eigen/Eigen/src/Core/Map.h

// 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 <g.gael@free.fr>
//
// Eigen 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.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen 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 or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.

#ifndef EIGEN_MAP_H
#define EIGEN_MAP_H

/** \class Map
  *
  * \brief A matrix or vector expression mapping an existing array of data.
  *
  * \param MatrixType the equivalent matrix type of the mapped data
  * \param Options specifies whether the pointer is \c Aligned, or \c Unaligned.
  *                The default is \c Unaligned.
  *
  * This class represents a matrix or vector expression mapping an existing array of data.
  * It can be used to let Eigen interface without any overhead with non-Eigen data structures,
  * such as plain C arrays or structures from other libraries.
  *
  * \b Tip: to change the array of data mapped by a Map object, you can use the C++
  * placement new syntax:
  *
  * Example: \include Map_placement_new.cpp
  * Output: \verbinclude Map_placement_new.out
  *
  * This class is the return type of Matrix::Map() but can also be used directly.
  *
  * \sa Matrix::Map()
  */
template<typename MatrixType, int Options, typename StrideType>
struct ei_traits<Map<MatrixType, Options, StrideType> >
  : public ei_traits<MatrixType>
{
  typedef typename MatrixType::Scalar Scalar;
  enum {
    InnerStride = StrideType::InnerStrideAtCompileTime,
    OuterStride = StrideType::OuterStrideAtCompileTime,
    HasNoInnerStride = InnerStride <= 1,
    HasNoOuterStride = OuterStride == 0,
    HasNoStride = HasNoInnerStride && HasNoOuterStride,
    IsAligned = int(int(Options)&Aligned)==Aligned,
    IsDynamicSize = MatrixType::SizeAtCompileTime==Dynamic,
    KeepsPacketAccess = bool(HasNoInnerStride)
                        && ( bool(IsDynamicSize)
                           || HasNoOuterStride
                           || ( OuterStride!=Dynamic && ((int(OuterStride)*sizeof(Scalar))%16)==0 ) ),
    Flags0 = ei_traits<MatrixType>::Flags,
    Flags1 = IsAligned ? int(Flags0) |  AlignedBit : int(Flags0) & ~AlignedBit,
    Flags2 = HasNoStride ? int(Flags1) : int(Flags1 & ~LinearAccessBit),
    Flags = KeepsPacketAccess ? int(Flags2) : (int(Flags2) & ~PacketAccessBit)
  };
};

template<typename MatrixType, int Options, typename StrideType> class Map
  : public MapBase<Map<MatrixType, Options, StrideType>,
                   typename MatrixType::template MakeBase<
                     Map<MatrixType, Options, StrideType>
                   >::Type>
{
  public:

    typedef MapBase<Map,typename MatrixType::template MakeBase<Map>::Type> Base;

    EIGEN_DENSE_PUBLIC_INTERFACE(Map)

    inline int innerStride() const
    {
      return StrideType::InnerStrideAtCompileTime != 0 ? m_stride.inner() : 1;
    }

    inline int outerStride() const
    {
      return StrideType::OuterStrideAtCompileTime != 0 ? m_stride.outer()
           : IsVectorAtCompileTime ? this->size()
           : int(Flags)&RowMajorBit ? this->cols()
           : this->rows();
    }

    inline Map(const Scalar* data, const StrideType& stride = StrideType())
      : Base(data), m_stride(stride) {}

    inline Map(const Scalar* data, int size, const StrideType& stride = StrideType())
      : Base(data, size), m_stride(stride) {}

    inline Map(const Scalar* data, int rows, int cols, const StrideType& stride = StrideType())
      : Base(data, rows, cols), m_stride(stride) {}

    EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Map)

  protected:
    StrideType m_stride;
};

template<typename _Scalar, int _Rows, int _Cols, int _StorageOrder, int _MaxRows, int _MaxCols>
inline Matrix<_Scalar, _Rows, _Cols, _StorageOrder, _MaxRows, _MaxCols>
  ::Matrix(const Scalar *data)
{
  _set_noalias(Eigen::Map<Matrix>(data));
}

#endif // EIGEN_MAP_H