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TSet

A set with an optional KeyFuncs parameters for customizing how the elements are compared and searched.

API > API/Runtime > API/Runtime/Core

A set with an optional KeyFuncs parameters for customizing how the elements are compared and searched. E.g. You can specify a mapping from elements to keys if you want to find elements by specifying a subset of the element type. It uses a TSparseArray of the elements, and also links the elements into a hash with a number of buckets proportional to the number of elements. Addition, removal, and finding are O(1).

The ByHash() functions are somewhat dangerous but particularly useful in two scenarios: Heterogeneous lookup to avoid creating expensive keys like FString when looking up by const TCHAR*. You must ensure the hash is calculated in the same way as ElementType is hashed. If possible put both ComparableKey and ElementType hash functions next to each other in the same header to avoid bugs when the ElementType hash function is changed. Reducing contention around hash tables protected by a lock. It is often important to incur the cache misses of reading key data and doing the hashing before acquiring the lock.

   
Name TSet
Type class
Header File /Engine/Source/Runtime/Core/Public/Containers/Set.h
Include Path #include "Containers/Set.h"

Syntax

template<typename InElementType, typename KeyFuncs, typename Allocator>  
class TSet

Derived Classes

Constructors

Name Remarks Include Path Unreal Specifiers

TSet ( TSet< ElementType, KeyFuncs, OtherAllocator >&& Other
)

 Constructor for moving elements from a TSet with a different SetAllocator Containers/Set.h  

TSet ()

 Initialization constructor. Containers/Set.h  

TSet ( const TSet& Copy
)

 Copy constructor. Containers/Set.h  

TSet ( TArrayView< const ElementType > InArrayView
)

   Containers/Set.h  

TSet ( TArray< ElementType >&& InArray
)

   Containers/Set.h  
  Containers/Set.h  

TSet ( std::initializer_list< ElementType > InitList
)

 Initializer list constructor. Containers/Set.h  

TSet ( TSet&& Other
)

 Move constructor. Containers/Set.h  

TSet ( const TSet< ElementType, KeyFuncs, OtherAllocator >& Other
)

 Constructor for copying elements from a TSet with a different SetAllocator Containers/Set.h  

Destructors

Name Remarks Include Path Unreal Specifiers

~TSet()

 Destructor. Containers/Set.h  

Classes

Name Remarks
FElementCompareClass Extracts the element value from the set's element structure and passes it to the user provided comparison class.
TBaseIterator The base type of whole set iterators.
TBaseKeyIterator The base type of whole set iterators.
TConstIterator Used to iterate over the elements of a const TSet.
TConstKeyIterator Used to iterate over the elements of a const TSet.
TIterator Used to iterate over the elements of a TSet.
TKeyIterator Used to iterate over the elements of a TSet.

Typedefs

Name Type Remarks Include Path
AllocatorType Allocator   Containers/Set.h
ElementArrayType TSparseArray< SetElementType, typename Allocator::SparseArrayAllocator >   Containers/Set.h
ElementInitType KeyFuncs::ElementInitType   Containers/Set.h
ElementType InElementType   Containers/Set.h
HashType typename Allocator::HashAllocator::template ForElementType< FSetElementId >   Containers/Set.h
IntrusiveUnsetOptionalStateType TSet   Containers/Set.h
KeyFuncsType KeyFuncs   Containers/Set.h
KeyInitType KeyFuncs::KeyInitType   Containers/Set.h
SetElementType TSetElement< InElementType >   Containers/Set.h
SizeType typename Allocator::SparseArrayAllocator::ElementAllocator::SizeType   Containers/Set.h
TRangedForConstIterator TBaseIterator< true, true >   Containers/Set.h
TRangedForIterator TBaseIterator< false, true >   Containers/Set.h
USizeType std::make_unsigned_t< SizeType >   Containers/Set.h

Constants

Name Type Remarks Include Path
bHasIntrusiveUnsetOptionalState bool Start - intrusive TOptional state //. Containers/Set.h

Variables

Protected

Name Type Remarks Include Path Unreal Specifiers
Elements ElementArrayType   Containers/Set.h  
Hash HashType   Containers/Set.h  
HashSize int32   Containers/Set.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

FSetElementId Add ( InElementType&& InElement,
bool* bIsAlreadyInSetPtr
)

   Containers/Set.h  

FSetElementId Add ( const InElementType& InElement,
bool* bIsAlreadyInSetPtr
)

 Adds an element to the set. Containers/Set.h  

FSetElementId AddByHash ( uint32 KeyHash,
InElementType&& InElement,
bool* bIsAlreadyInSetPtr
)

   Containers/Set.h  

FSetElementId AddByHash ( uint32 KeyHash,
const InElementType& InElement,
bool* bIsAlreadyInSetPtr
)

