RWTPtrHashMultiMap(3C++) RWTPtrHashMultiMap(3C++)
Name
RWTPtrHashMultiMap<K,T,H,EQ> - Rogue Wave library class
Synopsis
#include <rw/tphmmap.h>
RWTPtrHashMultiMap<K,T,H,EQ> m;
Standard C++ Library Dependent!RWTPtrHashMultiMap requires the Standard C++ Library.
Description
This class maintains a pointer-based collection of associatoins of type
pair<K* const, T*>. These pairs are stored according to a hash object of
type H. H must provide a hash function on elements of type K via a
public member
unsigned long operator()(const K& x)
Equivalent keys within the collection will be 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)
which should return true if x and y are equivalent.
RWTPtrHashMultiMap<K,T,H,EQ> may contain multiple keys that compare equal
to each other. (RWTPtrHashMap<K,T,H,EQ> will not accept a key that
compares equal to any key already in the collection.) Equality is based
on the comparison object and not on the == operator.
Persistence
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Isomorphic
Examples
//
// tphmap.cpp
//
#include<rw/tphmmap.h>
#include<rw/cstring.h>
#include<iostream.h>
struct silly_hash{
unsigned long operator()(RWCString x) const
{ return x.length() * (long)x[0]; }
};
int main(){
RWCString snd = "Second";
RWTPtrHashMultiMap<RWCString,int,silly_hash,equal_to<RWCString> >
contest;
contest.insert(new RWCString("First"), new int(7));
contest.insert(&snd, new int(3));
contest.insert(&snd, new int(6)); // duplicate key OK
contest.insert(new RWCString("Third"), new int(2));
cout << "There were " << contest.occurrencesOf(&snd)
<< " second place winners." << endl;
return 0;
}
Program Output:
There were 2 second place winners.
Related Classes
Class RWTPtrHashMap<K,T,H,EQ> offers the same interface to a pointer-
based collection that will not accept multiple keys that compare equal to
each other.
rw_hashmultimap<<K*,T*>,rw_deref_hash<H,K>,rw_deref_compare<EQ,K> > is
the C++-standard style collection that serves as the underlying
implementation for this collection.
Public Typedefs
typedef rw_deref_hash<H,K> container_hash;
typedef rw_deref_compare<EQ,K> container_eq;
typedef rw_hashmultimap<K*,T*,container_hash,container_eq>
container_type;
typedef container_type::size_type size_type;
typedef container_type::difference_type difference_type;
typedef container_type::iterator iterator;
typedef container_type::const_iterator const_iterator;
typedef pair <K* const, T*> value_type;
typedef pair <K* const, T*>& reference;
typedef const pair <K* const, T*>& const_reference;
typedef K* value_type_key;
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typedef T* value_type_data;
typedef K*& reference_key;
typedef T*& reference_data;
typedef const K*const& const_reference_key;
typedef const T*const& const_reference_data;
Public Constructors
RWTPtrHashMultiMap<K,T,H,EQ>();
Constructs an empty map.
RWTPtrHashMultiMap<K,T,H,EQ>(const container_type& m);
Constructs a multi-map by doing an element by element copy from the C++
Standard Library style hashed multi-map, m.
RWTPtrHashMultiMap<K,T,H,EQ>
(const RWTPtrHashMultiMap<K,T,H,EQ>& rwm);
Copy constructor.
RWTPtrHashMultiMap<K,T,H,EQ>
(value_type* first, value_type* last);
Constructs a map by copying elements from the array of pairs pointed to
by first, up to, but not including, the pair pointed to by last.
RWTPtrHashMultiMap<K,T,H,EQ>
(const H& h, size_type sz = RWDEFAULT_CAPACITY);
This Tools.h++ 6.x style constructor creates an empty hashed multi-map
which uses the hash object h and has an initial capacity of sz.
Public Member Operators
RWTPtrHashMultiMap<K,T,H,EQ>&
operator=(const container_type&jjj m);
RWTPtrHashMultiMap<K,T,H,EQ>&
operator=(const RWTPtrHashMultiMap<K,T,H,EQ>& m);
Destroys all associations in self and replaces them by copying all
associations from m.
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bool
operator==(const RWTPtrHashMultiMap<K,T,H,EQ>& m);
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 keys
that compare equal to each other. Keys are dereferenced before being
compared.
Public Member Functions
void
apply(void (*fn)(const K*, T*&,void*),void* d);
void
apply(void (*fn)(const K*, const T*, void*), void* d) const;
Applies the user-defined function pointed to by fn to every association
in the collection. self function must have one of the prototypes:
void yourfun(const K* key, T*& a, void* d);
void yourfun(const K* key, const T* a, void* d);
Client data may be passed through parameter d.
void
applyToKeyAndValue(void (*fn)(const K*, T*&,void*),void* d);
void
applyToKeyAndValue
(void (*fn)(const K*, const T*, void*), void* d) const;
This is a deprecated version of the apply member above. It behaves
exactly the same as apply.
iterator
begin();
const_iterator
begin() const;
Returns an iterator positioned at the first pair in self.
size_type
capacity() const;
Returns the number of buckets (slots) available in the underlying hash
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representation. See resize below.
void
clear();
Clears the collection by removing all items from self.
void
clearAndDestroy();
Removes all associations from the collection and uses operator delete to
destroy the objects pointed to by the keys and their associated items.
