text: // This file is part of Eigen, a lightweight C++ template library
  // for linear algebra.
  //
  // Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
  // Copyright (C) 2006-2010 Benoit Jacob <jacob.benoit.1@gmail.com>
  //
  // 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_BLOCK_H
  #define EIGEN_BLOCK_H
  
  namespace Eigen { 
  
  /** \class Block
    * \ingroup Core_Module
    *
    * \brief Expression of a fixed-size or dynamic-size block
    *
    * \param XprType the type of the expression in which we are taking a block
    * \param BlockRows the number of rows of the block we are taking at compile time (optional)
    * \param BlockCols the number of columns of the block we are taking at compile time (optional)
    *
    * This class represents an expression of either a fixed-size or dynamic-size block. It is the return
    * type of DenseBase::block(Index,Index,Index,Index) and DenseBase::block<int,int>(Index,Index) and
    * most of the time this is the only way it is used.
    *
    * However, if you want to directly maniputate block expressions,
    * for instance if you want to write a function returning such an expression, you
    * will need to use this class.
    *
    * Here is an example illustrating the dynamic case:
    * \include class_Block.cpp
    * Output: \verbinclude class_Block.out
    *
    * \note Even though this expression has dynamic size, in the case where \a XprType
    * has fixed size, this expression inherits a fixed maximal size which means that evaluating
    * it does not cause a dynamic memory allocation.
    *
    * Here is an example illustrating the fixed-size case:
    * \include class_FixedBlock.cpp
    * Output: \verbinclude class_FixedBlock.out
    *
    * \sa DenseBase::block(Index,Index,Index,Index), DenseBase::block(Index,Index), class VectorBlock
    */
  
  namespace internal {
  template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
  struct traits<Block<XprType, BlockRows, BlockCols, InnerPanel> > : traits<XprType>
  {
    typedef typename traits<XprType>::Scalar Scalar;
    typedef typename traits<XprType>::StorageKind StorageKind;
    typedef typename traits<XprType>::XprKind XprKind;
    typedef typename nested<XprType>::type XprTypeNested;
    typedef typename remove_reference<XprTypeNested>::type _XprTypeNested;
    enum{
      MatrixRows = traits<XprType>::RowsAtCompileTime,
      MatrixCols = traits<XprType>::ColsAtCompileTime,
      RowsAtCompileTime = MatrixRows == 0 ? 0 : BlockRows,
      ColsAtCompileTime = MatrixCols == 0 ? 0 : BlockCols,
      MaxRowsAtCompileTime = BlockRows==0 ? 0
                           : RowsAtCompileTime != Dynamic ? int(RowsAtCompileTime)
                           : int(traits<XprType>::MaxRowsAtCompileTime),
      MaxColsAtCompileTime = BlockCols==0 ? 0
                           : ColsAtCompileTime != Dynamic ? int(ColsAtCompileTime)
                           : int(traits<XprType>::MaxColsAtCompileTime),
      XprTypeIsRowMajor = (int(traits<XprType>::Flags)&RowMajorBit) != 0,
      IsRowMajor = (MaxRowsAtCompileTime==1&&MaxColsAtCompileTime!=1) ? 1
                 : (MaxColsAtCompileTime==1&&MaxRowsAtCompileTime!=1) ? 0
                 : XprTypeIsRowMajor,
      HasSameStorageOrderAsXprType = (IsRowMajor == XprTypeIsRowMajor),
      InnerSize = IsRowMajor ? int(ColsAtCompileTime) : int(RowsAtCompileTime),
      InnerStrideAtCompileTime = HasSameStorageOrderAsXprType
                               ? int(inner_stride_at_compile_time<XprType>::ret)
                               : int(outer_stride_at_compile_time<XprType>::ret),
      OuterStrideAtCompileTime = HasSameStorageOrderAsXprType
                               ? int(outer_stride_at_compile_time<XprType>::ret)
                               : int(inner_stride_at_compile_time<XprType>::ret),
      MaskPacketAccessBit = (InnerSize == Dynamic || (InnerSize % packet_traits<Scalar>::size) == 0)
                         && (InnerStrideAtCompileTime == 1)
                          ? PacketAccessBit : 0,
      MaskAlignedBit = (InnerPanel && (OuterStrideAtCompileTime!=Dynamic) && (((OuterStrideAtCompileTime * int(sizeof(Scalar))) % 16) == 0)) ? AlignedBit : 0,
      FlagsLinearAccessBit = (RowsAtCompileTime == 1 || ColsAtCompileTime == 1) ? LinearAccessBit : 0,
      FlagsLvalueBit = is_lvalue<XprType>::value ? LvalueBit : 0,
      FlagsRowMajorBit = IsRowMajor ? RowMajorBit : 0,
      Flags0 = traits<XprType>::Flags & ( (HereditaryBits & ~RowMajorBit) |
                                          DirectAccessBit |
                                          MaskPacketAccessBit |
                                          MaskAlignedBit),
      Flags = Flags0 | FlagsLinearAccessBit | FlagsLvalueBit | FlagsRowMajorBit
    };
  };
  