 Adds an element to the set. Containers/Set.h  

void Append ( TSet< ElementType, KeyFuncs, OtherAllocator >&& OtherSet
)

   Containers/Set.h  

void Append ( const TSet< ElementType, KeyFuncs, OtherAllocator >& OtherSet
)

 Add all items from another set to our set (union without creating a new set) Containers/Set.h  

void Append ( TArray< ElementType, ArrayAllocator >&& InElements
)

   Containers/Set.h  

void Append ( TArrayView< const ElementType > InElements
)

   Containers/Set.h  

void Append ( TSet< typename TContainerElementTypeCompatibility< ElementType >::CopyFromOtherType, OtherKeyFuncs, ...
)

 Add all items from another set to our set (union without creating a new set) Compatible element type version. Containers/Set.h  

void Append ( std::initializer_list< ElementType > InitList
)

   Containers/Set.h  

void Append ( const TSet< typename TContainerElementTypeCompatibility< ElementType >::CopyFromOtherType, OtherKeyF...
)

 Add all items from another set to our set (union without creating a new set) Compatible element type version. Containers/Set.h  

TArray< ElementType > Array()

   Containers/Set.h  

TRangedForIterator begin ()

 DO NOT USE DIRECTLY STL-like iterators to enable range-based for loop support. Containers/Set.h  

TRangedForConstIterator begin ()

   Containers/Set.h  

void CheckAddress ( const ElementType* Addr
) const

 Checks that the specified address is not part of an element within the container. Containers/Set.h  

void Compact()

 Compacts the allocated elements into a contiguous range. Containers/Set.h  

void CompactStable ()

 Compacts the allocated elements into a contiguous range. Containers/Set.h  

bool Contains ( KeyInitType Key
) const

 Checks if the element contains an element with the given key. Containers/Set.h  

bool ContainsByHash ( uint32 KeyHash,
const ComparableKey& Key
) const

 Checks if the element contains an element with the given key. Containers/Set.h  

void CopyUnfrozen ( const FMemoryUnfreezeContent& Context,
void* Dst
) const

   Containers/Set.h  

void CountBytes ( FArchive& Ar
) const

 Tracks the container's memory use through an archive. Containers/Set.h  

TConstIterator CreateConstIterator()

 Creates a const iterator for the contents of this set Containers/Set.h  

TIterator CreateIterator()

 Creates an iterator for the contents of this set Containers/Set.h  

TSet Difference ( const TSet& OtherSet
) const

   Containers/Set.h  

void Dump ( FOutputDevice& Ar
)

 Describes the set's contents through an output device. Containers/Set.h  

void DumpHashElements ( FOutputDevice& Ar
)

   Containers/Set.h  

FSetElementId Emplace ( ArgsType&& Args,
bool* bIsAlreadyInSetPtr
)

 Adds an element to the set. Containers/Set.h  

FSetElementId EmplaceByHash ( uint32 KeyHash,
ArgsType&& Args,
bool* bIsAlreadyInSetPtr
)

 Adds an element to the set. Containers/Set.h  

void Empty ( int32 ExpectedNumElements
)

 Removes all elements from the set, potentially leaving space allocated for an expected number of elements about to be added. Containers/Set.h  

TRangedForIterator end ()

   Containers/Set.h  

TRangedForConstIterator end ()

   Containers/Set.h  

ElementType * Find ( KeyInitType Key
)

 Finds an element with the given key in the set. Containers/Set.h  

const ElementType * Find ( KeyInitType Key
) const

 Finds an element with the given key in the set. Containers/Set.h  

const ElementType * FindArbitraryElement ()

   Containers/Set.h  

ElementType * FindArbitraryElement ()

 Finds any element in the set and returns a pointer to it. Containers/Set.h  

const ElementType * FindByHash ( uint32 KeyHash,
const ComparableKey& Key
) const

   Containers/Set.h  

ElementType * FindByHash ( uint32 KeyHash,
const ComparableKey& Key
)

 Finds an element with a pre-calculated hash and a key that can be compared to KeyType. Containers/Set.h  

FSetElementId FindId ( KeyInitType Key
) const

 Finds an element with the given key in the set. Containers/Set.h  

FSetElementId FindIdByHash ( uint32 KeyHash,
const ComparableKey& Key
) const

 Finds an element with a pre-calculated hash and a key that can be compared to KeyType Containers/Set.h  

ElementType & FindOrAdd ( InElementType&& InElement,
bool* bIsAlreadyInSetPtr
)

   Containers/Set.h  

ElementType & FindOrAdd ( const InElementType& InElement,
bool* bIsAlreadyInSetPtr
)

 Adds an element to the set if not already present and returns a reference to the added or existing element. Containers/Set.h  

