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[MSM] how to use a compilation firewall around inner state machines
by Mark Bartosik 30 Jul '14

30 Jul '14

I have a state machine implemented with MSM (eUML) that currently has 80 transitions, there are two inner state machines. Compilation time is not great, but I have been dealing with it by BOOST_MSM_FAVOR_COMPILE_TIME and using parallel compilation where possible. Slow compilation time is an irritation and productivity killer, but my larger worry is that eventually the compiler will run out of memory. Especially as I will likely have to add another inner state machine with about 40 more transitions. Current we are using VS2008 but planning on moving everyone in the team to the VS2012 toolset but running under the VS2013 environment. I don't know if this will help, I doubt it. Currently compilation memory usage is up to 2.5GB per translation unit. So I would like to use a compilation firewall around the inner state machines. My plan is to implement concrete types for the inner state machines, with a process_event function: boost::msm::back::HandledEnum process_event( const boost::any & event ); Then within this function test for each event type to be handled by the inner state machine, and forward to a regular MSM state machine contained within the inner concrete type. I am hoping that this, plus on_entry and on_exit functions is about all I need to do. I expect that I will be able to get this to work, although an example on how to put a concrete wrapper around an inner state machine would be great, and importantly a list of limitations and work arounds for this technique would be helpful. My problem is that the outer state machine transition table has rows like this: exit_pt_( inner_state, inner_state_some_pseudo_exit_state ) / do_some_stuff() == outer_s2, exit_pt_( inner_state, inner_state_other_pseudo_exit_state ) / do_other_stuff() == outer_s3, If inner_state becomes a concrete type, then I don't know if this can be handled, and if so how? My best idea so far is for the inner_state to call process_event on the outer state machine and rewrite the outer machine's state transition table thus: inner_state + some_synthetic_event / do_some_stuff() == outer_s2, inner_state + other_synthetic_event / do_other_stuff() == outer_s3 The xxxx_synthetic_event's would be generated from within the inner state machine when it reaches one of the pseudo exit states. So in summary I would like to know: 1) Is there a documented example of putting a concrete wrapper around a inner state machine. 2) What is the list of limitations of doing this. e.g. exit_pt_ not working. 3) How should I deal with transitions in the outer state machine that were making use of exit_pt_ P.S. I've got to say that I think MSM is great! thanks - - Mark

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equivalent of java.util.properties
by David Frank 30 Jul '14

30 Jul '14

I'm wondering if there is a boost equivalent of the java.util.properties package which can read java properties file. Thanks, Dave.

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revisiting casting a boost::shared_ptr to void*
by Chris Cleeland 30 Jul '14

30 Jul '14

I'm resurrecting this topic: https://groups.google.com/forum/#!searchin/boost-list/shared_ptr$20void*/bo… because there is an unaddressed issue in it that I'm about to run into: "... beware the pointee may be deleted if the last copy of the shared pointer goes out of scope, as the raw pointer won't have incremented the reference count." I cannot be the first person to run into this--a common issue when crossing an API boundary. Has anyone come up with a good, safe solution wherein the reference count gets properly incremented? -- Chris Cleeland

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[Graph] Large Graphs: performace boost
by Sensei 30 Jul '14

30 Jul '14

Dear all, Facing an increasing size in my experiments, I am wondering now if my data structure is still valid. I need to traverse a graph (with my custom A*) that now can easily contain 10M-100M nodes and 100M-400M edges. The graph is (now) without weights, but this may change in the future. The only thing that is guaranteed not to change is that the graph is immutable. The graphs might even be larger, and at some point I will move to parallel BGL, but not now. To spare some memory, I am using a CSR graph: typedef boost::compressed_sparse_row_graph<boost::bidirectionalS> boost_graph; graph_ = new boost_graph(boost::edges_are_unsorted_multi_pass, results.begin(), results.end(), nodelist().size()); I am dubious if this the best solution. I have two objectives right now, optimize with respect to 1) memory consumption, and 2) graph traversal time. The main operation I need to do on graph is just "given a node, find the adjacent ones" (with my A*). Do you suggest to switch to another graph data structure? How do you think I will sacrifice time for memory, and vice versa, if I move for instance to an adjacency list? Thanks for any suggestion!