  template<typename XprType, int BlockRows=Dynamic, int BlockCols=Dynamic, bool InnerPanel = false,
           bool HasDirectAccess = internal::has_direct_access<XprType>::ret> class BlockImpl_dense;
           
  } // end namespace internal
  
  template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel, typename StorageKind> class BlockImpl;
  
  template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel> class Block
    : public BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, typename internal::traits<XprType>::StorageKind>
  {
      typedef BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, typename internal::traits<XprType>::StorageKind> Impl;
    public:
      //typedef typename Impl::Base Base;
      typedef Impl Base;
      EIGEN_GENERIC_PUBLIC_INTERFACE(Block)
      EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Block)
    
      /** Column or Row constructor
        */
      inline Block(XprType& xpr, Index i) : Impl(xpr,i)
      {
        eigen_assert( (i>=0) && (
            ((BlockRows==1) && (BlockCols==XprType::ColsAtCompileTime) && i<xpr.rows())
          ||((BlockRows==XprType::RowsAtCompileTime) && (BlockCols==1) && i<xpr.cols())));
      }
  
      /** Fixed-size constructor
        */
      inline Block(XprType& xpr, Index a_startRow, Index a_startCol)
        : Impl(xpr, a_startRow, a_startCol)
      {
        EIGEN_STATIC_ASSERT(RowsAtCompileTime!=Dynamic && ColsAtCompileTime!=Dynamic,THIS_METHOD_IS_ONLY_FOR_FIXED_SIZE)
        eigen_assert(a_startRow >= 0 && BlockRows >= 1 && a_startRow + BlockRows <= xpr.rows()
               && a_startCol >= 0 && BlockCols >= 1 && a_startCol + BlockCols <= xpr.cols());
      }
  
      /** Dynamic-size constructor
        */
      inline Block(XprType& xpr,
            Index a_startRow, Index a_startCol,
            Index blockRows, Index blockCols)
        : Impl(xpr, a_startRow, a_startCol, blockRows, blockCols)
      {
        eigen_assert((RowsAtCompileTime==Dynamic || RowsAtCompileTime==blockRows)
            && (ColsAtCompileTime==Dynamic || ColsAtCompileTime==blockCols));
        eigen_assert(a_startRow >= 0 && blockRows >= 0 && a_startRow  <= xpr.rows() - blockRows
            && a_startCol >= 0 && blockCols >= 0 && a_startCol <= xpr.cols() - blockCols);
      }
  };
           
  // The generic default implementation for dense block simplu forward to the internal::BlockImpl_dense
  // that must be specialized for direct and non-direct access...
  template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
  class BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, Dense>
    : public internal::BlockImpl_dense<XprType, BlockRows, BlockCols, InnerPanel>
  {
      typedef internal::BlockImpl_dense<XprType, BlockRows, BlockCols, InnerPanel> Impl;
      typedef typename XprType::Index Index;
    public:
      typedef Impl Base;
      EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl)
      inline BlockImpl(XprType& xpr, Index i) : Impl(xpr,i) {}
      inline BlockImpl(XprType& xpr, Index a_startRow, Index a_startCol) : Impl(xpr, a_startRow, a_startCol) {}
      inline BlockImpl(XprType& xpr, Index a_startRow, Index a_startCol, Index blockRows, Index blockCols)
        : Impl(xpr, a_startRow, a_startCol, blockRows, blockCols) {}
  };
  
  namespace internal {
  
  /** \internal Internal implementation of dense Blocks in the general case. */
  template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel, bool HasDirectAccess> class BlockImpl_dense
    : public internal::dense_xpr_base<Block<XprType, BlockRows, BlockCols, InnerPanel> >::type
  {
      typedef Block<XprType, BlockRows, BlockCols, InnerPanel> BlockType;
    public:
  
      typedef typename internal::dense_xpr_base<BlockType>::type Base;
      EIGEN_DENSE_PUBLIC_INTERFACE(BlockType)
      EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl_dense)
  
      class InnerIterator;
  
