May 2012 - Boost - lists.preview.boost.org

[type_traits] has_equal_to< std::vector<T> > always true_
by lcaminiti 15 Jul '12

15 Jul '12

-- View this message in context: http://boost.2283326.n4.nabble.com/boost-type-traits-has-equal-to-std-vecto… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[xpressive] Compiler error on VC7.1
by Robert Dailey 10 Jul '12

10 Jul '12

Hi, I'm using Boost 1.49 Xpressive on VC7.1. When I compile the following code, I get compiler errors (these do not appear on VC9): sregex const& rex = bos >> _serverName >> !as_xpr("_GWDomino") >> ".diagnostics" >> *(as_xpr(".base")|".renamed"); 'rex' is really a function parameter in my real world use case. I'm passing the entire static regex into a function that takes a 'sregex const&'. I get the compiler error below. Anyone know why this is happening? C:\Code\work\cmake-decomp\build-vc7\third_party\boost\1.49.0-stlport-5.2.1\include\boost\proto\traits.hpp(691) : error C2664: 'boost::proto::exprns_::expr<Tag,Args,Arity>::expr(const boost::proto::exprns_::expr<Tag,Args,Arity> &)' : cannot convert parameter 1 from 'boost::proto::detail::as_expr<T,Generator,WantsBasicExpr>::result_type' to 'const boost::proto::exprns_::expr<Tag,Args,Arity> &' with [ Tag=boost::proto::tagns_::tag::terminal, Args=boost::proto::argsns_::term<boost::proto::detail::as_expr<const char [10],boost::proto::detail::base_generator<boost::proto::default_generator>::type,false>::value_type>, Arity=0 ] and [ T=const char [10], Generator=boost::proto::detail::base_generator<boost::proto::default_generator>::type, WantsBasicExpr=false ] and [ Tag=boost::proto::tagns_::tag::terminal, Args=boost::proto::argsns_::term<boost::proto::detail::as_expr<const char [10],boost::proto::detail::base_generator<boost::proto::default_generator>::type,false>::value_type>, Arity=0 ] Reason: cannot convert from 'boost::proto::detail::as_expr<T,Generator,WantsBasicExpr>::result_type' to 'const boost::proto::exprns_::expr<Tag,Args,Arity>' with [ T=const char [10], Generator=boost::proto::detail::base_generator<boost::proto::default_generator>::type, WantsBasicExpr=false ] and [ Tag=boost::proto::tagns_::tag::terminal, Args=boost::proto::argsns_::term<boost::proto::detail::as_expr<const char [10],boost::proto::detail::base_generator<boost::proto::default_generator>::type,false>::value_type>, Arity=0 ] No constructor could take the source type, or constructor overload resolution was ambiguous \Code\work\cmake-decomp\server\exchange\tools\uploadlog\uploader.cpp(1372) : see reference to function template instantiation 'const boost::add_const<T>::type boost::proto::functional::as_expr<>::operator ()<char,10>(const char (&)[10]) const' being compiled with [ T=boost::proto::detail::as_expr<const char [10],boost::proto::detail::base_generator<boost::proto::default_generator>::type,false>::result_type ]

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[Review Request] Inclusion of the Boost.Polygon Voronoi Library
by Andrii Sydorchuk 04 Jul '12

04 Jul '12

Boost community, It has been two years since I started development of the Voronoi library as part of the Google Summer of Code 2010. Finally I feel that the library is ready to become public and would like to request a review for the inclusion into the Boost.Polygon library. Features: - Robust and efficient implementation of the sweepline algorithm that allows to construct Voronoi diagram, Delaunay triangulation and medial axis of a set of points and line segments. - Coordinates of the output geometries are computed within the 64 machine epsilon relative error (6 mantissa bits). - Voronoi diagram data structure that allows efficient traversal and data association with the output Voronoi graph. - No 3rd party dependencies (e.g. GMP, MPFR), all the required multiple precision types are implemented as part of the library. - The input and output coordinate type domains are configurable via coordinate type traits, thus allowing to compute coordinates of the Voronoi vertices within any required precision. - The full construction of the Voronoi diagram of 100 000 points takes only 0.27 seconds (see benchmarks). The full list of features could be found here: http://svn.boost.org/svn/boost/sandbox/gtl/doc/voronoi_main.htm Limitations: - Input geometries should have integer coordinates; - Input segment data sets should not contain intersection points, except segment's endpoints. Information on why the first limitation is not sufficient is explained here: http://svn.boost.org/svn/boost/sandbox/gtl/doc/voronoi_advanced_tutorial.htm The second limitation could be waved using native Boost.Polygon functionality: http://svn.boost.org/svn/boost/sandbox/gtl/doc/gtl_polygon_set_concept.htm Resources: The code is already merged with the Boost.Polygon sandbox branch. All the Voronoi related files are prefixed with "voronoi". - Code location: http://svn.boost.org/svn/boost/sandbox/gtl - Main documentation page: http://svn.boost.org/svn/boost/sandbox/gtl/doc/voronoi_main.htm or http://svn.boost.org/svn/boost/sandbox/gtl/doc/index.htm - Benchmarks: http://svn.boost.org/svn/boost/sandbox/gtl/doc/voronoi_benchmark.htm - Examples: http://svn.boost.org/svn/boost/sandbox/gtl/libs/polygon/example/output_data/ - Tests: http://svn.boost.org/svn/boost/sandbox/gtl/libs/polygon/test/ - Tutorials: http://svn.boost.org/svn/boost/sandbox/gtl/doc/voronoi_basic_tutorial.htm and http://svn.boost.org/svn/boost/sandbox/gtl/doc/voronoi_advanced_tutorial.htm - Official Google+ page: https://plus.google.com/b/109395909314556242008/ Review manager: I would kindly ask Simonson, Lucanus J. the author of the Boost.Polygon library to be my review manager. PS. The library was designed in a user friendly way, so I would invite everyone to give it a try! No configuration of the geometric or predicate kernels is required. Simply follow the basic tutorial: http://svn.boost.org/svn/boost/sandbox/gtl/doc/voronoi_basic_tutorial.htm Thanks and have fun, Andrii

