===================================================================
RCS file: /home/cvs/OpenXM_contrib/gmp/mpz/Attic/scan1.c,v
retrieving revision 1.1.1.1
retrieving revision 1.1.1.3
diff -u -p -r1.1.1.1 -r1.1.1.3
--- OpenXM_contrib/gmp/mpz/Attic/scan1.c	2000/01/10 15:35:27	1.1.1.1
+++ OpenXM_contrib/gmp/mpz/Attic/scan1.c	2003/08/25 16:06:33	1.1.1.3
@@ -1,35 +1,142 @@
-/* mpz_scan1(op, startbit) -- Scan for the next set bit, starting at startbit.
+/* mpz_scan1 -- search for a 1 bit.
 
-Copyright (C) 1996 Free Software Foundation, Inc.
+Copyright 2000, 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. */
 
 #include "gmp.h"
 #include "gmp-impl.h"
+#include "longlong.h"
 
-unsigned long int
-#if __STDC__
-mpz_scan1 (mpz_srcptr u, unsigned long int starting_bit)
-#else
-mpz_scan1 (u, starting_bit)
-     mpz_srcptr u;
-     unsigned long int starting_bit;
-#endif
+
+/* mpn_scan0 can't be used for the inverted u<0 search since there might not
+   be a 0 bit before the end of the data.  mpn_scan1 could be used under u>0
+   (except when in the high limb), but usually the search won't go very far
+   so it seems reasonable to inline that code.  */
+
+unsigned long
+mpz_scan1 (mpz_srcptr u, unsigned long starting_bit)
 {
-  return mpn_scan1 (u->_mp_d, starting_bit);
+  mp_srcptr      u_ptr = PTR(u);
+  mp_size_t      size = SIZ(u);
+  mp_size_t      abs_size = ABS(size);
+  mp_srcptr      u_end = u_ptr + abs_size;
+  unsigned long  starting_limb = starting_bit / GMP_NUMB_BITS;
+  mp_srcptr      p = u_ptr + starting_limb;
+  mp_limb_t      limb;
+  int            cnt;
+
+  /* Past the end there's no 1 bits for u>=0, or an immediate 1 bit for u<0.
+     Notice this test picks up any u==0 too. */
+  if (starting_limb >= abs_size)
+    return (size >= 0 ? ULONG_MAX : starting_bit);
+
+  limb = *p;
+
+  if (size >= 0)
+    {
+      /* Mask to 0 all bits before starting_bit, thus ignoring them. */
+      limb &= (MP_LIMB_T_MAX << (starting_bit % GMP_NUMB_BITS));
+
+      if (limb == 0)
+        {
+          /* If it's the high limb which is zero after masking, then there's
+             no 1 bits after starting_bit.  */
+          p++;
+          if (p == u_end)
+            return ULONG_MAX;
+
+          /* Otherwise search further for a non-zero limb.  The high limb is
+             non-zero, if nothing else.  */
+          for (;;)
+            {
+              limb = *p;
+              if (limb != 0)
+                break;
+              p++;
+              ASSERT (p < u_end);
+            }
+        }
+    }
+  else
+    {
+      mp_srcptr  q;
+
+      /* If there's a non-zero limb before ours then we're in the ones
+         complement region.  Search from *(p-1) downwards since that might
+         give better cache locality, and since a non-zero in the middle of a
+         number is perhaps a touch more likely than at the end.  */
+      q = p;
+      while (q != u_ptr)
+        {
+          q--;
+          if (*q != 0)
+            goto inverted;
+        }
+
+      if (limb == 0)
+        {
+          /* Skip zero limbs, to find the start of twos complement.  The
+             high limb is non-zero, if nothing else.  This search is
+             necessary so the -limb is applied at the right spot. */
+          do
+            {
+              p++;
+              ASSERT (p < u_end);
+              limb = *p;
+            }
+          while (limb == 0);
+
+          /* Apply twos complement, and look for a 1 bit in that.  Since
+             limb!=0 here, also have (-limb)!=0 so there's certainly a 1
+             bit.  */
+          limb = -limb;
+          goto got_limb;
+        }
+
+      /* Adjust so ~limb implied by searching for 0 bit becomes -limb.  */
+      limb--;
+
+    inverted:
+      /* Now seeking a 0 bit. */
+
+      /* Mask to 1 all bits before starting_bit, thus ignoring them. */
+      limb |= (CNST_LIMB(1) << (starting_bit % GMP_NUMB_BITS)) - 1;
+
+      /* Search for a limb which is not all ones.  If the end is reached
+         then the zero immediately past the end is the result.  */
+      while (limb == GMP_NUMB_MAX)
+        {
+          p++;
+          if (p == u_end)
+            return abs_size * GMP_NUMB_BITS;
+          limb = *p;
+        }
+
+      /* Now seeking low 1 bit. */
+      limb = ~limb;
+    }
+
+ got_limb:
+  /* Mask to 0 all bits above the lowest 1 bit. */
+  ASSERT (limb != 0);
+  limb &= -limb;
+
+  count_leading_zeros (cnt, limb);
+  return (p - u_ptr) * GMP_NUMB_BITS + GMP_LIMB_BITS - 1 - cnt;
 }