January 2008 - Boost-users - lists.preview.boost.org

base 64 encoding
by Eames, Andrew 04 Jan '08

04 Jan '08

Hi, I'm trying to encode base64 data by composing base64_from_binary with transform_width but this doesn't appear to work correctly when the data is not a multiple of 3 long. What is the correct way to handle this - do I have to handle the padding myself by extending the input data and then patching the tail of the result? Thanks Andrew

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Serialization and polymorphism
by Ricardo Mayerhofer 04 Jan '08

04 Jan '08

Hi all, I'm trying to find a way to use Boost serialization with polymorphism but wasn't able to make it so far. E.g. I have an abstract class named ILog and two classes that inherits from it. Now I have a vector of ILog. How do I serialize this vector? Thanks. Ricardo

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Re: [Boost-users] base 64 encoding
by Chad Walters 04 Jan '08

04 Jan '08

The simplest workaround would probably be to pad the encoded output to a multiple of 3 by adding 0, 1, or 2 '=' characters as needed. Eames, Andrew" <andrew(a)cognex.com> wrote: But there is still the problem with running off the end of the source - If the source is not a multiple of 3 bytes then the input iterator will run off the end of the input sequence which can cause an error. Andrew

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Re: [Boost-users] [Boost.MPL and Boost.Fusion] Combinatorial gamewith typelists
by dariomt＠gmail.com 04 Jan '08

04 Jan '08

Tobias Schwinger wrote: > Here's an MPL-based solution. Whoa! Thanks a lot! > compiles with GCC4 For me it also works with VS2003 Right now I'm still scratching my head in astonishment ;) I'll definitely come back looking for some more help to understand your solution. Thanks again.

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[date-time] Fwd: Problems when constructing time_duration and ptime from string
by Filip Konvička 04 Jan '08

04 Jan '08

-----Original Message----- From: Kahánek Petr Sent: Friday, January 04, 2008 10:22 AM To: 'boost-users(a)lists.boost.org' Subject: Problems when constructing time_duration and ptime from string Hi, It seems there are problems with duration/ptime construction from string, no matter if one uses duration_from_string, time_from_string or operator >>. Lets have the following code. Using Windows XP service pack 2, MSVS2005 SP 1, Boost 1-34.1 #include <string> #include <boost/date_time/posix_time/posix_time.hpp> using namespace std; using namespace boost; using namespace boost::posix_time; int _tmain(int argc, _TCHAR* argv[]) { string str; time_duration td; ptime time; // try to construct duration and ptime from string where there's no blank space between date and time // 1) duration_from_string will pass // 2) "time_duration >>" will pass // 3) time_from_string will throw // 4) "ptime >>" will pass str = "2007-01-2010:00:05"; td = duration_from_string(str); cout << "\"" << str << "\" == " << to_simple_string(td) << endl; stringstream ss(str); ss >> td; cout << "\"" << str << "\" == " << to_simple_string(td) << endl; try { time = time_from_string(str); cout << "\"" << str << "\" == " << time << endl; } catch(exception& e) { cout << "time_from_string could not construct time from \"" << str << "\", " << e.what() << endl; } try { stringstream ss(str); ss >> time; cout << "\"" << str << "\" == " << time << endl; } catch(exception& e) { cout << "operator >> could not get time from '" << "', " << e.what() << endl; } cout << endl << endl; // try to construct duration and ptime from "2007-01-20-1.xwerf" (mangled delimiters, rubbish in place of // fractional sec.) --> none will throw str = "2007-01-20-1.xwerf"; td = duration_from_string(str); cout << "\"" << str << "\" == " << to_simple_string(td) << endl; stringstream ss2(str); ss2 >> td; cout << "\"" << str << "\" == " << to_simple_string(td) << endl; time = time_from_string(str); cout << "\"" << str << "\" == " << time << endl; stringstream ss3(str); ss3 >> time; cout << "\"" << str << "\" == " << time << endl; cout << endl << endl; // try to construct duration and ptime from "2007.01.20.1.xwerf" (mangled delimiters, rubbish in place of // fractional sec.) --> none will throw str = "2007.01.20.1.0xwerf"; td = duration_from_string(str); cout << "\"" << str << "\" == " << to_simple_string(td) << endl; stringstream ss4(str); ss4 >> td; cout << "\"" << str << "\" == " << to_simple_string(td) << endl; time = time_from_string(str); cout << "\"" << str << "\" == " << time << endl; ss4 >> time; cout << "\"" << str << "\" == " << time << endl; cout << endl << endl; // try to construct duration and ptime from "2008-01-03" // none will throw, duration created although delimiter is "-", ptime created incorrectly str = "2008-01-03"; td = duration_from_string(str); cout << "\"" << str << "\" == " << to_simple_string(td) << endl; stringstream ss5(str); ss5 >> td; cout << "\"" << str << "\" == " << to_simple_string(td) << endl; str = "2008-01-03"; time = time_from_string(str); cout << "\"" << str << "\" == " << time << endl; stringstream ss6(str); ss6 >> time; cout << "\"" << str << "\" == " << time << endl; // even if duration is constructed, printing it to cout with operator << without conversion to string // will assert in strftime.c if hours are out of scope [0,23], or if minutes/seconds are out of [0,59] cout << str << " == " << td << endl; // CRASH return 0; } Output from this program: "2007-01-2010:00:05" == 2007:34:30 "2007-01-2010:00:05" == 2007:34:30 time_from_string could not construct time from "2007-01-2010:00:05", bad lexical cast: source type value could not be interpreted as target "2007-01-2010:00:05" == not-a-date-time "2007-01-20-1.xwerf" == 2007:01:20.100000 "2007-01-20-1.xwerf" == 2007:01:20.100000 "2007-01-20-1.xwerf" == 2007-Apr-13 15:01:20.100000 "2007-01-20-1.xwerf" == 2007-Apr-13 15:01:20.100000 "2007.01.20.1.0xwerf" == 2007:01:20.100000 "2007.01.20.1.0xwerf" == 2007:01:20.100000 "2007.01.20.1.0xwerf" == 2007-Apr-13 15:01:20.100000 "2007.01.20.1.0xwerf" == 2007-Apr-13 15:01:20.100000 "2008-01-03" == 2008:01:03 "2008-01-03" == 2008:01:03 "2008-01-03" == 2008-Mar-26 16:01:03 "2008-01-03" == 2008-Mar-26 16:01:03 ..and then it will assert on cout << td. Durations that have hours out of [0,23] or min/sec out of [0,59] are parsed successfully but cannot be printed to cout using << (assert in strftime.c). Workaround for "pure date", e.g. "2007-01-10", is to append "0" to it. "2007-01-10 0" is parsed OK. I guess these can be considered bugs? Br, Petr

