January 2007 - Boost-users - lists.preview.boost.org

What's wrong in regular expression
by Игорь Микушкин 15 Jan '07

15 Jan '07

Hello! I wrote the regular expression: ^\s*(?:([A-Za-z_]*)\s*=\s*([A-Za-z0-9_/\.]*)\s*)*$ for splitting lines like: name = abc value1 = def value2 = ghi I need the result like: match [1] = name match [2] = abc ... match [6] = ghi But I get ! : match [1] = value2 match [2] = ghi (the last 2 matches) What is wrong in my expression? Thank You. --------------------------------- Вы уже с Yahoo!? Испытайте обновленную и улучшенную Yahoo! Почту!

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[graph design] Advise needed - edge-to-edge passing cost
by james.jones＠firstinvestors.com 15 Jan '07

15 Jan '07

From: "Anton A. Patrushev" <anton(a)orkney.co.jp> > I need to construct a graph with following requirements: > 1. Edges should have a cost (trivial) > 2. Vertices should have a cost (also trivial) > 3. For each edge I need to define a costs of passing from this edge to > any other adjacent edge (my problem is here!) > It means that just vertex cost doesn't work - from one edge I can pass > to several edges through the same vertex and I need separate cost for > each way. > I can't split edges and vertices to many, 'cause in my case it will > drastically increase the data. > > Can anybody, please, make an advise how to implement the third rule? I'm not sure if this solves your problem, but have you considered constructing the dual of your graph and then using the vertex cost? - James Jones Administrative Data Mgmt. Webmaster 375 Raritan Center Pkwy, Suite A Data Architect Edison, NJ 08837

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[Boost.Serialization] Best way to serialize binary data?
by sadrok 14 Jan '07

14 Jan '07

Hello I need to serialize some raw binary data. What is the best way to do it for all three archive implementations? I've had troubles with the two text-based ones giving me base64 errors on loading when I use load_binary. Also I noticed that the xml_?archive doesn't produce nice XML when I use save/load_binary. Thanks -- sadrok(a)gmail.com Yahoo! IM: sadrok_za Jabber ID: sadrok(a)jabber.obsidian.co.za

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Boost conversion to struct tm for version 1.31
by debayan.bhattacharya＠firstinvestors.com 12 Jan '07

12 Jan '07

Hi all, I need some help converting a boost::gregorian::date to struct tm in version 1.31. to_tm(date) function dont seems to work in this version. Your help is greatly appreciated. Thanks Debayan

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serialize std::map
by Mark Wyszomierski 12 Jan '07

12 Jan '07

Hi, I'm experiencing a runtime error while using boost's serialization for std::map. I am defining a map like: std::map<int, CSomeData> m; and serializing it as I do any other container or primitive type. However when the map contains more than two elements, there is a runtime exception when reading a serialized file back in. I'm using visual studio 8. Following is the exact source code I'm trying this with (very short sample app). Can anyone see what I'm doing wrong, or if there is an error with the boost code? I took a look at the written file in a binary editor and it looks fine. #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/serialization/map.hpp> #include <fstream> #include <string> #include <map> using namespace std; // This is a test class to use as the map data. class CSomeData { public: CSomeData(){}; CSomeData(float f0, string str0) { m_f0 = f0; m_str0 = str0; } float m_f0; string m_str0; private: friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version) { ar & m_f0; ar & m_str0; } }; // This is the class we really want to try serializing. class CTest { public: CTest(){}; CTest(int nNumber) { m_nNumber = nNumber; // Fill with some dummy data. m_mTst.insert(make_pair(0, CSomeData(0.23f, "hi hi hi"))); m_mTst.insert(make_pair(1, CSomeData(7.65f, "second one"))); m_mTst.insert(make_pair(2, CSomeData(9.23f, "third one"))); m_mTst.insert(make_pair(3, CSomeData(5.6766, "chosen one"))); } ~CTest(){}; int m_nNumber; map<int, CSomeData> m_mTst; private: friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version) { ar & m_nNumber; ar & m_mTst; } }; int main() { std::ofstream ofs("filename"); // Write class instance to archive. Writing seems to work ok. const CTest ct(5); { boost::archive::binary_oarchive oa(ofs); oa << ct; } // Try to restore it sometime later. CTest ctNew; { std::ifstream ifs("filename", std::ios::binary); boost::archive::binary_iarchive ia(ifs); // READING CAUSES THE EXCEPTION! ia >> ctNew; } return 0; } Thanks, Mark

