Re: [Boost-users] [Serialization] a coupla crashes fromhiearchycomplexity

From: Reusser, Edward (Edward.Reusser_at_[hidden])
Date: 2006-11-13 16:05:33

Robert,

 

I would need permission to send you the exact library code.  I am
reluctant to do this primarily because recreating my exact build
environment would be a hassle (we are using gnumake on the PC).  I also
would need to do this directly to you, as I could not post this code
into a public forum.

 

Having said that, any recursive descent parser has complexity limits
based on stack size.  It would be pretty easy to create test cases that
probe these complexity limits for the various archive types.  I would
like to see how much (approximately)  stack space is allocated in the
runtime for each level of xml hierarchy, and also for the text archives.

 

The main complexity seems to be because I am using shared_ptr's
extensively at all levels of the hierarchy.  Thus, I have 2 levels
nested for each class, the <px> data </px> and the actual data, which is
in turn being represented by a collection of shared_ptr's, etc.  I am
also using std::map of shared pointers, and std::set of shared_ptr's.  I
also use enable_shared_from_this<T> for my base classes, then statically
cast the resultant shared pointers internally for the derived classes.
This is to get around a Linux problem which I can describe more fully if
you like (would take a few pages of explanation).

 

So for example:

 

class Base : public boost:enable_shared_from_this<Base>

{

      virtual boost::shared_ptr<Base> GetSharedFromThis()

    {

        return shared_from_this();

    }

 

};

 

class Derived1 : public Base

{

public:

      virtual boost::shared_ptr<Derived1> GetSharedFromThis()

    {

        return static_pointer_cast<Derived1>( shared_from_this() );

    }

};

 

class Derived2 : public Base

{

public:

      virtual boost::shared_ptr<Derived2> GetSharedFromThis()

    {

        return static_pointer_cast<Derived2>( shared_from_this() );

    }

};

 

I am assuming that I do not need to call
boost::serialization::base_object<boost::enable_shared_from_this<Base>
>( *this );  

 

When I serialize the base class.  Could that be the problem?

 

I think what I am going to do is go back into the program and simply
eliminate all of the shared_ptr serializations.  I can serialize to raw
pointers, and then just create the shared_ptr's from those pointers
explicitly in my case.  I simply do not ever have any shared_ptr's with
multiple reference counts to worry about.

 

I will let you know what happens.

 

 

________________________________

From: Robert Ramey [mailto:ramey_at_[hidden]] 
Sent: Monday, November 13, 2006 8:30 AM
To: boost-users_at_[hidden]
Subject: Re: [Boost-users] [Serialization] a coupla crashes
fromhiearchycomplexity

 

I would be curious to see your particular case.  The fact that different
archives give problems that seem related to nesting depth suggest along
with the fact that this hasn't been reported suggests that there is some
sort of use case or error which hasn't been considered.

 

Robert Ramey

        "Reusser, Edward" <Edward.Reusser_at_[hidden]> wrote in message
news:5E916BAE1732F344BAFD713DF2373479016EA059_at_SV-MSG-01.amer.actel.com..
.

        I am using the serialization library in boost 1.33.1.  I am
compiling on windows using the VC 7.1 compiler.

         

        The problem I am having is that when I use xml_iarchive and
xml_oarchive, everything works just fine for simple cases, but if the
xml gets very deep ( same exact class hierarchy, just more data
organized a little more complexly) I am getting runtime stack overflow
crashes in the spirit parser.  I figured I could solve that by simply
substituting text_iarchive and text_oarchive.   Please note that I am
simply substituting in these archive types instead of using the xml
archive headers, which work.  There are no other code changes anywhere.

         

        Now I am getting the following compiler error:

         

        \boost\mpl\eval_if.hpp(40) : fatal error C1204: compiler limit :
internal structure overflow

         

        Any suggestions?  I can try increasing the stack size of my
current application to eliminate the xml runtime stack overflow problem,
but I am uneasy doing this until I understand how to calculate the stack
sizes required, and why it is happening.  Furthermore, I would prefer
using the text archives, since the data is more compact than the xml
ones.

         

        Ed Reusser 

        Principal Software Engineer

        Actel Corporation

        [phone]

        
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