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// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include <algorithm>
#include <utility>
#include "common/assert.h"
#include "core/file_sys/vfs_concat.h"
#include "core/file_sys/vfs_static.h"
namespace FileSys {
ConcatenatedVfsFile::ConcatenatedVfsFile(std::string&& name_, ConcatenationMap&& concatenation_map_)
: concatenation_map(std::move(concatenation_map_)), name(std::move(name_)) {
DEBUG_ASSERT(this->VerifyContinuity());
}
bool ConcatenatedVfsFile::VerifyContinuity() const {
u64 last_offset = 0;
for (auto& entry : concatenation_map) {
if (entry.offset != last_offset) {
return false;
}
last_offset = entry.offset + entry.file->GetSize();
}
return true;
}
ConcatenatedVfsFile::~ConcatenatedVfsFile() = default;
VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(std::string&& name,
std::vector<VirtualFile>&& files) {
// Fold trivial cases.
if (files.empty()) {
return nullptr;
}
if (files.size() == 1) {
return files.front();
}
// Make the concatenation map from the input.
std::vector<ConcatenationEntry> concatenation_map;
concatenation_map.reserve(files.size());
u64 last_offset = 0;
for (auto& file : files) {
const auto size = file->GetSize();
concatenation_map.emplace_back(ConcatenationEntry{
.offset = last_offset,
.file = std::move(file),
});
last_offset += size;
}
return VirtualFile(new ConcatenatedVfsFile(std::move(name), std::move(concatenation_map)));
}
VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(
u8 filler_byte, std::string&& name, std::vector<std::pair<u64, VirtualFile>>&& files) {
// Fold trivial cases.
if (files.empty()) {
return nullptr;
}
if (files.size() == 1) {
return files.begin()->second;
}
// Make the concatenation map from the input.
std::vector<ConcatenationEntry> concatenation_map;
concatenation_map.reserve(files.size());
u64 last_offset = 0;
// Iteration of a multimap is ordered, so offset will be strictly non-decreasing.
for (auto& [offset, file] : files) {
const auto size = file->GetSize();
if (offset > last_offset) {
concatenation_map.emplace_back(ConcatenationEntry{
.offset = last_offset,
.file = std::make_shared<StaticVfsFile>(filler_byte, offset - last_offset),
});
}
concatenation_map.emplace_back(ConcatenationEntry{
.offset = offset,
.file = std::move(file),
});
last_offset = offset + size;
}
return VirtualFile(new ConcatenatedVfsFile(std::move(name), std::move(concatenation_map)));
}
std::string ConcatenatedVfsFile::GetName() const {
if (concatenation_map.empty()) {
return "";
}
if (!name.empty()) {
return name;
}
return concatenation_map.front().file->GetName();
}
std::size_t ConcatenatedVfsFile::GetSize() const {
if (concatenation_map.empty()) {
return 0;
}
return concatenation_map.back().offset + concatenation_map.back().file->GetSize();
}
bool ConcatenatedVfsFile::Resize(std::size_t new_size) {
return false;
}
VirtualDir ConcatenatedVfsFile::GetContainingDirectory() const {
if (concatenation_map.empty()) {
return nullptr;
}
return concatenation_map.front().file->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 {
const ConcatenationEntry key{
.offset = offset,
.file = nullptr,
};
// Read nothing if the map is empty.
if (concatenation_map.empty()) {
return 0;
}
// Binary search to find the iterator to the first position we can check.
// It must exist, since we are not empty and are comparing unsigned integers.
auto it = std::prev(std::upper_bound(concatenation_map.begin(), concatenation_map.end(), key));
u64 cur_length = length;
u64 cur_offset = offset;
while (cur_length > 0 && it != concatenation_map.end()) {
// Check if we can read the file at this position.
const auto& file = it->file;
const u64 map_offset = it->offset;
const u64 file_size = file->GetSize();
if (cur_offset > map_offset + file_size) {
// Entirely out of bounds read.
break;
}
// Read the file at this position.
const u64 file_seek = cur_offset - map_offset;
const u64 intended_read_size = std::min<u64>(cur_length, file_size - file_seek);
const u64 actual_read_size =
file->Read(data + (cur_offset - offset), intended_read_size, file_seek);
// Update tracking.
cur_offset += actual_read_size;
cur_length -= actual_read_size;
it++;
// If we encountered a short read, we're done.
if (actual_read_size < intended_read_size) {
break;
}
}
return cur_offset - offset;
}
std::size_t ConcatenatedVfsFile::Write(const u8* data, std::size_t length, std::size_t offset) {
return 0;
}
bool ConcatenatedVfsFile::Rename(std::string_view new_name) {
return false;
}
} // namespace FileSys
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