sol3::core::SeqRingWriter Class Reference

#include <sol3/core/seq_ring.h>

Public Member Functions
	SeqRingWriter (uint32_t slot_type, void *data, size_t data_size, size_t n_slots, size_t slot_size)
uint64_t	write (void const *header_data, size_t header_size, void const *payload_data, size_t payload_size)
uint64_t	head () const
flatbuffers::span< uint8_t const >	slotSpan (uint64_t seq) const
size_t	slotCount () const
	Number of slots. More...
size_t	slotSize () const
	Size in bytes of each slot. More...
uint32_t	slotType () const

Static Public Member Functions
static size_t	minDataSize (size_t n_slots, size_t slot_size)
	Minimum backing data size to hold n_slots of slot_size bytes. More...

Detailed Description

Low level slotted ring buffer with sequence lock style writing access. This datastructure allows for single writer, multi-reader with no back pression on writer. It employes a seqlock which allows readers to detect if the data they are reading has been overwritten/torn by the writer.

This datastructure is meant to be initialized in a raw shared memory region, and uses a stable memory interface to this region. Uses a fixed number of slots, each having a fixed slize.

Constructor & Destructor Documentation

SeqRingWriter()

sol3::core::SeqRingWriter::SeqRingWriter	(	uint32_t	slot_type,
		void *	data,
		size_t	data_size,
		size_t	n_slots,
		size_t	slot_size
	)

Create a writer over a ring with type, memory range, and shape. This will initialize the datastructure in the memory range. The memory range should not be shared with readers until after this function returns.

Member Function Documentation

head()

uint64_t sol3::core::SeqRingWriter::head

(

)

const

Return the sequence number associated with the head of the datastructure. A return value of 0 means no valid slot has been written yet.

minDataSize()

static size_t sol3::core::SeqRingWriter::minDataSize ( size_t  n_slots, size_t  slot_size  )

static

Minimum backing data size to hold n_slots of slot_size bytes.

slotCount()

size_t sol3::core::SeqRingWriter::slotCount

(

)

const

Number of slots.

slotSize()

size_t sol3::core::SeqRingWriter::slotSize

(

)

const

Size in bytes of each slot.

slotSpan()

flatbuffers::span<uint8_t const> sol3::core::SeqRingWriter::slotSpan

(

uint64_t

seq

)

const

Returns a byte span for a slot that has been written. Sequence value 0 is a sentinel for "invalid / not written" and always returns an empty span. If the requested sequence has not been written, or has been overwritten by a later call to write(), this returns an empty span.

The size will be the size of the written header + payload

slotType()

uint32_t sol3::core::SeqRingWriter::slotType

(

)

const

The type represented by data in each slot. Typically this is the flatbuffer file_identifier

write()

uint64_t sol3::core::SeqRingWriter::write	(	void const *	header_data,
		size_t	header_size,
		void const *	payload_data,
		size_t	payload_size
	)

Write header+payload into the next slot, returning the sequence number of the slot written to.

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The documentation for this class was generated from the following file:

• /workspaces/astro/sol3-sdk/cpp/sol3/core/seq_ring.h