1 files changed, 378 insertions, 0 deletions
diff --git a/gnu/lib/libg++/g++-include/BSTSet.ccP b/gnu/lib/libg++/g++-include/BSTSet.ccP
new file mode 100644
index 000000000000..6a69d8f45b28
--- /dev/null
+++ b/gnu/lib/libg++/g++-include/BSTSet.ccP
@@ -0,0 +1,378 @@
+// This may look like C code, but it is really -*- C++ -*-
+/* 
+Copyright (C) 1988 Free Software Foundation
+    written by Doug Lea (dl@rocky.oswego.edu)
+
+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.
+*/
+
+#ifdef __GNUG__
+#pragma implementation
+#endif
+#include <stream.h>
+#include "<T>.BSTSet.h"
+
+
+/*
+ traversal primitives
+*/
+
+
+<T>BSTNode* <T>BSTSet::leftmost()
+{
+  <T>BSTNode* t = root;
+  if (t != 0) while (t->lt != 0) t = t->lt;
+  return t;
+}
+
+<T>BSTNode* <T>BSTSet::rightmost()
+{
+  <T>BSTNode* t = root;
+  if (t != 0) while (t->rt != 0) t = t->rt;
+  return t;
+}
+
+<T>BSTNode* <T>BSTSet::succ(<T>BSTNode* t)
+{
+  if (t == 0)
+    return 0;
+  if (t->rt != 0)
+  {
+    t = t->rt;
+    while (t->lt != 0) t = t->lt;
+    return t;
+  }
+  else
+  {
+    for (;;)
+    {
+      if (t->par == 0 || t == t->par->lt)
+        return t->par;
+      else
+        t = t->par;
+    }
+  }
+}
+
+<T>BSTNode* <T>BSTSet::pred(<T>BSTNode* t)
+{
+  if (t == 0)
+    return 0;
+  else if (t->lt != 0)
+  {
+    t = t->lt;
+    while (t->rt != 0) t = t->rt;
+    return t;
+  }
+  else
+  {
+    for (;;)
+    {
+      if (t->par == 0 || t == t->par->rt)
+        return t->par;
+      else
+        t = t->par;
+    }
+  }
+}
+
+
+Pix <T>BSTSet::seek(<T&> key)
+{
+  <T>BSTNode* t = root;
+  for (;;)
+  {
+    if (t == 0)
+      return 0;
+    int comp = <T>CMP(key, t->item);
+    if (comp == 0)
+      return Pix(t);
+    else if (comp < 0)
+      t = t->lt;
+    else
+      t = t->rt;
+  }
+}
+
+
+Pix <T>BSTSet::add(<T&> item)
+{
+  if (root == 0)
+  {
+    ++count;
+    root = new <T>BSTNode(item);
+    return Pix(root);
+  }
+
+  <T>BSTNode* t = root;
+  <T>BSTNode* p = root;
+  int comp;
+  for (;;)
+  {
+    if (t == 0)
+    {
+      ++count;
+      t = new <T>BSTNode(item);
+      if (comp > 0)
+        p->lt = t;
+      else
+        p->rt = t;
+      t->par = p;
+      return Pix(t);
+    }
+    p = t;
+    comp = <T>CMP(t->item, item);
+    if (comp == 0)
+      return Pix(t);
+    else if (comp > 0)
+      t = t->lt;
+    else
+      t = t->rt;
+  }
+}
+
+
+void <T>BSTSet::del(<T&> key)
+{
+  <T>BSTNode* t = root;
+  <T>BSTNode* p = root;
+  int comp;
+  for (;;)
+  {
+    if (t == 0)
+      return;
+    comp = <T>CMP(key, t->item);
+    if (comp == 0)
+    {
+      --count;
+      <T>BSTNode* repl;
+      if (t->lt == 0)
+        repl = t->rt;
+      else if (t->rt == 0)
+        repl = t->lt;
+      else
+      {
+        <T>BSTNode* prepl = t;
+        repl = t->lt;
+        while (repl->rt != 0)
+        {
+          prepl = repl;
+          repl = repl->rt;
+        }
+        if (prepl != t)
+        {
+          prepl->rt = repl->lt;
+          if (prepl->rt != 0) prepl->rt->par = prepl;
+          repl->lt = t->lt;
+          if (repl->lt != 0) repl->lt->par = repl;
+        }
+        repl->rt = t->rt;
+        if (repl->rt != 0) repl->rt->par = repl;
+      }
+      if (t == root)
+      {
+        root = repl;
+        if (repl != 0) repl->par = 0;
+      }
