vfs_concat: Rewrite and fix ConcatenatedVfsFile
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3e5c3d0f16
commit
44fdac334c
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@ -5,10 +5,22 @@
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#include <algorithm>
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#include <utility>
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#include "common/assert.h"
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#include "core/file_sys/vfs_concat.h"
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namespace FileSys {
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bool VerifyConcatenationMap(std::map<u64, VirtualFile> map) {
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for (auto iter = map.begin(); iter != --map.end();) {
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const auto old = iter++;
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if (old->first + old->second->GetSize() != iter->first) {
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return false;
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}
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}
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return map.begin()->first == 0;
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}
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VirtualFile ConcatenateFiles(std::vector<VirtualFile> files, std::string name) {
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if (files.empty())
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return nullptr;
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@ -27,7 +39,10 @@ ConcatenatedVfsFile::ConcatenatedVfsFile(std::vector<VirtualFile> files_, std::s
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}
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}
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ConcatenatedVfsFile::~ConcatenatedVfsFile() = default;
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ConcatenatedVfsFile::ConcatenatedVfsFile(std::map<u64, VirtualFile> files_, std::string name)
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: files(std::move(files_)), name(std::move(name)) {
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ASSERT(VerifyConcatenationMap(files));
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}
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std::string ConcatenatedVfsFile::GetName() const {
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if (files.empty())
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@ -62,28 +77,25 @@ bool ConcatenatedVfsFile::IsReadable() const {
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}
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std::size_t ConcatenatedVfsFile::Read(u8* data, std::size_t length, std::size_t offset) const {
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auto entry = files.end();
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std::pair<u64, VirtualFile> entry = *files.rbegin();
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for (auto iter = files.begin(); iter != files.end(); ++iter) {
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if (iter->first > offset) {
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entry = --iter;
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entry = *--iter;
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break;
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}
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}
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// Check if the entry should be the last one. The loop above will make it end().
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if (entry == files.end() && offset < files.rbegin()->first + files.rbegin()->second->GetSize())
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--entry;
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if (entry == files.end())
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if (entry.first + entry.second->GetSize() <= offset)
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return 0;
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const auto remaining = entry->second->GetSize() + offset - entry->first;
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if (length > remaining) {
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return entry->second->Read(data, remaining, offset - entry->first) +
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Read(data + remaining, length - remaining, offset + remaining);
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const auto read_in =
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std::min(entry.first + entry.second->GetSize() - offset, entry.second->GetSize());
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if (length > read_in) {
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return entry.second->Read(data, read_in, offset - entry.first) +
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Read(data + read_in, length - read_in, offset + read_in);
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}
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return entry->second->Read(data, length, offset - entry->first);
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return entry.second->Read(data, std::min(read_in, length), offset - entry.first);
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}
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std::size_t ConcatenatedVfsFile::Write(const u8* data, std::size_t length, std::size_t offset) {
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@ -93,4 +105,5 @@ std::size_t ConcatenatedVfsFile::Write(const u8* data, std::size_t length, std::
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bool ConcatenatedVfsFile::Rename(std::string_view name) {
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return false;
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}
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} // namespace FileSys
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@ -4,22 +4,54 @@
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#pragma once
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#include <map>
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#include <memory>
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#include <string_view>
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#include <boost/container/flat_map.hpp>
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#include "core/file_sys/vfs.h"
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#include "core/file_sys/vfs_static.h"
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namespace FileSys {
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class ConcatenatedVfsFile;
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// Wrapper function to allow for more efficient handling of files.size() == 0, 1 cases.
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VirtualFile ConcatenateFiles(std::vector<VirtualFile> files, std::string name = "");
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// Convenience function that turns a map of offsets to files into a concatenated file, filling gaps
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// with template parameter.
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template <u8 filler_byte>
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VirtualFile ConcatenateFiles(std::map<u64, VirtualFile> files, std::string name = "") {
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if (files.empty())
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return nullptr;
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if (files.size() == 1)
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return files.begin()->second;
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for (auto iter = files.begin(); iter != --files.end();) {
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const auto old = iter++;
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if (old->first + old->second->GetSize() != iter->first) {
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files.emplace(old->first + old->second->GetSize(),
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std::make_shared<StaticVfsFile<filler_byte>>(iter->first - old->first -
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old->second->GetSize()));
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}
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}
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if (files.begin()->first != 0)
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files.emplace(0, std::make_shared<StaticVfsFile<filler_byte>>(files.begin()->first));
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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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// Class that wraps multiple vfs files and concatenates them, making reads seamless. Currently
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// read-only.
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class ConcatenatedVfsFile : public VfsFile {
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friend VirtualFile ConcatenateFiles(std::vector<VirtualFile> files, std::string name);
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template <u8 filler_byte>
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friend VirtualFile ConcatenateFiles(std::map<u64, VirtualFile> files, std::string name);
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ConcatenatedVfsFile(std::vector<VirtualFile> files, std::string name);
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ConcatenatedVfsFile(std::map<u64, VirtualFile> files, std::string name);
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public:
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~ConcatenatedVfsFile() override;
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@ -36,7 +68,7 @@ public:
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private:
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// Maps starting offset to file -- more efficient.
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boost::container::flat_map<u64, VirtualFile> files;
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std::map<u64, VirtualFile> files;
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std::string name;
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};
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