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Formal Review Request: TypeErasure
by Steven Watanabe 30 Jun '12

30 Jun '12

AMDG I'd like to request a formal review of the TypeErasure library that I've posted about several times before here. The TypeErasure library is a generalization of boost::any and boost::function. It allows easy composition of arbitrary type erased operators. As an example of basic usage, we can simulate Boost.Any: any<mpl::vector<copy_constructible<>, typeid_<> > > x(10); int i = any_cast<int>(x); // i == 10 The library is available in the Boost Sandbox at http://svn.boost.org/svn/boost/sandbox/type_erasure/ You can download archives with pre-built documentation from http://sourceforge.net/projects/steven-watanabe.u/files/ Online documentation can be found here: http://steven_watanabe.users.sourceforge.net/type_erasure/libs/type_erasure/ In Christ, Steven Watanabe

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[pool] Objects of varying sizes
by Robert Dailey 27 Jun '12

27 Jun '12

Is it possible to create a pool for polymorphic types? For example: class A; class B : public A; class C : public A; I want to create a pool of type A, but the allocation can be for B or C at any time. Will this work?

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[serialization] Reading newer archives - was throwing unsupported_class_version, now crashes
by Nikolay Mladenov 25 Jun '12

25 Jun '12

Hi Robert, I remember that in the past the serialization library was throwing unsupported_class_version exception when reading of archives with future class versions. This no longer seems to be the case. We had older version of software crash when reading newer archive. The only place that I found to mention unsupported_class_version is commented out and I do not understand the attached note: BOOST_DLLEXPORT void iserializer<Archive, T>::load_object_data( basic_iarchive & ar, void *x, const unsigned int file_version ) const { // note: we now comment this out. Before we permited archive // version # to be very large. Now we don't. To permit // readers of these old archives, we have to suppress this // code. Perhaps in the future we might re-enable it but // permit its suppression with a runtime switch. #if 0 // trap case where the program cannot handle the current version if(file_version > static_cast<const unsigned int>(version())) boost::serialization::throw_exception( archive::archive_exception( boost::archive::archive_exception::unsupported_class_version, get_debug_info() ) ); #endif // make sure call is routed through the higest interface that might // be specialized by the user. boost::serialization::serialize_adl( boost::serialization::smart_cast_reference<Archive &>(ar), * static_cast<T *>(x), file_version ); } To allow class to read serialized objects of newer version by default seems very dangerous. I generally requires extra work from the class author and without it will most likely crash. So isn't it better to have an additional trait that a class author needs to define, if a class should be allowed read future versions? something like namespace boost{ namespace serialization { template<class T> struct allow_future_versions : mpl::false_ {}; }} #define BOOST_SERIALIZATION_ALLOW_FUTURE_VERSIONS(T) \ namespace boost{ namespace serialization \ { \ template<> struct allow_future_versions<T> : mpl::true_ {}; \ }} and change the code above to: BOOST_DLLEXPORT void iserializer<Archive, T>::load_object_data( basic_iarchive & ar, void *x, const unsigned int file_version ) const { // trap case where the program cannot handle the current version if( ! boost::serialization::allow_future_versions<T>::value && file_version > static_cast<const unsigned int>(version())) boost::serialization::throw_exception( archive::archive_exception( boost::archive::archive_exception::unsupported_class_version, get_debug_info() ) ); ...... Thanks in advance, Nikolay Mladenov Sitius Automation Inc.

