summaryrefslogtreecommitdiff
path: root/rts/gmp/mpz/hamdist.c
diff options
context:
space:
mode:
Diffstat (limited to 'rts/gmp/mpz/hamdist.c')
-rw-r--r--rts/gmp/mpz/hamdist.c62
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);
+}