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

1.1       maekawa     1: /* mpz_hamdist(mpz_ptr op1, mpz_ptr op2) -- Compute the hamming distance
                      2:    between OP1 and OP2.  If one of the operands is negative, return ~0.  (We
                      3:    could make the function well-defined when both operands are negative, but
                      4:    that would probably not be worth the trouble.
                      5:
                      6: Copyright (C) 1994, 1996 Free Software Foundation, Inc.
                      7:
                      8: This file is part of the GNU MP Library.
                      9:
                     10: The GNU MP Library is free software; you can redistribute it and/or modify
                     11: it under the terms of the GNU Library General Public License as published by
                     12: the Free Software Foundation; either version 2 of the License, or (at your
                     13: option) any later version.
                     14:
                     15: The GNU MP Library is distributed in the hope that it will be useful, but
                     16: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     17: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
                     18: License for more details.
                     19:
                     20: You should have received a copy of the GNU Library General Public License
                     21: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     22: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     23: MA 02111-1307, USA. */
                     24:
                     25: #include "gmp.h"
                     26: #include "gmp-impl.h"
                     27:
                     28: unsigned long int
                     29: #if __STDC__
                     30: mpz_hamdist (mpz_srcptr u, mpz_srcptr v)
                     31: #else
                     32: mpz_hamdist (u, v)
                     33:      mpz_srcptr u;
                     34:      mpz_srcptr v;
                     35: #endif
                     36: {
                     37:   mp_srcptr up, vp;
                     38:   mp_size_t usize, vsize, size;
                     39:   unsigned long int count;
                     40:
                     41:   usize = u->_mp_size;
                     42:   vsize = v->_mp_size;
                     43:
                     44:   if ((usize | vsize) < 0)
                     45:     return ~ (unsigned long int) 0;
                     46:
                     47:   up = u->_mp_d;
                     48:   vp = v->_mp_d;
                     49:
                     50:   if (usize > vsize)
                     51:     {
                     52:       count = mpn_popcount (up + vsize, usize - vsize);
                     53:       size = vsize;
                     54:     }
                     55:   else
                     56:     {
                     57:       count = mpn_popcount (vp + usize, vsize - usize);
                     58:       size = usize;
                     59:     }
                     60:
                     61:   return count + mpn_hamdist (up, vp, size);
                     62: }