CODEWITHSUNDEEP
cflatbuffers
vk-code
vk-code

Reputation: 1088

flatcc union as top element

i referred following link to understand how Union is encoded/ decoded in flatbuffers.

https://google.github.io/flatbuffers/flatbuffers_guide_tutorial.html https://github.com/dvidelabs/flatcc#unions

i have defined my IDL as follows

table EthEndpoint
{
    // ethernet fields
}

table WifiEndpoint
{
    // wifi fields
}

union EndpointData
{
    EthEndpoint,
    WifiEndpoint
}


flatcc_builder_t builder;
flatcc_builder_init(&builder);

EthEndpoint_start(&builder)
// populate using EthEndpoint_*_add(&builder, ...)
EthEndpoint_ref_t eth_ep = EthEndpoint_end(&builder);

EndpointData_ref_t ep = EndpointData_as_EthEndpoint(eth_ep);

how to add ep to builder? There are no generated methods EndpointData_start/ EndpointData_end/ EndpointData_create.

size_t size;
void *buf = flatcc_builder_get_direct_buffer(&builder, &size);

// store the buffer to disk
flatcc_builder_clear(&builder);

how to add ep to builder? there is no EndpointData_start/ EndpointData_end/ EndpointData_create.

Upvotes: 0

Views: 232

Answers (1)

Aardappel
Aardappel

Reputation: 6074

You can't have a union as root of a buffer. Add a table that wraps it, then use the generated code to set both type and value.

Upvotes: 1

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