    // Copyright (C) 2003  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #undef DLIB_ARRAY_KERNEl_ABSTRACT_
    #ifdef DLIB_ARRAY_KERNEl_ABSTRACT_

    #include "../interfaces/enumerable.h"
    #include "../serialize.h"
    #include "../algs.h"

    namespace dlib
    {

        template <
            typename T,
            typename mem_manager = default_memory_manager
            >
        class array : public enumerable<T>
        {

            /*!
                REQUIREMENTS ON T
                    T must have a default constructor.

                REQUIREMENTS ON mem_manager
                    must be an implementation of memory_manager/memory_manager_kernel_abstract.h or
                    must be an implementation of memory_manager_global/memory_manager_global_kernel_abstract.h or
                    must be an implementation of memory_manager_stateless/memory_manager_stateless_kernel_abstract.h
                    mem_manager::type can be set to anything.

                POINTERS AND REFERENCES TO INTERNAL DATA
                    front(), back(), swap(), max_size(), set_size(), and operator[]
                    functions do not invalidate pointers or references to internal data.
                    All other functions have no such guarantee.

                INITIAL VALUE
                    size() == 0
                    max_size() == 0

                ENUMERATION ORDER
                    The enumerator will iterate over the elements of the array in the
                    order (*this)[0], (*this)[1], (*this)[2], ...

                WHAT THIS OBJECT REPRESENTS
                    This object represents an ordered 1-dimensional array of items,
                    each item is associated with an integer value.  The items are
                    numbered from 0 though size() - 1 and the operator[] functions
                    run in constant time.

                    Also note that unless specified otherwise, no member functions
                    of this object throw exceptions.
            !*/

            public:

                typedef T type;
                typedef T value_type;
                typedef mem_manager mem_manager_type;

                array (
                );
                /*!
                    ensures
                        - #*this is properly initialized
                    throws
                        - std::bad_alloc or any exception thrown by T's constructor
                !*/

                explicit array (
                    unsigned long new_size
                );
                /*!
                    ensures
                        - #*this is properly initialized
                        - #size() == new_size
                        - #max_size() == new_size
                        - All elements of the array will have initial values for their type.
                    throws
                        - std::bad_alloc or any exception thrown by T's constructor
                !*/

                ~array (
                );
                /*!
                    ensures
                        - all memory associated with *this has been released
                !*/

                void clear (
                );
                /*!
                    ensures
                        - #*this has its initial value
                    throws
                        - std::bad_alloc or any exception thrown by T's constructor
                            if this exception is thrown then the array object is unusable
                            until clear() is called and succeeds
                !*/

                const T& operator[] (
                    unsigned long pos
                ) const;
                /*!
                    requires
                        - pos < size()
                    ensures
                        - returns a const reference to the element at position pos
                !*/

                T& operator[] (
                    unsigned long pos
                );
                /*!
                    requires
                        - pos < size()
                    ensures
                        - returns a non-const reference to the element at position pos
                !*/

                void set_size (
                    unsigned long size
                );
                /*!
                    requires
                        - size <= max_size()
                    ensures
                        - #size() == size
                        - any element with index between 0 and size - 1 which was in the
                          array before the call to set_size() retains its value and index.
                          All other elements have undetermined (but valid for their type)
                          values.  (e.g. this object might buffer old T objects and reuse
                          them without reinitializing them between calls to set_size())
                        - #at_start() == true
                    throws
                        - std::bad_alloc or any exception thrown by T's constructor
                            may throw this exception if there is not enough memory and
                            if it does throw then the call to set_size() has no effect
                !*/

                unsigned long max_size(
                ) const;
                /*!
                    ensures
                        - returns the maximum size of *this
                !*/

                void set_max_size(
                    unsigned long max
                );
                /*!
                    ensures
                        - #max_size() == max
                        - #size() == 0
                        - #at_start() == true
                    throws
                        - std::bad_alloc or any exception thrown by T's constructor
                            may throw this exception if there is not enough
                            memory and if it does throw then max_size() == 0
                !*/

                void swap (
                    array<T>& item
                );
                /*!
                    ensures
                        - swaps *this and item
                !*/

                void sort (
                );
                /*!
                    requires
                        - T must be a type with that is comparable via operator<
                    ensures
                        - for all elements in #*this the ith element is <= the i+1 element
                        - #at_start() == true
                    throws
                        - std::bad_alloc or any exception thrown by T's constructor
                            data may be lost if sort() throws
                !*/

                void resize (
                    unsigned long new_size
                );
                /*!
                    ensures
                        - #size() == new_size
                        - #max_size() == max(new_size,max_size())
                        - for all i < size() && i < new_size:
                            - #(*this)[i] == (*this)[i]
                              (i.e. All the original elements of *this which were at index
                              values less than new_size are unmodified.)
                        - for all valid i >= size():
                            - #(*this)[i] has an undefined value
                              (i.e. any new elements of the array have an undefined value)
                    throws
                        - std::bad_alloc or any exception thrown by T's constructor.
                           If an exception is thrown then it has no effect on *this.
                !*/

                const T& back (
                ) const;
                /*!
                    requires
                        - size() != 0
                    ensures
                        - returns a const reference to (*this)[size()-1]
                !*/

                T& back (
                );
                /*!
                    requires
                        - size() != 0
                    ensures
                        - returns a non-const reference to (*this)[size()-1]
                !*/

                void pop_back (
                    T& item
                );
                /*!
                    requires
                        - size() != 0
                    ensures
                        - #size() == size() - 1
                        - swaps (*this)[size()-1] into item
                        - All elements with an index less than size()-1 are
                          unmodified by this operation.
                !*/

                void pop_back (
                );
                /*!
                    requires
                        - size() != 0
                    ensures
                        - #size() == size() - 1
                        - All elements with an index less than size()-1 are
                          unmodified by this operation.
                !*/

                void push_back (
                    T& item
                );
                /*!
                    ensures
                        - #size() == size()+1
                        - swaps item into (*this)[#size()-1]
                        - #back() == item
                        - #item has some undefined value (whatever happens to
                          get swapped out of the array)
                    throws
                        - std::bad_alloc or any exception thrown by T's constructor.
                           If an exception is thrown then it has no effect on *this.
                !*/

                typedef T* iterator;
                typedef const T* const_iterator;

                iterator begin(
                );
                /*!
                    ensures
                        - returns an iterator that points to the first element in this array or
                          end() if the array is empty.
                !*/

                const_iterator begin(
                ) const;
                /*!
                    ensures
                        - returns a const iterator that points to the first element in this
                          array or end() if the array is empty.
                !*/

                iterator end(
                );
                /*!
                    ensures
                        - returns an iterator that points to one past the end of the array.
                !*/

                const_iterator end(
                ) const;
                /*!
                    ensures
                        - returns a const iterator that points to one past the end of the
                          array.
                !*/

            private:

                // restricted functions
                array(array<T>&);        // copy constructor
                array<T>& operator=(array<T>&);    // assignment operator

        };

        template <
            typename T
            >
        inline void swap (
            array<T>& a,
            array<T>& b
        ) { a.swap(b); }
        /*!
            provides a global swap function
        !*/

        template <
            typename T
            >
        void serialize (
            const array<T>& item,
            std::ostream& out
        );
        /*!
            provides serialization support
        !*/

        template <
            typename T
            >
        void deserialize (
            array<T>& item,
            std::istream& in
        );
        /*!
            provides deserialization support
        !*/

    }

    #endif // DLIB_ARRAY_KERNEl_ABSTRACT_