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Class template unordered_multiset

boost::intrusive::unordered_multiset

Synopsis

// In header: <boost/intrusive/unordered_set.hpp>

template<typename T,  Options> 
class unordered_multiset {
public:
  // types
  typedef            ;          
  typedef              ;            
  typedef          ;        
  typedef         ;       
  typedef               ;             
  typedef         ;       
  typedef             ;           
  typedef       ;     
  typedef       ;     
  typedef             ;           
  typedef             ;           
  typedef                ;              
  typedef           ;         
  typedef            ;          
  typedef              ;            
  typedef        ;      
  typedef    ;  
  typedef        ;      
  typedef  ;
  typedef           ;         
  typedef                  ;                
  typedef              ;            
  typedef        ;      

  // construct/copy/destruct
  (,  = , 
                               = ,  = );
  template<typename Iterator> 
    (, , , 
                        = ,  = , 
                        = );
  (unordered_multiset &&);
  unordered_multiset & (unordered_multiset &&);
  ~();

  // public member functions
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
   (unordered_multiset &);
  template<typename Cloner, typename Disposer> 
     (unordered_multiset &, , );
  template<typename Cloner, typename Disposer> 
     (unordered_multiset &&, , );
   ();
  template<typename Iterator>  (, );
   ();
   (, ) ;
   ();
  template<typename KeyType, typename KeyHasher, typename KeyEqual> 
     (, , );
  template<typename Disposer> 
     (, ) ;
  template<typename Disposer> 
     (, , ) ;
  template<typename Disposer> 
     (, );
  template<typename KeyType, typename KeyHasher, typename KeyEqual, 
           typename Disposer> 
     (, , , 
                                );
   () ;
  template<typename Disposer>  () ;
   () ;
  template<typename KeyType, typename KeyHasher, typename KeyEqual> 
     (, , ) ;
   ();
  template<typename KeyType, typename KeyHasher, typename KeyEqual> 
     (, , );
   () ;
  template<typename KeyType, typename KeyHasher, typename KeyEqual> 
     (, , ) ;
   ();
  template<typename KeyType, typename KeyHasher, typename KeyEqual> 
     
    (, , );
   
  () ;
  template<typename KeyType, typename KeyHasher, typename KeyEqual> 
     
    (, , ) ;
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
  template<typename KeyType, typename KeyHasher> 
     (, ) ;
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
   () ;
   ();
   ();
   ( = );
   ();
   () ;

  // public static functions
   () ;
   () ;
   () ;
   () ;
};

Description

The class template unordered_multiset is an intrusive container, that mimics most of the interface of std::tr1::unordered_multiset as described in the C++ TR1.

unordered_multiset is a semi-intrusive container: each object to be stored in the container must contain a proper hook, but the container also needs additional auxiliary memory to work: unordered_multiset needs a pointer to an array of type bucket_type to be passed in the constructor. This bucket array must have at least the same lifetime as the container. This makes the use of unordered_multiset more complicated than purely intrusive containers. bucket_type is default-constructible, copyable and assignable

The template parameter T is the type to be managed by the container. The user can specify additional options and if no options are provided default options are used.

The container supports the following options: base_hook<>/member_hook<>/value_traits<>, constant_time_size<>, size_type<>, hash<> and equal<> bucket_traits<>, power_2_buckets<> and cache_begin<>.

unordered_multiset only provides forward iterators but it provides 4 iterator types: iterator and const_iterator to navigate through the whole container and local_iterator and const_local_iterator to navigate through the values stored in a single bucket. Local iterators are faster and smaller.

It's not recommended to use non constant-time size unordered_multisets because several key functions, like "empty()", become non-constant time functions. Non constant-time size unordered_multisets are mainly provided to support auto-unlink hooks.

unordered_multiset, unlike std::unordered_set, does not make automatic rehashings nor offers functions related to a load factor. Rehashing can be explicitly requested and the user must provide a new bucket array that will be used from that moment.

Since no automatic rehashing is done, iterators are never invalidated when inserting or erasing elements. Iterators are only invalidated when rehasing.

unordered_multiset public construct/copy/destruct

  1. ( b_traits, 
                                 hash_func = , 
                                 equal_func = , 
                                 v_traits = );
  2. template<typename Iterator> 
      ( b,  e,  b_traits, 
                          hash_func = , 
                          equal_func = , 
                          v_traits = );
  3. (unordered_multiset && x);

    Effects: to-do

  4. unordered_multiset & (unordered_multiset && x);

    Effects: to-do

  5. ~();

    Effects: Detaches all elements from this. The objects in the unordered_set are not deleted (i.e. no destructors are called).

