMPTY)
+            break;
+
+        this_file_offset = entry.first.sibling;
+    }
+}
+
+void ProcessDirectory(VirtualFile file, size_t dir_offset, size_t file_offset, size_t data_offset,
+                      u32 this_dir_offset, std::shared_ptr<VectorVfsDirectory> parent) {
+    while (true) {
+        auto entry = GetEntry<DirectoryEntry>(file, dir_offset + this_dir_offset);
+        auto current = std::make_shared<VectorVfsDirectory>(
+            std::vector<VirtualFile>{}, std::vector<VirtualDir>{}, parent, entry.second);
+
+        if (entry.first.child_file != ROMFS_ENTRY_EMPTY) {
+            ProcessFile(file, file_offset, data_offset, entry.first.child_file, current);
+        }
+
+        if (entry.first.child_dir != ROMFS_ENTRY_EMPTY) {
+            ProcessDirectory(file, dir_offset, file_offset, data_offset, entry.first.child_dir,
+                             current);
+        }
+
+        parent->AddDirectory(current);
+        if (entry.first.sibling == ROMFS_ENTRY_EMPTY)
+            break;
+        this_dir_offset = entry.first.sibling;
+    }
+}
+
+VirtualDir ExtractRomFS(VirtualFile file) {
+    RomFSHeader header{};
+    if (file->ReadObject(&header) != sizeof(RomFSHeader))
+        return nullptr;
+
+    if (header.header_size != sizeof(RomFSHeader))
+        return nullptr;
+
+    const u64 file_offset = header.file_meta.offset;
+    const u64 dir_offset = header.directory_meta.offset + 4;
+
+    const auto root =
+        std::make_shared<VectorVfsDirectory>(std::vector<VirtualFile>{}, std::vector<VirtualDir>{},
+                                             file->GetContainingDirectory(), file->GetName());
+
+    ProcessDirectory(file, dir_offset, file_offset, header.data_offset, 0, root);
+
+    VirtualDir out = std::move(root);
+
+    while (out->GetSubdirectory("") != nullptr)
+        out = out->GetSubdirectory("");
+
+    return out;
+}
+} // namespace FileSys