// ===============================================================
// Copyright(c)'1994-2009 by The Givaro group
// This file is part of Givaro.
// Givaro is governed by the CeCILL-B license under French law
// and abiding by the rules of distribution of free software.
// see the COPYRIGHT file for more details.
// Author: J-G. Dumas
// Time-stamp: <01 Apr 11 17:18:03 Jean-Guillaume.Dumas@imag.fr>
// Description: generic rational fraction reconstruction
// ===============================================================
#ifndef __GIVARO_poly1_ratrecon_INL
#define __GIVARO_poly1_ratrecon_INL


namespace Givaro {

template <class Domain>
void Poly1Dom<Domain,Dense>::ratrecon(typename Poly1Dom<Domain,Dense>::Rep& N, typename Poly1Dom<Domain,Dense>::Rep& D, const typename Poly1Dom<Domain,Dense>::Rep& P, const typename Poly1Dom<Domain,Dense>::Rep& M, const Degree& dk) const {

  Degree degU, degV;
  this->degree(degU,P); this->degree(degV,M);
  if ((degU < dk) || (degV == 0)) { this->assign(N,P); this->assign(D,one); return ; }
  if ((degV < 0) || (degU == 0)) { this->assign(N,one); this->assign(D,one); return ; }

  typename Poly1Dom<Domain,Dense>::Rep U;
  this->assign(N, M);
  this->assign(U, P);

  Degree degN;
  typename Poly1Dom<Domain,Dense>::Rep Q, D0;
  this->assign(D0,this->zero);
  this->assign(D,this->one);
//   do {
//       this->divmod(Q,N,V,U);

//       this->assign(V,U);
//       this->assign(U,N);
//       this->maxpy(TMP2,Q,D,D0);
//       this->assign(D0,D);
//       this->assign(D,TMP2);
//       this->degree(degN, N);
//       if (degN <= dk) break;
//   } while (degN>=0);

  do {
      this->divmodin(Q,N,U);
      this->maxpyin(D0,Q,D);
      this->degree(degN, N);
      if ((degN <= dk) || (degN <0)) {
          this->assign(D,D0);
          break;
      }

      this->divmodin(Q,U,N);
      this->maxpyin(D,Q,D0);

      this->degree(degN, U);
      if (degN <= dk) {
          this->assign(N,U);
          break;
      }

  } while (degN>=0);


//   do {
//       this->divmod(Q,N,V,U);
//       this->maxpyin(D0,Q,D);
//       this->degree(degN, N);
//       if ((degN <= dk) || (degN <0)) {
//           this->assign(D,D0);
//           break;
//       }
//       this->assign(V,N);

//       this->divmod(Q,N,U,V);
//       this->maxpyin(D,Q,D0);

//       this->degree(degN, N);
//       if (degN <= dk) break;

//       this->assign(U,N);
//   } while (degN>=0);

}


template <class Domain>
bool Poly1Dom<Domain,Dense>::ratreconcheck(typename Poly1Dom<Domain,Dense>::Rep& N, typename Poly1Dom<Domain,Dense>::Rep& D, const typename Poly1Dom<Domain,Dense>::Rep& P, const typename Poly1Dom<Domain,Dense>::Rep& M, const Degree& dk) const {
  Degree degU, degV;
  this->degree(degU,P); this->degree(degV,M);
  if ((degU < dk) || (degV == 0)) { this->assign(N,P); this->assign(D,one); return true; }
  if ((degV < 0) || (degU == 0)) { this->assign(N,one); this->assign(D,one); return false; }


  ratrecon(N,D,P,M,dk);


  typename Poly1Dom<Domain,Dense>::Rep G;
  Degree degG;
  if ( degree(degG, gcd(G, N, D)) > 0)
      return false;

  Type_t r; leadcoef(r, D);
  if (! _domain.isOne(r)) {
      this->divin(D, r);
      this->divin(N, r);
  }

  return true;
}

} // Givaro

#endif // __GIVARO_poly1_ratrecon_INL
