suyu/src/core/file_sys/vfs_concat.cpp

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// 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"
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#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;
}
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VirtualFile ConcatenateFiles(std::vector<VirtualFile> files, std::string name) {
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if (files.empty())
return nullptr;
if (files.size() == 1)
return files[0];
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return std::shared_ptr<VfsFile>(new ConcatenatedVfsFile(std::move(files), std::move(name)));
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}
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ConcatenatedVfsFile::ConcatenatedVfsFile(std::vector<VirtualFile> files_, std::string name)
: name(std::move(name)) {
std::size_t next_offset = 0;
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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));
}
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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 {
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if (files.empty())
return 0;
return files.rbegin()->first + files.rbegin()->second->GetSize();
}
bool ConcatenatedVfsFile::Resize(std::size_t new_size) {
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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();
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for (auto iter = files.begin(); iter != files.end(); ++iter) {
if (iter->first > offset) {
entry = *--iter;
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break;
}
}
if (entry.first + entry.second->GetSize() <= offset)
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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);
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}
return entry.second->Read(data, std::min(read_in, length), offset - entry.first);
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}
std::size_t ConcatenatedVfsFile::Write(const u8* data, std::size_t length, std::size_t offset) {
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return 0;
}
bool ConcatenatedVfsFile::Rename(std::string_view name) {
return false;
}
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} // namespace FileSys