PayloadOffsetCache

PayloadOffsetCache

#include <sbio/core/state_handle.hh>

struct PayloadOffsetCache

Defined in src/lib/sbio/core/state_handle.hh:169

A cache of field offsets within fetched DataUnits.

The cache is intended to live on the SegmentCursor which can be constructed in a safe manner per each EPolicy (defined via SegmentState). Usage in this manner allows safe writes to the cache without synchronization.

Note

Field identication within the PayloadOffsetCache is determined by the field’s position within the MetadataInventory MODULO the slot count. In normal usage this is fine, as typically only a few fields are accessed, however, it does mean that two fields can evict each other from a cache slot. Absence of an offset in the cache simply means that i must be recalculated using the correct mechanism for the FormatTraits being read.

Note

Cached offsets are hints as for some data formats, the offset may change over time (e.g. if variably sized output is supported). It is the callers responsibility to verify the validity of the offset!

Public Methods

Return	Name	Description
SBIO_HD bool	find const inline	Look up the cached offset of a field.
SBIO_HD void	store inline	Cache the offset at which a field was found.

---

find

const inline

inline SBIO_HD bool find(hd_std::uint32_t field_id, hd_std::uint32_t & offset) const

Defined in src/lib/sbio/core/state_handle.hh:180

Look up the cached offset of a field.

Returns

true if the field has a cached offset.

Parameters

Parameter	Type	Description
field_id	hd_std::uint32_t	The field’s position in the MetadataInventory.
offset	hd_std::uint32_t &	The cached offset, if found.

---

store

inline

inline SBIO_HD void store(hd_std::uint32_t field_id, hd_std::uint32_t offset)

Defined in src/lib/sbio/core/state_handle.hh:196

Cache the offset at which a field was found.

Parameters

Parameter	Type	Description
field_id	hd_std::uint32_t	The field’s position in the MetadataInventory.
offset	hd_std::uint32_t	The offset of the field within the DataUnit.

Public Static Attributes

Return	Name	Description
constexpr hd_std::size_t	NumSlots static constexpr
constexpr hd_std::uint32_t	NoField static constexpr

---

NumSlots

static constexpr

constexpr hd_std::size_t NumSlots { 8 }

Defined in src/lib/sbio/core/state_handle.hh:170

---

NoField

static constexpr

constexpr hd_std::uint32_t NoField { 0xFFFFFFFFu }

Defined in src/lib/sbio/core/state_handle.hh:171

Private Attributes

Return	Name	Description
hd_std::array< Slot, NumSlots >	m_slots

---

m_slots

hd_std::array< Slot, NumSlots > m_slots {}

Type: hd_std::array< Slot, NumSlots >

Defined in src/lib/sbio/core/state_handle.hh:206