text: // This file is part of Eigen, a lightweight C++ template library
  // for linear algebra.
  //
  // Copyright (C) 2007-2010 Benoit Jacob <jacob.benoit.1@gmail.com>
  // Copyright (C) 2008 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_MAPBASE_H
  #define EIGEN_MAPBASE_H
  
  #define EIGEN_STATIC_ASSERT_INDEX_BASED_ACCESS(Derived) \
        EIGEN_STATIC_ASSERT((int(internal::evaluator<Derived>::Flags) & LinearAccessBit) || Derived::IsVectorAtCompileTime, \
                            YOU_ARE_TRYING_TO_USE_AN_INDEX_BASED_ACCESSOR_ON_AN_EXPRESSION_THAT_DOES_NOT_SUPPORT_THAT)
  
  namespace Eigen { 
  
  /** \ingroup Core_Module
    *
    * \brief Base class for dense Map and Block expression with direct access
    *
    * This base class provides the const low-level accessors (e.g. coeff, coeffRef) of dense
    * Map and Block objects with direct access.
    * Typical users do not have to directly deal with this class.
    *
    * This class can be extended by through the macro plugin \c EIGEN_MAPBASE_PLUGIN.
    * See \link TopicCustomizing_Plugins customizing Eigen \endlink for details.
    *
    * The \c Derived class has to provide the following two methods describing the memory layout:
    *  \code Index innerStride() const; \endcode
    *  \code Index outerStride() const; \endcode
    *
    * \sa class Map, class Block
    */
  template<typename Derived> class MapBase<Derived, ReadOnlyAccessors>
    : public internal::dense_xpr_base<Derived>::type
  {
    public:
  
      typedef typename internal::dense_xpr_base<Derived>::type Base;
      enum {
        RowsAtCompileTime = internal::traits<Derived>::RowsAtCompileTime,
        ColsAtCompileTime = internal::traits<Derived>::ColsAtCompileTime,
        InnerStrideAtCompileTime = internal::traits<Derived>::InnerStrideAtCompileTime,
        SizeAtCompileTime = Base::SizeAtCompileTime
      };
  
      typedef typename internal::traits<Derived>::StorageKind StorageKind;
      typedef typename internal::traits<Derived>::Scalar Scalar;
      typedef typename internal::packet_traits<Scalar>::type PacketScalar;
      typedef typename NumTraits<Scalar>::Real RealScalar;
      typedef typename internal::conditional<
                           bool(internal::is_lvalue<Derived>::value),
                           Scalar *,
                           const Scalar *>::type
                       PointerType;
  
      using Base::derived;
  //    using Base::RowsAtCompileTime;
  //    using Base::ColsAtCompileTime;
  //    using Base::SizeAtCompileTime;
      using Base::MaxRowsAtCompileTime;
      using Base::MaxColsAtCompileTime;
      using Base::MaxSizeAtCompileTime;
      using Base::IsVectorAtCompileTime;
      using Base::Flags;
      using Base::IsRowMajor;
  
      using Base::rows;
      using Base::cols;
      using Base::size;
      using Base::coeff;
      using Base::coeffRef;
      using Base::lazyAssign;
      using Base::eval;
  
      using Base::innerStride;
      using Base::outerStride;
      using Base::rowStride;
      using Base::colStride;
  
      // bug 217 - compile error on ICC 11.1
      using Base::operator=;
  
      typedef typename Base::CoeffReturnType CoeffReturnType;
  
      /** \copydoc DenseBase::rows() */
      EIGEN_DEVICE_FUNC inline Index rows() const { return m_rows.value(); }
      /** \copydoc DenseBase::cols() */
      EIGEN_DEVICE_FUNC inline Index cols() const { return m_cols.value(); }
  
      /** Returns a pointer to the first coefficient of the matrix or vector.
        *
        * \note When addressing this data, make sure to honor the strides returned by innerStride() and outerStride().
        *
        * \sa innerStride(), outerStride()
        */
      EIGEN_DEVICE_FUNC inline const Scalar* data() const { return m_data; }
  
      /** \copydoc PlainObjectBase::coeff(Index,Index) const */
      EIGEN_DEVICE_FUNC
      inline const Scalar& coeff(Index rowId, Index colId) const
      {
        return m_data[colId * colStride() + rowId * rowStride()];
      }
  
