[Boost-bugs] [Boost C++ Libraries] #11148: attribute_value_set.size() is busted

Subject: [Boost-bugs] [Boost C++ Libraries] #11148: attribute_value_set.size() is busted
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-03-27 20:08:52

#11148: attribute_value_set.size() is busted
------------------------------+------------------------
 Reporter:  cnewbold          |      Owner:  andysem
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  log
  Version:  Boost 1.57.0      |   Severity:  Regression
 Keywords:                    |
------------------------------+------------------------
 The problem can be illustrated with some code like this:

 {{{

 using boost::log::attribute_value_set;
 const attribute_value_set& values(record.attribute_values());

 const boost::log::attribute_value_set::size_type count(
     values.size());

 for (attribute_value_set::value_type i : values)
 {
     ...
 }

 }}}

 Under some circumstances we see that the for loop iterates over more than
 'count' attribute values.

 The problem is in attribute_value_set::implementation::size(), which looks
 like this:

 {{{
 size_type size()
 {
     freeze();
     return (m_pEnd - m_pStorage);
 }
 }}}

 This works correctly when the set does not contain more attributes than
 fit in the pre-allocated block pointed to by m_pStorage. But, looking at
 attribute_value_set::implementation::insert_node(), we see that once the
 internal node storage is exhausted, additional nodes are allocated on-the-
 fly and are not accounted for in the computation in size():

 {{{
 node* insert_node(key_type key, bucket& b, node* where, mapped_type data)
 {
      node* p;
      if (m_pEnd != m_pEOS)
      {
             p = m_pEnd++;
             new (p) node(key, data, false);
      }
      else
      {
          p = new node(key, data, true);
      }

     ...

 }}}


 I have not looked, but this problem may also exist in other
 attribute_value_set like containers.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11148>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.