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378 lines (304 loc) · 10.4 KB
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/***************************************************************************
* Copyright (c) Wolf Vollprecht, Johan Mabille and Sylvain Corlay *
* Copyright (c) QuantStack *
* *
* Distributed under the terms of the BSD 3-Clause License. *
* *
* The full license is in the file LICENSE, distributed with this software. *
****************************************************************************/
#ifndef PY_ARRAY_BACKSTRIDES_HPP
#define PY_ARRAY_BACKSTRIDES_HPP
#include <cstddef>
#include <iterator>
namespace xt
{
/**************************
* pybackstrides_iterator *
**************************/
template <class B>
class pybackstrides_iterator
{
public:
using self_type = pybackstrides_iterator<B>;
using value_type = typename B::value_type;
using pointer = const value_type*;
using reference = value_type;
using difference_type = std::ptrdiff_t;
using iterator_category = std::random_access_iterator_tag;
pybackstrides_iterator(const B* b, std::size_t offset);
reference operator*() const;
pointer operator->() const;
reference operator[](difference_type n) const;
self_type& operator++();
self_type& operator--();
self_type operator++(int);
self_type operator--(int);
self_type& operator+=(difference_type n);
self_type& operator-=(difference_type n);
self_type operator+(difference_type n) const;
self_type operator-(difference_type n) const;
self_type operator-(const self_type& rhs) const;
std::size_t offset() const;
private:
const B* p_b;
std::size_t m_offset;
};
template <class B>
inline bool operator==(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs);
template <class B>
inline bool operator!=(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs);
template <class B>
inline bool operator<(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs);
template <class B>
inline bool operator<=(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs);
template <class B>
inline bool operator>(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs);
template <class B>
inline bool operator>=(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs);
/***********************
* pyarray_backstrides *
***********************/
template <class A>
class pyarray_backstrides
{
public:
using self_type = pyarray_backstrides<A>;
using array_type = A;
using value_type = typename array_type::size_type;
using const_reference = value_type;
using reference = const_reference;
using const_pointer = const value_type*;
using pointer = const_pointer;
using size_type = typename array_type::size_type;
using difference_type = typename array_type::difference_type;
using const_iterator = pybackstrides_iterator<self_type>;
using iterator = const_iterator;
using reverse_iterator = std::reverse_iterator<iterator>;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
pyarray_backstrides() = default;
pyarray_backstrides(const array_type& a);
bool empty() const;
size_type size() const;
value_type 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;
const_reverse_iterator rbegin() const;
const_reverse_iterator rend() const;
const_reverse_iterator crbegin() const;
const_reverse_iterator crend() const;
private:
const array_type* p_a;
};
/*****************************************
* pybackstrides_iterator implementation *
*****************************************/
template <class B>
inline pybackstrides_iterator<B>::pybackstrides_iterator(const B* b, std::size_t offset)
: p_b(b), m_offset(offset)
{
}
template <class B>
inline auto pybackstrides_iterator<B>::operator*() const -> reference
{
return p_b->operator[](m_offset);
}
template <class B>
inline auto pybackstrides_iterator<B>::operator->() const -> pointer
{
// Returning the address of a temporary
value_type res = p_b->operator[](m_offset);
return &res;
}
template <class B>
inline auto pybackstrides_iterator<B>::operator[](difference_type n) const -> reference
{
return p_b->operator[](m_offset + n);
}
template <class B>
inline auto pybackstrides_iterator<B>::operator++() -> self_type&
{
++m_offset;
