// This may look like C code, but it is really -*- C++ -*-
/* 
Copyright (C) 1988 Free Software Foundation
    written by Dirk Grunwald (grunwald@cs.uiuc.edu)
    adapted for libg++ 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.
*/

#ifndef <T>PHPQ_h
#ifdef __GNUG__
#pragma interface
#endif
#define <T>PHPQ_h 1

#include "<T>.PQ.h"

#ifndef <T>PHPQIndex
#define <T>PHPQIndex unsigned short
#endif

struct <T>PHPQNode
{
  <T>PHPQIndex   sibling;
  <T>PHPQIndex   children;
  <T>            item;
  char           valid;
};


class <T>PHPQ : public <T>PQ
{
  <T>PHPQNode*  storage;        // table -- freelist in storage[0].sibling
  int           root;
  int           size;

  void          prealloc(int);
  int           check_sibling_list(int);

public:

                <T>PHPQ(int sz = DEFAULT_INITIAL_CAPACITY);
                <T>PHPQ(<T>PHPQ&);
                ~<T>PHPQ();

  Pix           enq(<T&> item);
  <T>           deq(); 

  <T>&          front();
  void          del_front();

  int           contains(<T&> item);

  void          clear(); 

  Pix           first(); 
  void          next(Pix& i);
  <T>&          operator () (Pix i);
  void          del(Pix i);
  Pix           seek(<T&> item);

  int           OK();                    // rep invariant
};


inline <T>PHPQ::~<T>PHPQ()
{
  delete [] storage;
}


inline <T> <T>PHPQ::deq()
{
  if (count == 0) error("deq of empty PQ");
  <T> x = storage[root].item;
  del_front();
  return x;
}


inline <T>& <T>PHPQ::front()
{
  if (count == 0) error("front of empty PQ");
  return storage[root].item;
}

inline int <T>PHPQ::contains(<T&> item)
{
  return seek(item) != 0;
}

inline <T>& <T>PHPQ::operator() (Pix p)
{
  if (p == 0) error("null Pix");
  return storage[int(p)].item;
}

#endif
