dynamic_data.h File Reference

Type-erased data container for runtime serialisation and deserialisation. More...

#include <memory>
#include <string_view>
#include "../serializer.h"

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Classes
class	vlink::DynamicData
	Runtime-typed container that serializes any VLink-compatible message type. More...

Namespaces
namespace	vlink

Detailed Description

Type-erased data container for runtime serialisation and deserialisation.

DynamicData stores a serialized payload (Bytes) together with a type-name tag (up to kOffset = 20 bytes) embedded in the leading bytes of the buffer. This allows the payload to be transported through channels that do not know the compile-time message type, and later deserialized back to the concrete type.

Internal layout

[ type name (20 bytes max) | serialized payload ]
^--- type_                      ^--- data_.data()

The type name is stored in-place in the first kOffset bytes of the Bytes buffer and exposed as a std::string_view pointing into that buffer.

Restrictions

• Cannot serialize or deserialize another DynamicData object (static_assert).
• Cannot serialize CDR types (static_assert).
• The type name string literal (including NUL) must be shorter than kOffset (20) bytes (static_assert).

Serialisation

vlink::DynamicData dd;
MyProtoMsg msg;
msg.set_value(42);
dd.load("MyProtoMsg", msg);
 
// Store/transport dd ...
 
MyProtoMsg recovered = dd.as<MyProtoMsg>();

Binary transport (operator<< / operator>>)

vlink::Bytes wire_bytes;
dd >> wire_bytes;   // serialize DynamicData to Bytes
 
vlink::DynamicData dd2;
dd2 << wire_bytes;  // deserialize Bytes back to DynamicData