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diff --git a/gnu/lib/libg++/g++-include/SkipSet.ccP b/gnu/lib/libg++/g++-include/SkipSet.ccP
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+// This may look like C code, but it is really -*- C++ -*-
+/*
+Copyright (C) 1991 Free Software Foundation
+
+This file is part of the GNU C++ Library. This 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
+option) any later version. This 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 License for more details.
+You should have received a copy of the GNU Library General Public
+License along with this library; if not, write to the Free Software
+Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/*
+ * Sets implemented via William Pugh SkipList algorithms.
+ * CACM, June 1990, p 668-676.
+ *
+ */
+
+#include <stream.h>
+#include <time.h>
+
+#include "<T>.SkipSet.h"
+
+MLCG* <T>SkipSet::gen = 0;
+int <T>SkipSetinit::count = 0;
+
+static int countbits(long bits)
+{
+ int n = 0;
+ while(bits>>=1L) n++;
+ return n;
+}
+
+<T>SkipSet::<T>SkipSet(long size)
+: level(0),
+ header(new <T>SkipSetNode (countbits(size)+1)),
+ max_levels (countbits(size)+1),
+ random_bits(gen->asLong()),
+ randoms_left(BITS_IN_RANDOM / 2)
+{
+ <T>SkipSetNodePtr *buffer_start = header->forward;
+ <T>SkipSetNodePtr *trav = &header->forward[max_levels];
+
+ count = 0;
+ while (trav > buffer_start)
+ *--trav = (<T>SkipSetNodePtr) header;
+}
+
+<T>SkipSet::<T>SkipSet(<T>SkipSet& b)
+: level (0),
+ header (new <T>SkipSetNode (b.max_levels)),
+ max_levels (b.max_levels),
+ random_bits (gen->asLong()),
+ randoms_left (BITS_IN_RANDOM / 2)
+{
+ <T>SkipSetNodePtr *buffer_start = header->forward;
+ <T>SkipSetNodePtr *trav = &header->forward[max_levels];
+
+ count = 0;
+
+ while (trav > buffer_start)
+ *--trav = (<T>SkipSetNodePtr)header;
+
+ for (<T>SkipSetNodePtr t = b.leftmost(); t; t = b.succ(t))
+ add(t->item);
+}
+
+/* relationals */
+
+int <T>SkipSet::operator == (<T>SkipSet& y)
+{
+ if (count != y.count)
+ return 0;
+ else
+ {
+ <T>SkipSetNodePtr t = leftmost();
+ <T>SkipSetNodePtr u = y.leftmost();
+ for (;;)
+ {
+ if (t == 0)
+ return 1;
+ else if (!<T>EQ(t->item, u->item))
+ return 0;
+ else
+ {
+ t = succ(t);
+ u = y.succ(u);
+ }
+ }
+ }
+}
+
+int <T>SkipSet::operator <= (<T>SkipSet& y)
+{
+ if (count > y.count)
+ return 0;
+ else
+ {
+ <T>SkipSetNodePtr t = leftmost();
+ <T>SkipSetNodePtr u = y.leftmost();
+ for (;;)
+ {
+ if (t == 0)
+ return 1;
+ else if (u == 0)
+ return 0;
+ int cmp = <T>CMP(t->item, u->item);
+ if (cmp == 0)
+ {
+ t = succ(t);
+ u = y.succ(u);
+ }
+ else if (cmp < 0)
+ return 0;
+ else
+ u = y.succ(u);
+ }
+ }
+}
+
+
+void <T>SkipSet::operator |=(<T>SkipSet& y)
+{
+ if (&y == this) return;
+ <T>SkipSetNodePtr u = y.leftmost();
+ while (u != 0)
+ {
+ add(u->item);
+ u = y.succ(u);
+ }
+}
+
+void <T>SkipSet::operator &= (<T>SkipSet& y)
+{
+ if (y.count == 0)
+ clear();
+ else if (&y != this && count != 0)
+ {
+ <T>SkipSetNodePtr t = leftmost();
+ while (t != 0)
+ {
+ <T>SkipSetNodePtr s = succ(t);
+ if (y.seek(t->item) == 0) del(t->item);
+ t = s;
+ }
+ }
+}
+
+
+void <T>SkipSet::operator -=(<T>SkipSet& y)
+{
+ if (&y == this)
+ clear();
+ else if (y.count != 0)
+ {
+ <T>SkipSetNodePtr t = leftmost();
+ while (t != 0)
+ {
+ <T>SkipSetNodePtr s = succ(t);
+ if (y.seek(t->item) != 0) del(t->item);
+ t = s;
+ }
+ }
+}
+
+Pix <T>SkipSet::add (<T&> i)
+{
+ <T>SkipSetNodePtr *update = new <T>SkipSetNodePtr[max_levels+1];
+ <T>SkipSetNodePtr curr = (<T>SkipSetNodePtr) this->header;
+ int l = level;
+ <T>SkipSetNodePtr temp;
+
+ do
+ {
+ while ((temp = curr->forward[l])!=header &&
+ <T>CMP(temp->item, i) < 0)
+ curr = temp;
+ update[l] = curr;
+ }
+ while (--l >= 0);
+