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hex/unhex()?
by Olaf van der Spek 19 Jun '12

19 Jun '12

Hi, Does Boost have hex/unhex() that support std::string? I can't find them and I think they'd be quite handy to have. -- Olaf

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[Locale] VC11 Regressions
by Joshua Boyce 18 Jun '12

18 Jun '12

I am currently porting some code to the VC11 compiler beta, and as part of that process I ran the unit tests on the libraries I use and noticed some failures in Boost.Locale under VC11 that are not present under VC10. Ones of the tests (test_winapi_collate) actually crashes (showing the WER dialog etc). Logs for comparison (tests were run on trunk): http://dl.dropbox.com/u/74751/cpp/boost/logs/locale-test-vc10-20120330-2143… http://dl.dropbox.com/u/74751/cpp/boost/logs/locale-test-vc11-20120330-2143… Has anyone else observed this or is it a configuration issue on my end?

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[pool] Improvements to boost.pool
by DUPUIS Etienne 18 Jun '12

18 Jun '12

Greetings, In the boost sandbox, under the /pool folder, I have committed a few small improvements and a few fixes for open tickets. Here is what I have changed : 1. I added boost::static_pool, a pool whose maximum size is known when initializing the pool; in which case all memory is allocated when calling the constructor. This is useful for software that must manage memory with great care. The implementation is a simple subclass of boost::pool. In the same vein, I also added boost::static_object_pool. 2. I also added boost::array_pool, a pool whose maximum size is known at compile time. The array_pool object hence already contains all memory it needs. Same for boost::array_object_pool. I am not sure that this is really useful and I am not sure I have picked a good name for it. 3. I handled ticket #3789 (https://svn.boost.org/trac/boost/ticket/3789) In short, releasing objects from a boost::object_pool was O(n) instead of expected O(1) and this constraint was required to keep the pool ordered so that the destructor of object_pool could destroy all objects that the calling program did not released. To solve this problem, I created an O(n log n) function which orders an unordered pool, a function that I called in the destructor. Thus, with my modification, releasing objects is O(1) and the destructor is O(n log n), or O(1) is the calling program was kind enough to release all objects. Although this does not change the API, it could have a negative impact on software that allocate large number of objects (using object_pool) but that never releases them. However, my modification greatly improves programs who repeatedly requests and releases objects. This modification also handles ticket #6610 (https://svn.boost.org/trac/boost/ticket/6610) 4. I added a pool.get_size() function (https://svn.boost.org/trac/boost/ticket/6865) that returns the current number of elements/objects for which the pool has allocated memory. 5. I clarified the meaning of the 'max_size' parameter, a recent addition to limit the amount of memory a pool can allocate with a single call to the allocator. See ticket #6867 (https://svn.boost.org/trac/boost/ticket/6867) for details. 6. I fixed miscellaneous minor tickets : #5902 (division by zero when requesting null sized buffers), #6561 (crash when releasing a null pointer), #6710 (integer overflows and possible crashes when requesting too many elements). 7. I added test cases for all modifications. I manually tested each case on Windows and used bjam on Linux, although I am not exactly sure that bjam did anything as it did not even report which test it ran. 8. I still need to update the documentation. Before doing that, I thought that I should submit my changes to the Boost community to see whether they are approved or not. And more prosaically, I still need to figure out how to generate the said documentation ! Now that these changes have been made in the sandbox, what is the next step to get them approved/amended/rejected ? Regards, Étienne Ce message et toutes les pièces jointes sont confidentiels et établis à l'intention exclusive de ses destinataires. Toute modification, édition, utilisation ou diffusion non autorisée est interdite. Si vous avez reçu ce message par erreur, merci de nous en avertir immédiatement. ATEME décline toute responsabilité au titre de ce message s'il a été altéré, déformé, falsifié ou encore édité ou diffusé sans autorisation. This message and any attachments are confidential and intended solely for the addressees. Any unauthorized modification, edition, use or dissemination is prohibited. If you have received this message by mistake, please notify us immediately. ATEME decline all responsibility for this message if it has been altered, deformed, falsified or even edited or disseminated without authorization. Note: To protect against computer viruses, e-mail programs may prevent sending or receiving certain types of file attachments.

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Review Request : Boost.Range Extension
by Akira Takahashi 11 Jun '12

11 Jun '12

Hi, Neil Groves and Boosters. OvenToBoost is a project that intend to add some features of Oven Range Library into Boost.Range. I'd like to request a review. Features: - Additional Range Adaptors (taken, taken_while, dropped, dropped_while, elements, elements_key, memoized, outdirected) - Extensions for using Lambda (regular function, regular operator) - Infinite Range (iteration function) - and additional range utilities. Future Plan: I have written primary features. If these features are accept, I'd like to implement/add following features: - Range of Range Adaptors (concatenated, transposed) - Cyclic Range - Range Utilities for String Source Code: https://github.com/faithandbrave/OvenToBoost Document: http://dl.dropbox.com/u/1682460/git/OvenToBoost/libs/range/doc/html/index.h… Regards, Akira >>======================== Akira Takahashi mailto:faithandbrave@gmail.com site: https://sites.google.com/site/faithandbrave/about/en

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