+      else
+      {
+        if (t == p->lt)
+          p->lt = repl;
+        else
+          p->rt = repl;
+        if (repl != 0) repl->par = p;
+      }
+      delete t;
+      return;
+    }
+    p = t;
+    if (comp < 0)
+      t = t->lt;
+    else
+      t = t->rt;
+  }
+}
+
+
+void <T>BSTSet::_kill(<T>BSTNode* t)
+{
+  if (t != 0)
+  {
+    _kill(t->lt);
+    _kill(t->rt);
+    delete t;
+  }
+}
+
+<T>BSTNode* <T>BSTSet::_copy(<T>BSTNode* t)
+{
+  if (t == 0)
+    return 0;
+  else
+  {
+    <T>BSTNode* u = new <T>BSTNode(t->item, _copy(t->lt), _copy(t->rt));
+    if (u->lt != 0) u->lt->par = u;
+    if (u->rt != 0) u->rt->par = u;
+    return u;
+  }
+}
+
+
+int <T>BSTSet::operator == (<T>BSTSet& y)
+{
+  if (count != y.count)
+    return 0;
+  else
+  {
+    <T>BSTNode* t = leftmost();
+    <T>BSTNode* 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>BSTSet::operator <= (<T>BSTSet& y)
+{
+  if (count > y.count)
+    return 0;
+  else
+  {
+    <T>BSTNode* t = leftmost();
+    <T>BSTNode* 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);
+    }
+  }
+}
+
+
+// linear-time, zero space overhead binary tree rebalancing from
+// Stout & Warren, ``Tree rebalancing in linear space and time''
+// CACM, Sept, 1986, p902.
+
+
+void <T>BSTSet::balance()
+{
+  if (count <= 2) return; // don't bother -- 
+                          // also we assume non-null root, below
+
+  // make re-attaching the root easy via trickery
+
+  struct _fake_node { _fake_node *lt, *rt, *par; } fake_root;
+
+  fake_root.rt = (_fake_node*)root; 
+  fake_root.par = 0;
+  <T>BSTNode* pseudo_root = (<T>BSTNode*)&fake_root;
+
+  // phase 1: tree-to-vine
+
+  <T>BSTNode* vine_tail = pseudo_root;
+  <T>BSTNode* remainder = root;
+
+  while (remainder != 0)
+  {
+    if (remainder->lt == 0)
+    {
+      vine_tail = remainder;
+      remainder = remainder->rt;
+    }
+    else
+    {
+      <T>BSTNode* tmp = remainder->lt;
+      remainder->lt = tmp->rt;
+      if (remainder->lt != 0) remainder->lt->par = remainder;
+      tmp->rt = remainder;
+      remainder->par = tmp;
+      vine_tail->rt = remainder = tmp;
+    }
+  }
+
+  // phase 2: vine-to-tree
+  
+  // Uses the slightly simpler version adapted from
+  // Day ``Balancing a binary tree'' Computer Journal, Nov. 1976,
+  // since it's not generally important whether the `stray' leaves are
+  // on the left or on the right.
+
+  unsigned int spines = count - 1;
+  while (spines > 1)
+  {
+    int compressions = spines >> 1; // compress every other node
+    spines -= compressions + 1;     // halve for next time
+
+    <T>BSTNode* scanner = pseudo_root;
+    while (compressions-- > 0)
+    {
+      <T>BSTNode* child = scanner->rt;
+      <T>BSTNode* grandchild = child->rt;
+      scanner->rt = grandchild;
+      grandchild->par = scanner;
+      child->rt = grandchild->lt;
+      if (child->rt != 0) child->rt->par = child;
+      grandchild->lt = child;
+      child->par = grandchild;
+      scanner = grandchild;
+    }
+  }
+
+  root = pseudo_root->rt;
+  root->par = 0;
+}
+
+
+int <T>BSTSet::OK()
+{
+  int v = 1;
+  if (root == 0) 
+    v = count == 0;
+  else
+  {
+    int n = 1;
+    <T>BSTNode* trail = leftmost();
+    <T>BSTNode* t = succ(trail);
+    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;
+}