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Diffstat (limited to 'boost/compute/iterator/counting_iterator.hpp')
-rw-r--r-- | boost/compute/iterator/counting_iterator.hpp | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/boost/compute/iterator/counting_iterator.hpp b/boost/compute/iterator/counting_iterator.hpp new file mode 100644 index 0000000000..304c1e05cf --- /dev/null +++ b/boost/compute/iterator/counting_iterator.hpp @@ -0,0 +1,185 @@ +//---------------------------------------------------------------------------// +// Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com> +// +// Distributed under the Boost Software License, Version 1.0 +// See accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt +// +// See http://boostorg.github.com/compute for more information. +//---------------------------------------------------------------------------// + +#ifndef BOOST_COMPUTE_ITERATOR_COUNTING_ITERATOR_HPP +#define BOOST_COMPUTE_ITERATOR_COUNTING_ITERATOR_HPP + +#include <string> +#include <cstddef> +#include <iterator> + +#include <boost/config.hpp> +#include <boost/iterator/iterator_facade.hpp> + +#include <boost/compute/detail/meta_kernel.hpp> +#include <boost/compute/type_traits/is_device_iterator.hpp> + +namespace boost { +namespace compute { + +// forward declaration for counting_iterator<T> +template<class T> class counting_iterator; + +namespace detail { + +// helper class which defines the iterator_facade super-class +// type for counting_iterator<T> +template<class T> +class counting_iterator_base +{ +public: + typedef ::boost::iterator_facade< + ::boost::compute::counting_iterator<T>, + T, + ::std::random_access_iterator_tag + > type; +}; + +template<class T, class IndexExpr> +struct counting_iterator_index_expr +{ + typedef T result_type; + + counting_iterator_index_expr(const T &init, const IndexExpr &expr) + : m_init(init), + m_expr(expr) + { + } + + const T &m_init; + IndexExpr m_expr; +}; + +template<class T, class IndexExpr> +inline meta_kernel& operator<<(meta_kernel &kernel, + const counting_iterator_index_expr<T, IndexExpr> &expr) +{ + return kernel << '(' << expr.m_init << '+' << expr.m_expr << ')'; +} + +} // end detail namespace + +/// \class counting_iterator +/// \brief The counting_iterator class implements a counting iterator. +/// +/// A counting iterator returns an internal value (initialized with \p init) +/// which is incremented each time the iterator is incremented. +/// +/// For example, this could be used to implement the iota() algorithm in terms +/// of the copy() algorithm by copying from a range of counting iterators: +/// +/// \snippet test/test_counting_iterator.cpp iota_with_copy +/// +/// \see make_counting_iterator() +template<class T> +class counting_iterator : public detail::counting_iterator_base<T>::type +{ +public: + typedef typename detail::counting_iterator_base<T>::type super_type; + typedef typename super_type::reference reference; + typedef typename super_type::difference_type difference_type; + + counting_iterator(const T &init) + : m_init(init) + { + } + + counting_iterator(const counting_iterator<T> &other) + : m_init(other.m_init) + { + } + + counting_iterator<T>& operator=(const counting_iterator<T> &other) + { + if(this != &other){ + m_init = other.m_init; + } + + return *this; + } + + ~counting_iterator() + { + } + + size_t get_index() const + { + return 0; + } + + template<class Expr> + detail::counting_iterator_index_expr<T, Expr> + operator[](const Expr &expr) const + { + return detail::counting_iterator_index_expr<T, Expr>(m_init, expr); + } + +private: + friend class ::boost::iterator_core_access; + + reference dereference() const + { + return m_init; + } + + bool equal(const counting_iterator<T> &other) const + { + return m_init == other.m_init; + } + + void increment() + { + m_init++; + } + + void decrement() + { + m_init--; + } + + void advance(difference_type n) + { + m_init += static_cast<T>(n); + } + + difference_type distance_to(const counting_iterator<T> &other) const + { + return difference_type(other.m_init) - difference_type(m_init); + } + +private: + T m_init; +}; + +/// Returns a new counting_iterator starting at \p init. +/// +/// \param init the initial value +/// +/// \return a counting_iterator with \p init. +/// +/// For example, to create a counting iterator which returns unsigned integers +/// and increments from one: +/// \code +/// auto iter = make_counting_iterator<uint_>(1); +/// \endcode +template<class T> +inline counting_iterator<T> make_counting_iterator(const T &init) +{ + return counting_iterator<T>(init); +} + +/// \internal_ (is_device_iterator specialization for counting_iterator) +template<class T> +struct is_device_iterator<counting_iterator<T> > : boost::true_type {}; + +} // end compute namespace +} // end boost namespace + +#endif // BOOST_COMPUTE_ITERATOR_COUNTING_ITERATOR_HPP |