/*
 * Copyright (c) 1995, 1996 Gunther Schadow.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#ifndef PG_UNIT_H_
#define PG_UNIT_H_

#include <pg_config.h>

#pragma interface

#include <Code.h>
#include <BaseUnit.h>
#include <UnitAtom.h>
#include <odbm.h>

class prefices
{
 public:
  static const int not_found;
  static const int best_fit;

  static int lookup(const char *sym, int  pfxlen, const char **root);
  static int lookup(const char *sym, int *pfxlen, const char **root);

 private:
  static struct prefix_s
    {
      const char *name;
      int   len;
      int   exponent;
    } tab[];
};

class Unit :  public Code
{
public:
  Unit();
  Unit(const Unit&);
  Unit(const char*);
  ~Unit();

  operator const char *() const;

  Unit& operator = (const Unit&); 
  Unit& operator = (const char*); 

  Unit operator * (const Unit&) const; 
  Unit operator / (const Unit&) const;

  Unit& operator *= (const Unit&); 
  Unit& operator /= (const Unit&);

  Unit& pow(int i);
  Unit& invert();

  bool operator == (const Unit&) const;
  bool operator == (const char*) const;
  bool operator != (const Unit&) const;
  bool operator != (const char*) const;

  typedef base_unit_vector dimension;

  friend double convert(double value, const Unit &from, const Unit &to);
  friend const dimension &dim(const Unit&);

  const struct UnitAtom::unit_s *operator->() const;

 private:
  UnitAtom::unit_s unit;

  void set(const char *);

  static char *invert(const char*);
  static char *pow(const char*, int);
  static bool tounit(const char *sym, size_t len, int &pfx, UnitAtom &ua);
};

#ifndef OUTLINE
# include "Unit.icc"
#endif

#endif /* !PG_UNIT_H_ */