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Re: [Boost-users] [Threads]
by Robert Marion 12 Jan '07

12 Jan '07

Manuel Jung wrote: >> Hi, >> >> I have a strange problem. The destructor of a class calls join_all(). >> But it seems that he hangs there. Even though some other code behind the >> join_all() is executed before it finishs! >> Lets get concret: >> >> seal::~seal() >> { >> ThgPrgs.join_all(); >> cout<<"Crabd quits, goodbye"<<endl; >> } > > Could you possibly post a small (complete) example that demonstrates the > behaviour? I am not able to guess where to problem might be from looking > at the destructor only. Are you expecting the destructor to be called once? Probably what is happening is your default constructor is being called more than once (during a copy operation) and you are unaware of it. So your destructor gets called more than once. Robert Marion

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[graph design] Advise needed - edge-to-edge passing cost
by Anton A. Patrushev 12 Jan '07

12 Jan '07

Dear all, I need to construct a graph with following requirements: 1. Edges should have a cost (trivial) 2. Vertices should have a cost (also trivial) 3. For each edge I need to define a costs of passing from this edge to any other adjacent edge (my problem is here!) It means that just vertex cost doesn't work - from one edge I can pass to several edges through the same vertex and I need separate cost for each way. I can't split edges and vertices to many, 'cause in my case it will drastically increase the data. Can anybody, please, make an advise how to implement the third rule? Thanks! Anton.

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[bind, tuple] Custom comparison of tuple elements
by Mark Ruzon 12 Jan '07

12 Jan '07

Assume we have a range of objects of type tuple<T1,T2> and a function object that compares two objects of type T1. How would a person sort this range using this function object and bind? I want something along the lines of: std::sort(first, last, boost::bind<bool>(comp, boost::bind(boost::get<0>, _1), boost::bind(boost::get<0>, _2))); but this isn't remotely close to compiling. I could create a custom function object, but I'd rather learn how to use bind properly. Thanks, Mark

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Re: [Boost-users] portland group compilers (pg++, pgi, pgCC)
by Sohail Somani 11 Jan '07

11 Jan '07

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Server Levent Yilmaz > But with building libraries such as serialization and filesystem, I am > stuck. I have a very limited knowledge of bjam or any other large > scale build system for that matter. Hi, you might try the boost-build mailing list for better results. Good luck! Sohail

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optional_shared_ptr or shared_lazy_ptr extension
by Ovanes Markarian 11 Jan '07

11 Jan '07

Hello all, after some time spent for evaluating the possible scenarios I came up with the following idea. Design of a type wrapper similar to functionality offered by boost:shared_ptr and boost:optional. Let me try to explain the requirements: 1. The new type must model pointer semantics to wrapped type. 2. It must be refernece countable and multi-thread safe in regards of shared operations (copy etc.) as it is the case with shared_ptr 3. It should be able to create the wrapped type on first non-const member access request, which assumes a multi-thread safe operation (when shared accross multiple threads) 4. It should support InPlace factory and custom deleter types 5. It should not pre-allocate the storage for the contained type 6. It should be possible to use static_pointer_cast, dynamic_pointer_cast and const_pointer_cast operations with the new type. Why is optional not an option for me: 1. It preallocates memory, which I would like to save and allocate at first request only 2. The type should not implement deep copy semantics for the contained value type if copied, but act much like a shared_ptr (shallow copy) The most important use case: class A; Main Thread lazy_ptr<A> ptr; Thread 1 | Thread 2 | Thread 3 ------------+--------------------+------------- copy of ptr | copy of ptr | copy of ptr (use_count == 4, get()const returns NULL) | ptr.get()non-const | (use_count == 4, get()non-c will return valid A*) use(*ptr) | | use(*ptr) (using the same instance as created from Thread 2) If dealing intensively with big size data structures this approach can save a lot of memory if none of the threads needs an instance. All comments are highly appreciated. I also posted some comments on the similar issue, but got a suggestion to use boost::optional. Since I was not aware of all the requirements at that time I could not go ahead with a discussion. With Kind Regards, Ovanes Markarian

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