// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2009 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/.

#ifndef EIGEN_SPARSE_BLOCK_H
#define EIGEN_SPARSE_BLOCK_H

namespace Eigen { 

template<typename XprType, int BlockRows, int BlockCols>
class BlockImpl<XprType,BlockRows,BlockCols,true,Sparse>
  : public SparseMatrixBase<Block<XprType,BlockRows,BlockCols,true> >
{
    typedef typename internal::remove_all<typename XprType::Nested>::type _MatrixTypeNested;
    typedef Block<XprType, BlockRows, BlockCols, true> BlockType;
public:
    enum { IsRowMajor = internal::traits<BlockType>::IsRowMajor };
protected:
    enum { OuterSize = IsRowMajor ? BlockRows : BlockCols };
public:
    EIGEN_SPARSE_PUBLIC_INTERFACE(BlockType)
    
    class InnerIterator: public XprType::InnerIterator
    {
      public:
        inline InnerIterator(const BlockType& xpr, Index outer)
          : XprType::InnerIterator(xpr.m_matrix, xpr.m_outerStart + outer), m_outer(outer)
        {}
        inline Index row() const { return IsRowMajor ? m_outer : this->index(); }
        inline Index col() const { return IsRowMajor ? this->index() : m_outer; }
      protected:
        Index m_outer;
    };
    class ReverseInnerIterator: public XprType::ReverseInnerIterator
    {
      public:
        inline ReverseInnerIterator(const BlockType& xpr, Index outer)
          : XprType::ReverseInnerIterator(xpr.m_matrix, xpr.m_outerStart + outer), m_outer(outer)
        {}
        inline Index row() const { return IsRowMajor ? m_outer : this->index(); }
        inline Index col() const { return IsRowMajor ? this->index() : m_outer; }
      protected:
        Index m_outer;
    };

    inline BlockImpl(const XprType& xpr, int i)
      : m_matrix(xpr), m_outerStart(i), m_outerSize(OuterSize)
    {}

    inline BlockImpl(const XprType& xpr, int startRow, int startCol, int blockRows, int blockCols)
      : m_matrix(xpr), m_outerStart(IsRowMajor ? startRow : startCol), m_outerSize(IsRowMajor ? blockRows : blockCols)
    {}

    EIGEN_STRONG_INLINE Index rows() const { return IsRowMajor ? m_outerSize.value() : m_matrix.rows(); }
    EIGEN_STRONG_INLINE Index cols() const { return IsRowMajor ? m_matrix.cols() : m_outerSize.value(); }

  protected:

    const typename XprType::Nested m_matrix;
    Index m_outerStart;
    const internal::variable_if_dynamic<Index, OuterSize> m_outerSize;
};


/***************************************************************************
* specialisation for SparseMatrix
***************************************************************************/

template<typename _Scalar, int _Options, typename _Index, int BlockRows, int BlockCols>
class BlockImpl<SparseMatrix<_Scalar, _Options, _Index>,BlockRows,BlockCols,true,Sparse>
  : public SparseMatrixBase<Block<SparseMatrix<_Scalar, _Options, _Index>,BlockRows,BlockCols,true> >
{
    typedef SparseMatrix<_Scalar, _Options, _Index> SparseMatrixType;
    typedef typename internal::remove_all<typename SparseMatrixType::Nested>::type _MatrixTypeNested;
    typedef Block<SparseMatrixType, BlockRows, BlockCols, true> BlockType;
public:
    enum { IsRowMajor = internal::traits<BlockType>::IsRowMajor };
    EIGEN_SPARSE_PUBLIC_INTERFACE(BlockType)
protected:
    enum { OuterSize = IsRowMajor ? BlockRows : BlockCols };
public:
    
    class InnerIterator: public SparseMatrixType::InnerIterator
    {
      public:
        inline InnerIterator(const BlockType& xpr, Index outer)
          : SparseMatrixType::InnerIterator(xpr.m_matrix, xpr.m_outerStart + outer), m_outer(outer)
        {}
        inline Index row() const { return IsRowMajor ? m_outer : this->index(); }
        inline Index col() const { return IsRowMajor ? this->index() : m_outer; }
      protected:
        Index m_outer;
    };
    class ReverseInnerIterator: public SparseMatrixType::ReverseInnerIterator
    {
      public:
        inline ReverseInnerIterator(const BlockType& xpr, Index outer)
          : SparseMatrixType::ReverseInnerIterator(xpr.m_matrix, xpr.m_outerStart + outer), m_outer(outer)
        {}
        inline Index row() const { return IsRowMajor ? m_outer : this->index(); }
        inline Index col() const { return IsRowMajor ? this->index() : m_outer; }
      protected:
        Index m_outer;
    };

