RHUnorderedSet#

Fully qualified name: carb::container::RHUnorderedSet

Defined in carb/container/RHUnorderedSet.h

template<typename Key, typename Hasher = std::hash<Key>, typename Equals = std::equal_to<Key>, size_t LoadFactorMax100 = kDefaultLoadFactor, typename Allocator = std::allocator<Key>> class RHUnorderedSet : public detail::RobinHood<detail::RobinHoodSetTraits<Key, std::hash<Key>, std::equal_to<Key>, std::allocator<Key>, kDefaultLoadFactor>>#

Implements an Unordered Set, that is: a container that contains a set of keys that all must be unique.

There is no defined order to the set of keys.

Iterator/reference/pointer invalidation (note differences from std::unordered_set):

Operation	Invalidates
All read operations	Never
`clear`, `rehash`, `reserve`, `operator=`, `insert`, `emplace`	Always
`erase`	Only the element removed
`swap`	All iterators, no pointers/references

Warning

This container is similar to, but not a drop-in replacement for std::unordered_set due to differences in iterator invalidation and memory layout.

Template Parameters:

Key – The key type
Hasher – A functor to use as a hashing function for Key
Equals – A functor to use to compare two Key values for equality
LoadFactorMax100 – The load factor to use for the table. This value must be in the range [10, 100] and represents the percentage of entries in the hash table that will be filled before resizing. Open-addressing hash maps with 100% usage have better memory usage but worse performance since they need “gaps” in the hash table to terminate runs. The default value is kDefaultLoadFactor.
Allocator – The Allocator to use. Must support rebind.

Public Types

using key_type = typename Base::key_type#: The key type.

using value_type = typename Base::value_type#: The value type (effectively const key_type)

using size_type = typename Base::size_type#: Unsigned integer type (typically size_t)

using difference_type = typename Base::difference_type#: Signed integer type (typically ptrdiff_t)

using hasher = typename Base::hasher#: The hash function.

using key_equal = typename Base::key_equal#: The key-equals function.

using reference = typename Base::reference#: value_type&

using const_reference = typename Base::const_reference#: const value_type&

using pointer = typename Base::const_pointer#: value_type*

using const_pointer = typename Base::const_pointer#: const value_type*

using iterator = typename Base::iterator#: A LegacyForwardIterator to value_type.

using const_iterator = typename Base::const_iterator#: A LegacyForwardIterator to const value_type

using find_iterator = typename Base::find_iterator#: A LegacyForwardIterator to value_type that proceeds to the next matching key when incremented.

using const_find_iterator = typename Base::const_find_iterator#: A LegacyForwardIterator to const value_type that proceeds to the next matching key when incremented.

using allocator_type = typename Base::allocator_type#: The Allocator.

Public Functions

constexpr RHUnorderedSet() noexcept = default#: Constructs empty container.

inline explicit RHUnorderedSet( size_type reserved, const hasher &h = hasher(), const key_equal &ke = key_equal(), const allocator_type &al = allocator_type(), )#

Constructor with reservation hint.

Parameters:

reserved – Minimal number of slots to reserve on initialization.
h – Hash function to use.
ke – Comparison function to use for all key comparisons of this container.
al – Allocator to use for all memory allocations of this container.

inline RHUnorderedSet(size_type reserved, const allocator_type &al)#

Constructor with reservation hint and allocator.

Parameters:

reserved – Minimal number of slots to reserve on initialization.
al – Allocator to use for all memory allocations of this container.

inline RHUnorderedSet( size_type reserved, const hasher &h, const allocator_type &al, )#

Constructor with reservation hint, hash function and allocator.

Parameters:

reserved – Minimal number of slots to reserve on initialization.
h – Hash function to use.
al – Allocator to use for all memory allocations of this container.

inline explicit RHUnorderedSet(const allocator_type &al)#

Constructor with allocator.

Parameters:: al – Allocator to use for all memory allocations of this container.

template<class InputIt> inline RHUnorderedSet( InputIt first, InputIt last, size_type reserved = 0, const hasher &h = hasher(), const key_equal &ke = key_equal(), const allocator_type &al = allocator_type(), )#

Constructs the container with the contents of range [first, last).

Note

If multiple elements in the range [first, last) have equivalent keys, the first encountered key will be inserted.

