Return to gcd_ui.c CVS log

Up to [local] / OpenXM_contrib / gmp / mpz

Annotation of OpenXM_contrib/gmp/mpz/gcd_ui.c, Revision 1.1.1.3

1.1       maekawa     1: /* mpz_gcd_ui -- Calculate the greatest common divisior of two integers.
                      2:
1.1.1.3 ! ohara       3: Copyright 1994, 1996, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
1.1       maekawa     4:
                      5: This file is part of the GNU MP Library.
                      6:
                      7: The GNU MP Library is free software; you can redistribute it and/or modify
1.1.1.2   maekawa     8: it under the terms of the GNU Lesser General Public License as published by
                      9: the Free Software Foundation; either version 2.1 of the License, or (at your
1.1       maekawa    10: option) any later version.
                     11:
                     12: The GNU MP Library is distributed in the hope that it will be useful, but
                     13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
1.1.1.2   maekawa    14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
1.1       maekawa    15: License for more details.
                     16:
1.1.1.2   maekawa    17: You should have received a copy of the GNU Lesser General Public License
1.1       maekawa    18: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     20: MA 02111-1307, USA. */
                     21:
1.1.1.2   maekawa    22: #include <stdio.h> /* for NULL */
1.1       maekawa    23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25:
                     26: unsigned long int
                     27: mpz_gcd_ui (mpz_ptr w, mpz_srcptr u, unsigned long int v)
                     28: {
1.1.1.3 ! ohara      29:   mp_size_t un;
1.1       maekawa    30:   mp_limb_t res;
                     31:
1.1.1.3 ! ohara      32: #if GMP_NAIL_BITS != 0
        !            33:   if (v > GMP_NUMB_MAX)
        !            34:     {
        !            35:       mpz_t vz;
        !            36:       mp_limb_t vlimbs[2];
        !            37:       vlimbs[0] = v & GMP_NUMB_MASK;
        !            38:       vlimbs[1] = v >> GMP_NUMB_BITS;
        !            39:       PTR(vz) = vlimbs;
        !            40:       SIZ(vz) = 2;
        !            41:       mpz_gcd (w, u, vz);
        !            42:       return;
        !            43:     }
        !            44: #endif
        !            45:
        !            46:   un = ABSIZ(u);
1.1       maekawa    47:
1.1.1.3 ! ohara      48:   if (un == 0)
1.1       maekawa    49:     res = v;
                     50:   else if (v == 0)
                     51:     {
1.1.1.3 ! ohara      52:       if (w != NULL)
1.1       maekawa    53:        {
1.1.1.3 ! ohara      54:          if (u != w)
        !            55:            {
        !            56:              MPZ_REALLOC (w, un);
        !            57:              MPN_COPY (PTR(w), PTR(u), un);
        !            58:            }
        !            59:          SIZ(w) = un;
1.1       maekawa    60:        }
                     61:       /* We can't return any useful result for gcd(big,0).  */
1.1.1.3 ! ohara      62:       return un > 1 ? 0 : PTR(u)[0];
1.1       maekawa    63:     }
                     64:   else
1.1.1.3 ! ohara      65:     res = mpn_gcd_1 (PTR(u), un, (mp_limb_t) v);
1.1       maekawa    66:
                     67:   if (w != NULL)
                     68:     {
1.1.1.3 ! ohara      69:       PTR(w)[0] = res;
        !            70:       SIZ(w) = res != 0;
1.1       maekawa    71:     }
                     72:   return res;
                     73: }