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

10 Jun '08

Hi, suppose i have container_type<range_type> seqs; i'm looking for iterator, whose instance I call i, such that if(*i == seq [j][k] ){ if(j<seqs.size()){ ++i; *i == seq[j+1][k] }else{ ++i; *i == seq[0][k+1] } if anyone has this or anything similar, could he/she kindly share it? the above is not quite the same as zip_iterator, as the parallel ranges all have the same type. also i'm aware that multi_arrays deal with this, but here i'm interested in arbitrary type. thanks for reading this thread, e.

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is there strided iterator already available somewhere?
by e r 10 Jun '08

10 Jun '08

hello, is there strided iterator already available somewhere? iter = vec.begin(); std::advance(iter,offset) for(unsigned int i=0; i<(vec.size()-offset)/stride; ++i){ /* do something with iter */ std::advance(iter,stride) } alternatively, a permutation iterator does not seem very practical here... thanks, e.

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metafunction invocation performance
by Hicham Mouline 09 Jun '08

09 Jun '08

Hello, I submitted a post a few days ago http://lists.boost.org/boost-users/2008/06/36852.php and I went to investigate on my own. Having not reached a solution to speed up the compilation, I looked again at the post and realized the code didn't compile due to a wrong paste. Apologies (if anyone tried), Anyways, here is the version that is too slow and runs out of mem during compilation on a P4 512Mb minimal redhat box with g++4.1 while, on core2duo 2Gb vista64 with intel 10.1, it compiles in 40s and runtime is correct. The point is to generate all template "curve" specializations for various tmpl arguments (constant, linear....) (cross product of 3 mpl sequences interpolator_types, extrapolator_types and integrator_types , each containing the possible tmpl type arguments 1, 2 and 3), and insert the fully specialized templates curve<T1, T2, T3> in a mpl vector "curve_types" to be used by make_variant_over. Regards, -------------------- #include <iostream> #include <boost/mpl/pair.hpp> #include <boost/mpl/placeholders.hpp> #include <boost/mpl/fold.hpp> #include <boost/mpl/vector/vector0.hpp> #include <boost/mpl/vector.hpp> #include <boost/mpl/joint_view.hpp> #include <boost/mpl/transform.hpp> #include <boost/mpl/for_each.hpp> #include <boost/mpl/size.hpp> #include <boost/variant.hpp> class constant {}; class linear {}; class polynomial {}; class cubic_spline {}; class simpson {}; template <typename inter, typename extra, typename integ> class curve {}; template <typename inter, typename extra, typename integ> struct curve_metafunction { typedef curve<inter,extra,integ> type; }; template<typename T> struct pair_with : boost::mpl::pair<T,boost::mpl::_> {}; template<typename pair> struct triple_with : curve_metafunction<typename pair::first, typename pair::second, boost::mpl::_> {}; template<typename Sequence1,typename Sequence2> struct sequence_product : boost::mpl::fold< Sequence1, boost::mpl::vector0<>, boost::mpl::joint_view< boost::mpl::_1, boost::mpl::transform< Sequence2, pair_with<boost::mpl::_2> > > > {}; template<typename SequencePair, typename Sequence> struct seq_seqpair_product : boost::mpl::fold< SequencePair, boost::mpl::vector0<>, boost::mpl::joint_view< boost::mpl::_1, boost::mpl::transform< Sequence, triple_with<boost::mpl::_2> > > > {}; template<typename Sequence1,typename Sequence2,typename Sequence3> struct seq_product : seq_seqpair_product< sequence_product<Sequence1,Sequence2>::type, Sequence3 > {}; typedef boost::mpl::vector<constant, linear, polynomial, cubic_spline> interpolator_types; typedef interpolator_types extrapolator_types; typedef boost::mpl::vector<simpson> integrator_types; typedef seq_product<interpolator_types, extrapolator_types,integrator_types>::type curve_types; struct type_printer { template <typename T> void operator()( T ) { std::cout<< typeid(T).name() <<std::endl; } }; int main() { std::cout<< boost::mpl::size<curve_types>::type::value <<std::endl; boost::mpl::for_each<curve_types>( type_printer() ); }

