RWTValHashMap< K, T, H, EQ, A > Class Template Reference
[STL Extension-based Collections]

Maintains a collection of keys, each with an associated item stored according to a hash object. More...

#include <rw/tvhdict.h>

Inherits RW_VMapAssoc< rw_hashmap< K, T, H, EQ,A >, RWTValHashMap< K, T, H, EQ,A >, K, T, std::less< K > >.

Inherited by RWStringToStreamType, and RWXmlStringToStreamType.

List of all members.

Public Types
typedef rw_hashmap< K, T, H, EQ,A >	container_type
typedef container_type::iterator	iterator
typedef container_type::const_iterator	const_iterator
typedef container_type::size_type	size_type
typedef container_type::value_type	value_type
typedef container_type::key_type	key_type
typedef T	data_type
typedef container_type::reference	reference
typedef container_type::const_reference	const_reference
Public Member Functions
container_type &	std ()
const container_type &	std () const
void	apply (void(*fn)(const K &, const T &, void *), void *d) const
void	apply (void(*fn)(const K &, T &, void *), void *d)
iterator	begin ()
const_iterator	begin () const
iterator	end ()
const_iterator	end () const
bool	isEmpty () const
size_type	entries () const
bool	operator== (const container_type &m) const
bool	operator== (const RWTValHashMap< K, T, H, EQ, A > &m) const
bool	operator!= (const container_type &stdc) const
bool	operator!= (const RWTValHashMap< K, T, H, EQ, A > &rwc) const
void	clear ()
bool	contains (bool(*fn)(const_reference, void *), void *d) const
bool	contains (const K &key) const
bool	find (bool(*fn)(const_reference, void *), void *d, std::pair< K, T > &r) const
bool	find (const K &key, K &r) const
bool	findValue (const K &key, T &r) const
bool	findKeyAndValue (const K &key, K &kr, T &tr) const
const K &	minElement () const
const K &	maxElement () const
size_type	occurrencesOf (bool(*fn)(const_reference, void *), void *d) const
size_type	occurrencesOf (const K &key) const
bool	remove (bool(*fn)(const_reference, void *), void *d)
bool	remove (const K &key)
size_type	removeAll (bool(*fn)(const_reference, void *), void *d)
size_type	removeAll (const K &key)
bool	insert (const K &key, const T &a)
bool	insert (K &&key, T &&a)
T &	operator[] (const K &key)
size_type	capacity () const
float	fillRatio () const
void	resize (size_type sz)
void	swap (RWTValHashMap< K, T, H, EQ, A > &other)
RWTValHashMap< K, T, H, EQ,A > &	operator= (const RWTValHashMap< K, T, H, EQ, A > &m)
RWTValHashMap< K, T, H, EQ,A > &	operator= (const rw_hashmap< K, T, H, EQ, A > &m)
RWTValHashMap< K, T, H, EQ,A > &	operator= (RWTValHashMap< K, T, H, EQ, A > &&rhs)
	RWTValHashMap ()
	RWTValHashMap (const rw_hashmap< K, T, H, EQ, A > &m)
	RWTValHashMap (const RWTValHashMap< K, T, H, EQ, A > &rws)
	RWTValHashMap (RWTValHashMap< K, T, H, EQ, A > &&rws)
	RWTValHashMap (const value_type *first, const value_type *last)
	RWTValHashMap (const H &h, size_type sz=64)
Related Functions
(Note that these are not member functions.)
template<class K , class T , class H , class EQ , class A >
RWvostream &	operator<< (RWvostream &strm, const RWTValHashMap< K, T, H, EQ, A > &coll)
template<class K , class T , class H , class EQ , class A >
RWFile &	operator<< (RWFile &strm, const RWTValHashMap< K, T, H, EQ, A > &coll)
template<class K , class T , class H , class EQ , class A >
RWvistream &	operator>> (RWvistream &strm, RWTValHashMap< K, T, H, EQ, A > &coll)
template<class K , class T , class H , class EQ , class A >
RWFile &	operator>> (RWFile &strm, RWTValHashMap< K, T, H, EQ, A > &coll)
template<class K , class T , class H , class EQ , class A >
RWvistream &	operator>> (RWvistream &strm, RWTValHashMap< K, T, H, EQ, A > *&p)
template<class K , class T , class H , class EQ , class A >
RWFile &	operator>> (RWFile &strm, RWTValHashMap< K, T, H, EQ, A > *&p)

