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Diffstat (limited to 'rts/gmp/mpz/hamdist.c')
-rw-r--r-- | rts/gmp/mpz/hamdist.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/rts/gmp/mpz/hamdist.c b/rts/gmp/mpz/hamdist.c new file mode 100644 index 0000000000..b039a653d2 --- /dev/null +++ b/rts/gmp/mpz/hamdist.c @@ -0,0 +1,62 @@ +/* mpz_hamdist(mpz_ptr op1, mpz_ptr op2) -- Compute the hamming distance + between OP1 and OP2. If one of the operands is negative, return ~0. (We + could make the function well-defined when both operands are negative, but + that would probably not be worth the trouble. + +Copyright (C) 1994, 1996 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 2.1 of the License, or (at your +option) any later version. + +The GNU MP Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public +License for more details. + +You should have received a copy of the GNU Lesser General Public License +along with the GNU MP Library; see the file COPYING.LIB. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +MA 02111-1307, USA. */ + +#include "gmp.h" +#include "gmp-impl.h" + +unsigned long int +#if __STDC__ +mpz_hamdist (mpz_srcptr u, mpz_srcptr v) +#else +mpz_hamdist (u, v) + mpz_srcptr u; + mpz_srcptr v; +#endif +{ + mp_srcptr up, vp; + mp_size_t usize, vsize, size; + unsigned long int count; + + usize = u->_mp_size; + vsize = v->_mp_size; + + if ((usize | vsize) < 0) + return ~ (unsigned long int) 0; + + up = u->_mp_d; + vp = v->_mp_d; + + if (usize > vsize) + { + count = mpn_popcount (up + vsize, usize - vsize); + size = vsize; + } + else + { + count = mpn_popcount (vp + usize, vsize - usize); + size = usize; + } + + return count + mpn_hamdist (up, vp, size); +} |