diff options
Diffstat (limited to 'boost/range/adaptor/strided.hpp')
| -rw-r--r-- | boost/range/adaptor/strided.hpp | 609 |
1 files changed, 478 insertions, 131 deletions
diff --git a/boost/range/adaptor/strided.hpp b/boost/range/adaptor/strided.hpp index e843f62fc0..c5fea86d5c 100644 --- a/boost/range/adaptor/strided.hpp +++ b/boost/range/adaptor/strided.hpp @@ -13,7 +13,7 @@ #include <boost/range/adaptor/argument_fwd.hpp> #include <boost/range/iterator_range.hpp> -#include <boost/iterator/iterator_adaptor.hpp> +#include <boost/iterator/iterator_facade.hpp> #include <iterator> namespace boost @@ -23,59 +23,102 @@ namespace boost // strided_iterator for wrapping a forward traversal iterator template<class BaseIterator, class Category> class strided_iterator - : public iterator_adaptor< + : public iterator_facade< strided_iterator<BaseIterator, Category> - , BaseIterator - , use_default - , boost::forward_traversal_tag + , typename iterator_value<BaseIterator>::type + , forward_traversal_tag + , typename iterator_reference<BaseIterator>::type + , typename iterator_difference<BaseIterator>::type > { friend class ::boost::iterator_core_access; - typedef iterator_adaptor< - strided_iterator<BaseIterator, Category> - , BaseIterator - , use_default - , boost::forward_traversal_tag - > super_t; + typedef iterator_facade< + strided_iterator<BaseIterator, Category> + , typename iterator_value<BaseIterator>::type + , forward_traversal_tag + , typename iterator_reference<BaseIterator>::type + , typename iterator_difference<BaseIterator>::type + > super_t; public: - typedef BOOST_DEDUCED_TYPENAME std::iterator_traits<BaseIterator>::difference_type difference_type; + typedef typename super_t::difference_type difference_type; + typedef typename super_t::reference reference; typedef BaseIterator base_iterator; + typedef std::forward_iterator_tag iterator_category; strided_iterator() - : m_last() + : m_it() + , m_last() , m_stride() { } - strided_iterator(base_iterator first, base_iterator it, base_iterator last, difference_type stride) - : super_t(it) + strided_iterator(base_iterator it, + base_iterator last, + difference_type stride) + : m_it(it) , m_last(last) , m_stride(stride) { } template<class OtherIterator> - strided_iterator(const strided_iterator<OtherIterator, Category>& other, - BOOST_DEDUCED_TYPENAME enable_if_convertible<OtherIterator, base_iterator>::type* = 0) - : super_t(other) + strided_iterator( + const strided_iterator<OtherIterator, Category>& other, + typename enable_if_convertible< + OtherIterator, + base_iterator + >::type* = 0 + ) + : m_it(other.base()) , m_last(other.base_end()) , m_stride(other.get_stride()) { } - base_iterator base_end() const { return m_last; } - difference_type get_stride() const { return m_stride; } + base_iterator base() const + { + return m_it; + } + + base_iterator base_end() const + { + return m_last; + } + + difference_type get_stride() const + { + return m_stride; + } private: void increment() { - base_iterator& it = this->base_reference(); - for (difference_type i = 0; (it != m_last) && (i < m_stride); ++i) - ++it; + for (difference_type i = 0; + (m_it != m_last) && (i < m_stride); ++i) + { + ++m_it; + } } + reference dereference() const + { + return *m_it; + } + + template<class OtherIterator> + bool equal( + const strided_iterator<OtherIterator, Category>& other, + typename enable_if_convertible< + OtherIterator, + base_iterator + >::type* = 0) const + { + return m_it == other.m_it; + } + + base_iterator m_it; base_iterator m_last; difference_type m_stride; }; @@ -83,214 +126,514 @@ namespace boost // strided_iterator for wrapping a bidirectional iterator template<class BaseIterator> class strided_iterator<BaseIterator, bidirectional_traversal_tag> - : public iterator_adaptor< + : public iterator_facade< strided_iterator<BaseIterator, bidirectional_traversal_tag> - , BaseIterator - , use_default - , bidirectional_traversal_tag + , typename iterator_value<BaseIterator>::type + , bidirectional_traversal_tag + , typename iterator_reference<BaseIterator>::type + , typename iterator_difference<BaseIterator>::type > { friend class ::boost::iterator_core_access; - typedef iterator_adaptor< - strided_iterator<BaseIterator, bidirectional_traversal_tag> - , BaseIterator - , use_default - , bidirectional_traversal_tag - > super_t; + typedef iterator_facade< + strided_iterator<BaseIterator, bidirectional_traversal_tag> + , typename iterator_value<BaseIterator>::type + , bidirectional_traversal_tag + , typename iterator_reference<BaseIterator>::type + , typename iterator_difference<BaseIterator>::type + > super_t; public: - typedef BOOST_DEDUCED_TYPENAME std::iterator_traits<BaseIterator>::difference_type difference_type; + typedef typename super_t::difference_type difference_type; + typedef typename super_t::reference reference; typedef BaseIterator base_iterator; + typedef typename boost::make_unsigned<difference_type>::type + size_type; + typedef std::bidirectional_iterator_tag iterator_category; strided_iterator() - : m_first() - , m_last() + : m_it() + , m_offset() + , m_index() , m_stride() { } - strided_iterator(base_iterator first, base_iterator it, base_iterator last, difference_type stride) - : super_t(it) - , m_first(first) - , m_last(last) + strided_iterator(base_iterator it, + size_type index, + difference_type stride) + : m_it(it) + , m_offset() + , m_index(index) , m_stride(stride) { + if (stride && ((m_index % stride) != 0)) + m_index += (stride - (m_index % stride)); } template<class OtherIterator> - strided_iterator(const strided_iterator<OtherIterator, bidirectional_traversal_tag>& other, - BOOST_DEDUCED_TYPENAME enable_if_convertible<OtherIterator, base_iterator>::type* = 0) - : super_t(other.base()) - , m_first(other.base_begin()) - , m_last(other.base_end()) + strided_iterator( + const strided_iterator< + OtherIterator, + bidirectional_traversal_tag + >& other, + typename enable_if_convertible< + OtherIterator, + base_iterator + >::type* = 0 + ) + : m_it(other.base()) + , m_offset(other.get_offset()) + , m_index(other.get_index()) , m_stride(other.get_stride()) { } - base_iterator base_begin() const { return m_first; } - base_iterator base_end() const { return m_last; } - difference_type get_stride() const { return m_stride; } + base_iterator base() const + { + return m_it; + } + + difference_type get_offset() const + { + return m_offset; + } + + size_type get_index() const + { + return m_index; + } + + difference_type get_stride() const + { + return m_stride; + } private: void increment() { - base_iterator& it = this->base_reference(); - for (difference_type i = 0; (it != m_last) && (i < m_stride); ++i) - ++it; + m_offset += m_stride; } void decrement() { - base_iterator& it = this->base_reference(); - for (difference_type i = 0; (it != m_first) && (i < m_stride); ++i) - --it; + m_offset -= m_stride; } - base_iterator m_first; - base_iterator m_last; + reference dereference() const + { + update(); + return *m_it; + } + + void update() const + { + std::advance(m_it, m_offset); + m_index += m_offset; + m_offset = 0; + } + + template<class OtherIterator> + bool equal( + const strided_iterator< + OtherIterator, + bidirectional_traversal_tag + >& other, + typename enable_if_convertible< + OtherIterator, + base_iterator + >::type* = 0) const + { + return (m_index + m_offset) == + (other.get_index() + other.get_offset()); + } + + mutable base_iterator m_it; + mutable difference_type m_offset; + mutable size_type m_index; difference_type m_stride; }; // strided_iterator implementation for wrapping a random access iterator template<class BaseIterator> class strided_iterator<BaseIterator, random_access_traversal_tag> - : public iterator_adaptor< - strided_iterator<BaseIterator, random_access_traversal_tag> - , BaseIterator - , use_default - , random_access_traversal_tag - > + : public iterator_facade< + strided_iterator<BaseIterator, random_access_traversal_tag> + , typename iterator_value<BaseIterator>::type + , random_access_traversal_tag + , typename iterator_reference<BaseIterator>::type + , typename iterator_difference<BaseIterator>::type + > { friend class ::boost::iterator_core_access; - typedef iterator_adaptor< - strided_iterator<BaseIterator, random_access_traversal_tag> - , BaseIterator - , use_default - , random_access_traversal_tag - > super_t; + typedef iterator_facade< + strided_iterator<BaseIterator, random_access_traversal_tag> + , typename iterator_value<BaseIterator>::type + , random_access_traversal_tag + , typename iterator_reference<BaseIterator>::type + , typename iterator_difference<BaseIterator>::type + > super_t; public: - typedef BOOST_DEDUCED_TYPENAME super_t::difference_type difference_type; + typedef typename super_t::difference_type difference_type; + typedef typename super_t::reference reference; typedef BaseIterator base_iterator; + typedef std::random_access_iterator_tag iterator_category; strided_iterator() - : m_first() - , m_last() + : m_it() + , m_first() , m_index(0) , m_stride() { } - strided_iterator(BaseIterator first, BaseIterator it, BaseIterator last, difference_type stride) - : super_t(it) + strided_iterator( + base_iterator first, + base_iterator it, + difference_type stride + ) + : m_it(it) , m_first(first) - , m_last(last) - , m_index(stride ? (it - first) / stride : 0) + , m_index(stride ? (it - first) : difference_type()) , m_stride(stride) { + if (stride && ((m_index % stride) != 0)) + m_index += (stride - (m_index % stride)); } template<class OtherIterator> - strided_iterator(const strided_iterator<OtherIterator, random_access_traversal_tag>& other, - BOOST_DEDUCED_TYPENAME enable_if_convertible<OtherIterator, BaseIterator>::type* = 0) - : super_t(other.base()) + strided_iterator( + const strided_iterator< + OtherIterator, + random_access_traversal_tag + >& other, + typename enable_if_convertible< + OtherIterator, + base_iterator + >::type* = 0 + ) + : m_it(other.base()) , m_first(other.base_begin()) - , m_last(other.base_end()) , m_index(other.get_index()) , m_stride(other.get_stride()) { } - base_iterator base_begin() const { return m_first; } - base_iterator base_end() const { return m_last; } - difference_type get_stride() const { return m_stride; } - difference_type get_index() const { return m_index; } + base_iterator base_begin() const + { + return m_first; + } + + base_iterator base() const + { + return m_it; + } + + difference_type get_stride() const + { + return m_stride; + } + + difference_type get_index() const + { + return m_index; + } private: void increment() { m_index += m_stride; - if (m_index < (m_last - m_first)) - this->base_reference() = m_first + m_index; - else - this->base_reference() = m_last; } void decrement() { m_index -= m_stride; - if (m_index >= 0) - this->base_reference() = m_first + m_index; - else - this->base_reference() = m_first; } void advance(difference_type offset) { - offset *= m_stride; - m_index += offset; - if (m_index < 0) - this->base_reference() = m_first; - else if (m_index > (m_last - m_first)) - this->base_reference() = m_last; - else - this->base_reference() = m_first + m_index; + m_index += (m_stride * offset); + } + + // Implementation detail: only update the actual underlying iterator + // at the point of dereference. This is done so that the increment + // and decrement can overshoot the valid sequence as is required + // by striding. Since we can do all comparisons just with the index + // simply, and all dereferences must be within the valid range. + void update() const + { + m_it = m_first + m_index; } template<class OtherIterator> - difference_type distance_to(const