/usr/include/dune/common/forloop.hh is in libdune-common-dev 2.4.1-1.
This file is owned by root:root, with mode 0o644.
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// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_COMMON_FORLOOP_HH
#define DUNE_COMMON_FORLOOP_HH
#include <utility>
/** \file
* \brief A static for loop for template meta-programming
*/
namespace Dune
{
#ifndef DOXYGEN
// GenericForLoop
// --------------
template< template< class, class > class Operation, template< int > class Value, int first, int last >
class GenericForLoop
: public Operation< Value< first >, GenericForLoop< Operation, Value, first+1, last > >
{
static_assert( (first <= last), "GenericForLoop: first > last" );
};
template< template< class, class > class Operation, template< int > class Value, int last >
class GenericForLoop< Operation, Value, last, last >
: public Value< last >
{};
// ForLoopHelper
// -------------
namespace ForLoopHelper
{
template< class A, class B >
struct Apply
{
template< typename... Params >
static void apply ( Params&&... params )
{
A::apply( std::forward<Params>(params)... );
B::apply( std::forward<Params>(params)... );
}
};
} // end namespace ForLoopHelper
#endif
/** \class ForLoop
* @brief A static loop using TMP
*
* The ForLoop takes a
* \code template<int i> class Operation \endcode
* template argument with a static apply method
* which is called for i=first...last (first<=last are int template arguments).
* A specialization for class template class Operation for i=first
* or i=last is not required. The class Operation must provide a
* static void function apply(...). Arguments (as references)
* can be passed through the ForLoop to this function.
*
* It is possible to pass a subclass to the ForLoop
* (since no specialization is needed).
*
* Example of usage:
* \code
* template<class Tuple>
* struct PrintTupleTypes
* {
* template <int i>
* struct Operation
* {
* template<class Stream>
* static void apply(Stream &stream, const std::string &prefix)
* {
* stream << prefix << i << ": "
* << className<typename tuple_element<i, Tuple>::type>()
* << std::endl;
* }
* };
* template<class Stream>
* static void print(Stream &stream, const std::string &prefix)
* {
* // cannot attach on-the-fly in the argument to ForLoop<..>::apply() since
* // that would yield an rvalue
* std::string extended_prefix = prefix+" ";
*
* stream << prefix << "tuple<" << std::endl;
* ForLoop<Operation, 0, tuple_size<Tuple>::value-1>::
* apply(stream, extended_prefix);
* stream << prefix << ">" << std::endl;
* }
* };
* \endcode
*
* \note Since Dune 2.4, ForLoop uses variadic templates and perfect forwarding and
* thus supports arbitrary numbers of arguments to apply(), which can be any
* combination of lvalues and rvalues.
*
*/
template< template< int > class Operation, int first, int last >
class ForLoop
: public GenericForLoop< ForLoopHelper::Apply, Operation, first, last >
{
static_assert( (first <= last), "ForLoop: first > last" );
};
}
#endif // #ifndef DUNE_COMMON_FORLOOP_HH
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