Class vector_map

Synopsis

#include <include/EASTL/vector_map.h>

template <typename Key, typename T, typename Compare = eastl::less<Key>, 
		  typename Allocator = EASTLAllocatorType, 
		  typename RandomAccessContainer = eastl::vector<eastl::pair<Key, T>, Allocator> >
class vector_map : public RandomAccessContainer

Description

vector_map

Implements a map via a random access container such as a vector.

Note that with vector_set, vector_multiset, vector_map, vector_multimap that the modification of the container potentially invalidates all existing iterators into the container, unlike what happens with conventional sets and maps.

Note that the erase functions return iterator and not void. This allows for more efficient use of the container and is consistent with the C++ language defect report #130 (DR 130)

Note that we set the value_type to be pair<Key, T> and not pair<const Key, T>. This means that the underlying container (e.g vector) is a container of pair<Key, T>. Our vector and deque implementations are optimized to assign values in-place and using a vector of pair<const Key, T> (note the const) would make it hard to use our existing vector implementation without a lot of headaches. As a result, at least for the time being we do away with the const. This means that the insertion type varies between map and vector_map in that the latter doesn't take const. This also means that a certain amount of automatic safety provided by the implementation is lost, as the compiler will let the wayward user modify a key and thus make the container no longer ordered behind its back.

Mentioned in

Inheritance

Ancestors: vector

Methods

vector_map overloadvector_map
count
emplace overloadInherited from base class:
emplace_back
emplace_back_unsorted
emplace_hint
equal_range overload
erase overload
find overload
find_as overload
insert overload
key_comp overload
lower_bound overload
operator= overload
operator[] overloadNote: vector_map operator[] returns a reference to the mapped_type, same as map does
push_back overloadFunctions which are disallowed due to being unsafe.
push_back_uninitialized
push_back_unsortedNOTE(rparolin): It is undefined behaviour if user code fails to ensure the container invariants are respected by performing an explicit call to 'sort' before any other operations on the container are performed that do not clear the elements.
swap
upper_bound overload
value_comp overload

Source

Lines 120-292 in include/EASTL/vector_map.h.

