February 2009 - Boost-users

[gil] get raw data from picture
by Stephan Menzel 22 Feb '09

22 Feb '09

Hi there, is there any way to get the raw YCbCr data out of a gil Image that has been read with jpeg_read_image()? *_memory is private in image.hpp and I'm not sure what it contains anyway. Any ideas? Thanks... Stephan

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[GIL] wrapper for QImage
by Tomas Van Verrewegen 22 Feb '09

22 Feb '09

Hi, I'm planning to write an image manipulation application using Boost.GIL as a backbone and Qt for the interface. Now I was thinking it might be a good idea to write a wrapper around QImage to give GIL direct access to the pixels of a QImage. I've been looking at the code and as far as I can tell I have 2 options: (1) create a new GIL image type that wraps the QImage (2) create a "qimage_pixel_iterator" and use "... interleaved_view(...)" Now my question(s): - Would (2) be enough, or is it necessary to also create (1)? - "QRgb" (Qt's pixel type) is a typedef for "unsigned int", so specialising eg. "template<class Pixel> struct gil::channel_type" for "unsigned int" seems somewhat suboptimal (is it an 8bit RGBA pixel or a 32bit Gray pixel?). Some sort of proxy class might be appropriate? Maybe a gil::pixel<...> subclass?

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Regex win vs. linux
by Adam Kornafeld 22 Feb '09

22 Feb '09

Hi, I'm seeking help for the following problem, using the regex library: the following line of code is meant to assist in parsing urls: boost::regex exp("(?is)(https?)://([^:/?#]+):?(\\d{1,5})?/?([^?#]*)?\ \??([^#]+)?#?(\\w*)"); It runs fine in a linux environment, however if compiled with VC9 on windows, it fails with: First-chance exception at 0x7c812aeb in test.exe: Microsoft C++ exception: boost ::exception_detail ::clone_impl <boost::exception_detail::error_info_injector<boost::regex_error> > at memory location 0x0012f768.. I thought that the expression might be too long, and indeed if I shorten the above line to: boost regex exp("(?is)(https?)://([^:/?#]+):?(\\d{1,5})?/?"); it runs fine on windows as well. Any help on what the cause of this can be, would be appreciated. Regards, ==Adam

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Formatted reports and statistics charts for Boost Unit Test Framework
by Slava Imeshev 22 Feb '09

22 Feb '09

Hi All, I just wanted to let you know that now Parabuild is integrated with Boost Unit Test Framework. It provides formatted reports and statistics charts from test logs generated as a part of Continuous Integration or daily and nightly builds: http://www.viewtier.com/products/parabuild/boost_unit_test_framework.h tm Regards, Slava Imeshev

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[accumulators] help/advise required: Need a container to hold accumulator_set
by dhruva 22 Feb '09

22 Feb '09

Hello, I am writing a wrapper class which gets data over time and has to compute a variety of statistics using boost::accumulators. The accumulator cannot be a variable on the stack (function local variable) as it will go out of scope after the function invocation. I will have to make it a member variable of a class. I will not know the type of calculations to requested at compile time. I therefore need a generic accumulator type as member and add the specific type at runtime. In short, I need a container to hold accumulator_set objects. Different type of accumulator_set objects in the container will perform different calculations. The type of calculation I want to perform will be based on input at runtime. pseudo code: #define MEAN 1 #define MAX 2 class calc { public: setmetric(int metricType) { accumulator_set<double, features<> > *pacc; if (1 == metricType) { pacc = new accumulator_set<double, features <tag::mean> >; } else if(2 == metricType) { pacc = new accumulator_set<double, features <tag::max> >; } m_Vacc.push_back(pacc); } compute(double input) { // I will iterate over the vector, get the accumulator_set objects // acc_obj(input) followed by extract } private: std::vector <accumulator_set<double, features<> > *> m_Vacc; }; If features could be added at runtime, I probably could have solved this problem. Other approach is to have an accumulator_set with all supported features (supported by my application) as dropable. Drop all the unnecessary features based on user input. By adding all supported types, I will get a complete accumulator_set class at compile time and having a container to hold it is straight forward. Any help or advise is really appreciated. I may have raised a lot of basic questions but I am a boost newbie and taking a plunge. -dhruva Cricket on your mind? Visit the ultimate cricket website. Enter http://beta.cricket.yahoo.com

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boost::asio::read_until reads too much!
by Rob Currey 22 Feb '09

22 Feb '09

executing this code: boost::asio::streambuf b; std::cout << "socket.available()=" << socket.available() << std::endl; size_t received = boost::asio::read_until(socket, b, "\r\n"); std::cout << "received=" << received << std::endl; std::cout << "b.size()=" << b.size() << std::endl; std::istream is(&b); std::getline(is, m_token); results in output of: socket.available()=34 received=26 b.size()=34 In my app I need to read the 8 bytes (after the 26) as binary (and hence don't use the streambuf to do so). Yet read_until has already consumed them from the socket and placed them in the streambuf :( Suggestions?