      /** Column or Row constructor
        */
      inline BlockImpl_dense(XprType& xpr, Index i)
        : m_xpr(xpr),
          // It is a row if and only if BlockRows==1 and BlockCols==XprType::ColsAtCompileTime,
          // and it is a column if and only if BlockRows==XprType::RowsAtCompileTime and BlockCols==1,
          // all other cases are invalid.
          // The case a 1x1 matrix seems ambiguous, but the result is the same anyway.
          m_startRow( (BlockRows==1) && (BlockCols==XprType::ColsAtCompileTime) ? i : 0),
          m_startCol( (BlockRows==XprType::RowsAtCompileTime) && (BlockCols==1) ? i : 0),
          m_blockRows(BlockRows==1 ? 1 : xpr.rows()),
          m_blockCols(BlockCols==1 ? 1 : xpr.cols())
      {}
  
      /** Fixed-size constructor
        */
      inline BlockImpl_dense(XprType& xpr, Index a_startRow, Index a_startCol)
        : m_xpr(xpr), m_startRow(a_startRow), m_startCol(a_startCol),
                      m_blockRows(BlockRows), m_blockCols(BlockCols)
      {}
  
      /** Dynamic-size constructor
        */
      inline BlockImpl_dense(XprType& xpr,
            Index a_startRow, Index a_startCol,
            Index blockRows, Index blockCols)
        : m_xpr(xpr), m_startRow(a_startRow), m_startCol(a_startCol),
                      m_blockRows(blockRows), m_blockCols(blockCols)
      {}
  
      inline Index rows() const { return m_blockRows.value(); }
      inline Index cols() const { return m_blockCols.value(); }
  
      inline Scalar& coeffRef(Index rowId, Index colId)
      {
        EIGEN_STATIC_ASSERT_LVALUE(XprType)
        return m_xpr.const_cast_derived()
                 .coeffRef(rowId + m_startRow.value(), colId + m_startCol.value());
      }
  
      inline const Scalar& coeffRef(Index rowId, Index colId) const
      {
        return m_xpr.derived()
                 .coeffRef(rowId + m_startRow.value(), colId + m_startCol.value());
      }
  
      EIGEN_STRONG_INLINE const CoeffReturnType coeff(Index rowId, Index colId) const
      {
        return m_xpr.coeff(rowId + m_startRow.value(), colId + m_startCol.value());
      }
  
      inline Scalar& coeffRef(Index index)
      {
        EIGEN_STATIC_ASSERT_LVALUE(XprType)
        return m_xpr.const_cast_derived()
               .coeffRef(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
                         m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
      }
  
      inline const Scalar& coeffRef(Index index) const
      {
        return m_xpr.const_cast_derived()
               .coeffRef(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
                         m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
      }
  
      inline const CoeffReturnType coeff(Index index) const
      {
        return m_xpr
               .coeff(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
                      m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
      }
  
      template<int LoadMode>
      inline PacketScalar packet(Index rowId, Index colId) const
      {
        return m_xpr.template packet<Unaligned>
                (rowId + m_startRow.value(), colId + m_startCol.value());
      }
  
      template<int LoadMode>
      inline void writePacket(Index rowId, Index colId, const PacketScalar& val)
      {
        m_xpr.const_cast_derived().template writePacket<Unaligned>
                (rowId + m_startRow.value(), colId + m_startCol.value(), val);
      }
  
      template<int LoadMode>
      inline PacketScalar packet(Index index) const
      {
        return m_xpr.template packet<Unaligned>
                (m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
                 m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
      }
  
      template<int LoadMode>
      inline void writePacket(Index index, const PacketScalar& val)
      {
        m_xpr.const_cast_derived().template writePacket<Unaligned>
           (m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
            m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0), val);
      }
  
