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- //---------------------------------------------------------------------------//
- // 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;
- const 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
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