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Help to design a thread server for boost::thread_group seems useless
by lemmel lemmel 04 Jan '08

04 Jan '08

It seems that thread_group doesn't perform any task after the thread termination (see http://thread.gmane.org/gmane.comp.lib.boost.user/5694) and then doesn't manage the memory. So the following code : ------------------------- CODE --------------------------- BEGIN ----------------------- #include #include class Toto { public: Toto(){std::cout << "I'm builded\n";} Toto(const Toto&){std::cout << "I'm builded\n";} void operator() () {std::cout << "I'm called\n";} ~Toto(){std::cout << "I'm destructed\n";} }; int main(int, char **) { boost::thread_group thread; while (true) { thread.create_thread(Toto()); sleep(1); } thread.join_all(); return EXIT_SUCCESS; } ------------------------- CODE --------------------------- END ----------------------- consumes endlessly a finite memory. How can I do in order to free the memory after the thread termination ? I can't use the join/join_all for at the same time I may need to create other threads (e.g. a tcp socket server), and I can't know if a thread is running or not (there is no such methods in the thread class, http://www.boost.org/doc/html/boost/thread.html) _________________________________________________________________ Microsoft vous recommande de mettre à jour Internet Explorer. http://specials.fr.msn.com/IE7P25

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Problems when constructing time_duration and ptime from string
by Kahánek Petr 04 Jan '08

