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/**
* @file aka_view_iterators.hh
*
* @author Nicolas Richart
*
* @date creation Thu Nov 15 2018
*
* @brief View iterators
*
* @section LICENSE
*
* Copyright (©) 2010-2011 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* Akantu is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* Akantu is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "aka_common.hh"
//#include "aka_types.hh"
/* -------------------------------------------------------------------------- */
#include <memory>
/* -------------------------------------------------------------------------- */
#ifndef __AKANTU_AKA_VIEW_ITERATORS_HH__
#define __AKANTU_AKA_VIEW_ITERATORS_HH__
namespace akantu {
template <typename T, Int ndim> class TensorBase;
}
namespace akantu {
/* -------------------------------------------------------------------------- */
/* Iterators */
/* -------------------------------------------------------------------------- */
namespace detail {
template <typename... V> constexpr auto product_all(V &&... v) {
std::common_type_t<int, V...> result = 1;
(void)std::initializer_list<int>{(result *= v, 0)...};
return result;
}
template <class R> struct IteratorHelper { static constexpr Int dim = 0; };
template <class Derived> struct IteratorHelper<Eigen::MatrixBase<Derived>> {
private:
using T = typename Derived::Scalar;
static constexpr Int m = Derived::RowsAtCompileTime;
static constexpr Int n = Derived::ColsAtCompileTime;
public:
static constexpr Int dim =
Eigen::MatrixBase<Derived>::IsVectorAtCompileTime ? 1 : 2;
using pointer = T *;
using proxy = Eigen::Map<Eigen::Matrix<T, m, n>>;
using const_proxy = Eigen::Map<const Eigen::Matrix<T, m, n>>;
};
template <class Derived> struct IteratorHelper<Eigen::Map<Derived>> {
private:
using T = typename Derived::Scalar;
static constexpr Int m = Derived::RowsAtCompileTime;
static constexpr Int n = Derived::ColsAtCompileTime;
public:
static constexpr Int dim =
Derived::IsVectorAtCompileTime and m != 1 ? 1 : 2;
using pointer = T *;
using proxy = Eigen::Map<Derived>;
using const_proxy = Eigen::Map<const Derived>;
};
template <typename T, Int _dim> struct IteratorHelper<TensorBase<T, _dim>> {
static constexpr Int dim = _dim;
using pointer = T *;
using proxy = TensorProxy<T, _dim>;
using const_proxy = TensorProxy<const T, _dim>;
};
template <typename T, Int _dim> struct IteratorHelper<TensorProxy<T, _dim>> {
static constexpr Int dim = _dim;
using pointer = T *;
using proxy = TensorProxy<T, _dim>;
using const_proxy = TensorProxy<const T, _dim>;
};
/* ------------------------------------------------------------------------ */
template <class R, class daughter, class IR = R,
Int dim = IteratorHelper<std::decay_t<R>>::dim>
class internal_view_iterator {
protected:
using helper = IteratorHelper<std::decay_t<R>>;
using internal_value_type = IR;
using internal_pointer = IR *;
using scalar_pointer = typename helper::pointer;
using proxy_t = typename helper::proxy;
static constexpr int dim_ = dim;
public:
using pointer = proxy_t *;
using value_type = proxy_t;
using reference = proxy_t &;
using difference_type = Int;
using iterator_category = std::random_access_iterator_tag;
private:
template <class ProxyType, std::size_t... I>
constexpr auto get_new_proxy(scalar_pointer data,
std::index_sequence<I...>) const {
return ProxyType(data, dims[I]...);
}
constexpr auto get_new_proxy(scalar_pointer data) {
return this->template get_new_proxy<proxy_t>(
data, std::make_index_sequence<dim>());
}
constexpr auto get_new_proxy(scalar_pointer data) const {
return this->template get_new_proxy<proxy_t>(
data, std::make_index_sequence<dim>());
}
template <std::size_t... I>
constexpr void reset_proxy(std::index_sequence<I...>) {
new (&proxy) proxy_t(ret_ptr, dims[I]...);
}
constexpr auto reset_proxy() {
return reset_proxy(std::make_index_sequence<dim>());
}
protected:
template <typename OR, typename OD, typename OIR,
std::enable_if_t<std::is_convertible<
decltype(std::declval<OIR>().data()),
decltype(std::declval<IR>().data())>::value> * = nullptr>
explicit internal_view_iterator(
internal_view_iterator<OR, OD, OIR, dim> & it)
: dims(it.dims), _offset(it._offset), initial(it.initial),
ret_ptr(it.ret_ptr), proxy(get_new_proxy(it.ret_ptr)) {}
template <typename OR, typename OD, typename OIR, Int _dim>
friend class internal_view_iterator;
template <typename... Args>
using valid_args_t = std::enable_if_t<
