diff --git a/src/core/core.cpp b/src/core/core.cpp
index b5f62690e7..4406ae30e7 100644
--- a/src/core/core.cpp
+++ b/src/core/core.cpp
@@ -117,8 +117,7 @@ FileSys::VirtualFile GetGameFileFromPath(const FileSys::VirtualFilesystem& vfs,
return nullptr;
}
- return FileSys::ConcatenatedVfsFile::MakeConcatenatedFile(std::move(concat),
- dir->GetName());
+ return FileSys::ConcatenatedVfsFile::MakeConcatenatedFile(concat, dir->GetName());
}
if (Common::FS::IsDir(path)) {
diff --git a/src/core/file_sys/romfs.cpp b/src/core/file_sys/romfs.cpp
index ddcfe5980e..fb5683a6bc 100644
--- a/src/core/file_sys/romfs.cpp
+++ b/src/core/file_sys/romfs.cpp
@@ -140,7 +140,8 @@ VirtualFile CreateRomFS(VirtualDir dir, VirtualDir ext) {
return nullptr;
RomFSBuildContext ctx{dir, ext};
- return ConcatenatedVfsFile::MakeConcatenatedFile(0, ctx.Build(), dir->GetName());
+ auto file_map = ctx.Build();
+ return ConcatenatedVfsFile::MakeConcatenatedFile(0, file_map, dir->GetName());
}
} // namespace FileSys
diff --git a/src/core/file_sys/vfs_concat.cpp b/src/core/file_sys/vfs_concat.cpp
index d23623aa04..853b893a1f 100644
--- a/src/core/file_sys/vfs_concat.cpp
+++ b/src/core/file_sys/vfs_concat.cpp
@@ -10,84 +10,105 @@
namespace FileSys {
-static bool VerifyConcatenationMapContinuity(const std::multimap<u64, VirtualFile>& map) {
- const auto last_valid = --map.end();
- for (auto iter = map.begin(); iter != last_valid;) {
- const auto old = iter++;
- if (old->first + old->second->GetSize() != iter->first) {
+ConcatenatedVfsFile::ConcatenatedVfsFile(ConcatenationMap&& concatenation_map_, std::string&& name_)
+ : 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 map.begin()->first == 0;
-}
-
-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.emplace(next_offset, file);
- next_offset += file->GetSize();
- }
-}
-
-ConcatenatedVfsFile::ConcatenatedVfsFile(std::multimap<u64, VirtualFile> files_, std::string name_)
- : files(std::move(files_)), name(std::move(name_)) {
- ASSERT(VerifyConcatenationMapContinuity(files));
+ return true;
}
ConcatenatedVfsFile::~ConcatenatedVfsFile() = default;
-VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(std::vector<VirtualFile> files,
- std::string name) {
- if (files.empty())
+VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(const std::vector<VirtualFile>& files,
+ std::string&& name) {
+ // Fold trivial cases.
+ if (files.empty()) {
return nullptr;
- if (files.size() == 1)
- return files[0];
+ }
+ if (files.size() == 1) {
+ return files.front();
+ }
- return VirtualFile(new ConcatenatedVfsFile(std::move(files), std::move(name)));
+ // 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) {
+ concatenation_map.emplace_back(ConcatenationEntry{
+ .offset = last_offset,
+ .file = file,
+ });
+
+ last_offset += file->GetSize();
+ }
+
+ return VirtualFile(new ConcatenatedVfsFile(std::move(concatenation_map), std::move(name)));
}
VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(u8 filler_byte,
- std::multimap<u64, VirtualFile> files,
- std::string name) {
- if (files.empty())
+ const std::multimap<u64, VirtualFile>& files,
+ std::string&& name) {
+ // Fold trivial cases.
+ if (files.empty()) {
return nullptr;
- if (files.size() == 1)
+ }
+ if (files.size() == 1) {
return files.begin()->second;
-
- const auto last_valid = --files.end();
- for (auto iter = files.begin(); iter != last_valid;) {
- const auto old = iter++;
- if (old->first + old->second->GetSize() != iter->first) {
- files.emplace(old->first + old->second->GetSize(),
- std::make_shared<StaticVfsFile>(filler_byte, iter->first - old->first -
- old->second->GetSize()));
- }
}
- // Ensure the map starts at offset 0 (start of file), otherwise pad to fill.
- if (files.begin()->first != 0)
- files.emplace(0, std::make_shared<StaticVfsFile>(filler_byte, files.begin()->first));
+ // Make the concatenation map from the input.
