#include <rw/tpmmap.h> RWTPtrMultiMap<K,T,C> m;
RWTPtrMultiMap requires the Standard C++ Library.
This class maintains a pointer-based collection of associations of type pair<K*, const T*>. The first part of the association is a key of type K*, the second is its associated item of type T*. Order is determined by the key according to a comparison object of type C. C must induce a total ordering on elements of type K via a public member
bool operator()(const K& x, const K& y)
which returns true if x and its partner should precede y and its partner within the collection. The structure less<T> from the C++-standard header file <functional> is an example. Note that keys will be dereferenced before being compared.
RWTPtrMultiMap<K,T,C> may contain multiple keys that compare equal to each other. (RWTPtrMap<K,T,C> 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. Given a comparison object comp, keys a and b are equal if
!comp(a,b) && !comp(b,a).
The value type must have operator== and operator< defined. This requirement is imposed by the Standard C++ Library.
Isomorphic.
In this example, a multimap of RWCStrings and RWDates is exercised.
//
// tpmmap.cpp
//
#include <rw/tpmmap.h>
#include <rw/cstring.h>
#include <rw/rwdate.h>
#include <iostream.h>
main(){
typedef RWTPtrMultiMap<RWCString, RWDate,
less<RWCString> > RWMMap;
RWMMap birthdays;
birthdays.insert(new RWCString("John"),
new RWDate(12, "April", 1975));
birthdays.insert(new RWCString("Ivan"),
new RWDate(2, "Nov", 1980));
birthdays.insert(new RWCString("Mary"),
new RWDate(22, "Oct", 1987));
birthdays.insert(new RWCString("Ivan"),
new RWDate(19, "June", 1971));
birthdays.insert(new RWCString("Sally"),
new RWDate(15, "March", 1976));
birthdays.insert(new RWCString("Ivan"),
new RWDate(6, "July", 1950));
// How many "Ivan"s?
RWCString ivanstr("Ivan");
RWMMap::size_type n = birthdays.occurrencesOf(&ivanstr);
RWMMap::size_type idx = 0;
cout << "There are " << n << " Ivans:" << endl;
RWMMap::const_iterator iter =
birthdays.std().lower_bound(&ivanstr);
while (++idx <= n)
cout << idx << ". " << *(*iter++).second << endl;
return 0;
}
Program Output:
There are 3 Ivans:
1. 11/02/80
2. 06/19/71
3. 07/06/50
Class RWTPtrMap<K,T,C> offers the same interface to a pointer-based collection that will not accept multiple keys that compare equal to each other. RWTPtrMultiSet<T,C> maintains a pointer-based collection of keys without the associated values.
Class multimap<K*,T*,deref_compare<C,K,allocator>> is the C++-standard collection that serves as the underlying implementation for this collection.
typedef rw_deref_compare<C,K> container_comp;
typedef multimap<K*,T*,container_comp,allocator>
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;
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;
RWTPtrMultiMap<K,T,C> (const container_comp& comp =container_comp());
Constructs an empty map with comparator comp.
RWTPtrMultiMap<K,T,C>(const container_type& m);
Constructs a multimap by copying all element from m.
RWTPtrMultiMap<K,T,C>(const RWTPtrMultiMap<K,T,C>& rwm);
Copy constructor.
RWTPtrMultiMap<K,T,C>(value_type* first,value_type* last, const container_comp& comp = container_comp());
Constructs a multimap by copying elements from the array of pairs pointed to by first, up to, but not including, the pair pointed to by last.
RWTPtrMultiMap<K,T,C>& operator=(const container_type& m); RWTPtrMultiMap<K,T,C>& operator=(const RWTPtrMultiMap<K,T,C>& m);
Destroys all associations in self and replaces them by copying all associations from m.
bool operator<(const RWTPtrMultiMap<K,T,C>& m);
Returns true if self compares lexicographically less than m, otherwise returns false. Keys in each collection are dereferenced before being compared. Assumes that type K has well-defined less-than semantics.
bool operator==(const RWTPtrMultiMap<K,T,C>& 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.
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. This 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.
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 this method if multiple pointers to the same object 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;
Returns the number of associations in self.
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 such that the expression (*j == *key) is true, 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.
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 such that the expression (*j == *key) is true and returns j. Returns rwnil if there is no such association.
K* remove(bool (*fn)(value_type,void*), void* d);
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.
container_type& std(); const container_type& std() const;
Returns a reference to the underlying C++-standard collection that serves as the implementation for self.
RWvostream&
operator<<(RWvostream& strm,
const RWTPtrMultiMap<K,T,C>& coll);
RWFile&
operator<<(RWFile& strm,
const RWTPtrMultiMap<K,T,C>& 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, RWTPtrMultiMap<K,T,C>& coll); RWFile& operator>>(RWFile& strm, RWTPtrMultiMap<K,T,C>& coll);
Restores the contents of the collection coll from the input stream strm.
RWvistream& operator>>(RWvistream& strm, RWTPtrMultiMap<K,T,C>*& p); RWFile& operator>>(RWFile& strm, RWTPtrMultiMap<K,T,C>*& 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.