release/1.1.5.1_cvsreleng/1

1 files changed, 395 insertions, 0 deletions

diff --git a/gnu/lib/libg++/g++-include/SkipSet.ccP b/gnu/lib/libg++/g++-include/SkipSet.ccP
new file mode 100644
index 000000000000..a1bf33d0fa01
--- /dev/null
+++ b/gnu/lib/libg++/g++-include/SkipSet.ccP
@@ -0,0 +1,395 @@
+// 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;
+}