/usr/include/ITK-4.9/itkEnableIf.h is in libinsighttoolkit4-dev 4.9.0-4ubuntu1.
This file is owned by root:root, with mode 0o644.
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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 itkEnableIf_h
#define itkEnableIf_h
namespace itk
{
/// \cond HIDE_META_PROGRAMMING
namespace mpl
{
/** \brief This is an implementation of the enable if idiom.
* \ingroup MetaProgrammingLibrary
* \ingroup ITKCommon
*
* Enable if is a common C++ meta-programming technique for example
* there is a boost implementation, for more information on its usage
* please see:
* http://www.boost.org/doc/libs/1_49_0/libs/utility/enable_if.html
*
* 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 SFINAE another implementation may be choosen.
*
* Example:
\code
template< typename TType>
typename EnableIfC<
IsSame<TType, typename NumericTraits<TType>::ValueType>::Value,
TType >::Type
GetComponent(const TType pix,
unsigned int itkNotUsed( idx ) ) const
{
return pix;
}
\endcode
*
* \sa \c EnableIf
*/
template <bool V, typename TType = void> struct EnableIfC {};
/// \cond SPECIALIZATION_IMPLEMENTATION
template <typename TType> struct EnableIfC<true, TType> { typedef TType Type; };
/// \endcond
/** \brief An implementation of the negation of the enable if idiom.
* \ingroup MetaProgrammingLibrary
* \ingroup ITKCommon
*
* \sa \c EnableIfC
* \sa \c DisableIf
*/
template <bool V, typename TType = void> struct DisableIfC {};
/// \cond SPECIALIZATION_IMPLEMENTATION
template <typename TType> struct DisableIfC<false, TType> { typedef TType Type; };
/// \endcond
/** \brief simplified way to dispose of \c enable_if.
* \ingroup MetaProgrammingLibrary
* \ingroup ITKCommon
* \tparam TCondition Condition type. It's expected to provide a boolean value
* through its \c Value member.
* \tparam TType Type to \em return when the \c TCondition is (a) true (type).
*
* This \em overload automatically fetches \c TCondition value. However, beware, it
* won't work with standard C++ traits or boost traits. Indeed, this \c
* enable_if overload expects the \em value to follow UpperCamelCase ITK naming
* policy instead of the standard snake_case policy.
*
* Example:
* \code
* template< typename TType>
* typename EnableIf<
* IsSame<TType, typename NumericTraits<TType>::ValueType>,
* TType >::Type
* GetComponent(const TType pix,
* unsigned int itkNotUsed( idx ) ) const
* {
* return pix;
* }
* \endcode
* \sa \c EnableIfC
* \sa \c DisableIf
*/
template <class TCondition, class TType = void>
struct EnableIf : public EnableIfC<TCondition::Value, TType> {};
/** \brief simplified way to dispose of \c disable_if.
* \ingroup MetaProgrammingLibrary
* \ingroup ITKCommon
* \tparam TCondition Condition type. It's expected to provide a boolean value
* through its \c Value member.
* \tparam TType Type to \em return when the \c TCondition is (a) false (type).
*
* This \em overload automatically fetches \c TCondition value. However, beware, it
* won't work with standard C++ traits or boost traits. Indeed, this \c
* enable_if overload expects the \em value to follow UpperCamelCase ITK naming
* policy instead of the standard snake_case policy.
*
* Example:
* \code
* template< typename TType>
* typename DisableIf<
* mpl::Not_<IsSame<TType, typename NumericTraits<TType>::ValueType>>,
* TType >::Type
* GetComponent(const TType pix,
* unsigned int itkNotUsed( idx ) ) const
* {
* return pix;
* }
* \endcode
* \sa \c EnableIfC
* \sa \c DisableIf
*/
template <class TCondition, class TType = void>
struct DisableIf : public DisableIfC<TCondition::Value, TType> {};
} // namespace itk::mpl
// itk::EnableIf(C), DisableIf(C) have move to itk::mpl
// Expect them to be deprecated.
using mpl::EnableIf;
using mpl::DisableIf;
using mpl::EnableIfC;
using mpl::DisableIfC;
/// \endcond
} // namespace itk
#endif // itkEnableIf_h
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