NoAlias.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009 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/.
// SPDX-License-Identifier: MPL-2.0
 
#ifndef EIGEN_NOALIAS_H
#define EIGEN_NOALIAS_H
 
// IWYU pragma: private
#include "./InternalHeaderCheck.h"
 
namespace Eigen {

template <typename ExpressionType, template <typename> class StorageBase>
class NoAlias {
 public:
  using Scalar = typename ExpressionType::Scalar;
 
  EIGEN_DEVICE_FUNC constexpr explicit NoAlias(ExpressionType& expression) : m_expression(expression) {}
 
  template <typename OtherDerived>
  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE ExpressionType& operator=(const StorageBase<OtherDerived>& other) {
    call_assignment_no_alias(m_expression, other.derived(),
                             internal::assign_op<Scalar, typename OtherDerived::Scalar>());
    return m_expression;
  }
 
  template <typename OtherDerived>
  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE ExpressionType& operator+=(const StorageBase<OtherDerived>& other) {
    call_assignment_no_alias(m_expression, other.derived(),
                             internal::add_assign_op<Scalar, typename OtherDerived::Scalar>());
    return m_expression;
  }
 
  template <typename OtherDerived>
  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE ExpressionType& operator-=(const StorageBase<OtherDerived>& other) {
    call_assignment_no_alias(m_expression, other.derived(),
                             internal::sub_assign_op<Scalar, typename OtherDerived::Scalar>());
    return m_expression;
  }
 
  EIGEN_DEVICE_FUNC constexpr ExpressionType& expression() const { return m_expression; }
 
 protected:
  ExpressionType& m_expression;
};

template <typename Derived>
NoAlias<Derived, MatrixBase> EIGEN_DEVICE_FUNC MatrixBase<Derived>::noalias() {
  return NoAlias<Derived, Eigen::MatrixBase>(derived());
}
 
}  // end namespace Eigen
 
#endif  // EIGEN_NOALIAS_H