    inline BlockImpl(const SparseMatrixType& xpr, int i)
      : m_matrix(xpr), m_outerStart(i), m_outerSize(OuterSize)
    {}

    inline BlockImpl(const SparseMatrixType& xpr, int startRow, int startCol, int blockRows, int blockCols)
      : m_matrix(xpr), m_outerStart(IsRowMajor ? startRow : startCol), m_outerSize(IsRowMajor ? blockRows : blockCols)
    {}

    template<typename OtherDerived>
    inline BlockType& operator=(const SparseMatrixBase<OtherDerived>& other)
    {
      typedef typename internal::remove_all<typename SparseMatrixType::Nested>::type _NestedMatrixType;
      _NestedMatrixType& matrix = const_cast<_NestedMatrixType&>(m_matrix);;
      // This assignement is slow if this vector set is not empty
      // and/or it is not at the end of the nonzeros of the underlying matrix.

      // 1 - eval to a temporary to avoid transposition and/or aliasing issues
      SparseMatrix<Scalar, IsRowMajor ? RowMajor : ColMajor, Index> tmp(other);

      // 2 - let's check whether there is enough allocated memory
      Index nnz           = tmp.nonZeros();
      Index nnz_previous  = nonZeros();
      Index free_size     = Index(matrix.data().allocatedSize()) + nnz_previous;
      Index nnz_head      = m_outerStart==0 ? 0 : matrix.outerIndexPtr()[m_outerStart];
      Index tail          = m_matrix.outerIndexPtr()[m_outerStart+m_outerSize.value()];
      Index nnz_tail      = matrix.nonZeros() - tail;

      if(nnz>free_size)
      {
        // realloc manually to reduce copies
        typename SparseMatrixType::Storage newdata(m_matrix.nonZeros() - nnz_previous + nnz);

        std::memcpy(&newdata.value(0), &m_matrix.data().value(0), nnz_head*sizeof(Scalar));
        std::memcpy(&newdata.index(0), &m_matrix.data().index(0), nnz_head*sizeof(Index));

        std::memcpy(&newdata.value(nnz_head), &tmp.data().value(0), nnz*sizeof(Scalar));
        std::memcpy(&newdata.index(nnz_head), &tmp.data().index(0), nnz*sizeof(Index));

        std::memcpy(&newdata.value(nnz_head+nnz), &matrix.data().value(tail), nnz_tail*sizeof(Scalar));
        std::memcpy(&newdata.index(nnz_head+nnz), &matrix.data().index(tail), nnz_tail*sizeof(Index));

        matrix.data().swap(newdata);
      }
      else
      {
        // no need to realloc, simply copy the tail at its respective position and insert tmp
        matrix.data().resize(nnz_head + nnz + nnz_tail);

        if(nnz<nnz_previous)
        {
          std::memcpy(&matrix.data().value(nnz_head+nnz), &matrix.data().value(tail), nnz_tail*sizeof(Scalar));
          std::memcpy(&matrix.data().index(nnz_head+nnz), &matrix.data().index(tail), nnz_tail*sizeof(Index));
        }
        else
        {
          for(Index i=nnz_tail-1; i>=0; --i)
          {
            matrix.data().value(nnz_head+nnz+i) = matrix.data().value(tail+i);
            matrix.data().index(nnz_head+nnz+i) = matrix.data().index(tail+i);
          }
        }

        std::memcpy(&matrix.data().value(nnz_head), &tmp.data().value(0), nnz*sizeof(Scalar));
        std::memcpy(&matrix.data().index(nnz_head), &tmp.data().index(0), nnz*sizeof(Index));
      }

      // update outer index pointers
      Index p = nnz_head;
      for(Index k=0; k<m_outerSize.value(); ++k)
      {
        matrix.outerIndexPtr()[m_outerStart+k] = p;
        p += tmp.innerVector(k).nonZeros();
      }
      std::ptrdiff_t offset = nnz - nnz_previous;
      for(Index k = m_outerStart + m_outerSize.value(); k<=matrix.outerSize(); ++k)
      {
        matrix.outerIndexPtr()[k] += offset;
      }

      return derived();
    }

    inline BlockType& operator=(const BlockType& other)
    {
      return operator=<BlockType>(other);
    }

    inline const Scalar* valuePtr() const
    { return m_matrix.valuePtr() + m_matrix.outerIndexPtr()[m_outerStart]; }
    inline Scalar* valuePtr()
    { return m_matrix.const_cast_derived().valuePtr() + m_matrix.outerIndexPtr()[m_outerStart]; }

    inline const Index* innerIndexPtr() const
    { return m_matrix.innerIndexPtr() + m_matrix.outerIndexPtr()[m_outerStart]; }
    inline Index* innerIndexPtr()
    { return m_matrix.const_cast_derived().innerIndexPtr() + m_matrix.outerIndexPtr()[m_outerStart]; }

    inline const Index* outerIndexPtr() const
    { return m_matrix.outerIndexPtr() + m_outerStart; }
    inline Index* outerIndexPtr()
    { return m_matrix.const_cast_derived().outerIndexPtr() + m_outerStart; }

