enumarray.hxx

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#ifndef INCLUDED_O3TL_ENUMARRAY_HXX
#define INCLUDED_O3TL_ENUMARRAY_HXX

#include <iterator>
#include <type_traits>
#include <cassert>

namespace o3tl {

template<typename EA>
class enumarray_iterator;
template<typename EA>
class enumarray_const_iterator;

template<typename E, typename V>
class enumarray final
{
public:
    typedef enumarray<E, V> self_type;
    typedef enumarray_iterator<self_type> iterator;
    typedef enumarray_const_iterator<self_type> const_iterator;

    typedef V             value_type;
    typedef E             key_type;
    typedef size_t        size_type;

    static const size_type max_index = static_cast<size_type>(E::LAST);

    const V& operator[](E index) const
    {
        assert(index>=static_cast<E>(0) && index<=E::LAST);
        return detail_values[static_cast<size_type>(index)];
    }

    V& operator[](E index)
    {
        assert(index>=static_cast<E>(0) && index<=E::LAST);
        return detail_values[static_cast<size_type>(index)];
    }

    void fill(V val)
    { for (size_type i=0; i<=max_index; ++i) detail_values[i] = val; }

    static size_type size()        { return max_index + 1; }
    iterator         begin()       { return iterator(*this, 0); }
    iterator         end()         { return iterator(*this, size()); }
    const_iterator   begin() const { return const_iterator(*this, 0); }
    const_iterator   end() const   { return const_iterator(*this, size()); }

    V*               data()       { return detail_values; }

//private:
    V detail_values[max_index + 1];
};


template<typename EA>
class enumarray_iterator {
    EA*         m_buf;
    size_t      m_pos;
public:
    typedef enumarray_iterator<EA>  self_type;
    typedef typename EA::value_type value_type;
    typedef typename EA::key_type   key_type;
    typedef std::bidirectional_iterator_tag iterator_category; //should be random access, but that would require define subtraction operators on the enums
    typedef
        typename std::make_signed<
            typename std::underlying_type<typename EA::key_type>::type>::type
        difference_type;
    typedef typename EA::value_type*   pointer;
    typedef typename EA::value_type&   reference;

    enumarray_iterator(EA& b, size_t start_pos)
         : m_buf(&b), m_pos(start_pos) {}
    value_type& operator*()  const { return (*m_buf)[static_cast<key_type>(m_pos)]; }
    value_type* operator->() const { return &(operator*()); }
    self_type&  operator++() { ++m_pos; return *this; }
    bool        operator!=(self_type const & other) const { return m_buf != other.m_buf || m_pos != other.m_pos; }
    bool        operator==(self_type const & other) const { return m_buf == other.m_buf && m_pos == other.m_pos; }
};

template<typename EA>
class enumarray_const_iterator {
    EA const *  m_buf;
    size_t      m_pos;
public:
    typedef enumarray_const_iterator<EA>    self_type;
    typedef typename EA::value_type const   value_type;
    typedef typename EA::key_type           key_type;
    typedef std::bidirectional_iterator_tag iterator_category; //should be random access, but that would require define subtraction operators on the enums
    typedef
        typename std::make_signed<
            typename std::underlying_type<typename EA::key_type>::type>::type
                                            difference_type;
    typedef typename EA::value_type const * pointer;
    typedef typename EA::value_type const & reference;

    enumarray_const_iterator(EA const & b, size_t start_pos)
         : m_buf(&b), m_pos(start_pos) {}
    value_type& operator*()  const { return (*m_buf)[static_cast<key_type>(m_pos)]; }
    value_type* operator->() const { return &(operator*()); }
    self_type&  operator++() { ++m_pos; return *this; }
    bool        operator!=(self_type const & other) const { return m_buf != other.m_buf || m_pos != other.m_pos; }
    bool        operator==(self_type const & other) const { return m_buf == other.m_buf && m_pos == other.m_pos; }
};

}; // namespace o3tl

#endif /* INCLUDED_O3TL_ENUMARRAY_HXX */

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