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Annotation of OpenXM_contrib/gmp/mpz/gcd_ui.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpz_gcd_ui -- Calculate the greatest common divisior of two integers.
                      2:
                      3: Copyright (C) 1994, 1996 Free Software Foundation, Inc.
                      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
                      8: it under the terms of the GNU Library General Public License as published by
                      9: the Free Software Foundation; either version 2 of the License, or (at your
                     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
                     14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Library General Public License
                     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:
                     22: #include "gmp.h"
                     23: #include "gmp-impl.h"
                     24:
                     25: unsigned long int
                     26: #if __STDC__
                     27: mpz_gcd_ui (mpz_ptr w, mpz_srcptr u, unsigned long int v)
                     28: #else
                     29: mpz_gcd_ui (w, u, v)
                     30:      mpz_ptr w;
                     31:      mpz_srcptr u;
                     32:      unsigned long int v;
                     33: #endif
                     34: {
                     35:   mp_size_t size;
                     36:   mp_limb_t res;
                     37:
                     38:   size = ABS (u->_mp_size);
                     39:
                     40:   if (size == 0)
                     41:     res = v;
                     42:   else if (v == 0)
                     43:     {
                     44:       if (w != NULL && u != w)
                     45:        {
                     46:          if (w->_mp_alloc < size)
                     47:            _mpz_realloc (w, size);
                     48:
                     49:          MPN_COPY (w->_mp_d, u->_mp_d, size);
                     50:        }
                     51:       w->_mp_size = size;
                     52:       /* We can't return any useful result for gcd(big,0).  */
                     53:       return size > 1 ? 0 : w->_mp_d[0];
                     54:     }
                     55:   else
                     56:     res = mpn_gcd_1 (u->_mp_d, size, v);
                     57:
                     58:   if (w != NULL)
                     59:     {
                     60:       w->_mp_d[0] = res;
                     61:       w->_mp_size = 1;
                     62:     }
                     63:   return res;
                     64: }