      /** \copydoc PlainObjectBase::coeff(Index) const */
      EIGEN_DEVICE_FUNC
      inline const Scalar& coeff(Index index) const
      {
        EIGEN_STATIC_ASSERT_INDEX_BASED_ACCESS(Derived)
        return m_data[index * innerStride()];
      }
  
      /** \copydoc PlainObjectBase::coeffRef(Index,Index) const */
      EIGEN_DEVICE_FUNC
      inline const Scalar& coeffRef(Index rowId, Index colId) const
      {
        return this->m_data[colId * colStride() + rowId * rowStride()];
      }
  
      /** \copydoc PlainObjectBase::coeffRef(Index) const */
      EIGEN_DEVICE_FUNC
      inline const Scalar& coeffRef(Index index) const
      {
        EIGEN_STATIC_ASSERT_INDEX_BASED_ACCESS(Derived)
        return this->m_data[index * innerStride()];
      }
  
      /** \internal */
      template<int LoadMode>
      inline PacketScalar packet(Index rowId, Index colId) const
      {
        return internal::ploadt<PacketScalar, LoadMode>
                 (m_data + (colId * colStride() + rowId * rowStride()));
      }
  
      /** \internal */
      template<int LoadMode>
      inline PacketScalar packet(Index index) const
      {
        EIGEN_STATIC_ASSERT_INDEX_BASED_ACCESS(Derived)
        return internal::ploadt<PacketScalar, LoadMode>(m_data + index * innerStride());
      }
  
      /** \internal Constructor for fixed size matrices or vectors */
      EIGEN_DEVICE_FUNC
      explicit inline MapBase(PointerType dataPtr) : m_data(dataPtr), m_rows(RowsAtCompileTime), m_cols(ColsAtCompileTime)
      {
        EIGEN_STATIC_ASSERT_FIXED_SIZE(Derived)
        checkSanity<Derived>();
      }
  
      /** \internal Constructor for dynamically sized vectors */
      EIGEN_DEVICE_FUNC
      inline MapBase(PointerType dataPtr, Index vecSize)
              : m_data(dataPtr),
                m_rows(RowsAtCompileTime == Dynamic ? vecSize : Index(RowsAtCompileTime)),
                m_cols(ColsAtCompileTime == Dynamic ? vecSize : Index(ColsAtCompileTime))
      {
        EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
        eigen_assert(vecSize >= 0);
        eigen_assert(dataPtr == 0 || SizeAtCompileTime == Dynamic || SizeAtCompileTime == vecSize);
        checkSanity<Derived>();
      }
  
      /** \internal Constructor for dynamically sized matrices */
      EIGEN_DEVICE_FUNC
      inline MapBase(PointerType dataPtr, Index rows, Index cols)
              : m_data(dataPtr), m_rows(rows), m_cols(cols)
      {
        eigen_assert( (dataPtr == 0)
                || (   rows >= 0 && (RowsAtCompileTime == Dynamic || RowsAtCompileTime == rows)
                    && cols >= 0 && (ColsAtCompileTime == Dynamic || ColsAtCompileTime == cols)));
        checkSanity<Derived>();
      }
  
      #ifdef EIGEN_MAPBASE_PLUGIN
      #include EIGEN_MAPBASE_PLUGIN
      #endif
  
    protected:
  
      template<typename T>
      EIGEN_DEVICE_FUNC
      void checkSanity(typename internal::enable_if<(internal::traits<T>::Alignment>0),void*>::type = 0) const
      {
  #if EIGEN_MAX_ALIGN_BYTES>0
        // innerStride() is not set yet when this function is called, so we optimistically assume the lowest plausible value:
        const Index minInnerStride = InnerStrideAtCompileTime == Dynamic ? 1 : Index(InnerStrideAtCompileTime);
        EIGEN_ONLY_USED_FOR_DEBUG(minInnerStride);
        eigen_assert((   ((internal::UIntPtr(m_data) % internal::traits<Derived>::Alignment) == 0)
                      || (cols() * rows() * minInnerStride * sizeof(Scalar)) < internal::traits<Derived>::Alignment ) && "data is not aligned");
  #endif
      }
  
      template<typename T>
      EIGEN_DEVICE_FUNC
      void checkSanity(typename internal::enable_if<internal::traits<T>::Alignment==0,void*>::type = 0) const
      {}
  
