[Boost-commit] svn:boost r70549 - in trunk/boost/spirit/home/qi/stream: . detail

Subject: [Boost-commit] svn:boost r70549 - in trunk/boost/spirit/home/qi/stream: . detail
From: hartmut.kaiser_at_[hidden]
Date: 2011-03-25 20:55:05

Author: hkaiser
Date: 2011-03-25 20:55:03 EDT (Fri, 25 Mar 2011)
New Revision: 70549
URL: http://svn.boost.org/trac/boost/changeset/70549

Log:
Spirit: fixing iterator handling in stream parser
Text files modified: 
   trunk/boost/spirit/home/qi/stream/detail/iterator_source.hpp |    27 +++++++++++++++++++++++----             
   trunk/boost/spirit/home/qi/stream/stream.hpp                 |     8 +++++++-                                
   2 files changed, 30 insertions(+), 5 deletions(-)

Modified: trunk/boost/spirit/home/qi/stream/detail/iterator_source.hpp
==============================================================================
--- trunk/boost/spirit/home/qi/stream/detail/iterator_source.hpp	(original)
+++ trunk/boost/spirit/home/qi/stream/detail/iterator_source.hpp	2011-03-25 20:55:03 EDT (Fri, 25 Mar 2011)
@@ -24,10 +24,10 @@
         typedef typename
             boost::detail::iterator_traits<Iterator>::value_type
         char_type;
-        typedef boost::iostreams::source_tag category;
+        typedef boost::iostreams::seekable_device_tag category;
 
-        iterator_source (Iterator& first_, Iterator const& last_)
-          : first(first_), last(last_)
+        iterator_source (Iterator const& first_, Iterator const& last_)
+          : first(first_), last(last_), pos(0)
         {}
 
         // Read up to n characters from the input sequence into the buffer s,
@@ -45,11 +45,30 @@
                 if (++first == last)
                     break;
             }
+
+            pos += bytes_read;
             return bytes_read;
         }
 
-        Iterator& first;
+        // Write is implemented only to satisfy the requirements of a 
+        // boost::iostreams::seekable_device. We need to have see support to
+        // be able to figure out how many characters have been actually 
+        // consumed by the stream.
+        std::streamsize write(const char*, std::streamsize) 
+        {
+            BOOST_ASSERT(false);    // not supported
+            return -1;
+        }
+
+        std::streampos seek(boost::iostreams::stream_offset, std::ios_base::seekdir way) 
+        {
+            BOOST_ASSERT(way == std::ios_base::cur);    // only support queries
+            return pos;                              // return current position
+        }
+
+        Iterator first;
         Iterator const& last;
+        std::streamsize pos;
 
     private:
         // silence MSVC warning C4512: assignment operator could not be generated

Modified: trunk/boost/spirit/home/qi/stream/stream.hpp
==============================================================================
--- trunk/boost/spirit/home/qi/stream/stream.hpp	(original)
+++ trunk/boost/spirit/home/qi/stream/stream.hpp	2011-03-25 20:55:03 EDT (Fri, 25 Mar 2011)
@@ -64,8 +64,14 @@
             typedef boost::iostreams::stream<source_device> instream;
 
             qi::skip_over(first, last, skipper);
-            instream in(first, last);
+
+            instream in(first, last);         // copies 'first'
             in >> attr;                       // use existing operator>>()
+
+            // advance the iterator if everything is ok
+            if (in.good())
+                std::advance(first, in.tellg());
+
             return in.good() || in.eof();
         }