return *this;
}
template <class B>
inline auto pybackstrides_iterator<B>::operator--() -> self_type&
{
--m_offset;
return *this;
}
template <class B>
inline auto pybackstrides_iterator<B>::operator++(int )-> self_type
{
self_type tmp(*this);
++m_offset;
return tmp;
}
template <class B>
inline auto pybackstrides_iterator<B>::operator--(int) -> self_type
{
self_type tmp(*this);
--m_offset;
return tmp;
}
template <class B>
inline auto pybackstrides_iterator<B>::operator+=(difference_type n) -> self_type&
{
m_offset += n;
return *this;
}
template <class B>
inline auto pybackstrides_iterator<B>::operator-=(difference_type n) -> self_type&
{
m_offset -= n;
return *this;
}
template <class B>
inline auto pybackstrides_iterator<B>::operator+(difference_type n) const -> self_type
{
return self_type(p_b, m_offset + n);
}
template <class B>
inline auto pybackstrides_iterator<B>::operator-(difference_type n) const -> self_type
{
return self_type(p_b, m_offset - n);
}
template <class B>
inline auto pybackstrides_iterator<B>::operator-(const self_type& rhs) const -> self_type
{
self_type tmp(*this);
tmp -= (m_offset - rhs.m_offset);
return tmp;
}
template <class B>
inline std::size_t pybackstrides_iterator<B>::offset() const
{
return m_offset;
}
template <class B>
inline bool operator==(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs)
{
return lhs.offset() == rhs.offset();
}
template <class B>
inline bool operator!=(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs)
{
return !(lhs == rhs);
}
template <class B>
inline bool operator<(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs)
{
return lhs.offset() < rhs.offset();
}
template <class B>
inline bool operator<=(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs)
{
return (lhs < rhs) || (lhs == rhs);
}
template <class B>
inline bool operator>(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs)
{
return !(lhs <= rhs);
}
template <class B>
inline bool operator>=(const pybackstrides_iterator<B>& lhs,
const pybackstrides_iterator<B>& rhs)
{
return !(lhs < rhs);
}
/**************************************
* pyarray_backstrides implementation *
**************************************/
template <class A>
inline pyarray_backstrides<A>::pyarray_backstrides(const array_type& a)
: p_a(&a)
{
}
template <class A>
inline bool pyarray_backstrides<A>::empty() const
{
return p_a->dimension() == 0;
}
template <class A>
inline auto pyarray_backstrides<A>::size() const -> size_type
{
return p_a->dimension();
}
template <class A>
inline auto pyarray_backstrides<A>::operator[](size_type i) const -> value_type
{
value_type sh = p_a->shape()[i];
value_type res = sh == 1 ? 0 : (sh - 1) * p_a->strides()[i];
return res;
}
template <class A>
inline auto pyarray_backstrides<A>::front() const -> const_reference
{
value_type sh = p_a->shape()[0];
value_type res = sh == 1 ? 0 : (sh - 1) * p_a->strides()[0];
return res;
}
template <class A>
inline auto pyarray_backstrides<A>::back() const -> const_reference
{
auto index = p_a->size() - 1;
value_type sh = p_a->shape()[index];
value_type res = sh == 1 ? 0 : (sh - 1) * p_a->strides()[index];
return res;
}
template <class A>
inline auto pyarray_backstrides<A>::begin() const -> const_iterator
{
return cbegin();
}
template <class A>
inline auto pyarray_backstrides<A>::end() const -> const_iterator
{
return cend();
}
template <class A>
inline auto pyarray_backstrides<A>::cbegin() const -> const_iterator
{
return const_iterator(this, 0);
}
template <class A>
inline auto pyarray_backstrides<A>::cend() const -> const_iterator
{
return const_iterator(this, size());
}
template <class A>
inline auto pyarray_backstrides<A>::rbegin() const -> const_reverse_iterator
{
return crbegin();
}
template <class A>
inline auto pyarray_backstrides<A>::rend() const -> const_reverse_iterator
{
return crend();
}
template <class A>
inline auto pyarray_backstrides<A>::crbegin() const -> const_reverse_iterator
{
return const_reverse_iterator(end());
}
template <class A>
inline auto pyarray_backstrides<A>::crend() const -> const_reverse_iterator
{
return const_reverse_iterator(begin());
}
}
#endif