May 2012 - Boost - lists.boost.org

question about C++11 guidelines
by Eric Niebler 06 May '12

06 May '12

Say I'm rewriting an existing Boost library and targeting C++11 users. I plan to ship C++03 and C++11 versions of my library side-by-side, so back-compat isn't an issue for the new code. Is there a reason to prefer using Boost's versions of utilities like enable_if, type traits, integral constant wrappers (e.g. mpl::int_), tuples, etc., over the now-standard ones? I'm leaning toward using std:: where I can, and falling back on Boost's versions only when there is a compelling reason. -- Eric Niebler BoostPro Computing http://www.boostpro.com

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Latest version and status of lockfree
by Julien Nitard 06 May '12

06 May '12

Hi All, Where can I find the latest version of boost.lockfree ? There's nothing in the sandbox or the vault (it seems). The latest commit on Tim's public git repo was done more than 6 month ago. Now that atomic has been accepted, are there any roadblocks to have boost.lockfree released ? Many thanks, Julien

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trac spam (was: [Boost C++ Libraries] #6866: affiliate revolution)
by Eric Niebler 06 May '12

06 May '12

Who maintains trac these days? Can we get this spammy ticket deleted? Thanks, Eric -------- Original Message -------- Subject: [Boost C++ Libraries] #6866: affiliate revolution Date: Fri, 04 May 2012 20:08:29 -0000 From: Boost C++ Libraries <noreply(a)lists.boost.org> CC: boost-bugs(a)lists.boost.org #6866: affiliate revolution ----------------------------------+----------------------------------------- Reporter: anonymous | Owner: eric_niebler Type: Tasks | Status: new Milestone: To Be Determined | Component: proto Version: Boost 1.37.0 | Severity: Cosmetic Keywords: affiliate revolution | ----------------------------------+----------------------------------------- [<link deleted> affiliate revolution] -- Ticket URL: <https://svn.boost.org/trac/boost/ticket/6866> Boost C++ Libraries <http://www.boost.org/> Boost provides free peer-reviewed portable C++ source libraries.

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[polygon] Trunk write access
by Andrii Sydorchuk 05 May '12

05 May '12

I sent a message recently to the Boost owners list to get write access to the Boost trunk, but haven't got any response yet. I am going to merge lately discussed Voronoi library and some updates to the Boost.Polygon. Those are approved by the library owner: Simonson, Lucanus J. Sorry for the rush. Regards, Andrii

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Red Hat Enterprise Linux Test Page
by Olaf van der Spek 05 May '12

05 May '12

Hi, This does not look right. ;) https://www.boost.org/ -- Olaf

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[dynamic_bitset] Endianess and Adaption Vs Copying
by Joel 04 May '12

04 May '12

I've noticed that the dynamic_bitset seems to have endian issues. For masking out the ith bit in a block, it uses 1 shifted left by i. As a result, the bits are not consecutive. For example if the block_type is uint8_t, and we have 16 bits in the bitset, then bits are numbered: 00 01 02 03 04 05 06 07 15 14 13 12 11 10 09 08 in memory. That doesn't seem right---7th and 8th bits should be adjacent. Does anyone have suggestions for controlling this? Second, has anyone adapted dynamic_bitset to be an adaptor for an existing memory range to avoid copying? Thanks! Joel

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[contract] syntax redesign
by Lorenzo Caminiti 04 May '12