aka::conjunction<aka::disjunction<std::is_integral<Args>,
std::is_enum<Args>>...>::value and
dim == sizeof...(Args),
int>;
public:
/// Generic constructor dor any tensor dimension
template <typename... Ns, valid_args_t<Ns...> = 0>
internal_view_iterator(scalar_pointer data, Ns... ns)
: dims({Int(ns)...}),
_offset(detail::product_all(std::forward<Ns>(ns)...)), initial(data),
ret_ptr(data), proxy(data, ns...) {}
// Specific constructor for Vector of static size 1
template <typename RD = std::decay_t<R>,
std::enable_if_t<aka::is_eigen_map<RD>::value and
RD::RowsAtCompileTime == 1 and
RD::ColsAtCompileTime == 1> * = nullptr>
constexpr internal_view_iterator(scalar_pointer data, Idx rows)
: dims({rows, 1}), _offset(rows), initial(data), ret_ptr(data),
proxy(data, rows, 1) {
assert(rows == 1 && "1x1 Matrix");
}
/// Specific constructor for Eigen::Map<Matrix> that look like
/// Eigen::Map<Vector>
template <typename RD = std::decay_t<R>,
std::enable_if_t<(RD::RowsAtCompileTime != 1) and
RD::ColsAtCompileTime == 1> * = nullptr>
constexpr internal_view_iterator(scalar_pointer data, Idx rows,
[[gnu::unused]] Idx cols)
: dims({rows}), _offset(rows), initial(data), ret_ptr(data),
proxy(data, rows, 1) {
assert(cols == 1 && "nx1 Matrix");
}
/// Default constructor for Eigen::Map<Vector>
template <Int _dim = dim, typename RD = std::decay_t<R>,
std::enable_if_t<_dim == 1> * = nullptr>
internal_view_iterator()
: proxy(reinterpret_cast<scalar_pointer>(0xdeadbeaf),
RD::RowsAtCompileTime == Eigen::Dynamic
? 1
: RD::RowsAtCompileTime) {
// initialized to a fake pointer to pass the static_assert in Eigen
// this proxy should not be returned
}
/// Default constructor for Eigen::Map<Matrix>
template <Int _dim = dim, typename RD = std::decay_t<R>,
std::enable_if_t<_dim == 2> * = nullptr>
internal_view_iterator()
: proxy(reinterpret_cast<scalar_pointer>(0xdeadbeaf),
RD::RowsAtCompileTime == Eigen::Dynamic ? 1
: RD::RowsAtCompileTime,
RD::ColsAtCompileTime == Eigen::Dynamic
? 1
: RD::ColsAtCompileTime) {
// initialized to a fake pointer to pass the `static_assert` in `Eigen
// this proxy should not be returned
}
template <Int _dim = dim, typename RD = std::decay_t<R>,
std::enable_if_t<(_dim > 2)> * = nullptr>
internal_view_iterator() {}
internal_view_iterator(const internal_view_iterator & it)
: dims(it.dims), _offset(it._offset), initial(it.initial),
ret_ptr(it.ret_ptr), proxy(get_new_proxy(it.ret_ptr)) {}
internal_view_iterator &
operator=(internal_view_iterator && it) noexcept = default;
internal_view_iterator(internal_view_iterator && it) noexcept = default;
virtual ~internal_view_iterator() = default;
template <typename OR, typename OD, typename OIR,
std::enable_if_t<std::is_convertible<
decltype(std::declval<OIR>().data()),
decltype(std::declval<IR>().data())>::value> * = nullptr>
inline internal_view_iterator &
operator=(const internal_view_iterator<OR, OD, OIR, dim> & it) {
this->dims = it.dims;
this->_offset = it._offset;
this->initial = it.initial;
this->ret_ptr = it.ret_ptr;
reset_proxy();
return *this;
}
inline internal_view_iterator &
operator=(const internal_view_iterator & it) {
if (this != &it) {
this->dims = it.dims;
this->_offset = it._offset;
this->initial = it.initial;
this->ret_ptr = it.ret_ptr;
reset_proxy();
}
return *this;
}
public:
Idx getCurrentIndex() {
return (this->ret_ptr - this->initial) / this->_offset;
}
inline reference operator*() {
this->reset_proxy();
return proxy;
}
inline pointer operator->() {
reset_proxy();
return &proxy;
}
inline daughter & operator++() {
ret_ptr += _offset;
return static_cast<daughter &>(*this);
}
inline daughter & operator--() {
ret_ptr -= _offset;
return static_cast<daughter &>(*this);
}
inline daughter & operator+=(Idx n) {
ret_ptr += _offset * n;
return static_cast<daughter &>(*this);
}
inline daughter & operator-=(Idx n) {
ret_ptr -= _offset * n;
return static_cast<daughter &>(*this);
}
inline auto operator[](Idx n) {
return get_new_proxy(ret_ptr + n * _offset);
}
inline auto operator[](Idx n) const {
return get_new_proxy(ret_ptr + n * _offset);
}
inline bool operator==(const internal_view_iterator & other) const {
return this->ret_ptr == other.ret_ptr;
}
inline bool operator!=(const internal_view_iterator & other) const {
return this->ret_ptr != other.ret_ptr;
}
inline bool operator<(const internal_view_iterator & other) const {
return this->ret_ptr < other.ret_ptr;
}
inline bool operator<=(const internal_view_iterator & other) const {