    Complexity: Linear to the number of elements in the unordered_set, if it's a safe-mode or auto-unlink value. Otherwise constant.

    Throws: Nothing.

unordered_multiset public member functions

  1.  () ;

    Effects: Returns an iterator pointing to the beginning of the unordered_set.

    Complexity: Amortized constant time. Worst case (empty unordered_set): O(this->bucket_count())

    Throws: Nothing.

  2.  () ;

    Effects: Returns a const_iterator pointing to the beginning of the unordered_set.

    Complexity: Amortized constant time. Worst case (empty unordered_set): O(this->bucket_count())

    Throws: Nothing.

  3.  () ;

    Effects: Returns a const_iterator pointing to the beginning of the unordered_set.

    Complexity: Amortized constant time. Worst case (empty unordered_set): O(this->bucket_count())

    Throws: Nothing.

  4.  () ;

    Effects: Returns an iterator pointing to the end of the unordered_set.

    Complexity: Constant.

    Throws: Nothing.

  5.  () ;

    Effects: Returns a const_iterator pointing to the end of the unordered_set.

    Complexity: Constant.

    Throws: Nothing.

  6.  () ;

    Effects: Returns a const_iterator pointing to the end of the unordered_set.

    Complexity: Constant.

    Throws: Nothing.

  7.  () ;

    Effects: Returns the hasher object used by the unordered_set.

    Complexity: Constant.

    Throws: If hasher copy-constructor throws.

  8.  () ;

    Effects: Returns the key_equal object used by the unordered_set.

    Complexity: Constant.

    Throws: If key_equal copy-constructor throws.

  9.  () ;

    Effects: Returns true if the container is empty.

    Complexity: if constant-time size and cache_begin options are disabled, average constant time (worst case, with empty() == true: O(this->bucket_count()). Otherwise constant.

    Throws: Nothing.

  10.  () ;

    Effects: Returns the number of elements stored in the unordered_set.

    Complexity: Linear to elements contained in *this if constant_time_size is false. Constant-time otherwise.

    Throws: Nothing.

  11.  (unordered_multiset & other);

    Requires: buckets must not be being used by any other resource.

    Effects: Constructs an empty unordered_set, storing a reference to the bucket array and copies of the key_hasher and equal_func functors.

    Complexity: Constant.

    Throws: If value_traits::node_traits::node constructor throws (this does not happen with predefined Boost.Intrusive hooks) or the copy constructor or invocation of hash_func or equal_func throws.

    Notes: buckets array must be disposed only after *this is disposed.

  12. template<typename Cloner, typename Disposer> 
       (unordered_multiset & src,  cloner, 
                       disposer);

    Requires: Disposer::operator()(pointer) shouldn't throw Cloner should yield to nodes that compare equal and produce the same hash than the original node.

    Effects: Erases all the elements from *this calling Disposer::operator()(pointer), clones all the elements from src calling Cloner::operator()(const_reference ) and inserts them on *this. The hash function and the equality predicate are copied from the source.

    If store_hash option is true, this method does not use the hash function.

    If any operation throws, all cloned elements are unlinked and disposed calling Disposer::operator()(pointer).

    Complexity: Linear to erased plus inserted elements.

    Throws: If cloner or hasher throw or hash or equality predicate copying throws. Basic guarantee.

  13. template<typename Cloner, typename Disposer> 
       (unordered_multiset && src,  cloner,  disposer);

    Requires: Disposer::operator()(pointer) shouldn't throw Cloner should yield to nodes that compare equal and produce the same hash than the original node.

    Effects: Erases all the elements from *this calling Disposer::operator()(pointer), clones all the elements from src calling Cloner::operator()(reference) and inserts them on *this. The hash function and the equality predicate are copied from the source.

    If store_hash option is true, this method does not use the hash function.

    If any operation throws, all cloned elements are unlinked and disposed calling Disposer::operator()(pointer).

    Complexity: Linear to erased plus inserted elements.

    Throws: If cloner or hasher throw or hash or equality predicate copying throws. Basic guarantee.

  14.  ( value);
  15. template<typename Iterator>  ( b,  e);

    Requires: Dereferencing iterator must yield an lvalue of type value_type.

    Effects: Equivalent to this->insert_equal(t) for each element in [b, e).

    Complexity: Average case O(N), where N is distance(b, e). Worst case O(N*this->size()).

    Throws: If the internal hasher or the equality functor throws. Basic guarantee.

    Note: Does not affect the validity of iterators and references. No copy-constructors are called.