04 May '12

Hello all, After a long time of inactivity for Boost.Contract, I am considering how to re-design its macro syntax to make it simpler. I can eliminate a large number of extra parenthesis based on a few pp tricks I've learned in processing Boost.Local's `const bind(type)& var`. Plus, I can provide (optional) support for variadics macros so to use comma-separated pp tuplets instead of parenthesized pp sequences on preprocessors with variadics. For example, I _think_ (but I've not implemented this yet) that I can simplify the syntax like this: #include <contract.hpp> #include <vector> #include "myvector/pushable.hpp" // Wrapper class that adds contracts to std::vector. CONTRACT_CLASS( template( typename T ) class (myvector) extends( public pushable<T> ) // Subcontracting. ) { CONTRACT_CLASS_INVARIANT( empty() == (size() == 0) // More invariants here (comma separated)... ) CONTRACT_FUNCTION( public void (push_back)( (const T&) element ) precondition( size() < max_size() // More preconditions here (comma separated)... ) postcondition( auto old_size = CONTRACT_OLDOF(size()), // Old value. size() == old_size + 1 // More postconditions here (comma separated)... ) ) { vector_.push_back(element); // Implementation. } // Rest of the class here (with more contracts if needed)... public: typedef typename std::vector<T>::size_type size_type; size_type size(void) const { return vector_.size(); } size_type max_size(void) const { return vector_.max_size(); } bool empty(void) const { return vector_.empty(); } const T& back(void) const { return vector_.back(); } private: std::vector<T> vector_; }; For a side-by-side comparison with N1962 syntax: http://svn.boost.org/svn/boost/sandbox/contract/libs/contract/doc/html/inde… For a comparison of the entire std::vector (plus Boost.ConceptCheck concepts): http://svn.boost.org/svn/boost/sandbox/contract/libs/contract/doc/html/cont… For a comparison for all Boost.Contract features (plus Boost.ConceptCheck concepts and Boost.Parameter named parameters): http://svn.boost.org/svn/boost/sandbox/contract/libs/contract/doc/html/cont… (Don't pay attention to the rest of the docs that are way out of date.) A few notes: * Extra parenthesis are still needed around class and function names. * Extra parenthesis are still needed around types (like for the parameter `(T) element`) but only if the type is not a C++ keyword (no parenthesis needed aournd int, double, void, etc) or it contains a symbol (parenthesis needed if & or * are used `(int&) x`, etc). * In postconditions, the `auto old_size = CONTRACT_OLDOF(size())` only copies the vector size (and not the entire vector :)) ). Similarly, `auto result = return` can be used to access the return value for non-void functions. (The `auto ...` is parsed by the pp and it's implemented using Boost.Typeof so no C++0x is required.) * Template declaration (but not instantiation) angular parenthesis <> are replaced by round parenthesis (). All of this _should_ be implementable in pure ISO C++. What do you think? Based on the discontent that the previous "parenthesized" syntax generated among Boosters, the key question is: Would you consider this new syntax usable?? Thanks, --Lorenzo

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[Countertree + Suballocator] New Version
by Francisco José Tapia 03 May '12

