/* /////////////////////////////////////////////////////////////////////////
* File: stlsoft/util/null.hpp (stlsoft_null.h
*
* Purpose: NULL_v template class. Include stlsoft_nulldef.h for NULL to be
* automatically the strong NULL.
*
* Created: 8th September 2002
* Updated: 12th March 2007
*
* Home: http://stlsoft.org/
*
* Copyright (c) 2002-2007, Matthew Wilson and Synesis Software
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name(s) of Matthew Wilson and Synesis Software nor the names of
* any contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* ////////////////////////////////////////////////////////////////////// */
/** \file stlsoft/util/null.hpp
*
* \brief [C++ only] Definition of the stlsoft::NULL_v class
* (\ref group__library__utility "Utility" Library).
*/
#ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_NULL
#define STLSOFT_INCL_STLSOFT_UTIL_HPP_NULL
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
# define STLSOFT_VER_STLSOFT_UTIL_HPP_NULL_MAJOR 4
# define STLSOFT_VER_STLSOFT_UTIL_HPP_NULL_MINOR 0
# define STLSOFT_VER_STLSOFT_UTIL_HPP_NULL_REVISION 1
# define STLSOFT_VER_STLSOFT_UTIL_HPP_NULL_EDIT 49
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/* /////////////////////////////////////////////////////////////////////////
* Includes
*/
#ifndef STLSOFT_INCL_STLSOFT_H_STLSOFT
# include
#endif /* !STLSOFT_INCL_STLSOFT_H_STLSOFT */
/* _STLSOFT_NULL_v_DEFINED */
#ifdef _STLSOFT_NULL_v_DEFINED
# undef _STLSOFT_NULL_v_DEFINED
#endif /* _STLSOFT_NULL_v_DEFINED */
#define _STLSOFT_NULL_v_DEFINED
#if defined(STLSOFT_COMPILER_IS_DMC) && \
__DMC__ < 0x0840
# undef _STLSOFT_NULL_v_DEFINED
#elif defined(STLSOFT_COMPILER_IS_MSVC) && \
_MSC_VER < 1310
# undef _STLSOFT_NULL_v_DEFINED
#elif defined(STLSOFT_COMPILER_IS_WATCOM)
# undef _STLSOFT_NULL_v_DEFINED
#endif /* compiler */
/* _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT */
#ifdef _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT
# undef _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT
#endif /* _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT */
#define _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT
#if defined(STLSOFT_COMPILER_IS_GCC)
# undef _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT
#elif defined(STLSOFT_COMPILER_IS_MWERKS)
# undef _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT
#endif /* compiler */
/* /////////////////////////////////////////////////////////////////////////
* Namespace
*/
#ifndef _STLSOFT_NO_NAMESPACE
namespace stlsoft
{
#endif /* _STLSOFT_NO_NAMESPACE */
/* /////////////////////////////////////////////////////////////////////////
* Classes
*/
#ifdef _STLSOFT_NULL_v_DEFINED
/** \brief Represents a type that can be an active replacement for NULL
*
* \ingroup group__library__utility
*
* This class can act as a replacement for the NULL macro, by being validly
* assigned to or equated with pointer types only, as in
*
* int i = NULL; // error
* int *p = NULL; // OK
*
* if(i == NULL) {} // error
* if(NULL == i) {} // error
*
* if(p == NULL) {} // OK
* if(NULL == p) {} // OK
*
*
* When used via inclusion of the file stlsoft_nulldef.h, the macro NULL is
* redefined as NULL_v(), such that expressions containing NULL will be valid
* against pointers only.
*/
struct NULL_v
{
// Construction
public:
/// Default constructor
NULL_v()
{}
/** \brief Static creation
*
* \ingroup group__library__utility
*/
public:
static NULL_v create()
{
return NULL_v();
}
// Conversion
public:
/// Implicit conversion operator (convertible to any pointer type)
template
operator T *() const
{
return 0;
}
#ifdef _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT
/// Implicit conversion operator (convertible to any pointer type)
template< ss_typename_param_k T2
, ss_typename_param_k C
>
operator T2 C::*() const
{
return 0;
}
#endif /* _STLSOFT_NULL_v_DEFINED_PTR_TO_MEMBER_SUPPORT */
/// Evaluates whether an instance of a type is null
///
/// \param rhs A reference arbitrary type which will be compared to null
template
ss_bool_t equal(T const& rhs) const
{
return rhs == 0;
}
/// \deprecated
template
ss_bool_t equals(T const& rhs) const
{
return equal(rhs);
}
// Not to be implemented
private:
void operator &() const;
#if !defined(STLSOFT_COMPILER_IS_GCC)
NULL_v(NULL_v const&);
NULL_v const& operator =(NULL_v const&);
#endif /* compiler */
};
#if 0
/** \brief operator == for NULL_v and an arbitrary type
*
* \ingroup group__library__utility
*/
template
inline ss_bool_t operator ==(NULL_v const& lhs, T const& rhs)
{
STLSOFT_STATIC_ASSERT(sizeof(rhs) == 4);
return lhs.equal(rhs);
}
/** \brief operator == for an arbitrary type and NULL_v
*
* \ingroup group__library__utility
*/
template
inline ss_bool_t operator ==(T const& lhs, NULL_v const& rhs)
{
STLSOFT_STATIC_ASSERT(sizeof(lhs) == 4);
return rhs.equal(lhs);
}
/** \brief operator != for NULL_v and an arbitrary type
*
* \ingroup group__library__utility
*/
template
inline ss_bool_t operator !=(NULL_v const& lhs, T const& rhs)
{
STLSOFT_STATIC_ASSERT(sizeof(rhs) == 4);
return !lhs.equal(rhs);
}
/** \brief operator != for an arbitrary type and NULL_v
*
* \ingroup group__library__utility
*/
template
inline ss_bool_t operator !=(T const& lhs, NULL_v const& rhs)
{
STLSOFT_STATIC_ASSERT(sizeof(lhs) == 4);
return !rhs.equal(lhs);
}
#endif /* 0 */
#endif /* _STLSOFT_NULL_v_DEFINED */
////////////////////////////////////////////////////////////////////////////
// Unit-testing
#ifdef STLSOFT_UNITTEST
# include "./unittest/null_unittest_.h"
#endif /* STLSOFT_UNITTEST */
/* ////////////////////////////////////////////////////////////////////// */
#ifndef _STLSOFT_NO_NAMESPACE
} // namespace stlsoft
#endif /* _STLSOFT_NO_NAMESPACE */
/* ////////////////////////////////////////////////////////////////////// */
#endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_NULL */
/* ////////////////////////////////////////////////////////////////////// */