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Boost Based Proxy
by asim 29 Jul '14

29 Jul '14

In SSl case proxy will become a tunnel so whatever encrypted data i will get from client i have to forward it to server.But i am unable to read content as connection is keep alive (means no end of file exception) and due to encryption no header based reading i can do then how to read it. -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-Based-Proxy-tp4665704.html Sent from the Boost - Users mailing list archive at Nabble.com.

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[Serialization] XML: Necessity of attribute class_id although class_name is given
by Frank Stähr 29 Jul '14

29 Jul '14

Hello everybody, I would like to know what the purpose of the xml attribute class_id is, how it works and in which cases it can be omitted. An example: “Base” is the (abstract) base class of _GMTF_ and _TTF_, and _Hist_ also has got a similar base class. If a pointer of Hist is a member of GMTF and you want to serialize a pointer of Base, you get something like: <filter class_id="0" class_name="GMTF"> <m_bufHalfMaxSize>4</m_bufHalfMaxSize> <m_cutDetector class_id="1" class_name="Hist"></m_cutDetector> </filter> Here, the macros • BOOST_CLASS_EXPORT_GUID(...), • BOOST_CLASS_IMPLEMENTATION(..., boost::serialization::object_serializable) and • BOOST_CLASS_TRACKING(..., boost::serialization::track_never) are used. The problem now is: Although the exact classes are given by human-readable class names (and used!), you cannot omit or change the class_id. If you edit the XML file by hand, it can become invalid (-> exception on reading). It seems that the class ids are just ascending non-negative numbers. What are the rules for choosing the class ids? Why are they necessary? Is there a trick to remove this attribute or at least to ignore it? Thanks, Frank -- Frank Stähr Technische Universität Berlin Communication Systems Group Sekr. EN1 Einsteinufer 17 10587 Berlin, Germany

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Pipe and Filters pattern with boost?
by Journeyer J. Joh 29 Jul '14

29 Jul '14

Hello list! I'd like to find a good approach to implement the Pipe and Filters pattern with boost. Could someone recommend me some useful boost library for this purpose? I only know asio. Is there any known example source code for this - Pipe and Filters pattern with boost. Thank you very much in advance! ---------------------------------------- Journeyer J. Joh o o s a p r o g r a m m e r a t g m a i l d o t c o m ----------------------------------------

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[Boost 1.56 Beta] [Serialization] Compilation problem with classes having special new operators
by Hijok Payne 28 Jul '14