template <typename Key, typename T, typename Compare = eastl::less<Key>, 
          typename Allocator = EASTLAllocatorType, 
          typename RandomAccessContainer = eastl::vector<eastl::pair<Key, T>, Allocator> >
class vector_map : public RandomAccessContainer
{
public:
    typedef RandomAccessContainer                                         base_type;
    typedef vector_map<Key, T, Compare, Allocator, RandomAccessContainer> this_type;
    typedef Allocator                                                     allocator_type;
    typedef Key                                                           key_type;
    typedef T                                                             mapped_type;
    typedef eastl::pair<Key, T>                                           value_type;
    typedef Compare                                                       key_compare;
    typedef map_value_compare<Key, value_type, Compare>                   value_compare;
    typedef value_type*                                                   pointer;
    typedef const value_type*                                             const_pointer;
    typedef value_type&                                                   reference;
    typedef const value_type&                                             const_reference;
    typedef typename base_type::size_type                                 size_type;
    typedef typename base_type::difference_type                           difference_type;
    typedef typename base_type::iterator                                  iterator;
    typedef typename base_type::const_iterator                            const_iterator;
    typedef typename base_type::reverse_iterator                          reverse_iterator;
    typedef typename base_type::const_reverse_iterator                    const_reverse_iterator;
    typedef eastl::pair<iterator, bool>                                   insert_return_type;
    using base_type::begin;
    using base_type::end;
    using base_type::get_allocator;
protected:
    value_compare mValueCompare; // To do: Make this variable go away via the zero base size optimization.
public:
    // We have an empty ctor and a ctor that takes an allocator instead of one for both
    // because this way our RandomAccessContainer wouldn't be required to have an constructor
    // that takes allocator_type. 
    vector_map();
    explicit vector_map(const allocator_type& allocator);
    explicit vector_map(const key_compare& comp, const allocator_type& allocator = EASTL_VECTOR_MAP_DEFAULT_ALLOCATOR);
    vector_map(const this_type& x);
    vector_map(this_type&& x);
    vector_map(this_type&& x, const allocator_type& allocator);
    vector_map(std::initializer_list<value_type> ilist, const key_compare& compare = key_compare(), const allocator_type& allocator = EASTL_VECTOR_MAP_DEFAULT_ALLOCATOR);
    template <typename InputIterator>
    vector_map(InputIterator first, InputIterator last); // allocator arg removed because VC7.1 fails on the default arg. To do: Make a second version of this function without a default arg.
    template <typename InputIterator>
    vector_map(InputIterator first, InputIterator last, const key_compare& compare); // allocator arg removed because VC7.1 fails on the default arg. To do: Make a second version of this function without a default arg.
    this_type& operator=(const this_type& x);
    this_type& operator=(std::initializer_list<value_type> ilist);
    this_type& operator=(this_type&& x);
    void swap(this_type& x);
    const key_compare& key_comp() const;
    key_compare&       key_comp();
    const value_compare& value_comp() const;
    value_compare&       value_comp();
    // Inherited from base class:
    //
    //     allocator_type& get_allocator();
    //     void            set_allocator(const allocator_type& allocator);
    //
    //     iterator       begin();
    //     const_iterator begin() const;
    //     const_iterator cbegin() const;
    //
    //     iterator       end();
    //     const_iterator end() const;
    //     const_iterator cend() const;
    //
    //     reverse_iterator       rbegin();
    //     const_reverse_iterator rbegin() const;
    //     const_reverse_iterator crbegin() const;
    //
    //     reverse_iterator       rend();
    //     const_reverse_iterator rend() const;
    //     const_reverse_iterator crend() const;
    //
    //     size_type size() const;
    //     bool      empty() const;
    //     void      clear();
    template <class... Args>
    eastl::pair<iterator, bool> emplace(Args&&... args);
    template <class... Args> 
    iterator emplace_hint(const_iterator position, Args&&... args);
    template <typename P, typename = eastl::enable_if_t<eastl::is_constructible_v<value_type, P&&>>>
    pair<iterator, bool> insert(P&& otherValue);
    eastl::pair<iterator, bool> insert(const value_type& value);
    pair<iterator, bool>        insert(const key_type& otherValue);
    pair<iterator, bool>        insert(key_type&& otherValue);
    iterator                    insert(const_iterator position, const value_type& value);
    iterator                    insert(const_iterator position, value_type&& value);
    void                        insert(std::initializer_list<value_type> ilist);
    template <typename InputIterator>
    void insert(InputIterator first, InputIterator last);
    iterator         erase(const_iterator position);
    iterator         erase(const_iterator first, const_iterator last);
    size_type        erase(const key_type& k);
    reverse_iterator erase(const_reverse_iterator position);
    reverse_iterator erase(const_reverse_iterator first, const_reverse_iterator last);
    iterator       find(const key_type& k);
    const_iterator find(const key_type& k) const;
    template <typename U, typename BinaryPredicate>
    iterator       find_as(const U& u, BinaryPredicate predicate);
    template <typename U, typename BinaryPredicate>
    const_iterator find_as(const U& u, BinaryPredicate predicate) const;
    size_type count(const key_type& k) const;
    iterator       lower_bound(const key_type& k);
    const_iterator lower_bound(const key_type& k) const;
    iterator       upper_bound(const key_type& k);
    const_iterator upper_bound(const key_type& k) const;
    eastl::pair<iterator, iterator>             equal_range(const key_type& k);
    eastl::pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
    template <typename U, typename BinaryPredicate> 
    eastl::pair<iterator, iterator>             equal_range(const U& u, BinaryPredicate predicate);
    template <typename U, typename BinaryPredicate> 
    eastl::pair<const_iterator, const_iterator> equal_range(const U& u, BinaryPredicate) const;
    // Note: vector_map operator[] returns a reference to the mapped_type, same as map does.
    // But there's an important difference: This reference can be invalidated by -any- changes  
    // to the vector_map that cause it to change capacity. This is unlike map, with which 
    // mapped_type references are invalidated only if that mapped_type element itself is removed
    // from the map. This is because vector is array-based and map is node-based. As a result
    // the following code that is safe for map is unsafe for vector_map for the case that 
    // the vMap[100] doesn't already exist in the vector_map:
    //     vMap[100] = vMap[0]
    mapped_type& operator[](const key_type& k);
    mapped_type& operator[](key_type&& k);
    // Functions which are disallowed due to being unsafe. 
    void      push_back(const value_type& value) = delete;
    reference push_back()                        = delete;
    void*     push_back_uninitialized()          = delete;
    template <class... Args>
    reference emplace_back(Args&&...)            = delete;
    // NOTE(rparolin): It is undefined behaviour if user code fails to ensure the container
    // invariants are respected by performing an explicit call to 'sort' before any other
    // operations on the container are performed that do not clear the elements.
    //
    // 'push_back_unsorted' and 'emplace_back_unsorted' do not satisfy container invariants
    // for being sorted. We provide these overloads explicitly labelled as '_unsorted' as an
    // optimization opportunity when batch inserting elements so users can defer the cost of
    // sorting the container once when all elements are contained. This was done to clarify
    // the intent of code by leaving a trace that a manual call to sort is required.
    // 
    template <typename... Args> decltype(auto) push_back_unsorted(Args&&... args)    
        { return base_type::push_back(eastl::forward<Args>(args)...); }
    template <typename... Args> decltype(auto) emplace_back_unsorted(Args&&... args) 
        { return base_type::emplace_back(eastl::forward<Args>(args)...); }
}; // vector_map





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