water::HashMap< KeyType, ValueType, HashFunctionType > Class Template Reference

#include <HashMap.h>

Classes
class	HashEntry
struct	Iterator

Public Member Functions
	HashMap (int numberOfSlots=defaultHashTableSize, HashFunctionType hashFunction=HashFunctionType())
	~HashMap ()
void	clear ()
int	size () const noexcept
ValueType	operator[] (KeyTypeParameter keyToLookFor) const
bool	contains (KeyTypeParameter keyToLookFor) const
bool	containsValue (ValueTypeParameter valueToLookFor) const
void	set (KeyTypeParameter newKey, ValueTypeParameter newValue)
void	remove (KeyTypeParameter keyToRemove)
void	removeValue (ValueTypeParameter valueToRemove)
void	remapTable (int newNumberOfSlots)
int	getNumSlots () const noexcept
template<class OtherHashMapType>
void	swapWith (OtherHashMapType &otherHashMap) noexcept
Iterator	begin () const noexcept
Iterator	end () const noexcept

Private Types
enum	{ defaultHashTableSize = 101 }

Private Member Functions
typedef	PARAMETER_TYPE (KeyType) KeyTypeParameter
typedef	PARAMETER_TYPE (ValueType) ValueTypeParameter
int	generateHashFor (KeyTypeParameter key) const

Private Attributes
HashFunctionType	hashFunctionToUse
Array< HashEntry * >	hashSlots
int	totalNumItems

Friends
struct	Iterator

Detailed Description

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>
class water::HashMap< KeyType, ValueType, HashFunctionType >

Holds a set of mappings between some key/value pairs.

The types of the key and value objects are set as template parameters. You can also specify a class to supply a hash function that converts a key value into an hashed integer. This class must have the form:

struct MyHashGenerator
{
    int generateHash (MyKeyType key, int upperLimit) const
    {
        // The function must return a value 0 <= x < upperLimit
        return someFunctionOfMyKeyType (key) % upperLimit;
    }
};

Like the Array class, the key and value types are expected to be copy-by-value types, so if you define them to be pointer types, this class won't delete the objects that they point to.

If you don't supply a class for the HashFunctionType template parameter, the default one provides some simple mappings for strings and ints.

HashMap<int, String> hash;
hash.set (1, "item1");
hash.set (2, "item2");
 
DBG (hash [1]); // prints "item1"
DBG (hash [2]); // prints "item2"
 
// This iterates the map, printing all of its key -> value pairs..
for (HashMap<int, String>::Iterator i (hash); i.next();)
    DBG (i.getKey() << " -> " << i.getValue());

Template Parameters

HashFunctionType

The class of hash function, which must be copy-constructible.

See also

CriticalSection, DefaultHashFunctions, NamedValueSet, SortedSet

Member Enumeration Documentation

anonymous enum

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

anonymous enum

private

Enumerator
defaultHashTableSize

Constructor & Destructor Documentation

HashMap()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

water::HashMap< KeyType, ValueType, HashFunctionType >::HashMap ( int numberOfSlots = defaultHashTableSize, HashFunctionType hashFunction = HashFunctionType() )

inlineexplicit

Creates an empty hash-map.

Parameters

numberOfSlots	Specifies the number of hash entries the map will use. This will be the "upperLimit" parameter that is passed to your generateHash() function. The number of hash slots will grow automatically if necessary, or it can be remapped manually using remapTable().
hashFunction	An instance of HashFunctionType, which will be copied and stored to use with the HashMap. This parameter can be omitted if HashFunctionType has a default constructor.

~HashMap()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

water::HashMap< KeyType, ValueType, HashFunctionType >::~HashMap ( )

inline

Destructor.