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Using boost 1.35.0 on Mac OS X with Xcode 3
by Phil Hystad 09 Jun '08

09 Jun '08

I am rebuilding a library that was last compiled a year ago using an earlier version of boost and an earlier version of Xcode (2.4) and an earlier version of Mac OS X (10.4). I downloaded boost_1_35_0 distro for my Mac and built it using the standard configuration and build procedures. That seemed to go OK. I am compiling C++ source code that formerly compiled, without errors or warnings, but now reports the following errors in many files: "error: 'snprintf' is not a member of 'std'" And, the offending line is the following from the c++locale.h file (the error is reported on the line referencing snprintf): #ifdef _GLIBCXX_USE_C99 const int __ret = std::snprintf(__out, __size, __fmt, __prec, __v); #else const int __ret = std::sprintf(__out, __fmt, __prec, __v); #endif Does anyone know the source of this problem. There is absolutely no changes in my source that is being compiled. I am dual posting this on both the boost-users and the Mac Xcode lists because I am not sure which is the more appropriate forum.

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Re: [Boost-users] [iterators][range] size compile failure in 1.35
by Thorsten Ottosen 09 Jun '08

09 Jun '08

Jeff Flinn skrev: > David Abrahams wrote: >> in 1.35 I'm pretty sure that iterator_range<T>::size() only works when T >> is a random access iterator, and filtered iterators are by necessity >> bidirectional. I suggest you use >> >> std::distance(r.begin(), r.end()) >> >> if you're willing to pay for O(N) execution. >> > > Hmm, it looks like that's what iterator_range<T>::size() did in 1.34.1 > while 1.35 returns m_Begin - m_End. Any idea why this was done? boost::distance(r) could also work. I did it as part of the general clean-up of the range lib. size() is expected to be O(1) by users, distance() is not. -Thorsten

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multi-threaded safe circular_buffer
by Selçuk Giray Özdamar 09 Jun '08

09 Jun '08

Hi everyone, I specialized the boost::circular_buffer template class for concurrent access. But I have no idea about how the locking strategy must be for copy ctor, and also assignment operator. I inserted question marks at the end of the related lines. Thanks in advance... template <class T> class CircularBuffer { typedef boost::circular_buffer<T> internal_buffer; typedef boost::shared_mutex ReadWriteMutex; typedef boost::shared_lock<boost::shared_mutex> ReadLock; typedef boost::unique_lock<boost::shared_mutex> WriteLock; public: // Constructors explicit CircularBuffer(capacity_type capacity = 10) : m_capacity(capacity) , m_buffer(capacity) { } // copy ctor CircularBuffer(const CircularBuffer& other) { //WriteLock w_lock(rw_mutex); ??????????? m_capacity = other.m_capacity; m_buffer = other.m_buffer; } size_type size() const { ReadLock r_lock(rw_mutex); return m_buffer.size(); } void push_back(param_value_type item = value_type()) { WriteLock w_lock(rw_mutex); m_buffer.push_back(item); } // assignment operator CircularBuffer& operator= (const CircularBuffer& other) { //WriteLock w_lock(rw_mutex); ?????????? if (this != &other) { m_capacity = other.m_capacity; m_buffer = other.m_buffer; } return *this; } private:// member variables capacity_type m_capacity; internal_buffer m_buffer; // rw_mutex for internal buffer mutable ReadWriteMutex rw_mutex; };

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serialize shared_array
by Hansi 09 Jun '08

09 Jun '08

Hello, Is it possible to serialize a shared_array?How? Best regards Hansjörg

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Converting seconds to minutes and seconds using boost::datetime
by Sean Farrow 09 Jun '08

09 Jun '08

Hi: Does boost::datetime allow me to convert seconds (such as 164) to minutes and seconds? If yes wha function does this. Sean. __________ Information from ESET NOD32 Antivirus, version of virus signature database 3167 (20080609) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

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serialization, 1.34/1.35 difference: serializing a vector
by Filip Peters 08 Jun '08

