iox::rp::RelativePointerData🔗

This are the data for a relative pointer. To be able so safely be used in the shared memory and prevent torn writes/reads, the class must not be larger than 64 bits and trivially copy-able.

#include <relative_pointer_data.hpp>

Public Types🔗

	Name
using uint16_t	id_t
using uint64_t	offset_t

Public Functions🔗

	Name
constexpr	RelativePointerData() =default Default constructed RelativePointerData which is logically equal to a nullptr.
constexpr	RelativePointerData(id_t id, offset_t offset) constructs a RelativePointerData from a given offset and segment id
id_t	id() const Getter for the id which identifies the segment.
offset_t	offset() const Getter for the offset within the segment.
void	reset() Resets the pointer to a logically nullptr.
bool	isLogicalNullptr() const Checks if the pointer is logically a nullptr.

Public Attributes🔗

	Name
constexpr id_t	ID_RANGE
constexpr id_t	NULL_POINTER_ID
constexpr id_t	MAX_VALID_ID
constexpr offset_t	OFFSET_RANGE id_t is 16 bit and the offset consumes the remaining 48 bits -> offset range is 2^48 - 1
constexpr offset_t	NULL_POINTER_OFFSET
constexpr offset_t	MAX_VALID_OFFSET
constexpr offset_t	LOGICAL_NULLPTR

Public Types Documentation🔗

using id_t🔗

using iox::rp::RelativePointerData::id_t =  uint16_t;

using offset_t🔗

using iox::rp::RelativePointerData::offset_t =  uint64_t;

Public Functions Documentation🔗

function RelativePointerData🔗

constexpr RelativePointerData() =default

Default constructed RelativePointerData which is logically equal to a nullptr.

function RelativePointerData🔗

constexpr RelativePointerData(
    id_t id,
    offset_t offset
)

constructs a RelativePointerData from a given offset and segment id

Parameters:

id is the unique id of the segment
offset is the offset within the segment

function id🔗

id_t id() const

Getter for the id which identifies the segment.

Return: the id which identifies the segment

function offset🔗

offset_t offset() const

Getter for the offset within the segment.

Return: the offset

function reset🔗

void reset()

Resets the pointer to a logically nullptr.

function isLogicalNullptr🔗

bool isLogicalNullptr() const

Checks if the pointer is logically a nullptr.

Return: true if logically a nullptr otherwise false

Public Attributes Documentation🔗

variable ID_RANGE🔗

static constexpr id_t ID_RANGE {std::numeric_limits<id_t>::max()};

Note: the maximum number of available ids

variable NULL_POINTER_ID🔗

static constexpr id_t NULL_POINTER_ID {[ID_RANGE](/v1.0.3/API-reference/utils/Classes/classiox_1_1rp_1_1RelativePointerData/#variable-id_range)};

Note: this represents the id of a logically nullptr

variable MAX_VALID_ID🔗

static constexpr id_t MAX_VALID_ID {[ID_RANGE](/v1.0.3/API-reference/utils/Classes/classiox_1_1rp_1_1RelativePointerData/#variable-id_range) - 1U};

Note: the maximum number of valid ids

variable OFFSET_RANGE🔗

static constexpr offset_t OFFSET_RANGE {(1ULL << 48U) - 1U};

id_t is 16 bit and the offset consumes the remaining 48 bits -> offset range is 2^48 - 1

variable NULL_POINTER_OFFSET🔗

static constexpr offset_t NULL_POINTER_OFFSET {[OFFSET_RANGE](/v1.0.3/API-reference/utils/Classes/classiox_1_1rp_1_1RelativePointerData/#variable-offset_range)};

Note: this represents the offset of a logically nullptr;

variable MAX_VALID_OFFSET🔗

static constexpr offset_t MAX_VALID_OFFSET {[OFFSET_RANGE](/v1.0.3/API-reference/utils/Classes/classiox_1_1rp_1_1RelativePointerData/#variable-offset_range) - 1U};

Note: the maximum offset which can be represented

variable LOGICAL_NULLPTR🔗

static constexpr offset_t LOGICAL_NULLPTR {[NULL_POINTER_OFFSET](/v1.0.3/API-reference/utils/Classes/classiox_1_1rp_1_1RelativePointerData/#variable-null_pointer_offset) << 16 | [NULL_POINTER_ID](/v1.0.3/API-reference/utils/Classes/classiox_1_1rp_1_1RelativePointerData/#variable-null_pointer_id)};

Note: internal representation of a nullptr

Updated on 31 May 2022 at 15:29:15 CEST