strided_iterator<OtherIterator, random_access_traversal_tag>& other, - BOOST_DEDUCED_TYPENAME enable_if_convertible<OtherIterator, BaseIterator>::type* = 0) const + difference_type distance_to( + const strided_iterator< + OtherIterator, + random_access_traversal_tag + >& other, + typename enable_if_convertible< + OtherIterator, base_iterator>::type* = 0) const { - if (other.base() >= this->base()) - return (other.base() - this->base() + (m_stride - 1)) / m_stride; - return (other.base() - this->base() - (m_stride - 1)) / m_stride; + BOOST_ASSERT((other.m_index - m_index) % m_stride == difference_type()); + return (other.m_index - m_index) / m_stride; } - bool equal(const strided_iterator& other) const + template<class OtherIterator> + bool equal( + const strided_iterator< + OtherIterator, + random_access_traversal_tag + >& other, + typename enable_if_convertible< + OtherIterator, base_iterator>::type* = 0) const { - return this->base() == other.base(); + return m_index == other.m_index; + } + + reference dereference() const + { + update(); + return *m_it; } private: + mutable base_iterator m_it; base_iterator m_first; - base_iterator m_last; difference_type m_index; difference_type m_stride; }; - template<class BaseIterator, class Difference> inline - strided_iterator<BaseIterator, BOOST_DEDUCED_TYPENAME iterator_traversal<BaseIterator>::type> - make_strided_iterator(BaseIterator first, BaseIterator it, - BaseIterator last, Difference stride) + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<Rng>::type, + forward_traversal_tag + > + make_begin_strided_iterator( + Rng& rng, + Difference stride, + forward_traversal_tag) + { + return strided_iterator< + typename range_iterator<Rng>::type, + forward_traversal_tag + >(boost::begin(rng), boost::end(rng), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<const Rng>::type, + forward_traversal_tag + > + make_begin_strided_iterator( + const Rng& rng, + Difference stride, + forward_traversal_tag) + { + return strided_iterator< + typename range_iterator<const Rng>::type, + forward_traversal_tag + >(boost::begin(rng), boost::end(rng), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<Rng>::type, + forward_traversal_tag + > + make_end_strided_iterator( + Rng& rng, + Difference stride, + forward_traversal_tag) + { + return strided_iterator< + typename range_iterator<Rng>::type, + forward_traversal_tag + >(boost::end(rng), boost::end(rng), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<const Rng>::type, + forward_traversal_tag + > + make_end_strided_iterator( + const Rng& rng, + Difference stride, + forward_traversal_tag) + { + return strided_iterator< + typename range_iterator<const Rng>::type, + forward_traversal_tag + >(boost::end(rng), boost::end(rng), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<Rng>::type, + bidirectional_traversal_tag + > + make_begin_strided_iterator( + Rng& rng, + Difference stride, + bidirectional_traversal_tag) + { + typedef typename range_difference<Rng>::type difference_type; + + return strided_iterator< + typename range_iterator<Rng>::type, + bidirectional_traversal_tag + >(boost::begin(rng), difference_type(), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<const Rng>::type, + bidirectional_traversal_tag + > + make_begin_strided_iterator( + const Rng& rng, + Difference stride, + bidirectional_traversal_tag) + { + typedef typename range_difference<const Rng>::type difference_type; + + return strided_iterator< + typename range_iterator<const Rng>::type, + bidirectional_traversal_tag + >(boost::begin(rng), difference_type(), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<Rng>::type, + bidirectional_traversal_tag + > + make_end_strided_iterator( + Rng& rng, + Difference stride, + bidirectional_traversal_tag) { - BOOST_ASSERT( stride >= 0 ); - typedef BOOST_DEDUCED_TYPENAME iterator_traversal<BaseIterator>::type traversal_tag; - return