DataArchive system which saves in native endian (for better performance working with local files), but is also able to load in any endian depending on archive's header information

5 files changed, 90 insertions, 3 deletions

diff --git a/core/src/Utils/IO/Archive.cpp b/core/src/Utils/IO/Archive.cpp
new file mode 100644
index 0000000..559c476
--- /dev/null
+++ b/core/src/Utils/IO/Archive.cpp
@@ -0,0 +1,65 @@
+#include "Archive.hpp"
+
+constexpr uint8_t kMagicNumbers[] = { 0x98, 0xd8, 0xa4, 0x65, 0x18, 0xa2, 0xd6, 0xa0 };
+constexpr size_t kMagicNumberCount = std::size(kMagicNumbers);
+
+constexpr uint8_t kByteOrderMark = []() {
+	switch (std::endian::native) {
+		case std::endian::little: return 0;
+		case std::endian::big: return 1;
+	}
+}();
+
+std::optional<DataArchive> DataArchive::SaveFile(const std::filesystem::path& path)
+{
+	auto archive = DataArchive(DataStream(std::fstream(path)));
+	auto& stream = archive.mStream;
+
+	stream.WriteBytes(kMagicNumberCount, kMagicNumbers);
+	stream.Write(kByteOrderMark);
+
+	stream.SetEndianness(std::endian::native);
+
+	return archive;
+}
+
+std::optional<DataArchive> DataArchive::LoadFile(const std::filesystem::path& path)
+{
+	auto archive = DataArchive(DataStream(std::fstream(path)));
+	auto& stream = archive.mStream;
+
+	uint8_t magicNumbers[kMagicNumberCount];
+	stream.ReadBytes(kMagicNumberCount, magicNumbers);
+
+	for (size_t i = 0; i < kMagicNumberCount; ++i) {
+		if (magicNumbers[i] != kMagicNumbers[i]) {
+			return {};
+		}
+	}
+
+	uint8_t byteOrderMark;
+	stream.Read(byteOrderMark);
+
+	switch (byteOrderMark) {
+		case 0: stream.SetEndianness(std::endian::little); break;
+		case 1: stream.SetEndianness(std::endian::big); break;
+		default: std::abort();
+	}
+
+	return archive;
+}
+
+const DataStream& DataArchive::GetStream() const
+{
+	return mStream;
+}
+
+DataStream& DataArchive::GetStream()
+{
+	return mStream;
+}
+
+DataArchive::DataArchive(DataStream stream)
+	: mStream(std::move(stream))
+{
+}
diff --git a/core/src/Utils/IO/Archive.hpp b/core/src/Utils/IO/Archive.hpp
new file mode 100644
index 0000000..72f79c6
--- /dev/null
+++ b/core/src/Utils/IO/Archive.hpp
@@ -0,0 +1,22 @@
+#pragma once
+
+#include "Utils/IO/DataStream.hpp"
+
+#include <filesystem>
+#include <optional>
+
+class DataArchive
+{
+private:
+	DataStream mStream;
+
+public:
+	static std::optional<DataArchive> SaveFile(const std::filesystem::path& path);
+	static std::optional<DataArchive> LoadFile(const std::filesystem::path& path);
+
+	const DataStream& GetStream()const;
+	DataStream& GetStream();
+
+private:
+	DataArchive(DataStream stream);
+};
diff --git a/core/src/Utils/IO/DataStream.cpp b/core/src/Utils/IO/DataStream.cpp
index 95e0b09..4880901 100644
--- a/core/src/Utils/IO/DataStream.cpp
+++ b/core/src/Utils/IO/DataStream.cpp
@@ -14,8 +14,6 @@ DataStream::DataStream(std::fstream stream)
 {
 }
 
-DataStream::~DataStream() = default;
-
 std::endian DataStream::GetEndianness() const
 {
 	return mEndian;
diff --git a/core/src/Utils/IO/DataStream.hpp b/core/src/Utils/IO/DataStream.hpp
index b965263..8dca00f 100644
--- a/core/src/Utils/IO/DataStream.hpp
+++ b/core/src/Utils/IO/DataStream.hpp
@@ -66,7 +66,6 @@ private:
 
 public:
 	DataStream(std::fstream stream);
-	~DataStream();
 
 	std::endian GetEndianness() const;
 	void SetEndianness(std::endian endianness);
diff --git a/core/src/Utils/IO/fwd.hpp b/core/src/Utils/IO/fwd.hpp
index 848c78f..f249e34 100644
--- a/core/src/Utils/IO/fwd.hpp
+++ b/core/src/Utils/IO/fwd.hpp
@@ -1,5 +1,8 @@
 #pragma once
 
+// Archive.hpp
+class DataArchive;
+
 // DataStream.hpp
 class SerializationStreamProxy;
 class DeserializationStreamProxy;