      PointerType m_data;
      const internal::variable_if_dynamic<Index, RowsAtCompileTime> m_rows;
      const internal::variable_if_dynamic<Index, ColsAtCompileTime> m_cols;
  };
  
  /** \ingroup Core_Module
    *
    * \brief Base class for non-const dense Map and Block expression with direct access
    *
    * This base class provides the non-const low-level accessors (e.g. coeff and coeffRef) of
    * dense Map and Block objects with direct access.
    * It inherits MapBase<Derived, ReadOnlyAccessors> which defines the const variant for reading specific entries.
    *
    * \sa class Map, class Block
    */
  template<typename Derived> class MapBase<Derived, WriteAccessors>
    : public MapBase<Derived, ReadOnlyAccessors>
  {
      typedef MapBase<Derived, ReadOnlyAccessors> ReadOnlyMapBase;
    public:
  
      typedef MapBase<Derived, ReadOnlyAccessors> Base;
  
      typedef typename Base::Scalar Scalar;
      typedef typename Base::PacketScalar PacketScalar;
      typedef typename Base::StorageIndex StorageIndex;
      typedef typename Base::PointerType PointerType;
  
      using Base::derived;
      using Base::rows;
      using Base::cols;
      using Base::size;
      using Base::coeff;
      using Base::coeffRef;
  
      using Base::innerStride;
      using Base::outerStride;
      using Base::rowStride;
      using Base::colStride;
  
      typedef typename internal::conditional<
                      internal::is_lvalue<Derived>::value,
                      Scalar,
                      const Scalar
                    >::type ScalarWithConstIfNotLvalue;
  
      EIGEN_DEVICE_FUNC
      inline const Scalar* data() const { return this->m_data; }
      EIGEN_DEVICE_FUNC
      inline ScalarWithConstIfNotLvalue* data() { return this->m_data; } // no const-cast here so non-const-correct code will give a compile error
  
      EIGEN_DEVICE_FUNC
      inline ScalarWithConstIfNotLvalue& coeffRef(Index row, Index col)
      {
        return this->m_data[col * colStride() + row * rowStride()];
      }
  
      EIGEN_DEVICE_FUNC
      inline ScalarWithConstIfNotLvalue& coeffRef(Index index)
      {
        EIGEN_STATIC_ASSERT_INDEX_BASED_ACCESS(Derived)
        return this->m_data[index * innerStride()];
      }
  
      template<int StoreMode>
      inline void writePacket(Index row, Index col, const PacketScalar& val)
      {
        internal::pstoret<Scalar, PacketScalar, StoreMode>
                 (this->m_data + (col * colStride() + row * rowStride()), val);
      }
  
      template<int StoreMode>
      inline void writePacket(Index index, const PacketScalar& val)
      {
        EIGEN_STATIC_ASSERT_INDEX_BASED_ACCESS(Derived)
        internal::pstoret<Scalar, PacketScalar, StoreMode>
                  (this->m_data + index * innerStride(), val);
      }
  
      EIGEN_DEVICE_FUNC explicit inline MapBase(PointerType dataPtr) : Base(dataPtr) {}
      EIGEN_DEVICE_FUNC inline MapBase(PointerType dataPtr, Index vecSize) : Base(dataPtr, vecSize) {}
      EIGEN_DEVICE_FUNC inline MapBase(PointerType dataPtr, Index rows, Index cols) : Base(dataPtr, rows, cols) {}
  
      EIGEN_DEVICE_FUNC
      Derived& operator=(const MapBase& other)
      {
        ReadOnlyMapBase::Base::operator=(other);
        return derived();
      }
  
      // In theory we could simply refer to Base:Base::operator=, but MSVC does not like Base::Base,
      // see bugs 821 and 920.
      using ReadOnlyMapBase::Base::operator=;
  };
  
  #undef EIGEN_STATIC_ASSERT_INDEX_BASED_ACCESS
  
  } // end namespace Eigen
  
  #endif // EIGEN_MAPBASE_H
  