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Version: 2.9.4 |
#include </home/zeitlin/src/wx/github/interface/wx/hashset.h>
This is a simple, type-safe, and reasonably efficient hash set class, whose interface is a subset of the interface of STL containers.
The interface is similar to std::tr1::hash_set or std::set classes but notice that, unlike std::set, the contents of a hash set is not sorted.
例:
class MyClass { ... }; // same, with MyClass* keys (only uses pointer equality!) WX_DECLARE_HASH_SET( MyClass*, ::wxPointerHash, ::wxPointerEqual, MySet1 ); // same, with int keys WX_DECLARE_HASH_SET( int, ::wxIntegerHash, ::wxIntegerEqual, MySet2 ); // declare a hash set with string keys WX_DECLARE_HASH_SET( wxString, ::wxStringHash, ::wxStringEqual, MySet3 ); MySet1 h1; MySet2 h1; MySet3 h3; // store and retrieve values h1.insert( new MyClass( 1 ) ); h3.insert( "foo" ); h3.insert( "bar" ); h3.insert( "baz" ); int size = h3.size(); // now is three bool has_foo = h3.find( "foo" ) != h3.end(); h3.insert( "bar" ); // still has size three // iterate over all the elements in the class MySet3::iterator it; for( it = h3.begin(); it != h3.end(); ++it ) { wxString key = *it; // do something useful with key }
WX_DECLARE_HASH_SET( KEY_T, // type of the keys HASH_T, // hasher KEY_EQ_T, // key equality predicate CLASSNAME); // name of the class
The HASH_T and KEY_EQ_T are the types used for the hashing function and key comparison. wxWidgets provides three predefined hashing functions: wxIntegerHash for integer types ( int, long, short, and their unsigned counterparts ), wxStringHash for strings ( wxString, wxChar*, char* ), and wxPointerHash for any kind of pointer. Similarly three equality predicates: wxIntegerEqual, wxStringEqual, wxPointerEqual are provided. Using this you could declare a hash set using int values like this:
WX_DECLARE_HASH_SET( int, ::wxIntegerHash, ::wxIntegerEqual, MySet ); // using an user-defined class for keys class MyKey { ... }; // hashing function class MyKeyHash { public: MyKeyHash() { } unsigned long operator()( const MyKey& k ) const { // compute the hash } MyKeyHash& operator=(const MyKeyHash&) { return *this; } }; // comparison operator class MyKeyEqual { public: MyKeyEqual() { } bool operator()( const MyKey& a, const MyKey& b ) const { // compare for equality } MyKeyEqual& operator=(const MyKeyEqual&) { return *this; } }; WX_DECLARE_HASH_SET( MyKey, // type of the keys ::MyKeyHash, // hasher ::MyKeyEqual, // key equality predicate CLASSNAME); // name of the class
In the documentation below you should replace wxHashSet with the name you used in the class declaration.
An iterator is similar to a pointer, and so you can use the usual pointer operations: ++it ( and it++ ) to move to the next element, *it to access the element pointed to, *it to access the value of the element pointed to. Hash sets provide forward only iterators, this means that you can't use --it, it + 3, it1 - it2.
Public Member Functions | |
| wxHashSet (size_type size=10) | |
| The size parameter is just a hint, the table will resize automatically to preserve performance. | |
| wxHashSet (const wxHashSet &set) | |
| Copy constructor. | |
| void | clear () |
| Removes all elements from the hash set. | |
| size_type | count (const key_type &key) const |
| Counts the number of elements with the given key present in the set. | |
| bool | empty () const |
| Returns true if the hash set does not contain any elements, false otherwise. | |
| size_type | erase (const key_type &key) |
| Erases the element with the given key, and returns the number of elements erased (either 0 or 1). | |
| Insert_Result | insert (const value_type &v) |
| Inserts the given value in the hash set. | |
| size_type | size () const |
| Returns the number of elements in the set. | |
| const_iterator | begin () const |
| Returns an iterator pointing at the first element of the hash set. | |
| iterator | begin () |
| Returns an iterator pointing at the first element of the hash set. | |
| const_iterator | end () const |
| Returns an iterator pointing at the one-after-the-last element of the hash set. | |
| iterator | end () |
| Returns an iterator pointing at the one-after-the-last element of the hash set. | |
| void | erase (iterator it) |
| Erases the element pointed to by the iterator. | |
| void | erase (const_iterator it) |
| Erases the element pointed to by the iterator. | |
| iterator | find (const key_type &key) const |
| If an element with the given key is present, the functions returns an iterator pointing at that element, otherwise an invalid iterator is returned; i.e. | |
| const_iterator | find (const key_type &key) const |
| If an element with the given key is present, the functions returns an iterator pointing at that element, otherwise an invalid iterator is returned; i.e. | |
| wxHashSet::wxHashSet | ( | size_type | size = 10 | ) |
The size parameter is just a hint, the table will resize automatically to preserve performance.
| wxHashSet::wxHashSet | ( | const wxHashSet & | set | ) |
Copy constructor.
| const_iterator wxHashSet::begin | ( | ) | const |
Returns an iterator pointing at the first element of the hash set.
Please remember that hash sets do not guarantee ordering.
| iterator wxHashSet::begin | ( | ) |
Returns an iterator pointing at the first element of the hash set.
Please remember that hash sets do not guarantee ordering.
| void wxHashSet::clear | ( | ) |
Removes all elements from the hash set.
| size_type wxHashSet::count | ( | const key_type & | key | ) | const |
Counts the number of elements with the given key present in the set.
This function returns only 0 or 1.
| bool wxHashSet::empty | ( | ) | const |
Returns true if the hash set does not contain any elements, false otherwise.
| const_iterator wxHashSet::end | ( | ) | const |
Returns an iterator pointing at the one-after-the-last element of the hash set.
Please remember that hash sets do not guarantee ordering.
| iterator wxHashSet::end | ( | ) |
Returns an iterator pointing at the one-after-the-last element of the hash set.
Please remember that hash sets do not guarantee ordering.
| size_type wxHashSet::erase | ( | const key_type & | key | ) |
Erases the element with the given key, and returns the number of elements erased (either 0 or 1).
| void wxHashSet::erase | ( | iterator | it | ) |
Erases the element pointed to by the iterator.
After the deletion the iterator is no longer valid and must not be used.
| void wxHashSet::erase | ( | const_iterator | it | ) |
Erases the element pointed to by the iterator.
After the deletion the iterator is no longer valid and must not be used.
| const_iterator wxHashSet::find | ( | const key_type & | key | ) | const |
If an element with the given key is present, the functions returns an iterator pointing at that element, otherwise an invalid iterator is returned; i.e.
hashset.find( non_existent_key ) == hashset.end()
| iterator wxHashSet::find | ( | const key_type & | key | ) | const |
If an element with the given key is present, the functions returns an iterator pointing at that element, otherwise an invalid iterator is returned; i.e.
hashset.find( non_existent_key ) == hashset.end()
| Insert_Result wxHashSet::insert | ( | const value_type & | v | ) |
Inserts the given value in the hash set.
The return value is equivalent to a
std::pair<wxHashMap::iterator, bool>
The iterator points to the inserted element, the boolean value is true if v was actually inserted.
| size_type wxHashSet::size | ( | ) | const |
Returns the number of elements in the set.
