\section{\class{wxHashMap}}\label{wxhashmap}
-This is a simple, type safe, and reasonably efficient hash map class,
-whose interface is a subset of the interface of STL containers.
+This is a simple, type-safe, and reasonably efficient hash map class,
+whose interface is a subset of the interface of STL containers. In
+particular, the interface is modelled after std::map, and the various,
+non standard, std::hash\_map.
\wxheading{Example}
\begin{verbatim}
class MyClass { /* ... */ };
- // declare an hash map with string keys and int values
+ // declare a hash map with string keys and int values
WX_DECLARE_STRING_HASH_MAP( int, MyHash5 );
// same, with int keys and MyClass* values
WX_DECLARE_HASH_MAP( int, MyClass*, wxIntegerHash, wxIntegerEqual, MyHash1 );
h2["Bill"] = "ABC";
wxString tmp = h2["Bill"];
// since element with key "Joe" is not present, this will return
- // the default value, that is an empty string in the case of wxString
+ // the default value, which is an empty string in the case of wxString
MyClass tmp2 = h2["Joe"];
// iterate over all the elements in the class
\end{verbatim}
The HASH\_T and KEY\_EQ\_T are the types
-used for the hashing function and key comparison. wxWindows provides
+used for the hashing function and key comparison. wxWidgets provides
three predefined hashing functions: {\tt wxIntegerHash}
for integer types ( {\tt int}, {\tt long}, {\tt short},
and their unsigned counterparts ), {\tt wxStringHash} for strings
wxIntegerHash,
wxIntegerEqual,
MyHash );
+
+ // 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_MAP( MyKey, // type of the keys
+ SOME_TYPE, // any type you like
+ MyKeyHash, // hasher
+ MyKeyEqual, // key equality predicate
+ CLASSNAME); // name of the class
\end{verbatim}
\latexignore{\rtfignore{\wxheading{Types}}}
\func{iterator}{begin}{}
-Returns an iterator pointing at the first element of the hash map
-( please remember that hash maps do not guarantee ordering ).
+Returns an iterator pointing at the first element of the hash map.
+Please remember that hash maps do not guarantee ordering.
\membersection{wxHashMap::clear}
\constfunc{bool}{empty}{}
-TRUE if the hash map does not contain any element, FALSE otherwise.
+Returns true if the hash map does not contain any element, false otherwise.
\membersection{wxHashMap::end}
\func{iterator}{end}{}
-Returns an iterator pointing at the one-after-the-last element of the hash map
-( please remember that hash maps do not guarantee ordering ).
+Returns an iterator pointing at the one-after-the-last element of the hash map.
+Please remember that hash maps do not guarantee ordering.
\membersection{wxHashMap::erase}
\func{size\_type}{erase}{\param{const key\_type\&}{ key}}
Erases the element with the given key, and returns the number of element
-erased ( either 0 or 1 ).
+erased (either 0 or 1).
\func{void}{erase}{\param{iterator}{ it}}
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. hashmap.find( non\_existent\_key ) == hashmap.end() ).
+is returned (i.e. hashmap.find( non\_existent\_key ) == hashmap.end()).
\membersection{wxHashMap::insert}