diff options
Diffstat (limited to 'src/core/file_sys/vfs/vfs_concat.cpp')
-rw-r--r-- | src/core/file_sys/vfs/vfs_concat.cpp | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/src/core/file_sys/vfs/vfs_concat.cpp b/src/core/file_sys/vfs/vfs_concat.cpp new file mode 100644 index 000000000..b5cc9a9e9 --- /dev/null +++ b/src/core/file_sys/vfs/vfs_concat.cpp @@ -0,0 +1,192 @@ +// 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/vfs_concat.h" +#include "core/file_sys/vfs/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 |