    Index nonZeros() const
    {
      if(m_matrix.isCompressed())
        return  std::size_t(m_matrix.outerIndexPtr()[m_outerStart+m_outerSize.value()])
              - std::size_t(m_matrix.outerIndexPtr()[m_outerStart]);
      else if(m_outerSize.value()==0)
        return 0;
      else
        return Map<const Matrix<Index,OuterSize,1> >(m_matrix.innerNonZeroPtr()+m_outerStart, m_outerSize.value()).sum();
    }

    const Scalar& lastCoeff() const
    {
      EIGEN_STATIC_ASSERT_VECTOR_ONLY(BlockImpl);
      eigen_assert(nonZeros()>0);
      if(m_matrix.isCompressed())
        return m_matrix.valuePtr()[m_matrix.outerIndexPtr()[m_outerStart+1]-1];
      else
        return m_matrix.valuePtr()[m_matrix.outerIndexPtr()[m_outerStart]+m_matrix.innerNonZeroPtr()[m_outerStart]-1];
    }

    EIGEN_STRONG_INLINE Index rows() const { return IsRowMajor ? m_outerSize.value() : m_matrix.rows(); }
    EIGEN_STRONG_INLINE Index cols() const { return IsRowMajor ? m_matrix.cols() : m_outerSize.value(); }

  protected:

    typename SparseMatrixType::Nested m_matrix;
    Index m_outerStart;
    const internal::variable_if_dynamic<Index, OuterSize> m_outerSize;

};

//----------

/** \returns the \a outer -th column (resp. row) of the matrix \c *this if \c *this
  * is col-major (resp. row-major).
  */
template<typename Derived>
typename SparseMatrixBase<Derived>::InnerVectorReturnType SparseMatrixBase<Derived>::innerVector(Index outer)
{ return InnerVectorReturnType(derived(), outer); }

/** \returns the \a outer -th column (resp. row) of the matrix \c *this if \c *this
  * is col-major (resp. row-major). Read-only.
  */
template<typename Derived>
const typename SparseMatrixBase<Derived>::ConstInnerVectorReturnType SparseMatrixBase<Derived>::innerVector(Index outer) const
{ return ConstInnerVectorReturnType(derived(), outer); }

/** \returns the \a outer -th column (resp. row) of the matrix \c *this if \c *this
  * is col-major (resp. row-major).
  */
template<typename Derived>
Block<Derived,Dynamic,Dynamic,true> SparseMatrixBase<Derived>::innerVectors(Index outerStart, Index outerSize)
{
  return Block<Derived,Dynamic,Dynamic,true>(derived(),
                                             IsRowMajor ? outerStart : 0, IsRowMajor ? 0 : outerStart,
                                             IsRowMajor ? outerSize : rows(), IsRowMajor ? cols() : outerSize);
  
}

/** \returns the \a outer -th column (resp. row) of the matrix \c *this if \c *this
  * is col-major (resp. row-major). Read-only.
  */
template<typename Derived>
const Block<const Derived,Dynamic,Dynamic,true> SparseMatrixBase<Derived>::innerVectors(Index outerStart, Index outerSize) const
{
  return Block<const Derived,Dynamic,Dynamic,true>(derived(),
                                                  IsRowMajor ? outerStart : 0, IsRowMajor ? 0 : outerStart,
                                                  IsRowMajor ? outerSize : rows(), IsRowMajor ? cols() : outerSize);
  
}

/** Generic implementation of sparse Block expression.
  * Real-only. 
  */
template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
class BlockImpl<XprType,BlockRows,BlockCols,InnerPanel,Sparse>
  : public SparseMatrixBase<Block<XprType,BlockRows,BlockCols,InnerPanel> >, internal::no_assignment_operator
{
  typedef typename internal::remove_all<typename XprType::Nested>::type _MatrixTypeNested;
  typedef Block<XprType, BlockRows, BlockCols, InnerPanel> BlockType;
public:
    enum { IsRowMajor = internal::traits<BlockType>::IsRowMajor };
    EIGEN_SPARSE_PUBLIC_INTERFACE(BlockType)

