Eigen/src/Core/ArrayWrapper.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_ARRAYWRAPPER_H
#define EIGEN_ARRAYWRAPPER_H

// IWYU pragma: private
#include "./InternalHeaderCheck.h"

namespace Eigen {

/** \class ArrayWrapper
 * \ingroup Core_Module
 *
 * \brief Expression of a mathematical vector or matrix as an array object
 *
 * This class is the return type of MatrixBase::array(), and most of the time
 * this is the only way it is used.
 *
 * \sa MatrixBase::array(), class MatrixWrapper
 */

namespace internal {
template <typename ExpressionType>
struct traits<ArrayWrapper<ExpressionType> > : public traits<remove_all_t<typename ExpressionType::Nested> > {
  typedef ArrayXpr XprKind;
  // Let's remove NestByRefBit
  enum {
    Flags0 = traits<remove_all_t<typename ExpressionType::Nested> >::Flags,
    LvalueBitFlag = is_lvalue<ExpressionType>::value ? LvalueBit : 0,
    Flags = (Flags0 & ~(NestByRefBit | LvalueBit)) | LvalueBitFlag
  };
};
}  // namespace internal

template <typename ExpressionType>
class ArrayWrapper : public ArrayBase<ArrayWrapper<ExpressionType> > {
 public:
  typedef ArrayBase<ArrayWrapper> Base;
  EIGEN_DENSE_PUBLIC_INTERFACE(ArrayWrapper)
  EIGEN_INHERIT_ASSIGNMENT_OPERATORS(ArrayWrapper)
  typedef internal::remove_all_t<ExpressionType> NestedExpression;

  typedef std::conditional_t<internal::is_lvalue<ExpressionType>::value, Scalar, const Scalar>
      ScalarWithConstIfNotLvalue;

  typedef typename internal::ref_selector<ExpressionType>::non_const_type NestedExpressionType;

  using Base::coeffRef;

  EIGEN_DEVICE_FUNC constexpr explicit EIGEN_STRONG_INLINE ArrayWrapper(ExpressionType& matrix)
      : m_expression(matrix) {}

  EIGEN_DEVICE_FUNC constexpr Index rows() const noexcept { return m_expression.rows(); }
  EIGEN_DEVICE_FUNC constexpr Index cols() const noexcept { return m_expression.cols(); }
  EIGEN_DEVICE_FUNC constexpr Index outerStride() const noexcept { return m_expression.outerStride(); }
  EIGEN_DEVICE_FUNC constexpr Index innerStride() const noexcept { return m_expression.innerStride(); }

  EIGEN_DEVICE_FUNC constexpr ScalarWithConstIfNotLvalue* data() { return m_expression.data(); }
  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return m_expression.data(); }

  EIGEN_DEVICE_FUNC inline const Scalar& coeffRef(Index rowId, Index colId) const {
    return m_expression.coeffRef(rowId, colId);
  }

  EIGEN_DEVICE_FUNC inline const Scalar& coeffRef(Index index) const { return m_expression.coeffRef(index); }

  template <typename Dest>
  EIGEN_DEVICE_FUNC inline void evalTo(Dest& dst) const {
    dst = m_expression;
  }

  EIGEN_DEVICE_FUNC constexpr const internal::remove_all_t<NestedExpressionType>& nestedExpression() const {
    return m_expression;
  }

  /** Forwards the resizing request to the nested expression
   * \sa DenseBase::resize(Index)  */
  EIGEN_DEVICE_FUNC void resize(Index newSize) { m_expression.resize(newSize); }
  /** Forwards the resizing request to the nested expression
   * \sa DenseBase::resize(Index,Index)*/
  EIGEN_DEVICE_FUNC void resize(Index rows, Index cols) { m_expression.resize(rows, cols); }

 protected:
  NestedExpressionType m_expression;
};

/** \class MatrixWrapper
 * \ingroup Core_Module
 *
 * \brief Expression of an array as a mathematical vector or matrix
 *
 * This class is the return type of ArrayBase::matrix(), and most of the time
 * this is the only way it is used.
 *
 * \sa MatrixBase::matrix(), class ArrayWrapper
 */

namespace internal {
template <typename ExpressionType>
struct traits<MatrixWrapper<ExpressionType> > : public traits<remove_all_t<typename ExpressionType::Nested> > {
  typedef MatrixXpr XprKind;
  // Let's remove NestByRefBit
  enum {
    Flags0 = traits<remove_all_t<typename ExpressionType::Nested> >::Flags,
    LvalueBitFlag = is_lvalue<ExpressionType>::value ? LvalueBit : 0,
    Flags = (Flags0 & ~(NestByRefBit | LvalueBit)) | LvalueBitFlag
  };
};
}  // namespace internal

template <typename ExpressionType>
class MatrixWrapper : public MatrixBase<MatrixWrapper<ExpressionType> > {
 public:
  typedef MatrixBase<MatrixWrapper<ExpressionType> > Base;
  EIGEN_DENSE_PUBLIC_INTERFACE(MatrixWrapper)
  EIGEN_INHERIT_ASSIGNMENT_OPERATORS(MatrixWrapper)
  typedef internal::remove_all_t<ExpressionType> NestedExpression;

  typedef std::conditional_t<internal::is_lvalue<ExpressionType>::value, Scalar, const Scalar>
      ScalarWithConstIfNotLvalue;

  typedef typename internal::ref_selector<ExpressionType>::non_const_type NestedExpressionType;

  using Base::coeffRef;

  EIGEN_DEVICE_FUNC constexpr explicit inline MatrixWrapper(ExpressionType& matrix) : m_expression(matrix) {}

  EIGEN_DEVICE_FUNC constexpr Index rows() const noexcept { return m_expression.rows(); }
  EIGEN_DEVICE_FUNC constexpr Index cols() const noexcept { return m_expression.cols(); }
  EIGEN_DEVICE_FUNC constexpr Index outerStride() const noexcept { return m_expression.outerStride(); }
  EIGEN_DEVICE_FUNC constexpr Index innerStride() const noexcept { return m_expression.innerStride(); }

  EIGEN_DEVICE_FUNC constexpr ScalarWithConstIfNotLvalue* data() { return m_expression.data(); }
  EIGEN_DEVICE_FUNC constexpr const Scalar* data() const { return m_expression.data(); }

  EIGEN_DEVICE_FUNC inline const Scalar& coeffRef(Index rowId, Index colId) const {
    return m_expression.derived().coeffRef(rowId, colId);
  }

  EIGEN_DEVICE_FUNC inline const Scalar& coeffRef(Index index) const { return m_expression.coeffRef(index); }

  EIGEN_DEVICE_FUNC constexpr const internal::remove_all_t<NestedExpressionType>& nestedExpression() const {
    return m_expression;
  }

  /** Forwards the resizing request to the nested expression
   * \sa DenseBase::resize(Index)  */
  EIGEN_DEVICE_FUNC void resize(Index newSize) { m_expression.resize(newSize); }
  /** Forwards the resizing request to the nested expression
   * \sa DenseBase::resize(Index,Index)*/
  EIGEN_DEVICE_FUNC void resize(Index rows, Index cols) { m_expression.resize(rows, cols); }

 protected:
  NestedExpressionType m_expression;
};

}  // end namespace Eigen

#endif  // EIGEN_ARRAYWRAPPER_H