Unigine::HashMap Class

// declare an enumeration
enum class MyEnum
{
	One,
	Two,
	Three,
};
// create a hash map using an initializer list
const HashMap<String, MyEnum> hashMap_1
{
	{ "One", MyEnum::One },
	{ "Two", MyEnum::Two },
	{ "Three", MyEnum::Three },
};
// check the result
for (const auto &k : hashMap_1)
	Log::message("%s : %d \n", k.key.get(), k.data);

Create a hash set using a copy constructor:

Source code (C++)

// create a hash map using an initializer list
const HashMap<String, int> initial{ { "a", 1 },{ "b", 2 },{ "c", 3 },{ "d", 4 }, };
// copy constructor
HashMap<String, int> copied(initial);
//check the result
for (const auto &k : copied)
	Log::message("%s : %d \n", k.key.get(), k.data);

You can change the created hash map by using the class member functions described in the article. Check some of the usage examples:

To add items to the current hash map, you can use one of the append() or insert() functions:

Source code (C++)

// create hash maps using initializer lists
HashMap<String, int> initial{ { "a", 1 }, { "b", 2 }, { "c", 3 }, };
const HashMap<String, int> to_append{ { "m", 7 }, { "n", 8 }, { "o", 9 }, };

// append items of one hash map to another
initial.append(to_append);
// insert an item into the "initial" hash map
initial.insert("s", 10);
// check the result
for (const auto &k : initial)
	Log::message("%s : %d \n", k.key.get(), k.data);

Get a value by the key from the hash map and insert an item if there is no such key:

Source code (C++)

// creare an empty hash map
HashMap<int, int> hashMap{ { 1, 10 } };

// try to get values by the specified keys
Log::message("Value %d\n", hashMap[1]);
// if there is no such key, it will be added to the hash map with the default value
Log::message("Value %d\n", hashMap[2]);
// check the result - the new item with the default value is added to the hash map
for (const auto &k: hashMap)
	Log::message("%d : %d \n", k.key, k.data);

Take an item from the hash map:

Source code (C++)

// create a hash map
HashMap<int, int> hashMap { {1, 1}, {2, 2}, {3, 3}, };

// declare a key and a value
const int key = 0;
const int value = 4;

// append a new item to the hash map
hashMap.append(key,value);

// get an item iterator by its key
auto it = hashMap.find(key);
// take the item from the hash map
int c = hashMap.take(it);

// check the result - the taken item is removed from the hash map
for (const auto &k : hashMap)
	Log::message("%d : %d \n", k.key, k.data);

Remove an item from the hash map:

Source code (C++)

// create a hash map
	HashMap<int, int> hashMap{ { 1, 1 },{ 2, 2 },{ 3, 3 }, };

	// get an item iterator by its key
	auto it = hashMap.find(2);
	// remove the item from the hash map
	hashMap.remove(it);

	// check the result
	for (const auto &k: hashMap)
		Log::message("%d : %d \n", k.key, k.data);

Get items by the values from the hash map:

Source code (C++)

// create a hash map
HashMap<String, int> hashMap{ { "a", 1 }, { "b", 2 }, { "c", 3 }, };
// get an item iterator by its value
auto it = hashMap.findData(2);
// check the result
Log::message("%s \n", it->key.get());

Get a value/values from the hash map:

Source code (C++)

// create a hash map
HashMap<String, int> hashMap{ { "a", 1 },{ "b", 2 },{ "c", 3 }, };
// get a key by its value
Log::message("%d \n", hashMap.value("a"));

// get a vector of all values of the hash map
Vector<int> ret = hashMap.values();
for (int i = 0; i < ret.size(); i++) Log::message("%d \n",ret[i]);

Methods:

Name	Description View: Sort by:
HashMap	Constructor.
append	Appends an item with a given key and value to the hash map.
insert	Inserts an item with a given key and value into the hash map.
take	Removes an item from the hash map by its key and returns an item value.
contains	Checks if an item with a specified key and value exists in the hash map.
findData	Searches for an item with a specified value in the hash map.
removeData	Removes the first occurrence of the specified value from the hash map.
get	Returns a value by a specified key.
operator []	Hash map item access.
value	Returns a value with a specified key from the hash map.
valueRef	Returns a reference to the value with a specified key from the hash map.
values	Returns a vector of all values of the hash map.
getValues	Appends hash map values to a given vector.
operator =	Assigns the specified hash map by copying it.
emplaceRange	Inserts the range of values specified by the argument iterators into the hash map.
contains	Checks if the given key is present in the hash map.
find	Returns the iterator of the specified key.
findFast	Finds an element with a specified key.
keys	Returns a vector containing all keys in the hash map.
getKeys	Adds keys of the hash to the specified vector.
getKey	Returns the key by its index.
remove	Removes the specified key from the hash map.
erase	Removes an element currently pointed to by the iterator from the hash map.
subtract	Removes the specified keys from the hash map.
clear	Removes all key-value pairs from the hash map.
destroy	Removes all key-value pairs from the hash map and releases the memory.
reserve	Reserves storage to avoid repeated reallocation.
shrink	Removes unused capacity.
begin	Returns an iterator that points to the first element in the hash map.
end	Returns an iterator that points to the location succeeding the last element in the hash map.
cbegin	Returns a const iterator that points to the first element in the hash map.
cend	Returns a const iterator that points to the location succeeding the last element in the hash map.
size	Returns the number of key-value pairs in the hash map.
space	Returns the current capacity (number of elements the hash can currently contain).
getMemoryUsage	Shows the amount of memory used by the hash map in bytes.
empty	Checks if the hash map is empty.
swap	Swaps this hash map with the hash map specified as the argument.

HashMap Class

Members

HashMap ( ) #

Default constructor that produces an empty hash map.

HashMap ( std::initializer_list<Pair<Key,Value>> list ) #

Constructor. Creates a hash map from given key-value pairs.

Arguments

std::initializer_list<Pair<Key,Value>> list - List of pairs.

HashMap ( const HashMap& o ) #

Constructor. Creates a hash map by copying a source hash map.

Arguments

const HashMap& o - Hash map.

HashMap ( HashMap&& o ) #

Constructor. Creates a hash map by moving a source hash map into it.

Arguments

HashMap&& o - Hash map.

Iterator append ( const Key& key, const Value& value ) #

Appends an item with a given key and value to the hash map.

Arguments

const Key& key - Key.
const Value& value - Value.

Return value

Item iterator.

Iterator append ( const Key& key, Value&& value ) #

Appends an item with a given key and value to the hash map.

Arguments

const Key& key - Key to be copied to the hash map.
Value&& value - Value to be moved to the hash map.

Return value

Item iterator.

Iterator append ( Key&& key, const Value& value ) #

Appends an item with a given key and value to the hash map.

Arguments

Key&& key - Key to be moved to the hash map.
const Value& value - Value to be copied to the hash map.

Return value

Item iterator.

Iterator append ( Key&& key, Value&& value ) #

Appends an item with a given key and value to the hash map.

Arguments

Key&& key - Key to be moved to the hash map.
Value&& value - Value to be moved to the hash map.

Return value

Item iterator.

Value& append ( const Key& key ) #

Appends an item with a given key to the hash map.

Arguments

const Key& key - Key.

Return value

Value.

Value& append ( Key&& key ) #

Appends an item with a given key to the hash map.

Arguments

Key&& key - Key to be moved to the hash map.

Return value

Value.

void append ( const HashMap& o ) #

Appends items with all available keys from the argument hash to the hash map.

Arguments

const HashMap& o - Hash map to be appended.

void append ( HashMap&& o ) #

Appends items with all available keys by moving the argument hash to the hash map.

Arguments

HashMap&& o - Hash map to be appended.

void append ( const Vector& vector ) #

Appends items with all available keys from the argument vector to the hash map.

Arguments

const Vector& vector - Vector containing the key (or keys) to be appended.

void append ( Vector&& vector ) #

Appends items with all available keys by moving the argument vector to the hash map.

Arguments

Vector&& vector - Vector containing the key (or keys) to be appended.

Iterator insert ( const Key& key, const Value& value ) #

Inserts an item with a given key and value into the hash map.

Arguments

const Key& key - Key.
const Value& value - Value.

Return value

Item iterator.