28 Jul '14

I was trying out the new Boost 1.56 beta and some of my serialization code fails to compile (they work fine with previous versions of Boost e.g. Boost 1.55). I am trying to do serialization of Eigen (http://eigen.tuxfamily.org/) matrices with following code: #include <Eigen/Core> #include <fstream> #include <boost/serialization/vector.hpp> #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> //Boost Serialization of Eigen Matrix namespace boost { template<class Archive, typename _Scalar, int _Rows, int _Cols, int _Options, int _MaxRows, int _MaxCols> inline void serialize(Archive & ar, Eigen::Matrix<_Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols>& t, const unsigned int file_version) { size_t rows = t.rows(), cols = t.cols(); ar & rows; ar & cols; if (rows * cols != t.size()) t.resize(rows, cols); ar & boost::serialization::make_array(t.data(), t.size()); } } //Simple helper for serialization to a file template <typename T> bool serialize(const T& data, const std::string& filename) { std::ofstream ofs(filename.c_str(), std::ios::out | std::ios::binary); if (!ofs.is_open()) return false; { // use scope to ensure archive goes out of scope before stream boost::archive::binary_oarchive oa(ofs); oa << data; } ofs.close(); return true; } //Simple helper for de-serialization from a file template <typename T> bool deSerialize(T& data, const std::string& filename) { std::ifstream ifs(filename.c_str(), std::ios::in | std::ios::binary); if (!ifs.is_open()) return false; { // use scope to ensure archive goes out of scope before stream boost::archive::binary_iarchive ia(ifs); ia >> data; } ifs.close(); return true; } int main(int argc, char *argv[]) { typedef Eigen::Vector3d VectorType; VectorType* vec = new VectorType(1, 2, 3); serialize(vec, "v4d.dat"); std::cout << "v4d =\n" << *vec << std::endl; VectorType* vec_in; deSerialize(vec_in, "v4d.dat"); std::cout << "v4d_in =\n" << *vec_in << std::endl; return 0; } The error in Visual studio 2013 says: boost/archive/detail/iserializer.hpp(237): error C2665: 'Eigen::PlainObjectBase<Eigen::Matrix<double,3,1,0,3,1>>::operator delete' : none of the 3 overloads could convert all the argument types 2> c:\users\abhijit\codes\installs\eigen\eigen-install\include\eigen3\eigen\src/Core/PlainObjectBase.h(132): could be 'void Eigen::PlainObjectBase<Eigen::Matrix<double,3,1,0,3,1>>::operator delete(void *,const std::nothrow_t &) throw()' 2> c:\users\abhijit\codes\installs\eigen\eigen-install\include\eigen3\eigen\src/Core/PlainObjectBase.h(132): or 'void Eigen::PlainObjectBase<Eigen::Matrix<double,3,1,0,3,1>>::operator delete(void *,void *) throw()' 2> while trying to match the argument list '(VectorType *, size_t)' 2> C:\Boost\boost-1_56_0_b1\boost/archive/detail/iserializer.hpp(224) : while compiling class template member function 'void boost::archive::detail::heap_allocation<T>::has_new_operator::invoke_delete(T *)' There is also the following note, but I cannot seem to understand this. // if compilation fails here, the likely cause that the class // T has a class specific new operator but no class specific // delete operator which matches the following signature. Fix // your program to have this. Note that adding operator delete // with only one parameter doesn't seem correct to me since // the standard(3.7.4.2) says " // "If a class T has a member deallocation function named // 'operator delete' with exactly one parameter, then that function // is a usual (non-placement) deallocation function" which I take // to mean that it will call the destructor of type T which we don't // want to do here. I want to understand this issue because this breaks a lot of existing code.

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Geometry: modifiable?
by Jeremy Murphy 28 Jul '14

28 Jul '14

Is there a generic way to modify geometry structurally? Say if I have a ring and I want to insert a new point? Or would I need to reach into the underlying container to make that kind of change? Thanks, cheers. Jeremy

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[SmartPtr] enable_shared_from_raw
by Gavin Lambert 27 Jul '14

27 Jul '14

Hi all, Firstly, any chance this could get some documentation? Is the author still around? I'm thinking about using this at the moment for two separate reasons (and ways in which enable_shared_from_this seems to fall short): 1. shared_from_this can't be used from the constructor (requiring factory-method-init shenanigans); reportedly (https://groups.google.com/forum/#!topic/boost-list/8JWFZ56ry6k) shared_from_raw can, although I can't find specific details on the caveats mentioned. 2. What I *really* want to be able to do is to create a child object (most commonly a callback functor) that contains a weak_ptr, and it seems silly (and badly performant) to use the usual factory-init pattern to call shared_from_this just to degrade it back to a weak_ptr. And it should be possible to obtain that weak_ptr before any shared_ptr exists, and "fix" it later to point at the real shared_ptr, especially if it is known that the weak_ptr will never actually be used until that real shared_ptr exists. enable_shared_from_raw almost seems to fit the bill (according to http://stackoverflow.com/questions/22184772/why-is-boostenable-shared-from-…) but I encountered the same problem as in this post (http://lists.boost.org/boost-users/2013/05/78833.php) it works with shared_from_raw but not weak_from_raw. However this change: https://github.com/boostorg/smart_ptr/pull/8 fixes that. It looks like the two calls went down different code paths for some reason I can't fathom. Making this change (or the similar-but-better-style one mentioned in the PR discussion) makes the above scenario work as expected. I'm not sure if there was some specific reason to not do this before or if it was just an oversight. Any chance this can make it into 1.56? Or is it too late for that? Regards, Gavin Lambert

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