/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkVariant.h,v $

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
/*-------------------------------------------------------------------------
  Copyright 2008 Sandia Corporation.
  Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
  the U.S. Government retains certain rights in this software.
-------------------------------------------------------------------------*/
// .NAME vtkVariant - A atomic type representing the union of many types
//
// .SECTION Description
//
// .SECTION Thanks
// Thanks to Patricia Crossno, Ken Moreland, Andrew Wilson and Brian Wylie from
// Sandia National Laboratories for their help in developing this class.


#ifndef __vtkVariant_h
#define __vtkVariant_h

#include "vtkType.h"           // To define type IDs and VTK_TYPE_USE_* flags
#include "vtkSystemIncludes.h" // To define ostream
#include "vtkSetGet.h"         // For vtkNotUsed macro
#include "vtkStdString.h"

//
// The following should be eventually placed in vtkSetGet.h
//

// This is same as extended template macro with an additional case for VTK_VARIANT
#define vtkExtraExtendedTemplateMacro(call)                                 \
  vtkExtendedTemplateMacro(call);                                            \
  vtkTemplateMacroCase(VTK_VARIANT, vtkVariant, call)

// This is same as Iterator Template macro with an additional case for VTK_VARIANT
#define vtkExtendedArrayIteratorTemplateMacro(call)                                      \
  vtkArrayIteratorTemplateMacro(call);                                                   \
  vtkArrayIteratorTemplateMacroCase(VTK_VARIANT, vtkVariant, call);

class vtkStdString;
class vtkUnicodeString;
class vtkObjectBase;
class vtkAbstractArray;
struct vtkVariantLessThan;

class VTK_COMMON_EXPORT vtkVariant
{
public:

  // Description:
  // Create an invalid variant.
  vtkVariant();

  // Description:
  // Destruct the variant.
  ~vtkVariant();

  // Description:
  // Copy constructor.
  vtkVariant(const vtkVariant & other);

  // Description:
  // Create a char variant.
  vtkVariant(char value);

  // Description:
  // Create an unsigned char variant.
  vtkVariant(unsigned char value);

  // Description:
  // Create a signed char variant.
  vtkVariant(signed char value);

  // Description:
  // Create a short variant.
  vtkVariant(short value);

  // Description:
  // Create an unsigned short variant.
  vtkVariant(unsigned short value);

  // Description:
  // Create an integer variant.
  vtkVariant(int value);

  // Description:
  // Create an unsigned integer variant.
  vtkVariant(unsigned int value);

  // Description:
  // Create an long variant.
  vtkVariant(long value);

  // Description:
  // Create an unsigned long variant.
  vtkVariant(unsigned long value);

#if defined(VTK_TYPE_USE___INT64)
  // Description:
  // Create an __int64 variant.
  vtkVariant(__int64 value);
  
  // Description:
  // Create an unsigned __int64 variant.
  vtkVariant(unsigned __int64 value);
#endif
#if defined(VTK_TYPE_USE_LONG_LONG)
  // Description:
  // Create a long long variant.
  vtkVariant(long long value);

  // Description:
  // Create an unsigned long long variant.
  vtkVariant(unsigned long long value);
#endif

  // Description:
  // Create a float variant.
  vtkVariant(float value);

  // Description:
  // Create a double variant.
  vtkVariant(double value);

  // Description:
  // Create a string variant from a const char*.
  vtkVariant(const char* value);

  // Description:
  // Create a string variant from a std string.
  vtkVariant(vtkStdString value);

  // Description:
  // Create a Unicode string variant
  vtkVariant(const vtkUnicodeString& value);

  // Description:
  // Create a vtkObjectBase variant.
  vtkVariant(vtkObjectBase* value);

  // Description:
  // Copy the value of one variant into another.
  const vtkVariant & operator= (const vtkVariant & other);

  // Description:
  // Get whether the variant value is valid.
  bool IsValid() const;

  // Description:
  // Get whether the variant is a string.
  bool IsString() const;

  // Description:
  // Get whether the variant is a Unicode string.
  bool IsUnicodeString() const;