---

Detailed Description

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>
class RWTValHashMap< K, T, H, EQ, A >

This class maintains a collection of keys, each with an associated item of type T. These pairs are stored according to a hash object of type H. Class A is an allocator of objects of class T. For more information about using custom allocators, please see the Essential Tools Module User's Guide.

H must provide a const hash function on elements of type K via public member

 unsigned long operator()(const K& x) const;

Equivalent keys within the collection are grouped together based on an equality object of type EQ. EQ must ensure this grouping via public member

 bool operator()(const K& x, const K& y) const;

which should return true if x and y are equivalent.

Note:

Any two keys that are equivalent must hash to the same value.

RWTValHashMap<K,T,H,EQ,A> will not accept a key that is equivalent to any key already in the collection. (RWTValHashMultiMap<K,T,H,EQ,A> may contain multiple keys that are equivalent to each other.) Equality is based on an equality object and not on the == operator. If your type has an == operator, then you may want to use the templatized std::equal_to function object provided by the C++ Standard Library; otherwise, you must define your own equality object.

The value type must have operator== defined. This requirement is imposed by the C++ Standard Library.

Synopsis

 #include <rw/tvhdict.h>
 RWTValHashMap<K,T,H,EQ,A> m;

Related Classes

Class RWTValHashMultiMap<K,T,H,EQ,A> offers the same interface to a collection that accepts multiple keys that compare equal to each other.

Class rw_hashmap<K,T,H,EQ,A> is the C++ Standard compliant collection that serves as the underlying implementation for this collection.

Persistence

Isomorphic

Examples

 #include <iostream>
 #include <functional>
 
 #include <rw/tvhdict.h>
 #include <rw/cstring.h>
 #include <rw/tools/datetime.h>
 
 struct simple_hash
 {
      unsigned long
      operator()(const RWCString& ref) const {
         size_t n = ref.length ();
         return (unsigned long)(n ? n * size_t (ref [0]) : 0);
      }
 };
 
 typedef RWTValHashMap<RWCString, RWDateTime, simple_hash,
                      std::equal_to<RWCString> > RW;
 
 int main()
 {
     RW birthdays;
   
     birthdays.insertKeyAndValue(
       "John",
       RWDateTime("April 12, 1975", RWDateTime::setDate)
     );
     birthdays.insertKeyAndValue("Ivan", RWDateTime("Nov 2, 1980", RWDateTime::setDate));
   
     // Alternative syntax:
     birthdays["Susan"] = RWDateTime("June 30, 1955", RWDateTime::setDate);
     birthdays["Gene"] = RWDateTime("Jan 5, 1981", RWDateTime::setDate);
   
     // Print a birthday:
     std::cout << birthdays["John"].asString('x') << std::endl;
     return 0;
 }

Program Output:

 04/12/75

---

Member Typedef Documentation

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef container_type::const_iterator RWTValHashMap< K, T, H, EQ, A >::const_iterator

Typedef for the const iterator.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef container_type::const_reference RWTValHashMap< K, T, H, EQ, A >::const_reference

Typedef for a const reference to a value in this container.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef rw_hashmap<K,T,H,EQ ,A > RWTValHashMap< K, T, H, EQ, A >::container_type

Typedef for the C++ Standard collection that serves as the underlying implementation for this class.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef T RWTValHashMap< K, T, H, EQ, A >::data_type

Typedef for the type of value.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef container_type::iterator RWTValHashMap< K, T, H, EQ, A >::iterator

Typedef for the non-const iterator.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef container_type::key_type RWTValHashMap< K, T, H, EQ, A >::key_type

Typedef for the type of key.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef container_type::reference RWTValHashMap< K, T, H, EQ, A >::reference

Typedef for a non-const reference to a value in this container.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef container_type::size_type RWTValHashMap< K, T, H, EQ, A >::size_type

Typedef for the type used to index into this container.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

typedef container_type::value_type RWTValHashMap< K, T, H, EQ, A >::value_type

Typedef for the type of elements in this container.

