flint-sys 0.9.0

Bindings to the FLINT C library
Documentation 
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/*
    Copyright (C) 2008, 2009 William Hart
    Copyright (C) 2009 Thomas Boothby

    This file is part of FLINT.

    FLINT is free software: you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License (LGPL) as published
    by the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.  See <https://www.gnu.org/licenses/>.
*/

#include <math.h>
#include "ulong_extras.h"

ulong n_factor_power235(ulong * exp, ulong n)
{
   static char mod63[63] = {7,7,4,0,5,4,0,5,6,5,4,4,0,4,4,0,5,4,5,4,4,0,
                            5,4,0,5,4,6,7,4,0,4,4,0,4,6,7,5,4,0,4,4,0,5,
                            4,4,5,4,0,5,4,0,4,4,4,6,4,0,5,4,0,4,6};
   static char mod61[61] = {7,7,0,3,1,1,0,0,2,3,0,6,1,5,5,1,1,0,0,1,3,4,
                            1,2,2,1,0,3,2,4,0,0,4,2,3,0,1,2,2,1,4,3,1,0,
                            0,1,1,5,5,1,6,0,3,2,0,0,1,1,3,0,7};
   static char mod44[44] = {7,7,0,2,3,3,0,2,2,3,0,6,7,2,0,2,3,2,0,2,3,6,
                            0,6,2,3,0,2,2,2,0,2,6,7,0,2,3,3,0,2,2,2,0,6};
   static char mod31[31] = {7,7,3,0,3,5,4,1,3,1,1,0,0,0,1,2,3,0,1,1,1,0,
                            0,2,0,5,4,2,1,2,6};
   char t;

   t = mod31[n%31];
   if (!t) return UWORD(0);

   t &= mod44[n%44];
   if (!t) return UWORD(0);

   t &= mod61[n%61];
   if (!t) return UWORD(0);

   t&= mod63[n%63];

   if (t & 1)
   {
      double x = sqrt((double) n);
      ulong y = (ulong) (x + 0.5);
      if (n == n_pow(y, 2))
      {
         *exp = 2;
         return y;
      }
   }

   if (t & 2)
   {
      double x = pow((double) n, 1.0 / 3.0);
      ulong y = (ulong) (x + 0.5);
      if (n == n_pow(y, 3))
      {
         *exp = 3;
         return y;
      }
   }

   if (t & 4)
   {
      double x = pow((double) n, 1.0 / 5.0);
      ulong y = (ulong) (x + 0.5);
      if (n == n_pow(y, 5))
      {
         *exp = 5;
         return y;
      }
   }

   return UWORD(0);
}