  // Description:
  // Get whether the variant is any numeric type.
  bool IsNumeric() const;

  // Description:
  // Get whether the variant is a float.
  bool IsFloat() const;

  // Description:
  // Get whether the variant is a double.
  bool IsDouble() const;

  // Description:
  // Get whether the variant is an char.
  bool IsChar() const;

  // Description:
  // Get whether the variant is an unsigned char.
  bool IsUnsignedChar() const;

  // Description:
  // Get whether the variant is an signed char.
  bool IsSignedChar() const;

  // Description:
  // Get whether the variant is an short.
  bool IsShort() const;

  // Description:
  // Get whether the variant is an unsigned short.
  bool IsUnsignedShort() const;

  // Description:
  // Get whether the variant is an int.
  bool IsInt() const;

  // Description:
  // Get whether the variant is an unsigned int.
  bool IsUnsignedInt() const;

  // Description:
  // Get whether the variant is an long.
  bool IsLong() const;

  // Description:
  // Get whether the variant is an unsigned long.
  bool IsUnsignedLong() const;

  // Description:
  // Get whether the variant is an __int64.
  bool Is__Int64() const;

  // Description:
  // Get whether the variant is an unsigned __int64.
  bool IsUnsigned__Int64() const;

  // Description:
  // Get whether the variant is long long.
  bool IsLongLong() const;

  // Description:
  // Get whether the variant is unsigned long long.
  bool IsUnsignedLongLong() const;

  // Description:
  // Get whether the variant is a VTK object pointer.
  bool IsVTKObject() const;

  // Description:
  // Get whether the variant is a VTK array (i.e. a subclass of vtkAbstractArray).
  bool IsArray() const;

  // Description:
  // Get the type of the variant.
  unsigned int GetType() const;

  // Description:
  // Get the type of the variant as a string.
  const char* GetTypeAsString() const;

  // Description:
  // Convert the variant to a string.
  vtkStdString ToString() const;

  // Description:
  // convert the variant to a Unicode string.
  vtkUnicodeString ToUnicodeString() const;

  // Description:
  // Convert the variant to a numeric type:
  // If it holds a numeric, cast to the appropriate type.
  // If it holds a string, attempt to convert the string to the appropriate type;
  //   set the valid flag to false when the conversion fails.
  // If it holds an array type, cast the first value of the array
  //   to the appropriate type.
  // Fail if it holds a VTK object which is not an array.
  float ToFloat(bool* valid = 0) const;
  double ToDouble(bool* valid = 0) const;
  char ToChar(bool* valid = 0) const;
  unsigned char ToUnsignedChar(bool* valid = 0) const;
  signed char ToSignedChar(bool* valid = 0) const;
  short ToShort(bool* valid = 0) const;
  unsigned short ToUnsignedShort(bool* valid = 0) const;
  int ToInt(bool* valid = 0) const;
  unsigned int ToUnsignedInt(bool* valid = 0) const;
  long ToLong(bool* valid = 0) const;
  unsigned long ToUnsignedLong(bool* valid = 0) const;
#if defined(VTK_TYPE_USE___INT64)
  __int64 To__Int64(bool* valid = 0) const;
  unsigned __int64 ToUnsigned__Int64(bool* valid = 0) const;
#endif
#if defined(VTK_TYPE_USE_LONG_LONG)
  long long ToLongLong(bool* valid = 0) const;
  unsigned long long ToUnsignedLongLong(bool* valid = 0) const;
#endif
  vtkTypeInt64 ToTypeInt64(bool* valid = 0) const;
  vtkTypeUInt64 ToTypeUInt64(bool* valid = 0) const;

  // Description:
  // Return the VTK object, or NULL if not of that type.
  vtkObjectBase* ToVTKObject() const;

  // Description:
  // Return the array, or NULL if not of that type.
  vtkAbstractArray* ToArray() const;

  template <typename T>
  T ToNumeric(bool* valid, T* vtkNotUsed(ignored)) const;

