ceph/src/boost/boost/spirit/home/support/iterators/line_pos_iterator.hpp

   1 /*==============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3     Copyright (c) 2010      Bryce Lelbach
   4     Copyright (c) 2014      Tomoki Imai
   5
   6     Distributed under the Boost Software License, Version 1.0. (See accompanying
   7     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8 ==============================================================================*/
   9
  10 #if !defined(BOOST_SPIRIT_SUPPORT_LINE_POS_ITERATOR)
  11 #define BOOST_SPIRIT_SUPPORT_LINE_POS_ITERATOR
  12
  13 #include <boost/iterator/iterator_adaptor.hpp>
  14 #include <boost/range/iterator_range_core.hpp>
  15
  16 namespace boost { namespace spirit
  17 {
  18     //[line_pos_iterator_class
  19     /*`The `line_pos_iterator` is a lightweight line position iterator.
  20        This iterator adapter only stores the current line number, nothing else.
  21        Unlike __classic__'s `position_iterator`, it does not store the
  22        column number and does not need an end iterator. The current column can
  23        be computed, if needed. */
  24     //`[heading Class Reference]
  25     template <class Iterator>
  26     class line_pos_iterator : public boost::iterator_adaptor<
  27         line_pos_iterator<Iterator>  // Derived
  28       , Iterator                     // Base
  29       , boost::use_default           // Value
  30       , boost::forward_traversal_tag // CategoryOrTraversal
  31     > {
  32     public:
  33         line_pos_iterator();
  34
  35         explicit line_pos_iterator(Iterator);
  36
  37         std::size_t position() const;
  38
  39     private:
  40         friend class boost::iterator_core_access;
  41
  42         void increment();
  43
  44         std::size_t line; // The line position.
  45         typename std::iterator_traits<Iterator>::value_type prev;
  46     };
  47     //]
  48
  49     template <class Iterator>
  50     line_pos_iterator<Iterator>::line_pos_iterator() :
  51         line_pos_iterator::iterator_adaptor_(), line(1), prev(0) { }
  52
  53     template <class Iterator>
  54     line_pos_iterator<Iterator>::line_pos_iterator(Iterator base) :
  55         line_pos_iterator::iterator_adaptor_(base), line(1), prev(0) { }
  56
  57     template <class Iterator>
  58     std::size_t line_pos_iterator<Iterator>::position() const
  59     {
  60         return line;
  61     }
  62
  63     template<class Iterator>
  64     void line_pos_iterator<Iterator>::increment()
  65     {
  66         typename std::iterator_traits<Iterator>::reference
  67           ref = *(this->base());
  68
  69         switch (ref) {
  70           case '\r':
  71             if (prev != '\n')
  72               ++line;
  73             break;
  74           case '\n':
  75             if (prev != '\r')
  76               ++line;
  77             break;
  78           default:
  79             break;
  80         }
  81
  82         prev = ref;
  83         ++this->base_reference();
  84     }
  85
  86     //[line_pos_iterator_utilities
  87     //`[heading get_line]
  88     template <class Iterator>
  89     inline std::size_t get_line(Iterator);
  90     /*`Get the line position. Returns -1 if Iterator is not a
  91        `line_pos_iterator`. */
  92
  93     //`[heading get_line_start]
  94     template <class Iterator>
  95     inline Iterator get_line_start(Iterator lower_bound, Iterator current);
  96     /*`Get an iterator to the beginning of the line. Applicable to any
  97        iterator. */
  98
  99     //`[heading get_current_line]
 100     template <class Iterator>
 101     inline iterator_range<Iterator>
 102     get_current_line(Iterator lower_bound, Iterator current,
 103                      Iterator upper_bound);
 104     /*`Get an `iterator_range` containing the current line. Applicable to any
 105        iterator. */
 106
 107     //`[heading get_column]
 108     template <class Iterator>
 109     inline std::size_t get_column(Iterator lower_bound, Iterator current,
 110                                   std::size_t tabs = 4);
 111     /*`Get the current column. Applicable to any iterator. */
 112     //]
 113
 114     template <class Iterator>
 115     inline std::size_t get_line(Iterator)
 116     {
 117         return -1;
 118     }
 119
 120     template <class Iterator>
 121     inline std::size_t get_line(line_pos_iterator<Iterator> i)
 122     {
 123         return i.position();
 124     }
 125
 126     template <class Iterator>
 127     inline Iterator get_line_start(Iterator lower_bound, Iterator current)
 128     {
 129         Iterator latest = lower_bound;
 130         bool prev_was_newline = false;
 131         for (Iterator i = lower_bound; i != current; ++i) {
 132             if (prev_was_newline) {
 133                 latest = i;
 134             }
 135             prev_was_newline = (*i == '\r') || (*i == '\n');
 136         }
 137         if (prev_was_newline) {
 138             latest = current;
 139         }
 140         return latest;
 141     }
 142
 143     template <class Iterator>
 144     inline Iterator get_line_end(Iterator current, Iterator upper_bound)
 145     {
 146         for (Iterator i = current; i != upper_bound; ++i) {
 147             if ((*i == '\n') || (*i == '\r')) {
 148                 return i;
 149             }
 150         }
 151         return upper_bound;
 152     }
 153
 154
 155     template <class Iterator>
 156     inline iterator_range<Iterator>
 157     get_current_line(Iterator lower_bound,
 158                      Iterator current,
 159                      Iterator upper_bound)
 160     {
 161         Iterator first = get_line_start(lower_bound, current);
 162         Iterator last = get_line_end(current, upper_bound);
 163         return iterator_range<Iterator>(first, last);
 164     }
 165
 166     template <class Iterator>
 167     inline std::size_t get_column(Iterator lower_bound,
 168                                   Iterator current,
 169                                   std::size_t tabs)
 170     {
 171         std::size_t column = 1;
 172         Iterator first = get_line_start(lower_bound, current);
 173
 174         for (Iterator i = first; i != current; ++i) {
 175           switch (*i) {
 176             case '\t':
 177               column += tabs - (column - 1) % tabs;
 178               break;
 179             default:
 180               ++column;
 181           }
 182         }
 183
 184         return column;
 185     }
 186
 187 }}
 188
 189 #endif // BOOST_SPIRIT_SUPPORT_LINE_POS_ITERATOR
 190