yuzu/src/core/file_sys/vfs_concat.cpp
2018-09-21 19:53:33 -04:00

110 lines
3.0 KiB
C++

// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <utility>
#include "common/assert.h"
#include "core/file_sys/vfs_concat.h"
namespace FileSys {
bool VerifyConcatenationMap(std::map<u64, VirtualFile> map) {
for (auto iter = map.begin(); iter != --map.end();) {
const auto old = iter++;
if (old->first + old->second->GetSize() != iter->first) {
return false;
}
}
return map.begin()->first == 0;
}
VirtualFile ConcatenateFiles(std::vector<VirtualFile> files, std::string name) {
if (files.empty())
return nullptr;
if (files.size() == 1)
return files[0];
return std::shared_ptr<VfsFile>(new ConcatenatedVfsFile(std::move(files), std::move(name)));
}
ConcatenatedVfsFile::ConcatenatedVfsFile(std::vector<VirtualFile> files_, std::string name)
: name(std::move(name)) {
std::size_t next_offset = 0;
for (const auto& file : files_) {
files[next_offset] = file;
next_offset += file->GetSize();
}
}
ConcatenatedVfsFile::ConcatenatedVfsFile(std::map<u64, VirtualFile> files_, std::string name)
: files(std::move(files_)), name(std::move(name)) {
ASSERT(VerifyConcatenationMap(files));
}
std::string ConcatenatedVfsFile::GetName() const {
if (files.empty())
return "";
if (!name.empty())
return name;
return files.begin()->second->GetName();
}
std::size_t ConcatenatedVfsFile::GetSize() const {
if (files.empty())
return 0;
return files.rbegin()->first + files.rbegin()->second->GetSize();
}
bool ConcatenatedVfsFile::Resize(std::size_t new_size) {
return false;
}
std::shared_ptr<VfsDirectory> ConcatenatedVfsFile::GetContainingDirectory() const {
if (files.empty())
return nullptr;
return files.begin()->second->GetContainingDirectory();
}
bool ConcatenatedVfsFile::IsWritable() const {
return false;
}
bool ConcatenatedVfsFile::IsReadable() const {
return true;
}
std::size_t ConcatenatedVfsFile::Read(u8* data, std::size_t length, std::size_t offset) const {
std::pair<u64, VirtualFile> entry = *files.rbegin();
for (auto iter = files.begin(); iter != files.end(); ++iter) {
if (iter->first > offset) {
entry = *--iter;
break;
}
}
if (entry.first + entry.second->GetSize() <= offset)
return 0;
const auto read_in =
std::min(entry.first + entry.second->GetSize() - offset, entry.second->GetSize());
if (length > read_in) {
return entry.second->Read(data, read_in, offset - entry.first) +
Read(data + read_in, length - read_in, offset + read_in);
}
return entry.second->Read(data, std::min(read_in, length), offset - entry.first);
}
std::size_t ConcatenatedVfsFile::Write(const u8* data, std::size_t length, std::size_t offset) {
return 0;
}
bool ConcatenatedVfsFile::Rename(std::string_view name) {
return false;
}
} // namespace FileSys