    /** Column or Row constructor
      */
    inline BlockImpl(const XprType& xpr, int i)
      : m_matrix(xpr),
        m_startRow( (BlockRows==1) && (BlockCols==XprType::ColsAtCompileTime) ? i : 0),
        m_startCol( (BlockRows==XprType::RowsAtCompileTime) && (BlockCols==1) ? i : 0),
        m_blockRows(xpr.rows()),
        m_blockCols(xpr.cols())
    {}

    /** Dynamic-size constructor
      */
    inline BlockImpl(const XprType& xpr, int startRow, int startCol, int blockRows, int blockCols)
      : m_matrix(xpr), m_startRow(startRow), m_startCol(startCol), m_blockRows(blockRows), m_blockCols(blockCols)
    {}

    inline int rows() const { return m_blockRows.value(); }
    inline int cols() const { return m_blockCols.value(); }

    inline Scalar& coeffRef(int row, int col)
    {
      return m_matrix.const_cast_derived()
               .coeffRef(row + m_startRow.value(), col + m_startCol.value());
    }

    inline const Scalar coeff(int row, int col) const
    {
      return m_matrix.coeff(row + m_startRow.value(), col + m_startCol.value());
    }

    inline Scalar& coeffRef(int index)
    {
      return m_matrix.const_cast_derived()
             .coeffRef(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
                       m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
    }

    inline const Scalar coeff(int index) const
    {
      return m_matrix
             .coeff(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
                    m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
    }
    
    inline const _MatrixTypeNested& nestedExpression() const { return m_matrix; }
    
    class InnerIterator : public _MatrixTypeNested::InnerIterator
    {
      typedef typename _MatrixTypeNested::InnerIterator Base;
      const BlockType& m_block;
      Index m_end;
    public:

      EIGEN_STRONG_INLINE InnerIterator(const BlockType& block, Index outer)
        : Base(block.derived().nestedExpression(), outer + (IsRowMajor ? block.m_startRow.value() : block.m_startCol.value())),
          m_block(block),
          m_end(IsRowMajor ? block.m_startCol.value()+block.m_blockCols.value() : block.m_startRow.value()+block.m_blockRows.value())
      {
        while(Base::index() < (IsRowMajor ? m_block.m_startCol.value() : m_block.m_startRow.value()))
          Base::operator++();
      }

      inline Index index()  const { return Base::index() - (IsRowMajor ? m_block.m_startCol.value() : m_block.m_startRow.value()); }
      inline Index outer()  const { return Base::outer() - (IsRowMajor ? m_block.m_startRow.value() : m_block.m_startCol.value()); }
      inline Index row()    const { return Base::row()   - m_block.m_startRow.value(); }
      inline Index col()    const { return Base::col()   - m_block.m_startCol.value(); }
      
      inline operator bool() const { return Base::operator bool() && Base::index() < m_end; }
    };
    class ReverseInnerIterator : public _MatrixTypeNested::ReverseInnerIterator
    {
      typedef typename _MatrixTypeNested::ReverseInnerIterator Base;
      const BlockType& m_block;
      Index m_begin;
    public:

      EIGEN_STRONG_INLINE ReverseInnerIterator(const BlockType& block, Index outer)
        : Base(block.derived().nestedExpression(), outer + (IsRowMajor ? block.m_startRow.value() : block.m_startCol.value())),
          m_block(block),
          m_begin(IsRowMajor ? block.m_startCol.value() : block.m_startRow.value())
      {
        while(Base::index() >= (IsRowMajor ? m_block.m_startCol.value()+block.m_blockCols.value() : m_block.m_startRow.value()+block.m_blockRows.value()) )
          Base::operator--();
      }

      inline Index index()  const { return Base::index() - (IsRowMajor ? m_block.m_startCol.value() : m_block.m_startRow.value()); }
      inline Index outer()  const { return Base::outer() - (IsRowMajor ? m_block.m_startRow.value() : m_block.m_startCol.value()); }
      inline Index row()    const { return Base::row()   - m_block.m_startRow.value(); }
      inline Index col()    const { return Base::col()   - m_block.m_startCol.value(); }
      
      inline operator bool() const { return Base::operator bool() && Base::index() >= m_begin; }
    };
  protected:
    friend class InnerIterator;
    friend class ReverseInnerIterator;

    const typename XprType::Nested m_matrix;
    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;

};

} // end namespace Eigen

#endif // EIGEN_SPARSE_BLOCK_H