Performance optimization

Avoid copying around the entire file table so that the speed doesn't decrease as the archive has more files.

include/ReArchive/ReArchive.h

@@ -4,6 +4,7 @@
 #include <vector>
 
 // TODO compression.
+// TODO allow the user to pass in the file table if they already have it to avoid de-serializing it over and over.
 namespace ReArchive {
     /// Creates a new empty archive.
     /// @param filesystem_path where the archive is to be created.

include/ReArchive/types/FileTable.h

@@ -16,7 +16,8 @@ public:
     void Append(const FileEntry& file_entry);
     void Remove(const FileEntry& file_entry);
     [[nodiscard]] bool Contains(const std::filesystem::path& entry ) const { return entries.contains(entry); }
-    [[nodiscard]] std::unordered_map<std::filesystem::path, FileEntry> GetEntries() const { return entries; }
+    [[nodiscard]] std::unordered_map<std::filesystem::path, FileEntry>* GetEntries() { return &entries; }
+    [[nodiscard]] const std::unordered_map<std::filesystem::path, FileEntry>* GetEntries() const { return &entries; }
     [[nodiscard]] int64_t Count() const { return entries.size(); }
 public:
     [[nodiscard]] static std::vector<unsigned char> Serialize(const FileTable& file_table);

main.cpp

@@ -85,7 +85,7 @@ void DisplayArchiveContents(const std::filesystem::path& archive) {
 
     auto file_table = result.second;
     std::cout << "path" << " | " << "size (bytes)" << std::endl;
-    for (const auto& e : file_table.GetEntries())
+    for (const auto& e : *file_table.GetEntries())
         std::cout << e.second.Path() << " " << e.second.Size() << std::endl;
 }
 
@@ -104,23 +104,11 @@ void AddFileToArchive(const std::filesystem::path& file_to_add, const std::files
         return;
     }
 
-    auto file_table_result = ReArchive::ReadFileTable(archive);
-    if (!file_table_result.first) {
-        std::cerr << "The specified path is inaccessible or not a valid archive." << std::endl;
-        return;
-    }
-
-    auto file_table = file_table_result.second;
-    if (file_table.Contains(file_to_add)) {
-        std::cerr << "The specified path for the file to be added already exists within the archive." << std::endl;
-        return;
-    }
-
     auto file_data = ReadFileFromDisk(file_to_add);
     auto result = ReArchive::WriteFile(archive, file_to_add, file_data.data(), file_data.size());
 
     if (!result)
-        std::cerr << "The specified path is inaccessible or not a valid archive." << std::endl;
+        std::cerr << "The specified path for the file to be added already exists within the archive." << std::endl;
 }
 
 void AddDirectoryToArchive(const std::filesystem::path& directory_to_add, const std::filesystem::path& archive) {
@@ -171,7 +159,7 @@ void ExtractArchive(const std::filesystem::path& archive) {
         return;
     }
 
-    for (const auto& entry : file_table_result.second.GetEntries()) {
+    for (const auto& entry : *file_table_result.second.GetEntries()) {
         if (std::filesystem::exists(entry.first))
             if (!GetConfirmation("File " + entry.first.string() + " already exists, overwrite?"))
                 continue;

src/ReArchive.cpp

@@ -49,7 +49,7 @@ FileTable GetFileTable(const Header& header, std::ifstream& in) {
         int64_t data_offset = be64toh(*reinterpret_cast<const int64_t*>(ptr));
         ptr += sizeof(int64_t);
 
-        result.Append(FileEntry(data_size, data_offset, path));
+        result.Append({ data_size, data_offset, path });
     }
     return result;
 }
@@ -122,9 +122,6 @@ bool ReArchive::WriteFile(const std::filesystem::path& archive, const std::files
     if (!std::filesystem::exists(archive))
         return false;
 
-    if (std::filesystem::is_directory(archive))
-        return false;
-
     // Busy-wait.
     while (locked.contains(archive)) {}
     locked.insert(archive);
@@ -146,9 +143,7 @@ bool ReArchive::WriteFile(const std::filesystem::path& archive, const std::files
     auto header = GetHeader(buffer.data());
     auto file_table = GetFileTable(header, in);
 
-    auto file_entries = file_table.GetEntries();
-    auto value = file_entries.find(file_path);
-    if (value != file_entries.end())
+    if (file_table.Contains(file_path))
         return false;
 
     in.close();
@@ -210,8 +205,8 @@ bool ReArchive::OverwriteFile(const std::filesystem::path& archive, const std::f
     const FileEntry* target = nullptr;
     auto file_entries = file_table.GetEntries();
 
-    auto value = file_entries.find(file_path);
-    if (value != file_entries.end())
+    auto value = file_entries->find(file_path);
+    if (value != file_entries->end())
         target = &value->second;
 
     if (!target)
@@ -265,8 +260,8 @@ std::vector<unsigned char> ReArchive::ReadFile(const std::filesystem::path& arch
     const FileEntry* target = nullptr;
     auto file_entries = file_table.GetEntries();
 
-    auto value = file_entries.find(file_path);
-    if (value != file_entries.end())
+    auto value = file_entries->find(file_path);
+    if (value != file_entries->end())
         target = &value->second;
 
     if (!target)
@@ -317,11 +312,11 @@ bool ReArchive::EraseFile(const std::filesystem::path& archive, const std::files
         return false;
 
     auto file_entries = current_file_table.GetEntries();
-    auto value = file_entries.find(file_path);
-    if (value != file_entries.end())
-        file_entries.erase(value);
+    auto value = file_entries->find(file_path);
+    if (value != file_entries->end())
+        file_entries->erase(value);
 
-    for (auto& e : file_entries) {
+    for (auto& e : *file_entries) {
         auto file_buffer = ReadFile(archive, e.first);
         if (!WriteFile(archive.string() + ".tmp", e.first, file_buffer.data(), (int64_t) file_buffer.size())) {
             std::filesystem::remove(archive.string() + ".tmp");

src/types/FileTable.cpp

@@ -18,14 +18,14 @@ void FileTable::Remove(const FileEntry& file_entry) {
 
 std::vector<unsigned char> FileTable::Serialize(const FileTable& file_table) {
     auto files = file_table.GetEntries();
-    int64_t count = files.size();
+    int64_t count = files->size();
     auto network_count = htobe64(count);
     std::vector<unsigned char> result(reinterpret_cast<unsigned char*>(&network_count), reinterpret_cast<unsigned char*>(&network_count) + sizeof(network_count));
 
-    if (files.empty())
+    if (files->empty())
         return result;
 
-    for (const auto& file : files) {
+    for (const auto& file : *files) {
         size_t current_size = result.size();
         auto serialization = FileEntry::Serialize(file.second);