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boost library advice wanted
by Sean Farrow 21 Feb '09

21 Feb '09

Hi: I am in the process of implementing a program that turned commands from voice recognition software in to code that are entered in to an application. there are approximately 200 codes available in this particular sofware I am automating. Wile I could use boost::stringAlgo along with the functions available in the stl there must be a better alternative. To give an idea of howthis would work the user might say: conditional new line, and [l] would be placed in the current document onscreen. the user could say skip 5 lines and [sk5] would be entered. >From this it is clar that: 1. some tokens are voiced by the user but are not needed when analysing the input. e.g lines is used for ease of use but not actually used in the analysis. 2. some tokens are only followed by certain othe tokens, e.g new can be followed by line, page or paragraph. tow queries: 1. What is the best boost library to use in this situation, boost.wav, boost.spirit, boost.xpressive or boost.tokenizer. 2. Has anybody else done anything like this, and hence can offer any implementation advice. Any help apreciated. Sean.

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[Question] Software documentation
by Mario Chacon 21 Feb '09

21 Feb '09

Hello: It's possible that some plugin or some another soft generate class diagram from the source?? I know that with oxygen can generate a beautiful HTML, but Can I do something more? Salud... masch...

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[serialization] newbie compilation question
by lenberman 21 Feb '09

21 Feb '09

I've got boost 1.38 built. When I try to build demo.cpp, it fails. I'm building in the serialization/examples subdirectory. I think this is a supported compiler. No doubt I'm doing something very stupid and hopefully very easy to fix. Thanks in advance. --Len make -k g++ --version g++ (Debian 4.3.2-1.1) 4.3.2 Copyright (C) 2008 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. g++ -g -I/share/space/net-srcs/boost_1_38_0 demo.cpp In file included from demo.cpp:16: /share/space/net-srcs/boost_1_38_0/boost/archive/tmpdir.hpp: In function ‘char* boost::archive::tmpdir()’: /share/space/net-srcs/boost_1_38_0/boost/archive/tmpdir.hpp:42: warning: deprecated conversion from string constant to ‘char*’ /tmp/ccezla7D.o: In function `boost::archive::text_iarchive& boost::serialization::smart_cast_impl::reference<boost::archive::text_iarchive&>::polymorphic::cross::cast<boost::archive::detail::basic_iarchive>(boost::archive::detail::basic_iarchive&)': /share/space/net-srcs/boost_1_38_0/boost/serialization/smart_cast.hpp:78: undefined reference to `typeinfo for boost::archive::detail::basic_iarchive' /tmp/ccezla7D.o: In function `boost::archive::text_oarchive& boost::serialization::smart_cast_impl::reference<boost::archive::text_oarchive&>::polymorphic::cross::cast<boost::archive::detail::basic_oarchive>(boost::archive::detail::basic_oarchive&)': /share/space/net-srcs/boost_1_38_0/boost/serialization/smart_cast.hpp:78: undefined reference to `typeinfo for boost::archive::detail::basic_oarchive' /tmp/ccezla7D.o: In function `~iserializer': /share/space/net-srcs/boost_1_38_0/boost/archive/detail/iserializer.hpp:141: undefined reference to `boost::archive::detail::basic_iserializer::~basic_iserializer()' /share/space/net-srcs/boost_1_38_0/boost/archive/detail/iserializer.hpp:141: undefined reference to `boost::archive::detail::basic_iserializer::~basic_iserializer()' ... more errors

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OT: generic template type from specific type?
by Neal Becker 21 Feb '09

21 Feb '09

Say I have: template<typename in_t> void F (in_t & in) ... main() { F<std::vector<int> > (...) Suppose in_t is a templated container, such as std::vector<int>. Is there a way within the function 'F' to get the generic container type, 'std::vector' when F is instantiated with a specific e.g., std::vector<int>? Maybe I'm missing something obvious :)

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