API Reference — trio/streams/MemoryStream

DefaultInstanceCreator<trio::MemoryStream>

Template specialization that registers trio::MemoryStream with the pma framework's creation policy.

Why this exists

The pma allocator framework uses policy traits to stay decoupled from concrete types: any type that wants to participate in pma-managed allocation must specialize DefaultInstanceCreator. This specialization delegates creation to FactoryCreate<trio::MemoryStream>, which in turn calls MemoryStream::create(). Without it, pma::create<MemoryStream>() would not compile.

Fields

Name Type Description
type FactoryCreate<trio::MemoryStream> required — the policy type that pma machinery uses to construct MemoryStream instances.

Relationships

  • DefaultInstanceDestroyer<trio::MemoryStream> — paired destruction policy; always defined alongside this specialization.
  • MemoryStream::create() — the factory method that FactoryCreate delegates to.

DefaultInstanceDestroyer<trio::MemoryStream>

Template specialization that registers trio::MemoryStream with the pma framework's destruction policy.

Why this exists

Paired with DefaultInstanceCreator<trio::MemoryStream>, this specialization completes the pma lifecycle contract for MemoryStream. It delegates destruction to FactoryDestroy<trio::MemoryStream>, which calls MemoryStream::destroy(). Both specializations must be present for pma-managed code to create and release MemoryStream instances safely.

Fields

Name Type Description
type FactoryDestroy<trio::MemoryStream> required — the policy type that pma machinery uses to destroy MemoryStream instances.

Relationships

  • DefaultInstanceCreator<trio::MemoryStream> — paired creation policy; always defined alongside this specialization.
  • MemoryStream::destroy() — the static method that FactoryDestroy delegates to.

MemoryStream

An in-memory byte stream backed by a heap-allocated buffer. Use this when you need a full BoundedIOStream interface without touching the filesystem — for instance, to serialize DNA data into a buffer for in-process transfer or round-trip codec testing.

When to use this

Reach for MemoryStream when the data volume fits in RAM and the consumer expects a stream interface (e.g., a BinaryStreamWriter or BinaryStreamReader). Use a file-backed stream instead when data must persist across process exit or when working with sizes that exceed available heap.

Example

// Create a memory stream with a pre-sized buffer
trio::MemoryStream* stream = trio::MemoryStream::create(4096u);

// ... write or read through the stream ...

// Release when done — ownership is always with the caller
trio::MemoryStream::destroy(stream);

Parameters

Name Type Description
initialSize std::size_t optional — initial capacity of the in-memory buffer in bytes. Omit to use the implementation default.
memRes MemoryResource* optional — custom memory resource for the allocation. Pass nullptr (or omit) to use the default allocator.

Watch out for

  • Copy construction and copy assignment are deleted. MemoryStream instances cannot be shared — transfer ownership via std::move or pass by pointer.
  • The caller is always responsible for calling destroy(instance) to release the instance. There is no RAII wrapper — skipping destroy leaks the buffer.