Iterator insert ( const Key& key, Value&& value ) #

Inserts an item with a given key and value into the hash map.

Arguments

const Key& key - Key to be copied to the hash map.
Value&& value - Value to be moved to the hash map.

Return value

Item iterator.

Iterator insert ( Key&& key, const Value& value ) #

Inserts an item with a given key and value into the hash map.

Arguments

Key&& key - Key to be moved to the hash map.
const Value& value - Value to be copied to the hash map.

Return value

Item iterator.

Iterator insert ( Key&& key, Value&& value ) #

Inserts an item with a given key and value into the hash map.

Arguments

Key&& key - Key to be moved to the hash map.
Value&& value - Value to be moved to the hash map.

Return value

Item iterator.

Value& insert ( const Key& key ) #

Inserts an item with a given key into the hash map.

Arguments

const Key& key - Key to be copied to the hash map.

Return value

Value.

Value& insert ( Key&& key ) #

Inserts an item with a given key into the hash map.

Arguments

Key&& key - Key to be moved to the hash map.

Return value

Value.

void insert ( const HashMap& o ) #

Inserts items with all available keys by copying the argument hash to the hash map.

Arguments

const HashMap& o - Hash map containing the key (or keys) to be inserted.

void insert ( HashMap&& o ) #

Inserts items with all available keys by moving the argument hash to the hash map.

Arguments

HashMap&& o - Hash map containing the key (or keys) to be inserted.

void insert ( const Vector& vector ) #

Inserts items with all available keys by copying the argument vector to the hash map.

Arguments

const Vector& vector - Vector containing the key (or keys) to be inserted.

void insert ( Vector&& vector ) #

Inserts items with all available keys by moving the argument vector to the hash map.

Arguments

Vector&& vector - Vector containing the key (or keys) to be inserted.

Value take ( const Key& key, const Value& def ) #

Removes an item from the hash map by its key and returns an item value. If there is no such item, the value set as default is returned.

Arguments

const Key& key - Key.
const Value& def

Return value

Removed item value.

Value take ( const Key& key ) #

Removes an item from the hash map by its key and returns an item value. If there is no such item, a default-constructed value is returned.

Arguments

const Key& key - Key.

Return value

Removed item value.

Value take ( Iterator it ) #

Removes an item from the hash map by its iterator and returns an item value. If there is no such item, a default-constructed value is returned.

Arguments

Iterator it - Item iterator.

Return value

Removed item value.

Value take ( ConstIterator it ) #

Removes an item from the hash map by its iterator and returns an item value. If there is no such item, a default-constructed value is returned.

Arguments

ConstIterator it - Item iterator.

Return value

Removed item value.

bool contains ( const Key& key, const Value& value ) const#

Checks if an item with a specified key and value exists in the hash map.

Arguments

const Key& key - Key.
const Value& value - Value.

Return value

true if an item exists; otherwise, false.

Iterator findData ( const Value& value ) #

Searches for an item with a specified value in the hash map.

Arguments

const Value& value - Value.

Return value

Item iterator.

ConstIterator findData ( const Value& value ) const#

Searches for an item with a specified value in the hash map.

Arguments

const Value& value - Value.

Return value

Item iterator.

void removeData ( const Value& value ) #

Removes the first occurrence of the specified value from the hash map.

Arguments

const Value& value - Value.

Value& get ( Key&& key ) #

Returns a value by a specified key.

Arguments

Key&& key - Key.

Return value

Value.

const Value& get ( const Key& key ) const#

Returns a value by a specified key.

Arguments

const Key& key - Key.

Return value

Value.

const Value& get ( const Key& key, const Value& value ) const#

Returns a value by a specified key. If there is no item with the key, the default value is returned.

Arguments

const Key& key - Key.
const Value& value - Default value.

Return value

Value.

Value& operator[] ( Key&& key ) #

Hash map item access. The value is returned if it is available by the key; if the item is unavailable, a new (Key,Value) pair is added.

Arguments

Key&& key - Key.

Return value

Accessed item value, if available.

Value& operator[] ( const Key& key ) const#

Hash map item access.

Arguments

const Key& key - Key.

Return value

Accessed item value.