  16.  ( i);
  17.  ( b,  e) ;
  18.  ( key);
  19. template<typename KeyType, typename KeyHasher, typename KeyEqual> 
       ( key,  hash_func, 
                       equal_func);

    Requires: "hash_func" must be a hash function that induces the same hash values as the stored hasher. The difference is that "hash_func" hashes the given key instead of the value_type.

    "equal_func" must be a equality function that induces the same equality as key_equal. The difference is that "equal_func" compares an arbitrary key with the contained values.

    Effects: Erases all the elements that have the same hash and compare equal with the given key.

    Returns: The number of erased elements.

    Complexity: Average case O(this->count(value)). Worst case O(this->size()).

    Throws: If hash_func or equal_func throw. Basic guarantee.

    Note: Invalidates the iterators (but not the references) to the erased elements. No destructors are called.

  20. template<typename Disposer> 
       ( i,  disposer) ;
  21. template<typename Disposer> 
       ( b,  e, 
                              disposer) ;
  22. template<typename Disposer> 
       ( key,  disposer);
  23. template<typename KeyType, typename KeyHasher, typename KeyEqual, 
             typename Disposer> 
       ( key,  hash_func, 
                                   equal_func,  disposer);

    Requires: Disposer::operator()(pointer) shouldn't throw.

    Effects: Erases all the elements with the given key. according to the comparison functor "equal_func". Disposer::operator()(pointer) is called for the removed elements.

    Returns: The number of erased elements.

    Complexity: Average case O(this->count(value)). Worst case O(this->size()).

    Throws: If hash_func or equal_func throw. Basic guarantee.

    Note: Invalidates the iterators to the erased elements.

  24.  () ;

    Effects: Erases all of the elements.

    Complexity: Linear to the number of elements on the container. if it's a safe-mode or auto-unlink value_type. Constant time otherwise.

    Throws: Nothing.

    Note: Invalidates the iterators (but not the references) to the erased elements. No destructors are called.

  25. template<typename Disposer>  ( disposer) ;

    Requires: Disposer::operator()(pointer) shouldn't throw.

    Effects: Erases all of the elements.

    Complexity: Linear to the number of elements on the container. Disposer::operator()(pointer) is called for the removed elements.

    Throws: Nothing.

    Note: Invalidates the iterators (but not the references) to the erased elements. No destructors are called.

  26.  ( key) ;
  27. template<typename KeyType, typename KeyHasher, typename KeyEqual> 
       ( key,  hash_func, 
                       equal_func) ;

    Requires: "hash_func" must be a hash function that induces the same hash values as the stored hasher. The difference is that "hash_func" hashes the given key instead of the value_type.

    "equal_func" must be a equality function that induces the same equality as key_equal. The difference is that "equal_func" compares an arbitrary key with the contained values.

    Effects: Returns the number of contained elements with the given key

    Complexity: Average case O(1), worst case O(this->size()).

    Throws: If hash_func or equal throw.

  28.  ( key);
  29. template<typename KeyType, typename KeyHasher, typename KeyEqual> 
       ( key,  hash_func,  equal_func);

    Requires: "hash_func" must be a hash function that induces the same hash values as the stored hasher. The difference is that "hash_func" hashes the given key instead of the value_type.

    "equal_func" must be a equality function that induces the same equality as key_equal. The difference is that "equal_func" compares an arbitrary key with the contained values.

    Effects: Finds an iterator to the first element whose key is "key" according to the given hash and equality functor or end() if that element does not exist.

    Complexity: Average case O(1), worst case O(this->size()).

    Throws: If hash_func or equal_func throw.

    Note: This function is used when constructing a value_type is expensive and the value_type can be compared with a cheaper key type. Usually this key is part of the value_type.

  30.  ( key) ;
  31. template<typename KeyType, typename KeyHasher, typename KeyEqual> 
       
      ( key,  hash_func,  equal_func) ;

    Requires: "hash_func" must be a hash function that induces the same hash values as the stored hasher. The difference is that "hash_func" hashes the given key instead of the value_type.

    "equal_func" must be a equality function that induces the same equality as key_equal. The difference is that "equal_func" compares an arbitrary key with the contained values.

    Effects: Finds an iterator to the first element whose key is "key" according to the given hasher and equality functor or end() if that element does not exist.

    Complexity: Average case O(1), worst case O(this->size()).

    Throws: If hash_func or equal_func throw.

    Note: This function is used when constructing a value_type is expensive and the value_type can be compared with a cheaper key type. Usually this key is part of the value_type.

  32.  ( key);
  33. template<typename KeyType, typename KeyHasher, typename KeyEqual> 
       
      ( key,  hash_func,  equal_func);

    Requires: "hash_func" must be a hash function that induces the same hash values as the stored hasher. The difference is that "hash_func" hashes the given key instead of the value_type.