+ std::vector<ConcatenationEntry> concatenation_map;
- return VirtualFile(new ConcatenatedVfsFile(std::move(files), std::move(name)));
+ 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) {
+ 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 = file,
+ });
+
+ last_offset = offset + file->GetSize();
+ }
+
+ return VirtualFile(new ConcatenatedVfsFile(std::move(concatenation_map), std::move(name)));
}
std::string ConcatenatedVfsFile::GetName() const {
- if (files.empty()) {
+ if (concatenation_map.empty()) {
return "";
}
if (!name.empty()) {
return name;
}
- return files.begin()->second->GetName();
+ return concatenation_map.front().file->GetName();
}
std::size_t ConcatenatedVfsFile::GetSize() const {
- if (files.empty()) {
+ if (concatenation_map.empty()) {
return 0;
}
- return files.rbegin()->first + files.rbegin()->second->GetSize();
+ return concatenation_map.back().offset + concatenation_map.back().file->GetSize();
}
bool ConcatenatedVfsFile::Resize(std::size_t new_size) {
@@ -95,10 +116,10 @@ bool ConcatenatedVfsFile::Resize(std::size_t new_size) {
}
VirtualDir ConcatenatedVfsFile::GetContainingDirectory() const {
- if (files.empty()) {
+ if (concatenation_map.empty()) {
return nullptr;
}
- return files.begin()->second->GetContainingDirectory();
+ return concatenation_map.front().file->GetContainingDirectory();
}
bool ConcatenatedVfsFile::IsWritable() const {
@@ -110,25 +131,45 @@ bool ConcatenatedVfsFile::IsReadable() const {
}
std::size_t ConcatenatedVfsFile::Read(u8* data, std::size_t length, std::size_t offset) const {
- auto entry = --files.end();
- for (auto iter = files.begin(); iter != files.end(); ++iter) {
- if (iter->first > offset) {
- entry = --iter;
+ 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 file_offset = it->offset;
+ const u64 file_size = file->GetSize();
+
+ if (cur_offset >= file_offset + file_size) {
+ // Entirely out of bounds read.
break;
}
+
+ // Read the file at this position.
+ const u64 intended_read_size = std::min<u64>(cur_length, file_size);
+ const u64 actual_read_size =
+ file->Read(data + (cur_offset - offset), intended_read_size, cur_offset - file_offset);
+
+ // Update tracking.
+ cur_offset += actual_read_size;
+ cur_length -= actual_read_size;
+ it++;
}
- if (entry->first + entry->second->GetSize() <= offset)
- return 0;
-
- const auto read_in =
- std::min<u64>(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<u64>(read_in, length), offset - entry->first);
+ return cur_offset - offset;
}
std::size_t ConcatenatedVfsFile::Write(const u8* data, std::size_t length, std::size_t offset) {
diff --git a/src/core/file_sys/vfs_concat.h b/src/core/file_sys/vfs_concat.h
index 9be0261b6d..6b329d5455 100644
--- a/src/core/file_sys/vfs_concat.h
+++ b/src/core/file_sys/vfs_concat.h
@@ -3,6 +3,7 @@
#pragma once
+#include <compare>
#include <map>
#include <memory>
#include "core/file_sys/vfs.h"
@@ -12,19 +13,33 @@ namespace FileSys {
// Class that wraps multiple vfs files and concatenates them, making reads seamless. Currently
// read-only.
class ConcatenatedVfsFile : public VfsFile {
- explicit ConcatenatedVfsFile(std::vector<VirtualFile> files, std::string name_);
- explicit ConcatenatedVfsFile(std::multimap<u64, VirtualFile> files, std::string name_);
+private:
+ struct ConcatenationEntry {
+ u64 offset;
+ VirtualFile file;
+
+ auto operator<=>(const ConcatenationEntry& other) const {
+ return this->offset <=> other.offset;
+ }
+ };
+ using ConcatenationMap = std::vector<ConcatenationEntry>;
+
+ explicit ConcatenatedVfsFile(std::vector<ConcatenationEntry>&& concatenation_map,
+ std::string&& name);
+ bool VerifyContinuity() const;
public:
~ConcatenatedVfsFile() override;
/// Wrapper function to allow for more efficient handling of files.size() == 0, 1 cases.
- static VirtualFile MakeConcatenatedFile(std::vector<VirtualFile> files, std::string name);
+ static VirtualFile MakeConcatenatedFile(const std::vector<VirtualFile>& files,
+ std::string&& name);
/// Convenience function that turns a map of offsets to files into a concatenated file, filling
/// gaps with a given filler byte.
- static VirtualFile MakeConcatenatedFile(u8 filler_byte, std::multimap<u64, VirtualFile> files,
- std::string name);
+ static VirtualFile MakeConcatenatedFile(u8 filler_byte,
+ const std::multimap<u64, VirtualFile>& files,
+ std::string&& name);
std::string GetName() const override;
std::size_t GetSize() const override;
@@ -37,8 +52,7 @@ public:
bool Rename(std::string_view new_name) override;
private:
- // Maps starting offset to file -- more efficient.
- std::multimap<u64, VirtualFile> files;
+ ConcatenationMap concatenation_map;
std::string name;
};