---

Constructor & Destructor Documentation

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap< K, T, H, EQ, A >::RWTValHashMap

(

)

[inline]

Constructs an empty map.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap< K, T, H, EQ, A >::RWTValHashMap

(

const rw_hashmap< K, T, H, EQ, A > &

m

)

[inline]

Constructs a map by copying all elements of m.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap< K, T, H, EQ, A >::RWTValHashMap

(

const RWTValHashMap< K, T, H, EQ, A > &

rws

)

[inline]

Copy constructor.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap< K, T, H, EQ, A >::RWTValHashMap

(

RWTValHashMap< K, T, H, EQ, A > &&

rws

)

[inline]

Move constructor. The constructed hash map takes ownership of the data owned by rws.

Condition:

This method is only available on platforms with rvalue reference support.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap< K, T, H, EQ, A >::RWTValHashMap	(	const value_type *	first,
		const value_type *	last
	)			[inline]

Constructs a map by copying elements from the array of value_type pairs pointed to by first, up to, but not including, the pair pointed to by last.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap< K, T, H, EQ, A >::RWTValHashMap	(	const H &	h,
		size_type	sz = 64
	)			[inline]

Creates an empty hashed map which uses the hash object h and has an initial capacity of sz.

---

Member Function Documentation

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

void RWTValHashMap< K, T, H, EQ, A >::apply	(	void(*)(const K &, T &, void *)	fn,
		void *	d
	)			[inline]

Applies the user-defined function pointed to by fn to every association in the collection. Client data may be passed through parameter d.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

void RWTValHashMap< K, T, H, EQ, A >::apply	(	void(*)(const K &, const T &, void *)	fn,
		void *	d
	)			const [inline]

Applies the user-defined function pointed to by fn to every association in the collection. Client data may be passed through parameter d.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

const_iterator RWTValHashMap< K, T, H, EQ, A >::begin

(

)

const [inline]

Returns an iterator positioned at the first pair in self.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

iterator RWTValHashMap< K, T, H, EQ, A >::begin

(

)

[inline]

Returns an iterator positioned at the first pair in self.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

size_type RWTValHashMap< K, T, H, EQ, A >::capacity

(

)

const [inline]

Returns the number of buckets (slots) available in the underlying hash representation. See resize().

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

void RWTValHashMap< K, T, H, EQ, A >::clear

(

void

)

[inline]

Clears the collection by removing all items from self. Each key and its associated item will have its destructor called.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::contains

(

const K &

key

)

const [inline]

Returns true if there exists a key j in self that compares equal to key, otherwise returns false.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::contains	(	bool(*)(const_reference, void *)	fn,
		void *	d
	)			const [inline]

Returns true if there exists an association a in self such that the expression ((*fn)(a,d)) is true, otherwise returns false. Client data may be passed through parameter d.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

const_iterator RWTValHashMap< K, T, H, EQ, A >::end

(

)

const [inline]

Returns an iterator positioned "just past" the last association in self.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

iterator RWTValHashMap< K, T, H, EQ, A >::end

(

)

[inline]

Returns an iterator positioned "just past" the last association in self.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

size_type RWTValHashMap< K, T, H, EQ, A >::entries

(

void

)

const [inline]

Returns the number of associations in self.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

float RWTValHashMap< K, T, H, EQ, A >::fillRatio

(

)

const [inline]

Returns the ratio entries() / capacity().