strided_iterator<BaseIterator, traversal_tag>(first, it, last, stride); + return strided_iterator< + typename range_iterator<Rng>::type, + bidirectional_traversal_tag + >(boost::end(rng), boost::size(rng), stride); } - template< class Rng - , class Category = BOOST_DEDUCED_TYPENAME iterator_traversal< - BOOST_DEDUCED_TYPENAME range_iterator<Rng>::type - >::type - > + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<const Rng>::type, + bidirectional_traversal_tag + > + make_end_strided_iterator( + const Rng& rng, + Difference stride, + bidirectional_traversal_tag) + { + return strided_iterator< + typename range_iterator<const Rng>::type, + bidirectional_traversal_tag + >(boost::end(rng), boost::size(rng), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<Rng>::type, + random_access_traversal_tag + > + make_begin_strided_iterator( + Rng& rng, + Difference stride, + random_access_traversal_tag) + { + return strided_iterator< + typename range_iterator<Rng>::type, + random_access_traversal_tag + >(boost::begin(rng), boost::begin(rng), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<const Rng>::type, + random_access_traversal_tag + > + make_begin_strided_iterator( + const Rng& rng, + Difference stride, + random_access_traversal_tag) + { + return strided_iterator< + typename range_iterator<const Rng>::type, + random_access_traversal_tag + >(boost::begin(rng), boost::begin(rng), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<Rng>::type, + random_access_traversal_tag + > + make_end_strided_iterator( + Rng& rng, + Difference stride, + random_access_traversal_tag) + { + return strided_iterator< + typename range_iterator<Rng>::type, + random_access_traversal_tag + >(boost::begin(rng), boost::end(rng), stride); + } + + template<class Rng, class Difference> inline + strided_iterator< + typename range_iterator<const Rng>::type, + random_access_traversal_tag + > + make_end_strided_iterator( + const Rng& rng, + Difference stride, + random_access_traversal_tag) + { + return strided_iterator< + typename range_iterator<const Rng>::type, + random_access_traversal_tag + >(boost::begin(rng), boost::end(rng), stride); + } + + template< + class Rng, + class Category = + typename iterator_traversal< + typename range_iterator<Rng>::type + >::type + > class strided_range : public iterator_range< - range_detail::strided_iterator< - BOOST_DEDUCED_TYPENAME range_iterator<Rng>::type, - Category - > - > + range_detail::strided_iterator< + typename range_iterator<Rng>::type, + Category + > + > { typedef range_detail::strided_iterator< - BOOST_DEDUCED_TYPENAME range_iterator<Rng>::type, - Category - > iter_type; + typename range_iterator<Rng>::type, + Category + > iter_type; typedef iterator_range<iter_type> super_t; public: template<class Difference> strided_range(Difference stride, Rng& rng) - : super_t(make_strided_iterator(boost::begin(rng), boost::begin(rng), boost::end(rng), stride), - make_strided_iterator(boost::begin(rng), boost::end(rng), boost::end(rng), stride)) + : super_t( + range_detail::make_begin_strided_iterator( + rng, stride, + typename iterator_traversal< + typename range_iterator<Rng>::type + >::type()), + range_detail::make_end_strided_iterator( + rng, stride, + typename iterator_traversal< + typename range_iterator<Rng>::type + >::type())) { BOOST_ASSERT( stride >= 0 ); } @@ -300,7 +643,10 @@ namespace boost class strided_holder : public holder<Difference> { public: - explicit strided_holder(Difference value) : holder<Difference>(value) {} + explicit strided_holder(Difference value) + : holder<Difference>(value) + { + } }; template<class Rng, class Difference> @@ -327,7 +673,8 @@ namespace boost namespace { const range_detail::forwarder<range_detail::strided_holder> - strided = range_detail::forwarder<range_detail::strided_holder>(); + strided = range_detail::forwarder< + range_detail::strided_holder>(); } template<class Range, class Difference> |