adaptor for C raw array

Author: JohanMabille

include/xtensor-python/xpointer_adaptor.hpp

@@ -0,0 +1,293 @@
+/***************************************************************************
+* Copyright (c) 2016, Johan Mabille and Sylvain Corlay                     *
+*                                                                          *
+* Distributed under the terms of the BSD 3-Clause License.                 *
+*                                                                          *
+* The full license is in the file LICENSE, distributed with this software. *
+****************************************************************************/
+
+#ifndef XPOINTER_ADAPTOR_HPP
+#define XPOINTER_ADAPTOR_HPP
+
+#include <iterator>
+#include <algorithm>
+#include <memory>
+
+namespace xt
+{
+
+    template <class T, class A = std::allocator<T>>
+    class xpointer_adaptor
+    {
+
+    public:
+
+        using allocator_type = A;
+        using value_type = typename allocator_type::value_type;
+        using reference = typename allocator_type::reference;
+        using const_reference = typename allocator_type::const_reference;
+        using pointer = typename allocator_type::pointer;
+        using const_pointer = typename allocator_type::const_pointer;
+        using size_type = typename allocator_type::size_type;
+        using difference_type = typename allocator_type::difference_type;
+
+        using iterator = pointer;
+        using const_iterator = const_pointer;
+        using reverse_iterator = std::reverse_iterator<iterator>;
+        using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+
+        xpointer_adaptor(pointer& data, size_type size,
+                         const allocator_type& alloc = allocator_type());
+        ~xpointer_adaptor() = default;
+
+        xpointer_adaptor(const xpointer_adaptor&) = default;
+        xpointer_adaptor& operator=(const xpointer_adaptor&);
+
+        xpointer_adaptor(xpointer_adaptor&&) = default;
+        xpointer_adaptor& operator=(xpointer_adaptor&&);
+
+        bool empty() const noexcept;
+        size_type size() const noexcept;
+
+        void resize(size_type count);
+        void resize(size_type count, const_reference value);
+
+        reference operator[](size_type i);
+        const_reference operator[](size_type i) const;
+
+        reference front();
+        const_reference front() const;
+
+        reference back();
+        const_reference back() const;
+
+        pointer data() noexcept;
+        const_pointer data() const noexcept;
+
+        iterator begin() noexcept;
+        iterator end() noexcept;
+
+        const_iterator begin() const noexcept;
+        const_iterator end() const noexcept;
+
+        const_iterator cbegin() const noexcept;
+        const_iterator cend() const noexcept;
+
+        reverse_iterator rbegin() noexcept;
+        reverse_iterator rend() noexcept;
+
+        const_reverse_iterator rbegin() const noexcept;
+        const_reverse_iterator rend() const noexcept;
+
+        const_reverse_iterator crbegin() const noexcept;
+        const_reverse_iterator crend() const noexcept;
+
+    private:
+
+        void resize_impl(size_type count);
+        void swap_and_destroy(pointer& old_data, size_type& old_size,
+                              pointer& new_data, size_type& new_size);
+
+        pointer& p_data;
+        size_type m_size;
+        allocator_type m_allocator;
+    };
+
+    template <class T, class A>
+    inline xpointer_adaptor<T, A>::xpointer_adaptor(pointer& data, size_type size,
+                                                    const allocator_type& alloc)
+        : p_data(data), m_size(size), m_allocator(alloc)
+    {
+    }
+
+    template <class T, class A>
+    inline xpointer_adaptor<T, A>&
+    xpointer_adaptor<T, A>::operator=(const xpointer_adaptor& rhs)
+    {
+        size_type new_size = rhs.size();
+        pointer new_data = m_allocator.allocate(new_size);
+        std::copy(rhs.begin(), rhs.end(), new_data);
+        swap_and_destroy(p_data, m_size, new_data, new_size);
+        return *this;
+    }
+
+    template <class T, class A>
+    inline xpointer_adaptor<T, A>&
+    xpointer_adaptor<T, A>::operator=(xpointer_adaptor&& rhs)
+    {
+        std::swap(p_data, rhs.p_data);
+        std::swap(m_size, rhs.m_size);
+        return *this;
+    }
+
+    template <class T, class A>
+    inline bool xpointer_adaptor<T, A>::empty() const noexcept
+    {
+        return size() == 0;
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::size() const noexcept -> size_type
+    {
+        return m_size;
+    }
+
+    template <class T, class A>
+    inline void xpointer_adaptor<T, A>::resize(size_type count)
+    {
+        resize_impl(count);
+    }
+
+    template <class T, class A>
+    inline void xpointer_adaptor<T, A>::resize(size_type count, const_reference value)
+    {
+        size_type old_size = size();
+        resize_impl(count);
+        if (count > old_size)
+        {
+            std::fill(begin() + old_size, end(), value);
+        }
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::operator[](size_type i) -> reference
+    {
+        return p_data[i];
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::operator[](size_type i) const -> const_reference
+    {
+        return p_data[i];
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::front() -> reference
+    {
+        return p_data[0];
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::front() const -> const_reference
+    {
+        return p_data[0];
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::back() -> reference
+    {
+        return p_data[size() - 1];
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::back() const -> const_reference
+    {
+        return p_data[size() - 1];
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::data() noexcept -> pointer
+    {
+        return p_data;
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::data() const noexcept -> const_pointer
+    {
+        return p_data;
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::begin() noexcept -> iterator
+    {
+        return data();
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::end() noexcept-> iterator
+    {
+        return data() + size();
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::begin() const noexcept -> const_iterator
+    {
+        return data();
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::end() const noexcept -> const_iterator
+    {
+        return data() + size();
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::cbegin() const noexcept -> const_iterator
+    {
+        return begin();
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::cend() const noexcept -> const_iterator
+    {
+        return end();
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::rbegin() noexcept -> reverse_iterator
+    {
+        return reverse_iterator(end());
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::rend() noexcept -> reverse_iterator
+    {
+        return reverse_iterator(begin());
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::rbegin() const noexcept -> const_reverse_iterator
+    {
+        return const_reverse_iterator(end());
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::rend() const noexcept -> const_reverse_iterator
+    {
+        return const_reverse_iterator(begin());
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::crbegin() const noexcept -> const_reverse_iterator
+    {
+        return rbegin()
+    }
+
+    template <class T, class A>
+    inline auto xpointer_adaptor<T, A>::crend() const noexcept -> const_reverse_iterator
+    {
+        return rend();
+    }
+
+    template <class T, class A>
+    inline void xpointer_adaptor<T, A>::resize_impl(size_type count)
+    {
+        pointer new_data = m_allocator.allocate(count);
+        size_type end = std::min(size(), count);
+        std::move(begin(), begin() + end, new_data);
+        swap_and_destroy(p_data, m_size, new_data, count);
+    }
+
+    template <class T, class A>
+    inline void xpointer_adaptor<T, A>::swap_and_destroy(pointer& old_data, size_type& old_size,
+                                                         pointer& new_data, size_type& new_size)
+    {
+        std::swap(old_data, new_data);
+        std::swap(old_size, new_size);
+        std::for_each(new_data, new_data + new_size,
+            [this](T& value) { m_allocator.destroy(&value); });
+        m_allocator.deallocate(new_data, new_size);
+    }
+}
+
+#endif