===================================================================
RCS file: /home/cvs/OpenXM_contrib/gmp/mpz/Attic/hamdist.c,v
retrieving revision 1.1
retrieving revision 1.1.1.3
diff -u -p -r1.1 -r1.1.1.3
--- OpenXM_contrib/gmp/mpz/Attic/hamdist.c	2000/01/10 15:35:27	1.1
+++ OpenXM_contrib/gmp/mpz/Attic/hamdist.c	2003/08/25 16:06:33	1.1.1.3
@@ -1,23 +1,20 @@
-/* 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.
+/* mpz_hamdist -- calculate hamming distance.
 
-Copyright (C) 1994, 1996 Free Software Foundation, Inc.
+Copyright 1994, 1996, 2001, 2002 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 Library General Public License as published by
-the Free Software Foundation; either version 2 of the License, or (at your
+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 Library General Public
+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 Library General Public License
+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. */
@@ -25,38 +22,145 @@ MA 02111-1307, USA. */
 #include "gmp.h"
 #include "gmp-impl.h"
 
-unsigned long int
-#if __STDC__
+
+unsigned long
 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;
+  mp_srcptr      up, vp;
+  mp_size_t      usize, vsize;
+  unsigned long  count;
 
-  usize = u->_mp_size;
-  vsize = v->_mp_size;
+  usize = SIZ(u);
+  vsize = SIZ(v);
 
-  if ((usize | vsize) < 0)
-    return ~ (unsigned long int) 0;
+  up = PTR(u);
+  vp = PTR(v);
 
-  up = u->_mp_d;
-  vp = v->_mp_d;
-
-  if (usize > vsize)
+  if (usize >= 0)
     {
-      count = mpn_popcount (up + vsize, usize - vsize);
-      size = vsize;
+      if (vsize < 0)
+        return ~ (unsigned long) 0;
+
+      /* positive/positive */
+
+      if (usize < vsize)
+        MPN_SRCPTR_SWAP (up,usize, vp,vsize);
+
+      count = 0;
+      if (vsize != 0)
+        count = mpn_hamdist (up, vp, vsize);
+
+      usize -= vsize;
+      if (usize != 0)
+        count += mpn_popcount (up + vsize, usize);
+
+      return count;
     }
   else
     {
-      count = mpn_popcount (vp + usize, vsize - usize);
-      size = usize;
-    }
+      mp_limb_t  ulimb, vlimb;
+      mp_size_t  old_vsize, step;
 
-  return count + mpn_hamdist (up, vp, size);
+      if (vsize >= 0)
+        return ~ (unsigned long) 0;
+
+      /* negative/negative */
+
+      usize = -usize;
+      vsize = -vsize;
+
+      /* skip common low zeros */
+      for (;;)
+        {
+          ASSERT (usize > 0);
+          ASSERT (vsize > 0);
+
+          usize--;
+          vsize--;
+
+          ulimb = *up++;
+          vlimb = *vp++;
+
+          if (ulimb != 0)
+            break;
+
+          if (vlimb != 0)
+            {
+              MPN_SRCPTR_SWAP (up,usize, vp,vsize);
+              ulimb = vlimb;
+              vlimb = 0;
+              break;
+            }
+        }
+
+      /* twos complement first non-zero limbs (ulimb is non-zero, but vlimb
+         might be zero) */
+      ulimb = -ulimb;
+      vlimb = -vlimb;
+      popc_limb (count, (ulimb ^ vlimb) & GMP_NUMB_MASK);
+
+      if (vlimb == 0)
+        {
+          unsigned long  twoscount;
+
+          /* first non-zero of v */
+          old_vsize = vsize;
+          do
+            {
+              ASSERT (vsize > 0);
+              vsize--;
+              vlimb = *vp++;
+            }
+          while (vlimb == 0);
+
+          /* part of u corresponding to skipped v zeros */
+          step = old_vsize - vsize - 1;
+          count += step * GMP_NUMB_BITS;
+          step = MIN (step, usize);
+          if (step != 0)
+            {
+              count -= mpn_popcount (up, step);
+              usize -= step;
+              up += step;
+            }
+
+          /* First non-zero vlimb as twos complement, xor with ones
+             complement ulimb.  Note -v^(~0^u) == (v-1)^u. */
+          vlimb--;
+          if (usize != 0)
+            {
+              usize--;
+              vlimb ^= *up++;
+            }
+          popc_limb (twoscount, vlimb);
+          count += twoscount;
+        }
+
+      /* Overlapping part of u and v, if any.  Ones complement both, so just
+         plain hamdist. */
+      step = MIN (usize, vsize);
+      if (step != 0)
+        {
+          count += mpn_hamdist (up, vp, step);
+          usize -= step;
+          vsize -= step;
+          up += step;
+          vp += step;
+        }
+
+      /* Remaining high part of u or v, if any, ones complement but xor
+         against all ones in the other, so plain popcount. */
+      if (usize != 0)
+        {
+        remaining:
+          count += mpn_popcount (up, usize);
+        }
+      else if (vsize != 0)
+        {
+          up = vp;
+          usize = vsize;
+          goto remaining;
+        }
+      return count;
+    }
 }