[Boost-commit] svn:boost r61331 - in trunk/libs/spirit/example/scheme: input support

Subject: [Boost-commit] svn:boost r61331 - in trunk/libs/spirit/example/scheme: input support
From: joel_at_[hidden]
Date: 2010-04-17 04:30:22

Author: djowel
Date: 2010-04-17 04:30:19 EDT (Sat, 17 Apr 2010)
New Revision: 61331
URL: http://svn.boost.org/trac/boost/changeset/61331

Log:
line_pos_iterator: a lighweight line position iterator.
Added:
   trunk/libs/spirit/example/scheme/support/
   trunk/libs/spirit/example/scheme/support/line_pos_iterator.hpp   (contents, props changed)
Text files modified: 
   trunk/libs/spirit/example/scheme/input/parse_sexpr_impl.hpp |     1 +                                       
   1 files changed, 1 insertions(+), 0 deletions(-)

Modified: trunk/libs/spirit/example/scheme/input/parse_sexpr_impl.hpp
==============================================================================
--- trunk/libs/spirit/example/scheme/input/parse_sexpr_impl.hpp	(original)
+++ trunk/libs/spirit/example/scheme/input/parse_sexpr_impl.hpp	2010-04-17 04:30:19 EDT (Sat, 17 Apr 2010)
@@ -14,6 +14,7 @@
 
 #include <input/sexpr.hpp>
 #include <input/parse_sexpr.hpp>
+#include <support/line_pos_iterator.hpp>
 
 namespace scheme { namespace input
 {

Added: trunk/libs/spirit/example/scheme/support/line_pos_iterator.hpp
==============================================================================
--- (empty file)
+++ trunk/libs/spirit/example/scheme/support/line_pos_iterator.hpp	2010-04-17 04:30:19 EDT (Sat, 17 Apr 2010)
@@ -0,0 +1,109 @@
+/*=============================================================================
+    Copyright (c) 2001-2010 Joel de Guzman
+
+    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)
+=============================================================================*/
+#if !defined(BOOST_SPIRIT_LINE_POS_ITERATOR)
+#define BOOST_SPIRIT_LINE_POS_ITERATOR
+
+#include <boost/iterator/iterator_adaptor.hpp>
+#include <boost/range/iterator_range.hpp>
+
+namespace scheme
+{
+    ///////////////////////////////////////////////////////////////////////////
+    // line_pos_iterator: a lighweight line position iterator. This iterator
+    // adapter only stores the current line number, nothing else. Unlike
+    // spirit classic's position_iterator, it does not store the column
+    // number and does not need an end iterator.
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename Iterator>
+    class line_pos_iterator
+      : public boost::iterator_adaptor<
+            line_pos_iterator<Iterator>     // Derived
+          , Iterator                        // Base
+          , boost::use_default              // Value
+          , boost::forward_traversal_tag    // CategoryOrTraversal
+        >
+    {
+    public:
+
+        line_pos_iterator()
+          : line_pos_iterator::iterator_adaptor_()
+            line(0), prev(0) {}
+
+        explicit line_pos_iterator(Iterator base)
+          : node_iter::iterator_adaptor_(base)
+            line(0), prev(0) {}
+
+        std::size_t position() const
+        {
+            return line;
+        }
+
+    private:
+
+        friend class boost::iterator_core_access;
+        void increment()
+        {
+            typename Iterator::reference ref = *(this->base());
+            switch (ref)
+            {
+                case '\r':
+                    if (prev != '\n')
+                       ++line;
+                    break;
+                case '\n':
+                    if (prev != '\r')
+                       ++line;
+                    break;
+                default:
+                    break;
+            }
+            prev = ref;
+        }
+
+        std::size_t line;
+        typename Iterator::value_type prev;
+    };
+
+    ///////////////////////////////////////////////////////////////////////////
+    // Utilities
+    ///////////////////////////////////////////////////////////////////////////
+
+    // Get an iterator to the beginning of the line. Applicable to any
+    // iterator.
+    template <typename Iterator>
+    inline Iterator
+    get_line_start(Iterator lower_bound, Iterator current)
+    {
+        Iterator latest = lower_bound;
+        for (Iterator i = lower_bound; i != current; ++i)
+        {
+            switch (*i)
+            {
+                case '\r':
+                case '\n':
+                    latest = i;
+            }
+        }
+        return latest;
+    }
+
+    // Get the iterator range containing the current line. Applicable to
+    // any iterator.
+    template <typename Iterator>
+    inline iterator_range<Iterator>
+    get_current_line(
+        Iterator lower_bound, Iterator current, Iterator upper_bound)
+    {
+        Iterator first = get_line_start(lower_bound, current);
+        Iterator last = get_line_start(current, upper_bound);
+        if (last == current)
+            last = upper_bound;
+        return iterator_range<Iterator>(first, last);
+    }
+}
+
+#endif