63 lines
1.7 KiB
C
63 lines
1.7 KiB
C
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/* mpz_hamdist(mpz_ptr op1, mpz_ptr op2) -- Compute the hamming distance
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between OP1 and OP2. If one of the operands is negative, return ~0. (We
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could make the function well-defined when both operands are negative, but
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that would probably not be worth the trouble.
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Copyright (C) 1994, 1996 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Library General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
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License for more details.
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You should have received a copy of the GNU Library General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA. */
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#include "gmp.h"
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#include "gmp-impl.h"
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unsigned long int
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#if __STDC__
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mpz_hamdist (mpz_srcptr u, mpz_srcptr v)
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#else
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mpz_hamdist (u, v)
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mpz_srcptr u;
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mpz_srcptr v;
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#endif
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{
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mp_srcptr up, vp;
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mp_size_t usize, vsize, size;
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unsigned long int count;
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usize = u->_mp_size;
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vsize = v->_mp_size;
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if ((usize | vsize) < 0)
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return ~ (unsigned long int) 0;
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up = u->_mp_d;
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vp = v->_mp_d;
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if (usize > vsize)
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{
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count = mpn_popcount (up + vsize, usize - vsize);
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size = vsize;
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}
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else
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{
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count = mpn_popcount (vp + usize, vsize - usize);
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size = usize;
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}
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return count + mpn_hamdist (up, vp, size);
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}
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