03 May '12

Hi this message is to announce the new version of the [countertree + suballocator] library. You can find the zip file with the code and the documentation in https://docs.google.com/file/d/0B9lWJ1Nhb_RhRXVHSS14aGxUZjJjWFdRVC0xZ2czZw/… or if you want a quick look , you can see in my web page http://fjtapia.webs.com/works/countertree/index.html *COUNTERTREE * This library is an implementation of a binary red-black counter tree. This tree have an additional counter in each leaf. This permit the access to the elements by the position, like in a vector. It is a random access container with random access iterators . With this tree we have vectors (cntree::vector_tree) with identical interface than std::vector. The vector_tree have the same speed inserting and deleting in any position (all the operations are O(log N)).It is slower than std:vector inserting and deleting at end, but much faster for to insert and delete in any other position. With ordered information, we have in the cntree namespace the classes set, multiset, map and multimap, with identical interface than the STL classes, with the plus of access to the elements by position, like in a vector. The iterators are random access , and you can subtract two iterators in a O(log N) time for to know the number of nodes between them (even with the end( ) and rend( ) iterators) For to show the utility of this, imagine a large unordered file with the information about the employees of a big company. You have indexes implemented with multimaps, with pairs [value, position], and use the upper_bound and lower_bound functions. You need to select the employees in a range of age and weight. With the boost:multimap you can know the number of elements of the selection. In the weight query we found 100 elements and in the age query 10000 elements. To travel the elements of the weight query asking for the age, is faster than the opposite. *SUBALLOCATOR * A very hard test for the allocators are the data structures which need a very high number (several millions) of elements of the same size, like the STL list, set, multiset, map or multimap. When the number of elements grow, many allocators begin to have speed problems. The solution proposed for this problem are the custom allocators. These allocators are very fast, but many of them present additional problems related with the memory consumption. And they don't work well when they must manage many types of data. When the allocators receive the request from the program, they request memory to the Operating System, and the memory consumed by the program grows up. When the program return to the allocators the request, many allocators have problems for to return the memory freed to the Operating System (The std::allocator of GCC 4.6 don't return well the memory, and the std::allocator of Visual C++, return, but it is slower than the GCC allocator) If you use only one allocator, you have a bad management or in the speed of equal size elements, or with a wide variety of elements. If you use two allocators, the memory freed by an allocator can't be used by the other, and the memory consumption is very high, and when decrease the number of elements to manage, the memory don't decrease. These problems are specially important in two environments : a) When you have a limited resources, as occurs in the mobile phones, pads ... b) When the programs must run continuously in a multitask environment The solution is the suballocator. It is a mechanism for to manage in a fast way a greater number (hundred millions) of elements with the same size. The suballocator is a layer over the allocator (any allocator with the STL interface). The suballocator receives an allocator as template parameter. When the suballocator needs memory, request memory from the allocator, and when the memory is not used, is returned to the allocator. The suballocator present the same interface than the STL allocator. Form the view point of the data structures, the suballocator is other allocator The suballocator always return the first element free. This improve the cache performance and the speed of the data structures. This simple memory schema permit to the allocators return memory to the Operating System and decrease the memory used by the program, as demonstrate the programs in the benchmarks, and you can see in the benchmark point. With the suballocator a) We have a very *fast allocation* (3 times faster than GCC 4.6 std::allocator, 3.5 times faster than Visual Studio 10 std::allocator ) b) Return memory to the allocator, for to be used by others types of data. Many allocators, return this memory to the Operating System, and *decrease the memory used by the program * c) You *can use with any allocator* if according with the STL definition. The suballocator provides speed and memory management to any allocator. d) In the insertion in a std::set<uint64_t> , the time spent by the allocator is around 1%, but the suballocator save around 35% of time . The suballocator always provide the first position free, This provide us a very compact data are, which *improve the cache performance* All the information showed here is explained and detailed in the point Suballocator. All the information is extracted from the programs in the benchmarks folder. *COUNTERTREE + SUBALLOCATOR* The join of the two ideas provide us data structures with a suballocator built-in. They are, in the namespace cntree, the vector_tree_pool, set_pool, multiset_pool,map_pool and multimap_pool, with identical interface than the STL classes but better performance. Tray it. It fast, useful and easy to understand and use,. They are the STL classes with a few additional functions. I had checked this code with GCC 4.6 (32 and 64) , CLANG/LLVM 3.0 and Visual Studio 1010 (32 and 64). If you find any error or problem in the code , the documentation or in any other part ( as friendly do Mr Rene Rivera in the first version). Please mail me ( fjtapia(a)gmail.com) or if you mail Boost, please insert [countertree] in the head of the message. Some days I have not time to read all messages arrived to my mail, but if I see that I detect and respond first. If you have some idea, or have any comment, please mail me, always two legs run more than only one in the pursuit of the goal, to be useful to the community of programmers in the same way than our predecessors had been useful to us. Sincerely yours Francisco Tapia fjtapia(a)gmail.com

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[release] scope_exit, local_function, utility/identity_type, and functional/overloaded_function
by lcaminiti 02 May '12

02 May '12

Hello release managers, I've been working in the trunk on a few libraries which are almost ready to be released: a) When is the release date? b) What do I have to do to merge into release? (This will be my 1st release merge :) ). 1) ScopeExit (improved) I'm waiting on MVSC 9 and 10 tests to cycle to make sure they all pass. Other compilers OK. 2) Utility/IdentityType (new) Should be ready to be merged into release. 3) Functional/OverloadedFunction (new) Should be ready to be merged into release. 4) LocalFunction (new) I'm making final fixes for some tests on some of compilers. Hopefully, I'll be done in 2 weeks max. For all of those, I've followed the checklist so I've run the code inspection tool, updated all docs, librariers.htm, and maintainers.txt. Thanks a lot. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-release-scope-exit-local-function-… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Trac Default Version
by Olaf van der Spek 02 May '12

02 May '12

Hi, Why's the default version when submitting a ticket still 1.48? -- Olaf

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