return this->ret_ptr <= other.ret_ptr;
}
inline bool operator>(const internal_view_iterator & other) const {
return this->ret_ptr > other.ret_ptr;
}
inline bool operator>=(const internal_view_iterator & other) const {
return this->ret_ptr >= other.ret_ptr;
}
inline auto operator+(difference_type n) const {
daughter tmp(static_cast<const daughter &>(*this));
tmp += n;
return tmp;
}
inline auto operator-(difference_type n) const {
daughter tmp(static_cast<const daughter &>(*this));
tmp -= n;
return tmp;
}
inline difference_type operator-(const internal_view_iterator & b) const {
return (this->ret_ptr - b.ret_ptr) / _offset;
}
inline scalar_pointer data() const { return ret_ptr; }
inline difference_type offset() const { return _offset; }
inline decltype(auto) getDims() const { return dims; }
protected:
std::array<Int, dim> dims;
difference_type _offset{0};
scalar_pointer initial{nullptr};
scalar_pointer ret_ptr{nullptr};
proxy_t proxy;
};
/* ------------------------------------------------------------------------ */
/**
* Specialization for scalar types
*/
template <class R, class daughter, class IR>
class internal_view_iterator<R, daughter, IR, 0> {
public:
using value_type = R;
using pointer = R *;
using reference = R &;
using const_reference = const R &;
using difference_type = Idx; // std::ptrdiff_t;
using iterator_category = std::random_access_iterator_tag;
static constexpr int dim_ = 0;
protected:
using internal_value_type = IR;
using internal_pointer = IR *;
public:
internal_view_iterator(pointer data = nullptr) : ret(data), initial(data){};
internal_view_iterator(const internal_view_iterator & it) = default;
internal_view_iterator(internal_view_iterator && it) = default;
virtual ~internal_view_iterator() = default;
inline internal_view_iterator &
operator=(const internal_view_iterator & it) = default;
Idx getCurrentIndex() { return (this->ret - this->initial); };
inline reference operator*() { return *ret; }
inline pointer operator->() { return ret; };
inline daughter & operator++() {
++ret;
return static_cast<daughter &>(*this);
}
inline daughter & operator--() {
--ret;
return static_cast<daughter &>(*this);
}
inline daughter & operator+=(const Idx n) {
ret += n;
return static_cast<daughter &>(*this);
}
inline daughter & operator-=(const Idx n) {
ret -= n;
return static_cast<daughter &>(*this);
}
inline reference operator[](const Idx n) { return ret[n]; }
inline bool operator==(const internal_view_iterator & other) const {
return ret == other.ret;
}
inline bool operator!=(const internal_view_iterator & other) const {
return ret != other.ret;
}
inline bool operator<(const internal_view_iterator & other) const {
return ret < other.ret;
}
inline bool operator<=(const internal_view_iterator & other) const {
return ret <= other.ret;
}
inline bool operator>(const internal_view_iterator & other) const {
return ret > other.ret;
}
inline bool operator>=(const internal_view_iterator & other) const {
return ret >= other.ret;
}
inline daughter operator-(difference_type n) const {
return daughter(ret - n);
}
inline daughter operator+(difference_type n) const {
return daughter(ret + n);
}
inline difference_type operator-(const internal_view_iterator & b) const {
return ret - b.ret;
}
inline pointer data() const { return ret; }
inline decltype(auto) getDims() const { return dims; }
protected:
std::array<int, 0> dims;
pointer ret{nullptr};
pointer initial{nullptr};
};
} // namespace detail
/* -------------------------------------------------------------------------- */
template <typename R> class view_iterator;
template <typename R>
class const_view_iterator
: public detail::internal_view_iterator<const R, const_view_iterator<R>,
R> {
public:
using parent =
detail::internal_view_iterator<const R, const_view_iterator, R>;
using value_type = typename parent::value_type;
using pointer = typename parent::pointer;
using reference = typename parent::reference;
using difference_type = typename parent::difference_type;
using iterator_category = typename parent::iterator_category;
protected:
template <typename Iterator, std::size_t... I>
static inline auto convert_helper(const Iterator & it,
std::index_sequence<I...>) {
return const_view_iterator(it.data(), it.getDims()[I]...);
}
template <typename Iterator> static inline auto convert(const Iterator & it) {
return convert_helper(it, std::make_index_sequence<parent::dim_>());
}
public:
const_view_iterator() : parent(){};
const_view_iterator(const const_view_iterator & it) = default;
const_view_iterator(const_view_iterator && it) noexcept = default;
template <typename P, typename... Ns>
const_view_iterator(P * data, Ns... ns) : parent(data, ns...) {}
const_view_iterator & operator=(const const_view_iterator & it) = default;
template <typename OR,
std::enable_if_t<not std::is_same<R, OR>::value> * = nullptr>
const_view_iterator(const const_view_iterator<OR> & it)
: parent(convert(it)) {}
template <typename OR,
std::enable_if_t<std::is_convertible<R, OR>::value> * = nullptr>
const_view_iterator(const view_iterator<OR> & it) : parent(convert(it)) {}
template <typename OR,
std::enable_if_t<not std::is_same<R, OR>::value and
std::is_convertible<R, OR>::value> * = nullptr>
const_view_iterator & operator=(const const_view_iterator<OR> & it) {
return dynamic_cast<const_view_iterator &>(parent::operator=(it));
}
template <typename OR,
std::enable_if_t<std::is_convertible<R, OR>::value> * = nullptr>
const_view_iterator operator=(const view_iterator<OR> & it) {
return convert(it);
}
};
template <class R, bool is_tensor_ = aka::is_tensor<R>::value>
struct ConstConverterIteratorHelper {
protected:
template <std::size_t... I>
static inline auto convert_helper(const view_iterator<R> & it,
std::index_sequence<I...>) {
return const_view_iterator<R>(it.data(), it.getDims()[I]...);
}
public:
static inline auto convert(const view_iterator<R> & it) {
return convert_helper(
it, std::make_index_sequence<
std::tuple_size<decltype(it.getDims())>::value>());
}
};
template <class R> struct ConstConverterIteratorHelper<R, false> {
static inline auto convert(const view_iterator<R> & it) {
return const_view_iterator<R>(it.data());
}
};
template <typename R>
class view_iterator
: public detail::internal_view_iterator<R, view_iterator<R>> {
public:
using parent = detail::internal_view_iterator<R, view_iterator>;
using value_type = typename parent::value_type;
using pointer = typename parent::pointer;
using reference = typename parent::reference;
using difference_type = typename parent::difference_type;
using iterator_category = typename parent::iterator_category;
public:
view_iterator() : parent(){};
view_iterator(const view_iterator & it) = default;
view_iterator(view_iterator && it) = default;
template <typename P, typename... Ns>
view_iterator(P * data, Ns... ns) : parent(data, ns...) {}
view_iterator & operator=(const view_iterator & it) = default;
operator const_view_iterator<R>() {
return ConstConverterIteratorHelper<R>::convert(*this);
}
};
namespace {
template <std::size_t dim, typename T> struct ViewIteratorHelper {
using type = TensorProxy<T, dim>;
};
template <typename T> struct ViewIteratorHelper<0, T> { using type = T; };
template <typename T> struct ViewIteratorHelper<1, T> {
using type = Eigen::Map<Eigen::Matrix<T, Eigen::Dynamic, 1>>;
};
template <typename T> struct ViewIteratorHelper<1, const T> {
using type = Eigen::Map<const Eigen::Matrix<T, Eigen::Dynamic, 1>>;
};
template <typename T> struct ViewIteratorHelper<2, T> {
using type = Eigen::Map<Eigen::Matrix<T, Eigen::Dynamic, Eigen::Dynamic>>;
};
template <typename T> struct ViewIteratorHelper<2, const T> {
using type =
Eigen::Map<const Eigen::Matrix<T, Eigen::Dynamic, Eigen::Dynamic>>;
};
template <std::size_t dim, typename T>
using ViewIteratorHelper_t = typename ViewIteratorHelper<dim, T>::type;
} // namespace
} // namespace akantu
#include <iterator>
namespace std {
template <typename R> struct iterator_traits<::akantu::const_view_iterator<R>> {
protected:
using iterator = ::akantu::const_view_iterator<R>;
public:
using iterator_category = typename iterator::iterator_category;
using value_type = typename iterator::value_type;
using difference_type = typename iterator::difference_type;
using pointer = typename iterator::pointer;
using reference = typename iterator::reference;
};
template <typename R> struct iterator_traits<::akantu::view_iterator<R>> {
protected:
using iterator = ::akantu::view_iterator<R>;
public:
using iterator_category = typename iterator::iterator_category;
using value_type = typename iterator::value_type;
using difference_type = typename iterator::difference_type;
using pointer = typename iterator::pointer;
using reference = typename iterator::reference;
};
} // namespace std
#endif /* !__AKANTU_AKA_VIEW_ITERATORS_HH__ */

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