fassign.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_ASSIGN_HH
#define DUNE_ASSIGN_HH
 
#include <dune/common/fvector.hh>
#include <dune/common/fmatrix.hh>
#include <dune/common/unused.hh>
 
namespace Dune {
 
  namespace {
 
    struct Zero {
      explicit Zero (int) {};
      operator double () { return 0.0; }
      operator int () { return 0; }
    } zero(0);
 
    struct NextRow {
      explicit NextRow (int) {};
    } nextRow(0);
  } // end empty namespace
 
  template <class T, int s>
  class fvector_assigner
  {
  private:
    FieldVector<T,s> & v;
    int c;
    bool temporary;
    fvector_assigner();
  public:
    fvector_assigner(fvector_assigner & a) : v(a.v), c(a.c), temporary(false)
    {}
    fvector_assigner(FieldVector<T,s> & _v, bool t) : v(_v), c(0), temporary(t)
    {};
    ~fvector_assigner()
    {
      if (!temporary && c!=s)
        DUNE_THROW(MathError, "Trying to assign " << c <<
                   " entries to a FieldVector of size " << s);
    }
    fvector_assigner & append (const T & t)
    {
      v[c++] = t;
      return *this;
    }
    fvector_assigner & append (Zero z)
    {
      DUNE_UNUSED_PARAMETER(z);
      while (c!=s) v[c++] = 0;
      return *this;
    }
    fvector_assigner & operator , (const T & t)
    {
      return append(t);
    }
    fvector_assigner & operator , (Zero z)
    {
      return append(z);
    }
  };
 
  template <class T, class K, int s>
  fvector_assigner<T,s> operator <<= (FieldVector<T,s> & v, const K & t)
  {
    return fvector_assigner<T,s>(v,true).append(t);
  }
 
  template <class T, int s>
  fvector_assigner<T,s> operator <<= (FieldVector<T,s> & v, Zero z)
  {
    return fvector_assigner<T,s>(v,true).append(z);
  }
 
  template <class T, int n, int m>
  class fmatrix_assigner
  {
  private:
    FieldMatrix<T,n,m> & A;
    int c;
    int r;
    bool temporary;
    bool thrown;
 
    void end_row()
    {
      if (!temporary && c!=m && !thrown) {
        thrown=true;
        DUNE_THROW(MathError, "Trying to assign " << c <<
                   " entries to a FieldMatrix row of size " << m);
      }
      c=0;
    }
  public:
    fmatrix_assigner(fmatrix_assigner & a) : A(a.A), c(a.c), r(a.r), temporary(false), thrown(a.thrown)
    {}
    fmatrix_assigner(FieldMatrix<T,n,m> & _A, bool t) : A(_A), c(0), r(0), temporary(t),
                                                        thrown(false)
    {};
    ~fmatrix_assigner()
    {
      end_row();
      if (!temporary && r!=n-1 && !thrown) {
        thrown=true;
        DUNE_THROW(MathError, "Trying to assign " << r <<
                   " rows to a FieldMatrix of size " << n << " x " << m);
      }
    }
    fmatrix_assigner & append (const T & t)
    {
      // Check whether we have passed the last row
      if(r>=m) {
        thrown=true;
        DUNE_THROW(MathError, "Trying to assign more than " << m <<
                   " rows to a FieldMatrix of size " << n << " x " << m);
      }
      A[r][c++] = t;
      return *this;
    }
    fmatrix_assigner & append (Zero z)
    {
      DUNE_UNUSED_PARAMETER(z);
      while (c!=m) A[r][c++] = 0;
      return *this;
    }
    fmatrix_assigner & append (NextRow nr)
    {
      DUNE_UNUSED_PARAMETER(nr);
      end_row();
      r++;
      return *this;
    }
    fmatrix_assigner & operator , (const T & t)
    {
      return append(t);
    }
    fmatrix_assigner & operator , (Zero z)
    {
      return append(z);
    }
    fmatrix_assigner & operator , (NextRow nr)
    {
      return append(nr);
    }
  };
 
  template <class T, class K, int n, int m>
  fmatrix_assigner<T,n,m> operator <<= (FieldMatrix<T,n,m> & v, const K & t)
  {
    return fmatrix_assigner<T,n,m>(v,true).append(t);
  }
 
  template <class T, int n, int m>
  fmatrix_assigner<T,n,m> operator <<= (FieldMatrix<T,n,m> & v, Zero z)
  {
    return fmatrix_assigner<T,n,m>(v,true).append(z);
  }
 
} // end namespace Dune
 
#endif // DUNE_ASSIGN_HH