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/*=========================================================================
*
* Copyright Insight Software Consortium
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#ifndef sitkEnableIf_h
#define sitkEnableIf_h
namespace itk
{
namespace simple
{
/* \brief This is an implementation of the enable if idiom.
*
* This template enables specialization of a templated function based
* on some traits or concepts. It is implemented with SFINAE.
*
* If the parameter V is true then the Type trait is the second
* template parameter, otherwise an implementation does not exist and
* with SFIANE another implementation may be choosen.
*
* Example:
* \code
* template<class TImageType>
* typename EnableIf<IsBasic<TImageType>::Value>::Type
* AllocateInternal ( unsigned int Width, unsigned int Height, unsigned int Depth );
*
* template<class TImageType>
* typename EnableIf<IsVector<TImageType>::Value>::Type
* AllocateInternal ( unsigned int Width, unsigned int Height, unsigned int Depth );
* \endcode
*
*/
template <bool V, class T = void> struct EnableIf {};
/** \cond SPECIALIZATION_IMPLEMENTATION */
template <class T> struct EnableIf<true, T> { typedef T Type; };
/**\endcond*/
/* \brief An implementation of the negation of the enable if idiom.
*
* \sa EnableIf
*/
template <bool V, class T = void> struct DisableIf {};
/** \cond SPECIALIZATION_IMPLEMENTATION */
template <class T> struct DisableIf<false, T> { typedef T Type; };
/**\endcond*/
}
}
#endif // sitkEnableIf_h
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