Parameters:

first – The first iterator defining the source range of elements to copy.
last – The last iterator defining the source range of elements to copy.
reserved – A hint to the minimal number of slots to reserve.
h – Hash function to use.
ke – Comparison function to use for all key comparisons of this container.
al – Allocator to use for all memory allocations of this container.

template<class InputIt> inline RHUnorderedSet( InputIt first, InputIt last, size_type reserved, const allocator_type &al, )#

Constructs the container with the contents of range [first, last).

Note

If multiple elements in the range [first, last) have equivalent keys, the first encountered key will be inserted.

Parameters:

first – The first iterator defining the source range of elements to copy.
last – The last iterator defining the source range of elements to copy.
reserved – A hint to the minimal number of slots to reserve.
al – Allocator to use for all memory allocations of this container.

template<class InputIt> inline RHUnorderedSet( InputIt first, InputIt last, size_type reserved, const hasher &h, const allocator_type &al, )#

Constructs the container with the contents of range [first, last).

Note

If multiple elements in the range [first, last) have equivalent keys, the first encountered key will be inserted.

Parameters:

first – The first iterator defining the source range of elements to copy.
last – The last iterator defining the source range of elements to copy.
reserved – A hint to the minimal number of slots to reserve.
h – Hash function to use.
al – Allocator to use for all memory allocations of this container.

inline RHUnorderedSet( std::initializer_list<value_type> init, size_type reserved = 0, const hasher &h = hasher(), const key_equal &ke = key_equal(), const allocator_type &al = allocator_type(), )#

Constructs the container with the contents of items from an initializer_list.

Note

If multiple elements in init have equivalent keys, the first encountered key will be inserted.

Parameters:

init – initializer list to initialize the elements of the container with.
reserved – A hint to the minimal number of slots to reserve. If not specified, init.size() is used.
h – Hash function to use.
ke – Comparison function to use for all key comparisons of this container.
al – Allocator to use for all memory allocations of this container.

inline RHUnorderedSet( std::initializer_list<value_type> init, size_type reserved, const allocator_type &al, )#

Constructs the container with the contents of items from an initializer_list.

Note

If multiple elements in init have equivalent keys, the first encountered key will be inserted.

Parameters:

init – initializer list to initialize the elements of the container with.
reserved – A hint to the minimal number of slots to reserve. If not specified, init.size() is used.
al – Allocator to use for all memory allocations of this container.

inline RHUnorderedSet( std::initializer_list<value_type> init, size_type reserved, const hasher &h, const allocator_type &al, )#

Constructs the container with the contents of items from an initializer_list.

Note

If multiple elements in init have equivalent keys, the first encountered key will be inserted.

Parameters:

init – initializer list to initialize the elements of the container with.
reserved – A hint to the minimal number of slots to reserve. If not specified, init.size() is used.
h – Hash function to use.
al – Allocator to use for all memory allocations of this container.

inline RHUnorderedSet(const RHUnorderedSet &other)#

Copy constructor.

Copies elements from another container.

Complexity: Linear in size of other.

Note

*this may have a different capacity() than other.

Parameters:: other – The other container to copy entries from.

inline RHUnorderedSet( const RHUnorderedSet &other, const Allocator &alloc, )#

Copy constructor.

Copies elements from another container.

Complexity: Linear in size of other.

Note

*this may have a different capacity() than other.

Parameters:

other – The other container to copy entries from.
alloc – The allocator to use for all memory allocations of this container.

inline RHUnorderedSet(RHUnorderedSet &&other)#

Move constructor.

Moves elements from another container.

Complexity: Constant.

Note

No move constructors on contained elements are invoked. other will be empty() after this operation.

Parameters:: other – The other container to move entries from.

inline RHUnorderedSet( RHUnorderedSet &&other, const Allocator &alloc, )#

Move constructor.

Moves elements from another container.

Complexity: Constant. If alloc is not equal to other.get_allocator(), then linear.

Note

No move constructors on contained elements are invoked. other will be empty() after this operation.

Parameters:

other – The other container to move entries from.
alloc – The Allocator to use for all memory allocations of this container.

~RHUnorderedSet() = default#

Destructor.

Destroys all contained elements and frees memory.

inline RHUnorderedSet &operator=(const RHUnorderedSet &other)#

Copy-assign operator.

Destroys all currently stored elements and copies elements from another container.

Parameters:: other – The other container to copy entries from.
Returns:: *this

inline RHUnorderedSet &operator=(RHUnorderedSet &&other)#

Move-assign operator.

Effectively swaps with another container.