      #ifdef EIGEN_PARSED_BY_DOXYGEN
      /** \sa MapBase::data() */
      inline const Scalar* data() const;
      inline Index innerStride() const;
      inline Index outerStride() const;
      #endif
  
      const typename internal::remove_all<typename XprType::Nested>::type& nestedExpression() const 
      { 
        return m_xpr; 
      }
        
      Index startRow() const 
      { 
        return m_startRow.value(); 
      }
        
      Index startCol() const 
      { 
        return m_startCol.value(); 
      }
  
    protected:
  
      const typename XprType::Nested m_xpr;
      const internal::variable_if_dynamic<Index, XprType::RowsAtCompileTime == 1 ? 0 : Dynamic> m_startRow;
      const internal::variable_if_dynamic<Index, XprType::ColsAtCompileTime == 1 ? 0 : Dynamic> m_startCol;
      const internal::variable_if_dynamic<Index, RowsAtCompileTime> m_blockRows;
      const internal::variable_if_dynamic<Index, ColsAtCompileTime> m_blockCols;
  };
  
  /** \internal Internal implementation of dense Blocks in the direct access case.*/
  template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
  class BlockImpl_dense<XprType,BlockRows,BlockCols, InnerPanel,true>
    : public MapBase<Block<XprType, BlockRows, BlockCols, InnerPanel> >
  {
      typedef Block<XprType, BlockRows, BlockCols, InnerPanel> BlockType;
    public:
  
      typedef MapBase<BlockType> Base;
      EIGEN_DENSE_PUBLIC_INTERFACE(BlockType)
      EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl_dense)
  
      /** Column or Row constructor
        */
      inline BlockImpl_dense(XprType& xpr, Index i)
        : Base(internal::const_cast_ptr(&xpr.coeffRef(
                (BlockRows==1) && (BlockCols==XprType::ColsAtCompileTime) ? i : 0,
                (BlockRows==XprType::RowsAtCompileTime) && (BlockCols==1) ? i : 0)),
               BlockRows==1 ? 1 : xpr.rows(),
               BlockCols==1 ? 1 : xpr.cols()),
          m_xpr(xpr)
      {
        init();
      }
  
      /** Fixed-size constructor
        */
      inline BlockImpl_dense(XprType& xpr, Index startRow, Index startCol)
        : Base(internal::const_cast_ptr(&xpr.coeffRef(startRow,startCol))), m_xpr(xpr)
      {
        init();
      }
  
      /** Dynamic-size constructor
        */
      inline BlockImpl_dense(XprType& xpr,
            Index startRow, Index startCol,
            Index blockRows, Index blockCols)
        : Base(internal::const_cast_ptr(&xpr.coeffRef(startRow,startCol)), blockRows, blockCols),
          m_xpr(xpr)
      {
        init();
      }
  
      const typename internal::remove_all<typename XprType::Nested>::type& nestedExpression() const 
      { 
        return m_xpr; 
      }
        
      /** \sa MapBase::innerStride() */
      inline Index innerStride() const
      {
        return internal::traits<BlockType>::HasSameStorageOrderAsXprType
               ? m_xpr.innerStride()
               : m_xpr.outerStride();
      }
  
      /** \sa MapBase::outerStride() */
      inline Index outerStride() const
      {
        return m_outerStride;
      }
  
    #ifndef __SUNPRO_CC
    // FIXME sunstudio is not friendly with the above friend...
    // META-FIXME there is no 'friend' keyword around here. Is this obsolete?
    protected:
    #endif
  
      #ifndef EIGEN_PARSED_BY_DOXYGEN
      /** \internal used by allowAligned() */
      inline BlockImpl_dense(XprType& xpr, const Scalar* data, Index blockRows, Index blockCols)
        : Base(data, blockRows, blockCols), m_xpr(xpr)
      {
        init();
      }
      #endif
  
    protected:
      void init()
      {
        m_outerStride = internal::traits<BlockType>::HasSameStorageOrderAsXprType
                      ? m_xpr.outerStride()
                      : m_xpr.innerStride();
      }
  
      typename XprType::Nested m_xpr;
      Index m_outerStride;
  };
  
  } // end namespace internal
  
  } // end namespace Eigen
  
  #endif // EIGEN_BLOCK_H
  