[#BloombergLP-bdlc-FlatHashTable_GroupControl]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlc.adoc[bdlc]::FlatHashTable_GroupControl
:relfileprefix: ../../
:mrdocs:

This class provides methods for making inquires to the data of a group control loading during construction.

== Synopsis

Declared in `<bdlc_flathashtable_groupcontrol.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class FlatHashTable_GroupControl;
----

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/Storage.adoc[`Storage`] 
| Packed control‐byte storage type (SSE2 `__m128i`).
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/2constructor.adoc[`FlatHashTable_GroupControl`]         [.small]#[constructor]#
| Create a group control query object using the specified `data`. The bytes of `data` have no alignment requirement. The behavior is undefined unless `data` has at least `k_SIZE` bytes available.
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/available.adoc[`available`] 
| Return a bit mask of the `k_SIZE` entries that are empty or erased. The bit at index `i` corresponds to the result for `data[i]`.
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/inUse.adoc[`inUse`] 
| Return a bit mask of the `k_SIZE` entries that are in use (i.e., not empty or erased). The bit at index `i` corresponds to the result for `data[i]`.
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/match.adoc[`match`] 
| Return a bit mask of the `k_SIZE` entries that have the specified `value`. The bit at index `i` corresponds to the result for `data[i]`. The behavior is undefined unless `0 == (0x80 & value)`.
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/neverFull.adoc[`neverFull`] 
| Return `true` if this group control was never full (i.e., has a value that is empty, but not erased).
|===


== Static Data Members

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/k_EMPTY.adoc[`k_EMPTY`] 
| Control‐byte value meaning the slot is empty.
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/k_ERASED.adoc[`k_ERASED`] 
| Control‐byte value meaning the slot was erased.
| xref:BloombergLP/bdlc/FlatHashTable_GroupControl/k_SIZE.adoc[`k_SIZE`] 
| Number of control bytes in one group (`sizeof(Storage)`).
|===



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