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::find	(	const K &	key,
		K &	r
	)			const [inline]

If there exists a key j in self that compares equal to key, assigns j to r and returns true. Otherwise, returns false and leaves the value of r unchanged.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::find	(	bool(*)(const_reference, void *)	fn,
		void *	d,
		std::pair< K, T > &	r
	)			const [inline]

If there exists an association a in self such that the expression ((*fn)(a,d)) is true, assigns a to r and returns true. Otherwise, returns false and leaves the value of r unchanged. Client data may be passed through parameter d.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::findKeyAndValue	(	const K &	key,
		K &	kr,
		T &	tr
	)			const [inline]

If there exists a key j in self that compares equal to key, assigns j to kr, assigns the item associated with j to tr, and returns true. Otherwise, returns false and leaves the values of kr and tr unchanged.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::findValue	(	const K &	key,
		T &	r
	)			const [inline]

If there exists a key j in self that compares equal to key, assigns the item associated with j to r and returns true. Otherwise, returns false and leaves the value of r unchanged.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::insert	(	K &&	key,
		T &&	a
	)			[inline]

Adds key with associated item a to the collection. Returns true if the insertion is successful, otherwise returns false. Insertion will fail if the collection already holds an association with the equivalent key.

Condition:

This method is only available on platforms with rvalue reference support.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::insert	(	const K &	key,
		const T &	a
	)			[inline]

Adds key with associated item a to the collection. Returns true if the insertion is successful, otherwise returns false. Insertion will fail if the collection already holds an association with the equivalent key.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::isEmpty

(

)

const [inline]

Returns true if there are no items in the collection, otherwise false.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

const K& RWTValHashMap< K, T, H, EQ, A >::maxElement

(

)

const [inline]

Returns a reference to the maximum key in the collection. Type K must have well-defined less-than semantics (K::operator<(const K&) or equivalent).

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

const K& RWTValHashMap< K, T, H, EQ, A >::minElement

(

)

const [inline]

Returns a reference to the minimum key in the collection. Type K must have well-defined less-than semantics (K::operator<(const K&) or equivalent).

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

size_type RWTValHashMap< K, T, H, EQ, A >::occurrencesOf

(

const K &

key

)

const [inline]

Returns the number of keys j in self that compare equal to key.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

size_type RWTValHashMap< K, T, H, EQ, A >::occurrencesOf	(	bool(*)(const_reference, void *)	fn,
		void *	d
	)			const [inline]

Returns the number of associations a in self such that the expression ((*fn)(a,d)) is true. Client data may be passed through parameter d.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::operator!=

(

const RWTValHashMap< K, T, H, EQ, A > &

rwc

)

const [inline]

Returns the negation of operator==().

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::operator!=

(

const container_type &

stdc

)

const [inline]

Returns the negation of operator==().

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap<K,T,H,EQ ,A >& RWTValHashMap< K, T, H, EQ, A >::operator=

(

RWTValHashMap< K, T, H, EQ, A > &&

rhs

)

[inline]

Move assignment. Self takes ownership of the data owned by rhs.

Condition:

This method is only available on platforms with rvalue reference support.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap<K,T,H,EQ ,A >& RWTValHashMap< K, T, H, EQ, A >::operator=

(

const rw_hashmap< K, T, H, EQ, A > &

m

)

[inline]

Destroys all elements of self and replaces them by copying all associations from m.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

RWTValHashMap<K,T,H,EQ ,A >& RWTValHashMap< K, T, H, EQ, A >::operator=

(

const RWTValHashMap< K, T, H, EQ, A > &

m

)

[inline]

Destroys all elements of self and replaces them by copying all associations from m.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::operator==

(

const RWTValHashMap< K, T, H, EQ, A > &

m

)

const [inline]

Returns true if self compares equal to m, otherwise returns false. Two collections are equal if both have the same number of entries, and iterating through both collections produces, in turn, individual pairs that compare equal to each other.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::operator==

(

const container_type &

m

)

const [inline]

Returns true if self compares equal to m, otherwise returns false. Two collections are equal if both have the same number of entries, and iterating through both collections produces, in turn, individual pairs that compare equal to each other.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

T& RWTValHashMap< K, T, H, EQ, A >::operator[]

(

const K &

key

)

[inline]

Looks up key and returns a reference to its associated item. If the key is not in the dictionary, then it is added with an associated item provided by the default constructor for type T.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::remove