    "equal_func" must be a equality function that induces the same equality as key_equal. The difference is that "equal_func" compares an arbitrary key with the contained values.

    Effects: Returns a range containing all elements with equivalent keys. Returns std::make_pair(this->end(), this->end()) if no such elements exist.

    Complexity: Average case O(this->count(key, hash_func, equal_func)). Worst case O(this->size()).

    Throws: If hash_func or the equal_func throw.

    Note: This function is used when constructing a value_type is expensive and the value_type can be compared with a cheaper key type. Usually this key is part of the value_type.

  34.  
    ( key) ;
  35. template<typename KeyType, typename KeyHasher, typename KeyEqual> 
       
      ( key,  hash_func,  equal_func) ;

    Requires: "hash_func" must be a hash function that induces the same hash values as the stored hasher. The difference is that "hash_func" hashes the given key instead of the value_type.

    "equal_func" must be a equality function that induces the same equality as key_equal. The difference is that "equal_func" compares an arbitrary key with the contained values.

    Effects: Returns a range containing all elements with equivalent keys. Returns std::make_pair(this->end(), this->end()) if no such elements exist.

    Complexity: Average case O(this->count(key, hash_func, equal_func)). Worst case O(this->size()).

    Throws: If the hasher or equal_func throw.

    Note: This function is used when constructing a value_type is expensive and the value_type can be compared with a cheaper key type. Usually this key is part of the value_type.

  36.  ( value) ;
  37.  ( value) ;
  38.  ( value) ;
  39.  ( value) ;
  40.  () ;

    Effects: Returns the number of buckets passed in the constructor or the last rehash function.

    Complexity: Constant.

    Throws: Nothing.

  41.  ( n) ;

    Requires: n is in the range [0, this->bucket_count()).

    Effects: Returns the number of elements in the nth bucket.

    Complexity: Constant.

    Throws: Nothing.

  42.  ( k) ;
  43. template<typename KeyType, typename KeyHasher> 
       ( k,  hash_func) ;

    Requires: "hash_func" must be a hash function that induces the same hash values as the stored hasher. The difference is that "hash_func" hashes the given key instead of the value_type.

    Effects: Returns the index of the bucket in which elements with keys equivalent to k would be found, if any such element existed.

    Complexity: Constant.

    Throws: If hash_func throws.

    Note: the return value is in the range [0, this->bucket_count()).

  44.  () ;

    Effects: Returns the bucket array pointer passed in the constructor or the last rehash function.

    Complexity: Constant.

    Throws: Nothing.

  45.  ( n) ;
  46.  ( n) ;
  47.  ( n) ;
  48.  ( n) ;
  49.  ( n) ;
  50.  ( n) ;
  51.  ( new_bucket_traits);
  52.  ();

    Note: This function is used when keys from inserted elements are changed (e.g. a language change when key is a string) but uniqueness and hash properties are preserved so a fast full rehash recovers invariants for *this without extracting and reinserting all elements again.

    Requires: Calls produced to the hash function should not alter the value uniqueness properties of already inserted elements. If hasher(key1) == hasher(key2) was true when elements were inserted, it shall be true during calls produced in the execution of this function.

    key_equal is not called inside this function so it is assumed that key_equal(value1, value2) should produce the same results as before for inserted elements.

    Effects: Reprocesses all values hold by *this, recalculating their hash values and redistributing them though the buckets.

    If store_hash option is true, this method uses the hash function and updates the stored hash value.

    Complexity: Average case linear in this->size(), worst case quadratic.

    Throws: If the hasher functor throws. Basic guarantee.

  53.  ( grow = );

    Requires:

    Effects:

    Complexity:

    Throws:

    Note: this method is only available if incremental<true> option is activated.

  54.  ( new_bucket_traits);
  55.  () ;

    Requires: incremental<> option must be set

    Effects: returns the current split count

    Complexity: Constant

    Throws: Nothing

unordered_multiset public static functions

  1.  ( value) ;
  2.  
    ( value) ;
  3.  ( n) ;

    Effects: Returns the nearest new bucket count optimized for the container that is bigger or equal than n. This suggestion can be used to create bucket arrays with a size that will usually improve container's performance. If such value does not exist, the higher possible value is returned.

    Complexity: Amortized constant time.

    Throws: Nothing.

  4.  ( n) ;

    Effects: Returns the nearest new bucket count optimized for the container that is smaller or equal than n. This suggestion can be used to create bucket arrays with a size that will usually improve container's performance. If such value does not exist, the lowest possible value is returned.

    Complexity: Amortized constant time.

    Throws: Nothing.


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