source: to-imperative/trunk/library/Arithm/gcd.cc @ 1035

// $Source$
// $Revision: 1035 $
// $Date: 2003-07-18 06:43:34 +0000 (Fri, 18 Jul 2003) $
// $Author: pooh $

#include <rf_core.hh>
#include <rf_short_int.hh>

namespace refal
{

using namespace rfrt;
using namespace rftype;

namespace Arithm
{

RF_DECL(Rem);

RF_FUNC(GCD, (RF_ARG s_Int1, s_Int2), (RF_RES s_Gcd))

  Term* p_Int1 = s_Int1.get_first();
  Term* p_Int2 = s_Int2.get_first();

  Expr e1, e2;

  if (p_Int1->get_type() == type_short_int) {
    intptr_t n = static_cast<ShortInt*>(p_Int1)->to_int();
    if (n < 0) e1 = ShortInt::create_expr(-n);
    else e1 = s_Int1;
  } else if (p_Int1->get_type() == type_int) {
    Integer* n = static_cast<Integer*>(p_Int1);
    if (n->sign() < 0) e1 = Integer::create_expr(-(*n));
    else e1 = s_Int1;
  } else {
    RF_LIB_ERROR("Invalid argument");
  }
  if (p_Int2->get_type() == type_short_int) {
    intptr_t n = static_cast<ShortInt*>(p_Int2)->to_int();
    if (n < 0) e2 = ShortInt::create_expr(-n);
    else e2 = s_Int2;
  } else if (p_Int2->get_type() == type_int) {
    Integer* n = static_cast<Integer*>(p_Int2);
    if (n->sign() < 0) e2 = Integer::create_expr(-(*n));
    else e2 = s_Int2;
  } else {
    RF_LIB_ERROR("Invalid argument");
  }

  Expr r;
  while (true) {
    p_Int2 = e2.get_first();
    if (p_Int2->get_type() == type_short_int) {
      if (static_cast<ShortInt*>(p_Int2)->to_int() == 0) break;
    } else if (p_Int2->get_type() == type_int) {
      if (static_cast<Integer*>(p_Int2)->sign() == 0) break;
    }
    RF_CALL(Rem, (e1, e2), (r));
    e1 = e2;
    e2 = r;
  }

  s_Gcd = e1;

RF_END

}

}