ceph/src/boost/libs/convert/include/boost/convert/detail/range.hpp

   1 // Copyright (c) 2009-2016 Vladimir Batov.
   2 // Use, modification and distribution are subject to the Boost Software License,
   3 // Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
   4
   5 #ifndef BOOST_CONVERT_DETAIL_RANGE_HPP
   6 #define BOOST_CONVERT_DETAIL_RANGE_HPP
   7
   8 #include <boost/convert/detail/has_member.hpp>
   9 #include <boost/convert/detail/char.hpp>
  10 #include <boost/utility/enable_if.hpp>
  11 #include <boost/range/iterator.hpp>
  12
  13 namespace boost { namespace cnv
  14 {
  15     namespace detail
  16     {
  17         template<typename T, bool is_class> struct is_range : mpl::false_ {};
  18
  19         template<typename T> struct is_range<T, /*is_class=*/true>
  20         {
  21             BOOST_DECLARE_HAS_MEMBER(has_begin, begin);
  22             BOOST_DECLARE_HAS_MEMBER(  has_end, end);
  23
  24             static bool const value = has_begin<T>::value && has_end<T>::value;
  25         };
  26     }
  27     template<typename T> struct is_range : detail::is_range<typename remove_const<T>::type, boost::is_class<T>::value> {};
  28     template<typename T, typename enable =void> struct range;
  29     template<typename T, typename enable =void> struct iterator;
  30
  31     template<typename T>
  32     struct iterator<T, typename enable_if<is_range<T> >::type>
  33     {
  34         typedef typename boost::range_iterator<T>::type             type;
  35         typedef typename boost::range_iterator<T const>::type const_type;
  36         typedef typename boost::iterator_value<type>::type    value_type;
  37     };
  38     template<typename T>
  39     struct iterator<T*, void>
  40     {
  41         typedef typename remove_const<T>::type value_type;
  42         typedef T*                                   type;
  43         typedef value_type const*              const_type;
  44     };
  45     template<typename T>
  46     struct range_base
  47     {
  48         typedef typename cnv::iterator<T>::value_type     value_type;
  49         typedef typename cnv::iterator<T>::type             iterator;
  50         typedef typename cnv::iterator<T>::const_type const_iterator;
  51         typedef const_iterator                           sentry_type;
  52
  53         iterator       begin () { return begin_; }
  54         const_iterator begin () const { return begin_; }
  55         void      operator++ () { ++begin_; }
  56 //      void      operator-- () { --end_; }
  57
  58         protected:
  59
  60         range_base (iterator b, iterator e) : begin_(b), end_(e) {}
  61
  62         iterator       begin_;
  63         iterator mutable end_;
  64     };
  65
  66     template<typename T>
  67     struct range<T, typename enable_if<is_range<T> >::type> : public range_base<T>
  68     {
  69         typedef range                                   this_type;
  70         typedef range_base<T>                           base_type;
  71         typedef typename base_type::iterator             iterator;
  72         typedef typename base_type::const_iterator const_iterator;
  73         typedef const_iterator                        sentry_type;
  74
  75         range (T& r) : base_type(r.begin(), r.end()) {}
  76
  77         iterator         end () { return base_type::end_; }
  78         const_iterator   end () const { return base_type::end_; }
  79         sentry_type   sentry () const { return base_type::end_; }
  80         bool           empty () const { return base_type::begin_ == base_type::end_; }
  81     };
  82
  83     template<typename T>
  84     struct range<T*, typename enable_if<cnv::is_char<T> >::type> : public range_base<T*>
  85     {
  86         typedef range                           this_type;
  87         typedef range_base<T*>                  base_type;
  88         typedef typename remove_const<T>::type value_type;
  89         typedef T*                               iterator;
  90         typedef value_type const*          const_iterator;
  91
  92         struct sentry_type
  93         {
  94             friend bool operator!=(iterator it, sentry_type) { return !!*it; }
  95         };
  96
  97         range (iterator b, iterator e =0) : base_type(b, e) {}
  98
  99         iterator       end ()       { return base_type::end_ ? base_type::end_ : (base_type::end_ = base_type::begin_ + size()); }
 100         const_iterator end () const { return base_type::end_ ? base_type::end_ : (base_type::end_ = base_type::begin_ + size()); }
 101         sentry_type sentry () const { return sentry_type(); }
 102         std::size_t   size () const { return std::char_traits<value_type>::length(base_type::begin_); }
 103         bool         empty () const { return !*base_type::begin_; }
 104     };
 105     template<typename T>
 106     struct range<T* const, void> : public range<T*>
 107     {
 108         range (T* b, T* e =0) : range<T*>(b, e) {}
 109     };
 110     template <typename T, std::size_t N>
 111     struct range<T [N], void> : public range<T*>
 112     {
 113         range (T* b, T* e =0) : range<T*>(b, e) {}
 114     };
 115 }}
 116
 117 #endif // BOOST_CONVERT_DETAIL_RANGE_HPP