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#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::span<const uint8_t, 8> DataArchive::GetMagicNumbers()
{
return std::span<const uint8_t, 8>{ kMagicNumbers };
}
std::optional<InputDataStream> DataArchive::LoadFile(const std::filesystem::path& path)
{
InputFileStream fileStream(path);
fileStream.SetReadInSize(1024);
InputDataStream stream(std::move(fileStream));
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 stream;
}
std::optional<OutputDataStream> DataArchive::SaveFile(const std::filesystem::path& path)
{
OutputFileStream fileStream(path, OutputFileStream::TruncateFile);
fileStream.SetMaxBufferSize(1024);
OutputDataStream stream(std::move(fileStream));
stream.WriteBytes(kMagicNumberCount, kMagicNumbers);
stream.Write(kByteOrderMark);
stream.SetEndianness(std::endian::native);
return stream;
}
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