contiguous_view.h

// © Joseph Cameron - All Rights Reserved
 
#ifndef JFC_CONTIGUOUS_VIEW_H
#define JFC_CONTIGUOUS_VIEW_H
 
namespace jfc {
template<class value_type_param>
class contiguous_view final {
public:
    using size_type = size_t;
    using value_type = value_type_param;

    template<class Pointer>
    constexpr contiguous_view(Pointer *pBegin, const size_type aSize)
    : m_pBegin(pBegin)
    , m_pEnd(pBegin + aSize)
    , m_Size(aSize)
    {}

    template<class Iterator>
    constexpr contiguous_view(Iterator iBegin, const size_type aSize)
    : contiguous_view(static_cast<value_type_param *>(&(*iBegin)), aSize)
    {}

    template<class Collection>
    constexpr contiguous_view(Collection &aCollection)
    : contiguous_view(static_cast<value_type_param *>(&(*aCollection.begin())), aCollection.size())
    {}

    template<class Pointer>
    contiguous_view(Pointer *pBegin, Pointer *pEnd)
    : contiguous_view(static_cast<value_type_param *>(&(*pBegin)), [pBegin, pEnd]() {
        size_type size(0);
 
        for(auto iter(pBegin); iter != pEnd; ++iter) 
            ++size;
 
        return size;
    }())
    {}

    template<class Iterator>
    contiguous_view(Iterator aBegin, Iterator aEnd)
    : contiguous_view(static_cast<value_type_param *>(&(*aBegin)), 
        static_cast<value_type_param *>(&(*aEnd)))
    {}

    constexpr contiguous_view() = default;

    constexpr contiguous_view(const contiguous_view &) = default;

    constexpr contiguous_view &operator=(const contiguous_view &rhv) = default;

    constexpr contiguous_view(contiguous_view &&) = default;
    
    constexpr contiguous_view &operator=(contiguous_view &&rhv) = default;

    [[nodiscard]] constexpr value_type &operator[](const size_type index) {
        return *(m_pBegin + index);
    }

    [[nodiscard]] constexpr const value_type &operator[](const size_type index) const {
        return *(m_pBegin + index);
    }

    [[nodiscard]] constexpr value_type_param *begin() {
        return m_pBegin;
    }
    
    [[nodiscard]] constexpr value_type_param *begin() const  { 
        return static_cast<const value_type *>(m_pBegin);
    }

    [[nodiscard]] constexpr value_type_param *end() {
        return m_pEnd;
    }

    [[nodiscard]] constexpr value_type_param *end() const  { 
        return static_cast<const value_type *>(m_pEnd);
    }

    [[nodiscard]] constexpr size_t size() const {
        return m_Size;
    }

    [[nodiscard]] constexpr bool empty() const {
        return m_Size == 0;
    }
 
private:
    value_type_param *m_pBegin = nullptr;
    
    value_type_param *m_pEnd = nullptr;
    
    size_type m_Size = 0;
};
}
 
#endif