xtensor-python/include/xtensor-python/pystrides_adaptor.hpp at master · phaustin/xtensor-python · GitHub

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/***************************************************************************

* *

* Distributed under the terms of the BSD 3-Clause License. *

* *

* The full license is in the file LICENSE, distributed with this software. *

****************************************************************************/

#ifndef PYSTRIDES_ADAPTOR_HPP

#define PYSTRIDES_ADAPTOR_HPP

#include <cstddef>

#include <iterator>

namespace xt

{

template <std::size_t N>

class pystrides_iterator;

template <std::size_t N>

class pystrides_adaptor

{

public:

using value_type = std::size_t;

using const_reference = value_type;

using const_pointer = const value_type*;

using size_type = std::size_t;

using difference_type = std::ptrdiff_t;

using const_iterator = pystrides_iterator<N>;

pystrides_adaptor() = default;

pystrides_adaptor(const_pointer data, size_type size);

bool empty() const noexcept;

size_type size() const noexcept;

const_reference operator[](size_type i) const;

const_reference front() const;

const_reference back() const;

const_iterator begin() const;

const_iterator end() const;

const_iterator cbegin() const;

const_iterator cend() const;

private:

const_pointer p_data;

size_type m_size;

};

/*************************************

* pystrides_iterator implementation *

*************************************/

template <std::size_t N>

class pystrides_iterator

{

public:

using self_type = pystrides_iterator<N>;

using value_type = typename pystrides_adaptor<N>::value_type;

using pointer = typename pystrides_adaptor<N>::const_pointer;

using reference = typename pystrides_adaptor<N>::const_reference;

using difference_type = typename pystrides_adaptor<N>::difference_type;

using iterator_category = std::random_access_iterator_tag;

inline pystrides_iterator(pointer current)

: p_current(current)

{

}

inline reference operator*() const { return *p_current / N; }

inline pointer operator->() const { return p_current; }

inline reference operator[](difference_type n) { return *(p_current + n) / N; }

inline self_type& operator++() { ++p_current; return *this; }

inline self_type& operator--() { --p_current; return *this; }

inline self_type operator++(int) { self_type tmp(*this); ++p_current; return tmp; }

inline self_type operator--(int) { self_type tmp(*this); --p_current; return tmp; }

inline self_type& operator+=(difference_type n) { p_current += n; return *this; }

inline self_type& operator-=(difference_type n) { p_current -= n; return *this; }

inline self_type operator+(difference_type n) const { return self_type(p_current + n); }

inline self_type operator-(difference_type n) const { return self_type(p_current - n); }

inline self_type operator-(const self_type& rhs) const

{

self_type tmp(*this);

tmp -= (p_current - rhs.p_current);

return tmp;

}

pointer get_pointer() const { return p_current; }

private:

pointer p_current;

};

template <std::size_t N>

inline bool operator==(const pystrides_iterator<N>& lhs,