Value value ( const Key& key ) const#

Returns a value with a specified key from the hash map. If there is no such key, returns a default-constructed value.

Arguments

const Key& key - Key.

Return value

Accessed item value.

Value value ( const Key& key, const Value& value ) const#

Returns a value with a specified key from the hash map. If there is no such key, returns the specified default value.

Arguments

const Key& key - Key.
const Value& value - Default value.

Return value

Accessed item value.

const Value& valueRef ( const Key& key ) const#

Returns a reference to the value with a specified key from the hash map. If there is no such key, returns a default-constructed valuee.

Arguments

const Key& key - Key.

Return value

Accessed item value.

const Value& valueRef ( const Key& key, const Value& value ) const#

Returns a reference to the value with a specified key from the hash map. If there is no such key, returns a default value.

Arguments

const Key& key
const Value& value - Default value.

Return value

Accessed item value.

Vector<Value> values ( ) const#

Returns a vector of all values of the hash map.

Return value

Vector of hash map values.

void getValues ( Vector<Value>& values ) const#

Appends hash map values to a given vector.

Arguments

Vector<Value>& values - Vector of hash map values.

HashMap & operator= ( const HashMap & o ) #

Assigns the specified hash map by copying it.

Arguments

const HashMap & o - Hash map.

Return value

Hash map.

HashMap & operator= ( HashMap&& o ) #

Assigns the specified hash map by moving it.

Arguments

HashMap&& o - Hash map.

Return value

Hash map.

emplaceRange ( InputIt first, InputIt last ) #

Inserts the range of values specified by the argument iterators into the hash map.

Arguments

InputIt first - Iterator that identifies the beginning of the range.
InputIt last - Iterator that identifies the end of the range.

bool contains ( const Key & k ) const#

Checks if the given key is present in the hash map.

Arguments

const Key & k - Key to be checked.

Return value

true if the hash map contains the specified key; otherwise, false.

Iterator find ( const Key & k ) const#

Returns the iterator of the specified key.

Arguments

const Key & k - Key to be checked.

Return value

Item iterator.

ConstIterator find ( const Key & k ) const#

Returns the iterator of the specified key.

Arguments

const Key & k - Key to be checked.

Return value

Item iterator.

Item * findFast ( const Key & key ) const#

Finds an element with a specified key.

Arguments

const Key & key - Key to look for.

Return value

Pointer to the hash map item.

Vector<Key> keys ( ) const#

Returns a vector containing all keys in the hash map.

Return value

Vector of keys.

void getKeys ( Vector<Key>& keys ) const#

Adds keys of the hash to the specified vector.

Arguments

Vector<Key>& keys - Vector to store the keys.

const Key & getKey ( size_t index ) const#

Returns the key by its index.

Arguments

size_t index - Index number of the key in the hash map.

Return value

Key.

bool remove ( const Key& k ) #

Removes the specified key from the hash map.

Arguments

const Key& k - Key to be removed.

Return value

true if the key is removed successfully; otherwise, false.

void remove ( Iterator it ) #

Removes an element currently pointed to by the iterator from the hash map.

Arguments

Iterator it - Iterator pointing to an element to be removed.

void remove ( ConstIterator it ) #

Removes an element currently pointed to by the iterator from the hash map.

Arguments

ConstIterator it - Iterator pointing to an element to be removed.

void remove ( const HashMap& o ) #

Removes the specified hash map from the current hash map.

Arguments

const HashMap& o - Hash map.

void remove ( const Vector<Key>& v ) #

Removes the specified keys from the hash map.

Arguments

const Vector<Key>& v - Vector storing the keys.

bool erase ( const ConstIterator & it ) #

Removes an element currently pointed to by the iterator from the hash map.

Arguments

const ConstIterator & it - Iterator pointing to the element to be removed.

Return value

true on success, otherwise false.

bool erase ( const Iterator & it ) #

Removes an element currently pointed to by the iterator from the hash map.

Arguments

const Iterator & it - Iterator pointing to the element to be removed.

Return value

true on success, otherwise false.

bool erase ( const Key& k ) #

Removes an element having the specified key from the hash map.

Arguments

const Key& k - Key of the element to be removed.

