Overview

template<typename Key, typename Value, typename Hash = pw::Hash, typename Equal = pw::EqualTo, typename SizeType = uint16_t>
class pw::DynamicHashMap< Key, Value, Hash, Equal, SizeType >

Unordered associative container, similar to std::unordered_map, but optimized for embedded environments.

Key features of pw::DynamicHashMap:

Uses a pw::Allocator for all memory operations.
Provides the std::unordered_map API, but adds try_* versions of operations that crash on allocation failure.
- insert() & try_insert()
- emplace() & try_emplace()
- rehash() & try_rehash()
- reserve() & try_reserve()
Hybrid storage model:
- Nodes: Stored in a dense DynamicPtrVector to enable efficient, linear iteration.
- Buckets: Stored in a DynamicDeque for O(1) average lookup.
Unstable Iteration: Uses "swap-and-pop" erasure for efficiency. Erasing an element moves the last element of the map into the erased position, changing the iteration order.
Never allocates in the constructor.

Public Types
using	key_type = Key

using	mapped_type = Value

using	value_type = KeyValueType

using	size_type = SizeType

using	difference_type = std::ptrdiff_t

using	hasher = Hash

using	key_equal = Equal

using	allocator_type = Allocator

using	reference = value_type &

using	const_reference = const value_type &

using	pointer = value_type *

using	const_pointer = const value_type *

using	iterator = Iterator< false >

using	const_iterator = Iterator< true >

using	node_type = NodeType

using	insert_return_type = std::pair< iterator, bool >

Public Member Functions
constexpr	DynamicHashMap (Allocator &allocator, const Hash &hash=Hash(), const Equal &equal=Equal()) noexcept

	DynamicHashMap (const DynamicHashMap &)=delete

DynamicHashMap &	operator= (const DynamicHashMap &)=delete

	DynamicHashMap (DynamicHashMap &&other) noexcept

DynamicHashMap &	operator= (DynamicHashMap &&other) noexcept

allocator_type &	get_allocator () const
	Returns the allocator used by this map.

iterator	begin ()

const_iterator	begin () const

const_iterator	cbegin () const

iterator	end ()

const_iterator	end () const

const_iterator	cend () const

bool	empty () const

size_type	size () const

size_type	max_size () const

void	clear ()

std::optional< insert_return_type >	try_insert (const value_type &value)

std::optional< insert_return_type >	try_insert (value_type &&)=delete

insert_return_type	insert (const value_type &value)
	Inserts a value into the map. Crashes on allocation failure.

insert_return_type	insert (value_type &&value)

template<typename InputIt , typename = containers::internal::EnableIfInputIterator<InputIt>>
void	insert (InputIt first, InputIt last)

void	insert (std::initializer_list< value_type > ilist)

template<typename K , typename... Args>
std::optional< std::pair< iterator, bool > >	try_emplace (K &&key, Args &&... args)

template<typename K , typename... Args>
std::pair< iterator, bool >	emplace (K &&key, Args &&... args)
	Constructs an element in-place. Crashes on allocation failure.

iterator	erase (iterator pos)

iterator	erase (const_iterator pos)

iterator	erase (const_iterator first, const_iterator last)

template<typename K >
size_type	erase (K &&key)

void	swap (DynamicHashMap &other) noexcept
	Swaps the contents of two maps. No allocations occur.

void	merge (DynamicHashMap &other)

void	merge (DynamicHashMap &&other)

mapped_type &	at (const key_type &key)

const mapped_type &	at (const key_type &key) const

template<typename U = mapped_type, typename = std::enable_if_t<std::is_default_constructible_v<U>>>
mapped_type &	operator[] (const key_type &key)

size_type	count (const key_type &key) const
	Returns the number of elements with key `key` (0 or 1).

iterator	find (const key_type &key)

const_iterator	find (const key_type &key) const

bool	contains (const key_type &key) const

std::pair< iterator, iterator >	equal_range (const key_type &key)

std::pair< const_iterator, const_iterator >	equal_range (const key_type &key) const

size_type	load_factor_percent () const

size_type	max_load_factor_percent () const

void	max_load_factor_percent (size_type percent)

bool	try_rehash (size_type count)

void	rehash (size_type count)

bool	try_reserve (size_type count)

void	reserve (size_type count)

The documentation for this class was generated from the following file:

pw_containers/public/pw_containers/dynamic_hash_map.h

Overview

Public Types

Public Member Functions