// $Id$
//
// Cassowary Incremental Constraint Solver
// Original Smalltalk Implementation by Alan Borning
// This C++ Implementation by Greg J. Badros, <gjb@cs.washington.edu>
// http://www.cs.washington.edu/homes/gjb
// (C) 1998, 1999 Greg J. Badros and Alan Borning
// See ../LICENSE for legal details regarding this software
//
// ClFloatVariable.h

#ifndef ClFloatVariable_H
#define ClFloatVariable_H

#if defined(HAVE_CONFIG_H) && !defined(CONFIG_H_INCLUDED) && !defined(CONFIG_INLINE_H_INCLUDED)
#include <cassowary/config-inline.h>
#define CONFIG_INLINE_H_INCLUDED
#endif

#include <cstdio>
#include <map>
#include <string>
#include "Cassowary.h"
#include "ClAbstractVariable.h"

using std::map;
using std::string;

class ClFloatVariable : public ClAbstractVariable {
public:
  typedef ClAbstractVariable super;

  ClFloatVariable(string name, Number Value = 0.0) :
    ClAbstractVariable(name),
    _value(Value)
    { }

  ClFloatVariable(Number Value = 0.0) :
    ClAbstractVariable(""),
    _value(Value)
    { }

  ClFloatVariable(long number, char *prefix, Number Value = 0.0) :
    ClAbstractVariable(number,prefix),
    _value(Value)
    { }

  virtual bool IsFloatVariable() const
    { return true; }

  // Return true if this a dummy variable (used as a marker variable
  // for required equality constraints).  Such variables aren't
  // allowed to enter the basis when pivoting.
  virtual bool IsDummy() const
    { return false; }

  // Return true if this a variable known outside the solver.  
  // (We need to give such variables a Value after solving is complete.)
  virtual bool IsExternal() const
    { return true; }

  // Return true if we can Pivot on this variable.
  virtual bool IsPivotable() const
    { return false; }

  // Return true if this is a restricted (or slack) variable.  Such
  // variables are constrained to be non-negative and occur only
  // internally to the simplex solver.
  virtual bool IsRestricted() const
    { return false; }

#ifndef CL_NO_IO
  // Prints a semi-descriptive representation to the stream, using the
  // name if there is one, and otherwise the hash number of this
  // object.
  //	EXAMPLE
  //	  [x:10.0]		-- name = "x", Value = 10.0
  virtual ostream &PrintOn(ostream &xo) const;
#endif
  
  // Return the current Value I hold.
  Number Value() const
    { return _value; }

  // Round the Value to an integer and return it
  int IntValue() const
    { return int(_value + 0.5); }

  // change the Value held -- should *not* use this if the variable is
  // in a solver -- instead use AddEditVar() and SuggestValue() interface
  void SetValue(Number Value)
    { _value = Value; }

  // permit overriding in subclasses in case something needs to be
  // done when the Value is changed by the solver
  // may be called when the Value hasn't actually changed -- just 
  // means the solver is setting the external variable
  virtual void ChangeValue(Number Value)
    { _value = Value; }

private:

  // similar to SetValue -- see caveat above -- made private for now
  // since it's probably the wrong thing and is too easy to invoke
  Number operator=(Number Value)
    { _value = Value; return Value; }

  // Copy constructor left undefined since we want to
  // outlaw passing by Value!  Will get a link error if you
  // try to use within ClFloatVariable.c, compile-time error everywhere else
  ClFloatVariable(const ClFloatVariable &);

  Number _value;

};



#endif