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suyu/src/core/file_sys/romfs.cpp

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C++

// 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));
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>{}, 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;
auto root =
std::make_shared<VectorVfsDirectory>(std::vector<VirtualFile>{}, std::vector<VirtualDir>{},
file->GetName(), file->GetContainingDirectory());
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