ElementType & FindOrAddByHash ( uint32 KeyHash,
ElementReferenceType&& InElement,
bool* bIsAlreadyInSetPtr
)

 Adds an element to the set if not already present and returns a reference to the added or existing element. Containers/Set.h  

ElementType & Get ( FSetElementId Id
)

 Accesses the identified element's value. Element must be valid (see @IsValidId). Containers/Set.h  

const ElementType & Get ( FSetElementId Id
) const

 Accesses the identified element's value. Element must be valid (see @IsValidId). Containers/Set.h  

SIZE_T GetAllocatedSize()

 Helper function to return the amount of memory allocated by this container Only returns the size of allocations made directly by the container, not the elements themselves. Containers/Set.h  

int32 GetMaxIndex()

   Containers/Set.h  

bool Includes ( const TSet< ElementType, KeyFuncs, Allocator >& OtherSet
) const

 Determine whether the specified set is entirely included within this set Containers/Set.h  

TSet Intersect ( const TSet& OtherSet
) const

   Containers/Set.h  

bool IsEmpty ()

 Returns true if the sets is empty and contains no elements. Containers/Set.h  

bool IsValidId ( FSetElementId Id
) const

 Checks whether an element id is valid. Containers/Set.h  

int32 Num()

   Containers/Set.h  

void Relax()

 Relaxes the set's hash to a size strictly bounded by the number of elements in the set. Containers/Set.h  

void Remove ( FSetElementId ElementId
)

 Removes an element from the set. Containers/Set.h  

int32 Remove ( KeyInitType Key
)

 Removes all elements from the set matching the specified key. Containers/Set.h  

int32 RemoveByHash ( uint32 KeyHash,
const ComparableKey& Key
)

 Removes all elements from the set matching the specified key. Containers/Set.h  

void Reserve ( int32 Number
)

 Preallocates enough memory to contain Number elements Containers/Set.h  

void Reset()

 Efficiently empties out the set but preserves all allocations and capacities Containers/Set.h  

void Shrink()

 Shrinks the set's element storage to avoid slack. Containers/Set.h  

void Sort ( const PREDICATE_CLASS& Predicate
)

 Sorts the set's elements using the provided comparison class. Containers/Set.h  

void SortFreeList ()

 Sort the free element list so that subsequent additions will occur in the lowest available TSparseArray index resulting in tighter packing without moving any existing items. Containers/Set.h  

void StableSort ( const PREDICATE_CLASS& Predicate
)

 Stable sorts the set's elements using the provided comparison class. Containers/Set.h  

TSet Union ( const TSet& OtherSet
) const

   Containers/Set.h  

bool VerifyHashElementsKey ( KeyInitType Key
) const

   Containers/Set.h  

void WriteMemoryImage ( FMemoryImageWriter& Writer
) const

   Containers/Set.h  

Static

Name Remarks Include Path Unreal Specifiers

static void AppendHash ( const FPlatformTypeLayoutParameters& LayoutParams,
FSHA1& Hasher
)

   Containers/Set.h  

static void Move ( SetType& ToSet,
SetType& FromSet
)

   Containers/Set.h  

Operators

Name Remarks Include Path Unreal Specifiers

const ElementType & operator[] ( FSetElementId Id
) const

 Accesses the identified element's value. Element must be valid (see @IsValidId). Containers/Set.h  

ElementType & operator[] ( FSetElementId Id
)

 Accesses the identified element's value. Element must be valid (see @IsValidId). Containers/Set.h  

TSet & operator= ( const TSet& Copy
)

 End - intrusive TOptional state //. Containers/Set.h  

TSet & operator= ( TSet&& Other
)

 Move assignment operator. Containers/Set.h  

TSet & operator= ( const TSet< ElementType, KeyFuncs, OtherAllocator >& Other
)

 Assignment operator for copying elements from a TSet with a different SetAllocator Containers/Set.h  

TSet & operator= ( TSet< typename TContainerElementTypeCompatibility< ElementType >::CopyFromOtherType, OtherKeyFuncs, ...
)

 Move assignment operator. Compatible element type version. Containers/Set.h  

TSet & operator= ( const TSet< typename TContainerElementTypeCompatibility< ElementType >::CopyFromOtherType, OtherKeyF...
)

 Assignment operator. Containers/Set.h  

TSet & operator= ( std::initializer_list< ElementType > InitList
)

 Initializer list assignment operator Containers/Set.h  

TSet & operator= ( TSet< ElementType, KeyFuncs, OtherAllocator >&& Other
)

 Assignment operator for moving elements from a TSet with a different SetAllocator Containers/Set.h  

bool operator== ( FIntrusiveUnsetOptionalState Tag
) const

   Containers/Set.h  

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