Member Function Documentation

begin()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

Iterator water::HashMap< KeyType, ValueType, HashFunctionType >::begin ( ) const

inlinenoexcept

Returns a start iterator for the values in this tree.

clear()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

void water::HashMap< KeyType, ValueType, HashFunctionType >::clear ( )

inline

Removes all values from the map. Note that this will clear the content, but won't affect the number of slots (see remapTable and getNumSlots).

contains()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

bool water::HashMap< KeyType, ValueType, HashFunctionType >::contains ( KeyTypeParameter keyToLookFor ) const

inline

Returns true if the map contains an item with the specied key.

containsValue()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

bool water::HashMap< KeyType, ValueType, HashFunctionType >::containsValue ( ValueTypeParameter valueToLookFor ) const

inline

Returns true if the hash contains at least one occurrence of a given value.

end()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

Iterator water::HashMap< KeyType, ValueType, HashFunctionType >::end ( ) const

inlinenoexcept

Returns an end iterator for the values in this tree.

generateHashFor()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

int water::HashMap< KeyType, ValueType, HashFunctionType >::generateHashFor ( KeyTypeParameter key ) const

inlineprivate

getNumSlots()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

int water::HashMap< KeyType, ValueType, HashFunctionType >::getNumSlots ( ) const

inlinenoexcept

Returns the number of slots which are available for hashing. Each slot corresponds to a single hash-code, and each one can contain multiple items.

See also

getNumSlots()

operator[]()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

ValueType water::HashMap< KeyType, ValueType, HashFunctionType >::operator[] ( KeyTypeParameter keyToLookFor ) const

inline

Returns the value corresponding to a given key. If the map doesn't contain the key, a default instance of the value type is returned.

Parameters

keyToLookFor

the key of the item being requested

PARAMETER_TYPE() [1/2]

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

typedef water::HashMap< KeyType, ValueType, HashFunctionType >::PARAMETER_TYPE ( KeyType )

private

PARAMETER_TYPE() [2/2]

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

typedef water::HashMap< KeyType, ValueType, HashFunctionType >::PARAMETER_TYPE ( ValueType )

private

remapTable()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

void water::HashMap< KeyType, ValueType, HashFunctionType >::remapTable ( int newNumberOfSlots )

inline

Remaps the hash-map to use a different number of slots for its hash function. Each slot corresponds to a single hash-code, and each one can contain multiple items.

See also

getNumSlots()

remove()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

void water::HashMap< KeyType, ValueType, HashFunctionType >::remove ( KeyTypeParameter keyToRemove )

inline

Removes an item with the given key.

removeValue()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

void water::HashMap< KeyType, ValueType, HashFunctionType >::removeValue ( ValueTypeParameter valueToRemove )

inline

Removes all items with the given value.

set()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

void water::HashMap< KeyType, ValueType, HashFunctionType >::set ( KeyTypeParameter newKey, ValueTypeParameter newValue )

inline

Adds or replaces an element in the hash-map. If there's already an item with the given key, this will replace its value. Otherwise, a new item will be added to the map.

size()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

int water::HashMap< KeyType, ValueType, HashFunctionType >::size ( ) const

inlinenoexcept

Returns the current number of items in the map.

swapWith()

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

template<class OtherHashMapType>

void water::HashMap< KeyType, ValueType, HashFunctionType >::swapWith ( OtherHashMapType & otherHashMap )

inlinenoexcept

Efficiently swaps the contents of two hash-maps.

Friends And Related Symbol Documentation

Iterator

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

friend struct Iterator

friend

Member Data Documentation

hashFunctionToUse

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

HashFunctionType water::HashMap< KeyType, ValueType, HashFunctionType >::hashFunctionToUse

private

hashSlots

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

Array<HashEntry*> water::HashMap< KeyType, ValueType, HashFunctionType >::hashSlots

private

totalNumItems

template<typename KeyType, typename ValueType, class HashFunctionType = DefaultHashFunctions>

int water::HashMap< KeyType, ValueType, HashFunctionType >::totalNumItems

private

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

• /home/runner/work/lmms-fork/lmms-fork/plugins/CarlaBase/carla/source/modules/water/containers/HashMap.h