08 Jun '08

I just tried serializing a simple vector, std::vector<unsigned int> vectortest; If I serialize out in 1.34, I can't read it in in 1.35. xml result from 1.35: <vectortest> <count>3</count> <item>1</item> <item>2</item> <item>3</item> </vectortest> from 1.34: <vectortest> <count>3</count> <item_version>0</item_version> <item>1</item> <item>2</item> <item>3</item> </vectortest> Notice the item_version, this causes an exception when reading it in with 1.35.... I need a way to get the behavior from 1.34 back.... Otherwise my files aren't readable anymore. small testprogram: #include <boost/config.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> //#include <boost/archive/binary_iarchive.hpp> //#include <boost/archive/binary_oarchive.hpp> #include <boost/serialization/vector.hpp> #include <boost/serialization/export.hpp> #include <fstream> #include <iomanip> int _tmain(int argc, _TCHAR* argv[]) { std::vector<unsigned int> testvector; testvector.push_back(1.); testvector.push_back(2.); testvector.push_back(3.); //this in 1.34 std::ofstream ofs( "testing2.txt", std::ios::binary ) ; boost::archive::xml_oarchive oa(ofs); oa << boost::serialization::make_nvp("vectortest", testvector); ofs.close(); //do this in 1.35 try{ std::ifstream ofs( "testing2.txt", std::ios::binary ) ; boost::archive::xml_iarchive ia(ofs); ia >> boost::serialization::make_nvp("vectortest", testvector2); ofs.close(); } catch(boost::archive::archive_exception testexception){ //reading a file from 1.34, will end up here std::string error = testexception.what(); } return 0; } ____________________________________________________________________________________ You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost. http://tc.deals.yahoo.com/tc/blockbuster/text5.com

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[test/signals] trying test thread safe signals with the boost unit test framework
by Richard Dingwall 07 Jun '08

07 Jun '08

Hi guys, Using the boost unit test framework, I'm trying to test a simple scenario: when a person's name is set, their 'updated' signal is triggered. Here's my person class: class person { public: person() : name_() {}; void name(const std::string & name) { name_ = name; updated(*this); }; boost::signal<void(const person & person)> updated; private: std::string name_; }; To test this, I've created a mock handler for the updated event. In it's destructor, it checks has been called (and also with the correct subject): struct mock_handler { mock_handler(const person & subject) : has_been_called_(false), subject_(subject) {}; // Handler. void operator()(const person & subject) { BOOST_TEST_MESSAGE("in mock_handler::operator()"); has_been_called_ = true; BOOST_CHECK_EQUAL(&subject == &subject_, true); }; // This handler must be called before it goes out of scope. ~mock_handler() { BOOST_TEST_MESSAGE("in mock_handler::~mock_handler()"); BOOST_CHECK_EQUAL(has_been_called_, true); }; private: bool has_been_called_; const person & subject_; }; And then writing my test case to use it: BOOST_AUTO_TEST_CASE(setting_name_triggers_update_signal) { BOOST_TEST_MESSAGE("entered test"); person subject; mock_handler handler(subject); subject.updated.connect(handler); subject.name("Richard"); BOOST_TEST_MESSAGE("exiting test"); } Unfortunately, when this code runs, it produces the following output: Running 1 test case... entered test in mock_handler::~mock_handler() test.cpp(46): error in "setting_name_triggers_update_signal": check has_been_called_ == true failed [0 != 1] in mock_handler::~mock_handler() test.cpp(46): error in "setting_name_triggers_update_signal": check has_been_called_ == true failed [0 != 1] in mock_handler::~mock_handler() test.cpp(46): error in "setting_name_triggers_update_signal": check has_been_called_ == true failed [0 != 1] in mock_handler::operator() exiting test in mock_handler::~mock_handler() test.cpp(46): error in "setting_name_triggers_update_signal": check has_been_called_ == true failed [0 != 1] in mock_handler::~mock_handler() *** 4 failures detected in test suite "tests" I'm not sure what's going on here, or why mock_handler's destructor is being called 4 extra times. Can anyone shed some light as to why this might be happening? Cheers, Rich

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