Return value

true on success, otherwise false.

void erase ( const HashMap& o ) #

Removes the specified hash map from the current hash map.

Arguments

const HashMap& o - Hash map to be removed.

void erase ( const Vector<Key>& v ) #

Removes the specified keys from the hash map.

Arguments

const Vector<Key>& v - Vector storing the keys.

void subtract ( const Vector<Key>& vector ) #

Removes the specified keys from the hash map.

Arguments

const Vector<Key>& vector - Vector storing the keys.

void subtract ( const HashMap & o ) #

Removes the specified hash map from the current hash map.

Arguments

const HashMap & o - Hash map to be removed.

void clear ( ) #

Removes all key-value pairs from the hash map.

void destroy ( ) #

Removes all key-value pairs from the hash map and releases the memory.

void reserve ( size_t size ) #

Reserves storage to avoid repeated reallocation.

Arguments

size_t size - Hash size to be reserved.

void shrink ( ) #

Removes unused capacity.

Iterator begin ( ) const#

Returns an iterator that points to the first element in the hash map.

Return value

Iterator pointing to the first element.

Iterator end ( ) const#

Returns an iterator that points to the location succeeding the last element in the hash map.

Return value

Iterator pointing to the last element.

ConstIterator cbegin ( ) const#

Returns a const iterator that points to the first element in the hash map.

Return value

ConstIterator pointing to the first element.

ConstIterator cend ( ) const#

Returns a const iterator that points to the location succeeding the last element in the hash map.

Return value

ConstIterator pointing to the last element.

Counter size ( ) const#

Returns the number of key-value pairs in the hash map.

Return value

Number of key-value pairs in the hash map.

Counter space ( ) const#

Returns the current capacity (number of elements the hash can currently contain).

Return value

Number of elements the hash can currently contain.

size_t getMemoryUsage ( ) const#

Shows the amount of memory used by the hash map in bytes.

Return value

Used memory in bytes.

bool empty ( ) const#

Checks if the hash map is empty.

Return value

true if the hash map is empty, otherwise false

void swap ( HashMap & o ) #

Swaps this hash map with the hash map specified as the argument.

Arguments

HashMap & o - Hash map.

Last update: 2024-12-24

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Unigine::HashMap Class

In This Article:

Methods:

HashMap Class

Members

HashMap ( ) #

HashMap ( std::initializer_list<Pair<Key,Value>> list ) #

Arguments

HashMap ( const HashMap& o ) #

Arguments

HashMap ( HashMap&& o ) #

Arguments

Iterator append ( const Key& key, const Value& value ) #

Arguments

Return value

Iterator append ( const Key& key, Value&& value ) #

Arguments

Return value

Iterator append ( Key&& key, const Value& value ) #

Arguments

Return value

Iterator append ( Key&& key, Value&& value ) #

Arguments

Return value

Value& append ( const Key& key ) #

Arguments

Return value

Value& append ( Key&& key ) #

Arguments

Return value

void append ( const HashMap& o ) #

Arguments

void append ( HashMap&& o ) #

Arguments

void append ( const Vector& vector ) #

Arguments

void append ( Vector&& vector ) #

Arguments

Iterator insert ( const Key& key, const Value& value ) #

Arguments

Return value

Iterator insert ( const Key& key, Value&& value ) #

Arguments

Return value

Iterator insert ( Key&& key, const Value& value ) #

Arguments

Return value

Iterator insert ( Key&& key, Value&& value ) #

Arguments

Return value

Value& insert ( const Key& key ) #

Arguments

Return value

Value& insert ( Key&& key ) #

Arguments

Return value

void insert ( const HashMap& o ) #

Arguments

void insert ( HashMap&& o ) #

Arguments

void insert ( const Vector& vector ) #

Arguments

void insert ( Vector&& vector ) #

Arguments

Value take ( const Key& key, const Value& def ) #

Arguments

Return value

Value take ( const Key& key ) #

Arguments

Return value

Value take ( Iterator it ) #

Arguments

Return value

Value take ( ConstIterator it ) #

Arguments

Return value

bool contains ( const Key& key, const Value& value ) const#

Arguments

Return value

Iterator findData ( const Value& value ) #