  // Description:
  // Determines whether two variants have the same value. They do
  // not need to be storing exactly the same type to have the same
  // value.  In practice you don't need to use this method: just use
  // operator== instead.  If you want precise equality down to the bit
  // level use the following idiom:
  //
  // vtkVariantStrictEquality comparator;
  // bool variantsEqual = comparator(firstVariant, secondVariant);
  bool IsEqual(const vtkVariant& other) const;

  // Description:
  // Compare two variants for equality, greater than, and less than.
  // These operators use the value represented by the variant instead
  // of the particular type/bit pattern used to represent it.  This
  // behavior is similar to the default behavior in C and C++,
  // including type promotion, with the following caveats:
  //
  // * When comparing type X with a string, type X will first be
  //   converted to string, then compared lexically (the usual
  //   behavior of string::operator< and company).  
  //
  // * vtkObject pointers will be converted to an unsigned integer of
  //   appropriate size.  If both variants contain vtkObjects then
  //   they are comparable directly.
  // 
  // * Comparing char values with strings will not work the way you
  //   might expect if you're treating a char as a numeric type.  Char
  //   values are written to strings as literal ASCII characters
  //   instead of numbers.
  //
  // This approach follows the principle of least surprise at the
  // expense of speed.  Casting integers to floating-point values is
  // relatively slow.  Casting numeric types to strings is very slow.
  // If you prefer speed at the expense of counterintuitive behavior
  // -- for example, when using vtkVariants as keys in STL containers
  // -- you can use the functors described at the bottom of this file.
  //
  // The actual definitions of these operators are in
  // vtkVariantInlineOperators.cxx.
  bool operator==(const vtkVariant &other) const;
  bool operator!=(const vtkVariant &other) const;
  bool operator<(const vtkVariant &other) const;
  bool operator>(const vtkVariant &other) const;
  bool operator<=(const vtkVariant &other) const;
  bool operator>=(const vtkVariant &other) const;




private:
  union
  {
    vtkStdString* String;
    vtkUnicodeString* UnicodeString;
    float Float;
    double Double;
    char Char;
    unsigned char UnsignedChar;
    signed char SignedChar;
    short Short;
    unsigned short UnsignedShort;
    int Int;
    unsigned int UnsignedInt;
    long Long;
    unsigned long UnsignedLong;
#if defined(VTK_TYPE_USE___INT64)
    __int64 __Int64;
    unsigned __int64 Unsigned__Int64;
#endif
#if defined(VTK_TYPE_USE_LONG_LONG)
    long long LongLong;
    unsigned long long UnsignedLongLong;
#endif
    vtkObjectBase* VTKObject;
  } Data;

  unsigned char Valid;
  unsigned char Type;

  friend struct vtkVariantLessThan;
  friend struct vtkVariantEqual;
  friend struct vtkVariantStrictWeakOrder;
  friend struct vtkVariantStrictEquality;
};

#include "vtkVariantInlineOperators.h" // needed for operator== and company

// A STL-style function object so you can compare two variants using
// comp(s1,s2) where comp is an instance of vtkVariantStrictWeakOrder.
// This is a faster version of operator< that makes no attempt to
// compare values.  It satisfies the STL requirement for a comparison
// function for ordered containers like map and set.

struct VTK_COMMON_EXPORT vtkVariantLessThan
{
public:
  bool operator()(const vtkVariant &s1, const vtkVariant &s2) const;
};

struct VTK_COMMON_EXPORT vtkVariantEqual
{
public:
  bool operator()(const vtkVariant &s1, const vtkVariant &s2) const;
};

struct VTK_COMMON_EXPORT vtkVariantStrictWeakOrder
{
public:
  bool operator()(const vtkVariant& s1, const vtkVariant& s2) const;
};

// Similarly, this is a fast version of operator== that requires that
// the types AND the values be equal in order to admit equality.

struct VTK_COMMON_EXPORT vtkVariantStrictEquality
{
public:
  bool operator()(const vtkVariant &s1, const vtkVariant &s2) const;
};

#endif