(

const K &

key

)

[inline]

Removes the first association with key j in self such that the expression (j == key) is true, and returns true. Returns false if there is no such association.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

bool RWTValHashMap< K, T, H, EQ, A >::remove	(	bool(*)(const_reference, void *)	fn,
		void *	d
	)			[inline]

Removes the first association a in self such that the expression ((*fn)(a,d)) is true, and returns true. Returns false if there is no such element. Client data may be passed through parameter d.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

size_type RWTValHashMap< K, T, H, EQ, A >::removeAll

(

const K &

key

)

[inline]

Removes all elements j in self that compare equal to key. Returns the number of items removed.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

size_type RWTValHashMap< K, T, H, EQ, A >::removeAll	(	bool(*)(const_reference, void *)	fn,
		void *	d
	)			[inline]

Removes all associations a in self such that the expression ((*fn)(a,d)) is true. Returns the number of items removed. Client data may be passed through parameter d.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

void RWTValHashMap< K, T, H, EQ, A >::resize

(

size_type

sz

)

[inline]

Changes the capacity of self by creating a new hashed map with a capacity of sz. This method copies every element of self into the new container and finally swaps the internal representation of the new container with the internal representation of self.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

const container_type& RWTValHashMap< K, T, H, EQ, A >::std

(

)

const [inline]

Returns a reference to the underlying collection that serves as the implementation for self. This reference may be used freely, providing access to the C++ Standard interface as well as interoperability with other software components that make use of the C++ Standard compliant collections.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

container_type& RWTValHashMap< K, T, H, EQ, A >::std

(

)

[inline]

Returns a reference to the underlying collection that serves as the implementation for self. This reference may be used freely, providing access to the C++ Standard interface as well as interoperability with other software components that make use of the C++ Standard compliant collections.

template<class K, class T, class H, class EQ, class A = std:: allocator < K >>

void RWTValHashMap< K, T, H, EQ, A >::swap

(

RWTValHashMap< K, T, H, EQ, A > &

other

)

[inline]

Swaps the data held by self with the data held by other, including the H and EQ objects. This method does not copy or destroy any of the items swapped; rather, it swaps the underlying hash tables.

---

Friends And Related Function Documentation

template<class K , class T , class H , class EQ , class A >

RWFile & operator<<	(	RWFile &	strm,
		const RWTValHashMap< K, T, H, EQ, A > &	coll
	)			[related]

Saves the collection coll onto the RWFile strm, or a reference to it if it has already been saved.

template<class K , class T , class H , class EQ , class A >

RWvostream & operator<<	(	RWvostream &	strm,
		const RWTValHashMap< K, T, H, EQ, A > &	coll
	)			[related]

Saves the collection coll onto the output stream strm, or a reference to it if it has already been saved.

template<class K , class T , class H , class EQ , class A >

RWFile & operator>>	(	RWFile &	strm,
		RWTValHashMap< K, T, H, EQ, A > *&	p
	)			[related]

Looks at the next object on the RWFile strm and either creates a new collection off the heap and sets p to point to it, or sets p to point to a previously read instance. If a collection is created off the heap, then the application is responsible for deleting it.

template<class K , class T , class H , class EQ , class A >

RWvistream & operator>>	(	RWvistream &	strm,
		RWTValHashMap< K, T, H, EQ, A > *&	p
	)			[related]

Looks at the next object on the input stream strm and either creates a new collection off the heap and sets p to point to it, or sets p to point to a previously read instance. If a collection is created off the heap, then the application is responsible for deleting it.

template<class K , class T , class H , class EQ , class A >

RWFile & operator>>	(	RWFile &	strm,
		RWTValHashMap< K, T, H, EQ, A > &	coll
	)			[related]

Restores the contents of the collection coll from the RWFile strm.

template<class K , class T , class H , class EQ , class A >

RWvistream & operator>>	(	RWvistream &	strm,
		RWTValHashMap< K, T, H, EQ, A > &	coll
	)			[related]

Restores the contents of the collection coll from the input stream strm.