Do not use self method if multiple pointers to the same keys or items are
stored.
bool
contains(const K* key) const;
Returns true if there exists a key j in self that compares equal to *key,
otherwise returns false.
bool
contains(bool (*fn)(value_type,void*),void* d) const;
Returns true if there exists an association a in self such that the
expression ((*fn)(a,d)) is true, otherwise returns false. fn points to a
user-defined tester function which must have prototype:
bool yourTester(value_type* a, void* d);
Client data may be passed through parameter d.
iterator
end();
const_iterator
end() const;
Returns an iterator positioned "just past" the last association in self.
size_type
entries() const;
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Returns the number of associations in self.
float
fillRatio() const;
Returns the ratio entries()/capacity().
const K*
find(const K* key) const;
If there exists a key j in self that compares equal to *key, then j is
returned. Otherwise, returns rwnil.
value_type
find(bool (*fn)(value_type,void*), void* d) const;
If there exists an association a in self such that the expression
((*fn)(a,d)) is true, then returns a. Otherwise, returns
pair<rwnil,rwnil>. fn points to a user-defined tester function which must
have prototype:
bool yourTester(value_type a, void* d);
Client data may be passed through parameter d.
T*
findValue(const K* key);
const T*
findValue(const K* key) const;
If there exists a key j in self that compares equal to *key, returns the
item associated with j. Otherwise, returns rwnil.
const K*
findKeyAndValue(const K* key, T*& tr);
const K*
findKeyAndValue(const K* key, const T*& tr) const;
If there exists a key j in self that compares equal to *key, assigns the
item associated with j to tr, and returns j. Otherwise, returns rwnil
and leaves the value of tr unchanged.
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bool
insert(K* key,T* a);
Adds key with associated item a to the collection. Returns true.
bool
insertKeyAndValue(K* key,T* a);
This is a deprecated version of the insert member above. It behaves
exactly the same as insert.
bool
isEmpty() const;
Returns true if there are no items in the collection, false otherwise.
size_type
occurrencesOf(const K* key) const;
Returns the number of keys j in self that compare equal to *key.
size_type
occurrencesOf
(bool(*fn)(value_type,void*),void* d)const;
Returns the number of associations a in self such that the
expression((*fn)(a,d)) is true. fn points to a user-defined tester
function which must have prototype:
bool yourTester(value_type a, void* d);
Client data may be passed through parameter d.
K*
remove(const K* key);
Removes the first association with key j in self that compares equal to
*key. Returns rwnil if there is no such association.
K*
remove(bool (*fn)(value_type,void*), void* d);
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Removes the first association a in self such that the expression
((*fn)(a,d)) is true and returns its key. Returns rwnil if there is no
such association. fn points to a user-defined tester function which must
have prototype:
bool yourTester(value_type a, void* d);
Client data may be passed through parameter d.
size_type
removeAll(const K* key);
Removes all associations with key j in self that compare equal to *key.
Returns the number of associations removed.
size_type
removeAll(bool (*fn)(value_type,void*), void* d);
Removes all associations a in self such that the expression
((*fn)(a,d))is true. Returns the number removed. fn points to a user-
defined tester function which must have prototype:
bool yourTester(value_type a, void* d);
Client data may be passed through parameter d.
void
resize(size_type sz);
Changes the capacity of self by creating a new hashed multi-map with a
capacity of sz . resize then copies every element of self into the new
container and finally swaps the internal representation of the new
container with self.
container_type&
std();
const container_type&
std() const;
Returns a reference to the underlying C++-standard collection that serves
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as the implementation for self.
Related Global Operators
RWvostream&
operator<<(RWvostream& strm,
const RWTPtrHashMultiMap<K,T,H,EQ>& coll);
RWFile&
operator<<(RWFile& strm,
const RWTPtrHashMultiMap<K,T,H,EQ>& coll);
Saves the collection coll onto the output stream strm, or a reference to
it if it has already been saved.
RWvistream&
operator>>(RWvistream& strm,
RWTPtrHashMultiMap<K,T,H,EQ>& coll);
RWFile&
operator>>(RWFile& strm,
RWTPtrHashMultiMap<K,T,H,EQ>& coll);
Restores the contents of the collection coll from the input stream strm.
RWvistream&
operator>>(RWvistream& strm,
RWTPtrHashMultiMap<K,T,H,EQ>*& p);
RWFile&
operator>>(RWFile& strm,
RWTPtrHashMultiMap<K,T,H,EQ>*& p);
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 you are responsible for deleting it.
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