A C++ template library for embedded applications
MIT licensed
Designed and
maintained by
John Wellbelove
Support the development
of the ETL
map / multimap

A fixed capacity map.
Uses std::less as the default key comparison method.
STL equivalent: std::map / std::multimap

This page just describes etl::map.

etl::map<typename TKey, typename TMapped, const size_t SIZE, TKeyCompare = etl::less>

Inherits from etl::imap<TKey, TMapped, TKeyCompare>
etl::imap may be used as a size independent pointer or reference type for any etl::map instance.
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Template deduction guides
C++17 and above

template <typename... TPairs>
etl::map(TPairs...)

Example
etl::map data{ etl::pair{0, 1}, etl::pair{2, 3}, etl::pair{4, 5}, etl::pair{6, 7} };
Defines data as an map of int/int pairs, of length 4, containing the supplied data.
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Make template
C++11 and above
template <typename TKey,
          typename TMapped,
          typename TKeyCompare = etl::less<TKey>,
          typename... TPairs>
constexpr auto make_flat_map(TValues&&... values)

Example
auto data = etl::make_map<int. int>(etl::pair{0, 1}, etl::pair{2, 3},
                                    etl::pair{4, 5}, etl::pair{6, 7});
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Member types

key_type                TKey
mapped_type             TMapped
value_type              etl or std::pair<key_type, mapped_type>
size_type               size_t
difference_type         ptrdiff_t
reference               value_type&
const_reference         const value_type&
pointer                 value_type*
const_pointer           const value_type*
iterator                Random access iterator
const_iterator          Constant random access iterator
reverse_iterator        etl or std::reverse_iterator<iterator>
const_reverse_iterator  etl or std::reverse_iterator<const_iterator>
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Constructor

etl::map<Tkey, TMapped, SIZE, TKeyCompare>();

template <typename TIterator>
etl::map<Tkey, TMapped, SIZE, TKeyCompare>(TIterator begin, TIterator end);

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Element access

TMapped& at(key_parameter_t key)
const TMapped& at(key_parameter_t key) const
Returns a reference or const reference to the indexed element.
Emits an etl::map_out_of_range if the key is not in the table. If assert or exceptions are not enabled then undefined
behaviour occurs.
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TMapped& operator[](key_parameter_t key)
const TMapped& operator[](key_parameter_t key) const
Returns a reference or const reference to the indexed element.
If the key does not exist then one is created using the default constructor. If the map is full then emits an
etl::map_full. If asserts or exceptions are not enabled then undefined behaviour occurs.
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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()
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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
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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).
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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.
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pair<const_iterator, const_iterator> equal_range(key_parameter_t key) const;
pair<iterator, iterator> equal_range(key_parameter_t key);
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.
The return type is either std::pair (default) or etl::pair (ETL_NO_STL)
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20.21.0
C++11 or above
For comparators that define is_transparent.

template <typename K>
iterator find(const K& key)

template <typename K>
const_iterator find(const K& key) const
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20.21.0
C++11 or above
template <typename K>
iterator lower_bound(const K& key)

template <typename K>
const_iterator lower_bound(const K& key) const
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20.21.0
C++11 or above
template <typename K>
iterator upper_bound(const K& key)

template <typename K>
const_iterator upper_bound(const K& key) const
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20.21.0
C++11 or above
template <typename K>
pair<iterator, iterator> equal_range(const K& key)

template <typename K>
pair<const_iterator, const_iterator> equal_range(const K& key) const
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20.21.0
bool contains(key_value_parameter_t key) const
Check if the container contains the key.

20.21.0
C++11 or above
For comparators that define is_transparent.
template <typename K>
bool contains(const K& k) const
Check if the container contains the key.
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Iterators

iterator begin()
const_iterator begin() const
const_iterator cbegin() const
Returns an iterator to the beginning of the map.
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iterator end()
const_iterator end() const
const_iterator cend() const
Returns an iterator to the end of the map.
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iterator rbegin()
const_iterator rbegin() const
const_iterator crbegin() const
Returns a reverse iterator to the beginning of the map.
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iterator rbegin()
const_iterator rbegin() const
const_iterator crbegin() const
Returns a reverse iterator to the beginning of the map.
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Capacity

bool empty() const
Returns true if the size of the map is zero, otherwise false.
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bool full() const
Returns true if the size of the map is SIZE, otherwise false.
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size_t size() const
Returns the size of the map.
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size_t max_size() const
Returns the maximum possible size of the map.
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size_t available() const
Returns the remaining available capacity in the map.
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Modifiers
<=20.19.0
template <typename TIterator>
void insert(TIterator begin, TIterator end);

>=20.20.0
template <typename TIterator>
iterator insert(TIterator begin, TIterator end);
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iterator insert(mapped_parameter_t value);
Inserts values in to the map.
If the map is full then emits an etl::map_full error. If asserts or exceptions are not enabled then undefined
behaviour occurs.
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template <typename TIterator>
iterator erase(TIterator begin, TIterator end);
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iterator erase(TIterator element);
Erases values in the map.
Iterator are not checked for validity.
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size_t erase(const key_type& key)

20.21.0
template <typename K>
size_t erase(K&& key)
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void clear();
Clears the map to a size of zero.
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Non-member functions

==  true if the contents of the maps are equal, otherwise false.
!=  true if the contents of the maps are not equal, otherwise false.
map.h / multimap.h