Parameters:: other – The other container to copy entries from.
Returns:: *this

inline std::pair<iterator, bool> insert(const value_type &value)#

Inserts an element into the container.

If insertion is successful, all iterators, references and pointers are invalidated.

Parameters:: value – The value to insert by copying.
Returns:: A pair consisting of an iterator to the inserted element (or the existing element that prevented the insertion) and a bool that will be true if insertion took place or false if insertion did not take place.

inline std::pair<iterator, bool> insert(value_type &&value)#

Inserts an element into the container.

If insertion is successful, all iterators, references and pointers are invalidated.

Parameters:: value – The value to insert by moving.
Returns:: A pair consisting of an iterator to the inserted element (or the existing element that prevented the insertion) and a bool that will be true if insertion took place or false if insertion did not take place.

template<typename P> inline std::pair<iterator, bool> insert( std::enable_if_t<std::is_constructible<value_type, P&&>::value, P&&> value, )#

Inserts an element into the container.

Only participates in overload resolution if std::is_constructible_v<value_type, P&&> is true.

If insertion is successful, all iterators, references and pointers are invalidated.

Parameters:: value – The value to insert by constructing via std::forward<P>(value).
Returns:: A pair consisting of an iterator to the inserted element (or the existing element that prevented the insertion) and a bool that will be true if insertion took place or false if insertion did not take place.

template<typename K, typename = std::enable_if_t<IsTransparent_v<K>>> inline std::pair<iterator, bool> insert( K &&value, )#

Inserts an element into the container.

If *this already contains an element which transparent compares equivalent to value, does nothing. Otherwise, constructs an object u of value_type with std::forward<K>(value) and then inserts u into *this.

If equal_range(u) != hash_function()(obj) || contains(u) is true, behavior is undefined. The value_type must be EmplaceConstructible into *this from std::forward<K>(value).

If insertion is successful, all iterators, references and pointers are invalidated.

Complexity: Average case: constant; worst case: linear over capacity()

Note

This overload participates in overload resolution only if Hash and KeyEqual are both transparent. This assumes that such Hash is callable with both K and Key type and that KeyEqual is transparent, which, together, allows calling this function without constructing an instance of Key.

Parameters:: value – A value of any type that can be transparently compared with a key.
Returns:: A pair consisting of an iterator to the inserted element (or the existing element that prevented the insertion) and a bool that will be true if insertion took place or false if insertion did not take place.

template<typename ...Args> inline std::pair<iterator, bool> emplace( Args&&... args, )#

Constructs an element in-place.

If insertion is successful, all iterators, references and pointers are invalidated.

Parameters:: args – The arguments to pass to the value_type constructor.
Returns:: A pair consisting of an iterator to the inserted element (or the existing element that prevented the insertion) and a bool that will be true if insertion took place or false if insertion did not take place.

inline size_type erase(const key_type &key)#

Removes elements with the given key.

References, pointers and iterators to the erased element are invalidated. All other iterators, pointers and references remain valid.

Parameters:: key – the key value of elements to remove
Returns:: the number of elements removed (either 1 or 0).

template<typename K, typename = std::enable_if_t<IsTransparent_v<K> && !std::is_convertible_v<K, const_iterator> && !std::is_convertible_v<K, const_find_iterator>>> inline size_type erase( K &&key, )#

Removes elements that can be transparently compared with the given key.

References, pointers and iterators to the erased element are invalidated. All other iterators, pointers and references remain valid.

Parameters:: key – A value of any type that can be transparently compared with a key denoting the elements to remove.
Returns:: the number of elements removed.

inline size_type count(const key_type &key) const#

Returns the number of elements matching the specified key.

Parameters:: key – The key to check for.
Returns:: The number of elements with the given key (either 1 or 0).

template<typename K, typename = std::enable_if_t<IsTransparent_v<K>>> inline size_type count( const K &key, ) const#

Returns the number of elements matching the specified key.

Returns the number of elements with key that compares equivalent to the specified argument key.

Note

This overload participates in overload resolution only if Hash and KeyEqual are both transparent. This assumes that such Hash is callable with both K and Key type and that KeyEqual is transparent, which, together, allows calling this function without constructing an instance of Key.

Parameters:: key – A value of any type that can be transparently compared with a key.
Returns:: Number of elements with key that compares equivalent to key.

Public Static Attributes

static constexpr size_t LoadFactor = Base::LoadFactor#: The container’s LoadFactor.