04 Jan '08

Hi, It seems there are problems with duration/ptime construction from string, no matter if one uses duration_from_string, time_from_string or operator >>. Lets have the following code. Using Windows XP service pack 2, MSVS2005 SP 1, Boost 1-34.1 #include <string> #include <boost/date_time/posix_time/posix_time.hpp> using namespace std; using namespace boost; using namespace boost::posix_time; int _tmain(int argc, _TCHAR* argv[]) { string str; time_duration td; ptime time; // try to construct duration and ptime from string where there's no blank space between date and time // 1) duration_from_string will pass // 2) "time_duration >>" will pass // 3) time_from_string will throw // 4) "ptime >>" will pass str = "2007-01-2010:00:05"; td = duration_from_string(str); cout << "\"" << str << "\" == " << to_simple_string(td) << endl; stringstream ss(str); ss >> td; cout << "\"" << str << "\" == " << to_simple_string(td) << endl; try { time = time_from_string(str); cout << "\"" << str << "\" == " << time << endl; } catch(exception& e) { cout << "time_from_string could not construct time from \"" << str << "\", " << e.what() << endl; } try { stringstream ss(str); ss >> time; cout << "\"" << str << "\" == " << time << endl; } catch(exception& e) { cout << "operator >> could not get time from '" << "', " << e.what() << endl; } cout << endl << endl; // try to construct duration and ptime from "2007-01-20-1.xwerf" (mangled delimiters, rubbish in place of // fractional sec.) --> none will throw str = "2007-01-20-1.xwerf"; td = duration_from_string(str); cout << "\"" << str << "\" == " << to_simple_string(td) << endl; stringstream ss2(str); ss2 >> td; cout << "\"" << str << "\" == " << to_simple_string(td) << endl; time = time_from_string(str); cout << "\"" << str << "\" == " << time << endl; stringstream ss3(str); ss3 >> time; cout << "\"" << str << "\" == " << time << endl; cout << endl << endl; // try to construct duration and ptime from "2007.01.20.1.xwerf" (mangled delimiters, rubbish in place of // fractional sec.) --> none will throw str = "2007.01.20.1.0xwerf"; td = duration_from_string(str); cout << "\"" << str << "\" == " << to_simple_string(td) << endl; stringstream ss4(str); ss4 >> td; cout << "\"" << str << "\" == " << to_simple_string(td) << endl; time = time_from_string(str); cout << "\"" << str << "\" == " << time << endl; ss4 >> time; cout << "\"" << str << "\" == " << time << endl; cout << endl << endl; // try to construct duration and ptime from "2008-01-03" // none will throw, duration created although delimiter is "-", ptime created incorrectly str = "2008-01-03"; td = duration_from_string(str); cout << "\"" << str << "\" == " << to_simple_string(td) << endl; stringstream ss5(str); ss5 >> td; cout << "\"" << str << "\" == " << to_simple_string(td) << endl; str = "2008-01-03"; time = time_from_string(str); cout << "\"" << str << "\" == " << time << endl; stringstream ss6(str); ss6 >> time; cout << "\"" << str << "\" == " << time << endl; // even if duration is constructed, printing it to cout with operator << without conversion to string // will assert in strftime.c if hours are out of scope [0,23], or if minutes/seconds are out of [0,59] cout << str << " == " << td << endl; // CRASH return 0; } Output from this program: "2007-01-2010:00:05" == 2007:34:30 "2007-01-2010:00:05" == 2007:34:30 time_from_string could not construct time from "2007-01-2010:00:05", bad lexical cast: source type value could not be interpreted as target "2007-01-2010:00:05" == not-a-date-time "2007-01-20-1.xwerf" == 2007:01:20.100000 "2007-01-20-1.xwerf" == 2007:01:20.100000 "2007-01-20-1.xwerf" == 2007-Apr-13 15:01:20.100000 "2007-01-20-1.xwerf" == 2007-Apr-13 15:01:20.100000 "2007.01.20.1.0xwerf" == 2007:01:20.100000 "2007.01.20.1.0xwerf" == 2007:01:20.100000 "2007.01.20.1.0xwerf" == 2007-Apr-13 15:01:20.100000 "2007.01.20.1.0xwerf" == 2007-Apr-13 15:01:20.100000 "2008-01-03" == 2008:01:03 "2008-01-03" == 2008:01:03 "2008-01-03" == 2008-Mar-26 16:01:03 "2008-01-03" == 2008-Mar-26 16:01:03 ..and then it will assert on cout << td. Durations that have hours out of [0,23] or min/sec out of [0,59] are parsed successfully but cannot be printed to cout using << (assert in strftime.c). Workaround for "pure date", e.g. "2007-01-10", is to append "0" to it. "2007-01-10 0" is parsed OK. I guess these can be considered bugs? Br, Petr

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boost::shared_ptr and casting operation
by Michael Bradley Jr 04 Jan '08

04 Jan '08

Hi, can someone please provide me an elegant way to solve the current problem. class A; class B : public A; boost::shared_ptr<A> pA; boost::shared_ptr<B> pB; Would like to cast pB to pA with a construct like the *static_cast* but that ain't really pretty ! Thanks in advance Michael

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Seg Fault using pool_allocator
by Nindi Singh 04 Jan '08

04 Jan '08

I am getting a seg fault on running the following code. _______________________________________________________________________ #include<map> #include<vector> #include<boost/pool/pool_alloc.hpp> typedef std::vector<double,boost::pool_allocator<double > > vector; int main() { std::map<unsigned long, vector> theStdMap; theStdMap[0]; } _________________________________________________________________________ I am using Ubuntu 7.10 AMD64 g++4.1 and g++4.2 boost 1.34.1 ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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SWIG vs Boost.Python vs PyCXX vs Py++
by Mathieu Malaterre 03 Jan '08

03 Jan '08

Hi there, After reading a couple of -outdated- references I am even more confused than when I started. I have been using swig for the longest time (not by choice), but I am given the opportunity to rethink this -bad- choice. I had heard lots of good thing about Boost.Python, so I decided to have a look at it. I realized that it is already replaced by another layer of abstraction: PyCXX or Py++ (is this correct so far?). So as of today could someone please let me know what are the main differences in between PyCXX and Py++ ? Our current built system is cmake and I would like to avoid adding a dependencie to bjam. What are the drawback of having a dependencie (link library) to boost (versus swig which does not have any). Thanks for comments, -- Mathieu References: http://retrograde-orbit.blogspot.com/2006/12/boost.html http://pyfltk.sourceforge.net/faq.php#boost1 http://people.web.psi.ch/geus/talks/europython2004_geus.pdf http://bob.pythonmac.org/archives/2005/03/11/swig-hate/ http://retrograde-orbit.blogspot.com/2006/12/boost.html http://www.boost-consulting.com/writing/bpl.html http://seal.web.cern.ch/seal/snapshot/work-packages/scripting/evaluation-re…

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