+ if (temp != header && <T>CMP(temp->item, i) == 0)
+ return Pix(temp);
+
+ if ((l = random_level ()) > level)
+ {
+ l = ++level;
+ update[l] = (<T>SkipSetNodePtr)header;
+ };
+
+ temp = new <T>RealSkipSetNode (i, l);
+ <T>SkipSetNodePtr *temp_forward = temp->forward;
+
+ do
+ {
+ <T>SkipSetNodePtr *curr_forward = update[l]->forward;
+
+ temp_forward[l] = curr_forward[l];
+ curr_forward[l] = temp;
+ }
+ while (--l >= 0);
+
+ count++;
+ delete update;
+ return Pix(temp);
+}
+
+void <T>SkipSet::del(<T&> key)
+{
+
+ int l = level;
+ int curr_level = level;
+ <T>SkipSetNodePtr *update = new <T>SkipSetNodePtr[max_levels+1];
+ <T>SkipSetNodePtr curr = (<T>SkipSetNodePtr)header;
+ <T>SkipSetNodePtr temp;
+
+ do
+ {
+ while ((temp = curr->forward[l])!=header
+ && <T>CMP(temp->item,key) < 0)
+ curr = temp;
+ update[l] = curr;
+ }
+ while (--l >= 0);
+
+ if (<T>CMP(temp->item,key)==0)
+ {
+ <T>SkipSetNodePtr *temp_forward = temp->forward;
+
+ for (l = 0;
+ l <= curr_level && (curr = update[l])->forward[l] == temp;
+ l++)
+ curr->forward[l] = temp_forward[l];
+
+ delete temp;
+
+ <T>SkipSetNodePtr *forward = header->forward;
+
+ while (forward[curr_level]==header && curr_level > 0)
+ curr_level--;
+
+ level = curr_level;
+ count--;
+ delete update;
+ return;
+ }
+}
+
+<T>SkipSetNodePtr <T>SkipSet::rightmost()
+{
+ <T>SkipSetNodePtr temp;
+ <T>SkipSetNode* curr = header;
+ int l = level;
+
+ do
+ while ((temp = curr->forward[l])!=header)
+ curr = temp;
+ while (--l >= 0);
+
+ return temp==header ? 0 : temp;
+}
+
+<T>SkipSetNodePtr <T>SkipSet::pred(<T>SkipSetNodePtr t)
+{
+ <T>SkipSetNodePtr temp, curr = (<T>SkipSetNodePtr) header;
+ int l = level;
+
+ do
+ while ((temp = curr->forward[l])!=t)
+ curr = temp;
+ while (--l >= 0);
+
+ return curr == header ? 0 : curr;
+}
+
+void <T>SkipSet::_kill()
+{
+ <T>SkipSetNode *p = this->header->forward[0];
+
+ while (p != header)
+ {
+ <T>SkipSetNodePtr q = p->forward[0];
+ delete p;
+ p = q;
+ }
+}
+
+void <T>SkipSet::clear()
+{
+ <T>SkipSetNodePtr *buffer_start = header->forward;
+ <T>SkipSetNodePtr *trav = &header->forward[level+1];
+ _kill();
+ count = 0;
+
+ while (trav > buffer_start)
+ *--trav = (<T>SkipSetNodePtr)header;
+}
+
+Pix <T>SkipSet::seek(<T&> key)
+{
+ <T>SkipSetNodePtr temp;
+ <T>SkipSetNode *curr = header;
+ int l = level;
+
+ do
+ {
+ while ((temp = curr->forward[l])!=header &&
+ <T>CMP(temp->item, key) < 0)
+ curr = temp;
+ }
+ while (--l >= 0);
+
+ if (<T>CMP(temp->item, key) != 0)
+ return 0;
+ else
+ {
+ return Pix(temp);
+ }
+}
+
+
+/*
+ * random function for probabilistic balancing
+ *
+ * Hardwired for p = .25. Not too flexible,
+ * but fast. Changing this would require a constructor
+ * that would accept a different value for p, etc.
+ * Perhaps someone else would like to implement this?
+ *
+ */
+int <T>SkipSet::random_level (void)
+{
+ int rlevel = 0;
+ int b;
+
+ do
+ {
+ b = random_bits & 3L;
+ if (!b)
+ rlevel++;
+ random_bits >>= 2;
+ if (--randoms_left == 0)
+ {
+ random_bits = gen->asLong();
+ randoms_left = BITS_IN_RANDOM / 2;
+ };
+ }
+ while (!b);
+
+ return rlevel > max_levels ? max_levels : rlevel;
+}
+
+int <T>SkipSet::OK()
+{
+ int v = 1;
+ if (header == 0)
+ v = 0;
+ else
+ {
+ int n = 0;
+ <T>SkipSetNodePtr trail = leftmost();
+ <T>SkipSetNodePtr t = 0;
+ if (trail) t = succ(trail);
+ if (t) n++;
+ while (t != 0)
+ {
+ ++n;
+ v &= <T>CMP(trail->item, t->item) < 0;
+ trail = t;
+ t = succ(t);
+ }
+ v &= n == count;
+ }
+ if (!v) error("invariant failure");
+ return v;
+}
+
+<T>SkipSetinit::<T>SkipSetinit()
+{
+ if (!count)
+ <T>SkipSet::gen = new MLCG(time(0));
+ count++;
+}
+
+<T>SkipSetinit::~<T>SkipSetinit()
+{
+ count--;
+ if (!count)
+ delete <T>SkipSet::gen;
+}
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