Implement struct serializer

[Baryonics]

No description provided.

[YanzhaoW]

Hi,

Please wait for pr #31 to finish before you start writing on this pull request.

[YanzhaoW]

Ok, #31 is merged. You could start to implement the class (make sure you have updated your local master branch).

First change EXPECT_FALSE to EXPECT_TRUE here:

srs-control/test/backend/srs/UnitTestStruct.cpp

Lines 83 to 87 in 8de00f5

	EXPECT_FALSE(res.has_value());
	auto struct_data = deserializer_converter.run(serializer_converter);
	EXPECT_FALSE(struct_data.has_value());

Then, implement the convert function here to make sure the test succeeds.

srs-control/backend/srs/converters/StructSerializer.cpp

Lines 17 to 23 in 8de00f5

	auto StructSerializer::convert([[maybe_unused]] const StructData* input, [[maybe_unused]] std::vector<char>& output)
	-> std::expected<std::size_t, std::string_view>
	{
	// NOTE: DO NOT do any memory allocation here. If heap data is needed, please initialize it in the constructor.
	output.clear();
	return std::unexpected{ "not implemented" };
	}

To do the testing, go to the build/bin folder and run

./unit_test_srs_backend

[YanzhaoW]

Thanks for the PR. Here are some suggestions/comments for now:

[YanzhaoW]

Maybe use binary_to_gray to be more consistent with gray_to_binary.

[YanzhaoW]

Looks great! Here are some further suggestions:

[YanzhaoW]

Well, this is not a good decision to create a new vector in a loop. When a new vector is created, you have the memory allocation (in heap), which is very slow and should be avoided.

What you could do is to create some buffer vector and initialize it only once in the constructor. In the loop, before you write something into it, reset all its members to be zero. Your compact_to_vector should take an non-const ref as its output:

void compact (const T& compact_data, std::vector<char>& output);

[YanzhaoW]

You sure output.resize(sizeof(std::uint64_t) / common::BYTE_BIT_LENGTH); is correct? sizeof(std::uint64_t) / common::BYTE_BIT_LENGTH always results in 1.