A C++ template library for embedded applications
Designed and maintained by
John Wellbelove
MIT licensed
Join the ETL community

unordered_set / unordered_multiset


A fixed capacity set.
Uses std::less as the default key comparison method.
STL equivalent: std::unordered_set / std::unordered_multiset

This page just describes etl::unordered_set.

template <typename     TKey,
          const size_t MAX_SIZE,
          const size_t MAX_BUCKETS = MAX_SIZE,
          typename     THash = etl::hash<TKey>,
          typename     TKeyEqual = etl::equal_to<TKey>>
class unordered_set

Inherits from iunordered_set<TKey, THash, TKeyEqual>
etl::iunordered_set may be used as a size independent pointer or reference type for any etl::unordered_set
instance.

____________________________________________________________________________________________________

Member types


value_type              pair<const TKey, T>
key_type                The type of the key value
hasher                  The type used to hash the key
key_equal               The functor used to compare keys
reference               A reference to a value_type
const_reference         A reference to a const value_type
pointer                 A pointer to a value_type
const_pointer           A pointer to a const value_type
size_type               The type used for size information
iterator                Random access iterator
const_iterator          Constant random access iterator
local_iterator          Iterator to a bucket
local_const_iterator    A const iterator to a bucket

____________________________________________________________________________________________________

Constructor


unordered_set()

Default constructor
____________________________________________________________________________________________________

unordered_set(const unordered_set& other)

Copy constructor
____________________________________________________________________________________________________

template <typename TIterator>
unordered_set(TIterator begin, TIterator end);

Construct from a range

____________________________________________________________________________________________________

Element access


iterator find(key_parameter_t key);
const_iterator find (key_parameter_t key) const;

Searches the container for an element with a key equivalent to key and returns an iterator to it if found, otherwise it
returns an iterator to etl::map::end()
____________________________________________________________________________________________________

size_type count(key_parameter_t key) const;

Count elements with a specific key.
Searches the container for elements with a key equivalent to key and returns the number of matches
____________________________________________________________________________________________________

iterator lower_bound(key_parameter_t key);
const_iterator lower_bound(key_parameter_t key) const;

Returns the iterator to the lower bound.
Returns an iterator pointing to the first element in the container whose key is not considered to go before key (i.e.,
either it is equivalent or goes after).
____________________________________________________________________________________________________

iterator upper_bound(key_parameter_t key);
const_iterator upper_bound(key_parameter_t key) const;

Return the iterator to the upper bound.
Returns an iterator pointing to the first element in the container whose key is considered to go after key.
____________________________________________________________________________________________________

pair<iterator, iterator> equal_range(key_parameter_t key);
pair<const_iterator, const_iterator> equal_range(key_parameter_t key) const;

Get the range of equal elements.
Returns the bounds of a range that includes all the elements in the container which have a key equivalent to key.

____________________________________________________________________________________________________

Iterators


iterator begin()
const_iterator begin() const
const_iterator cbegin() const

Returns an iterator to the beginning of the map.
____________________________________________________________________________________________________

iterator end()
const_iterator end() const
const_iterator cend() const

Returns an iterator to the end of the map.
____________________________________________________________________________________________________

iterator rbegin()
const_iterator rbegin() const
const_iterator crbegin() const

Returns a reverse iterator to the beginning of the map.
____________________________________________________________________________________________________

iterator rbegin()
const_iterator rbegin() const
const_iterator crbegin() const

Returns a reverse iterator to the beginning of the map.

____________________________________________________________________________________________________

Capacity


bool empty() const

Returns true if the size of the map is zero, otherwise false.
____________________________________________________________________________________________________

bool full() const

Returns true if the size of the map is SIZE, otherwise false.
____________________________________________________________________________________________________

size_t size() const

Returns the size of the map.
____________________________________________________________________________________________________

size_t max_size() const

Returns the maximum possible size of the map.
____________________________________________________________________________________________________

size_t available() const

Returns the remaining available capacity in the map.
____________________________________________________________________________________________________

size_type get_bucket_index(key_parameter_t key) const

Returns the bucket index for the key.
____________________________________________________________________________________________________

size_type bucket_size(key_parameter_t key) const

Returns the size of the bucket key.
____________________________________________________________________________________________________

size_type max_bucket_count() const

Returns the maximum number of the buckets the container can hold.
____________________________________________________________________________________________________

float load_factor() const

Returns the load factor = size / bucket_count
____________________________________________________________________________________________________

hasher hash_function() const

Returns the function that hashes the keys.
____________________________________________________________________________________________________

key_equal key_eq() const

Returns the function that compares the keys.

____________________________________________________________________________________________________

Modifiers


template <typename TIterator>
void assign(TIterator first, TIterator last)

Assigns elements from a range.
Clears the container before assigning.
___________________________________________________________________________________________________

pair<iterator, bool> insert(const value_type& key_value_pair)

iterator insert(const_iterator, const value_type& key_value_pair)

template <template TIterator>
void insert(TIterator first, TIterator last)

Inserts values in to the map.
If the set is full then emits an etl::unordered_set_full error. If asserts or exceptions are not enabled then
undefined behaviour occurs.
____________________________________________________________________________________________________

size_t erase(key_parameter_t key)

iterator erase(const_iterator ielement)

iterator erase(const_iterator first, const_iterator last)

Erases values in the set.
Iterator are not checked for validity.
____________________________________________________________________________________________________


void clear();

Clears the set to a size of zero.

____________________________________________________________________________________________________

Non-member functions


==  true if the contents of the sets are equal, otherwise false.
!=  true if the contents of the sets are not equal, otherwise false.
unordered_set.h / unordered_multset.h