November 2008 - Boost - lists.preview.boost.org

[alchemy] Boost on Adobe Alchemy
by Wilhansen Li 19 Nov '08

19 Nov '08

Hi guys, Adobe Labs just released their Alchemy ( http://labs.adobe.com/technologies/alchemy/) C/C++ to AVM2 compiler which basically compiles C/C++ code to .swf or .swc which can then be imported to Flash or Flex. I'm gonna try it out when I find some time next week. In any case, I'm interested in making Boost work in Alchemy but have no idea where to get started (aside from copy-pasting the generated header files for gcc for the header-only libraries). Is there anybody else interested in porting Boost over to Alchemy? Best Regards, Wil --

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subbitset
by Andreas Klein 19 Nov '08

19 Nov '08

Hello. I am using your dynamic_bitset and I encountered the following problem. I have realy large bits sets (>100000) bits. At some point I need do some xor Operations on only a small fraction of the bits. So I need a way to access the bits from index n to n+s-1. The bitclass has no convient way to do this. I suggest add the member function sub_bitset for that purpose. Example: a = 100000101101101001110101 ^^^^^^^ a.subbitset(3,7) b = 1001110 (The ^^^^^^^ marks the position of b in a). I implemented subbitset as follows: template<typename B, typename A> dynamic_bitset<B, A> dynamic_bitset<B, A>::subbitset(size_type n,size_type s) const { assert(n+s < size()); dynamic_bitset res(s); size_type const last = res.num_blocks() - 1; // num_blocks() is >= 1 size_type const last2 = num_blocks() - 1; size_type const div = n / bits_per_block; // div is <= last block_width_type const r = bit_index(n); const block_type * const b = &m_bits[0]; block_type * const bb = &res.m_bits[0]; if (r != 0) { block_width_type const ls = bits_per_block - r; for (size_type i = 0; i <= last; ++i) { if (div+i+1 >last2) { // Do we reach the last block? bb[i] = (b[div+i] >> r); break; } bb[i] = (b[div+i] >> r) | (b[div+i+1] << ls); } } else { for (size_type i = 0; i <= last; ++i) { if (i+div>last2) // Do we reach the last block? break; bb[i] = b[i+div]; } // note the '<=': the last iteration 'absorbs' // b[last-div] = b[last] >> 0; } // Zero unused bits block_width_type const rr = bit_index(s); if(rr != 0) bb[last] &= (1<<(block_type)(rr))-1; return res; } I guess, that I am not the only one who would benefit from the possibility to access subbitsets. I could also imagine that references to subbitsets could be of some use. Foe example I could imagine that one would use subbitset as follows. a= 00000000 b= 111 a.subbit(2,3) ^= b; -> a=00011100 But such a reference would be harder to implement and at the moment I do not need it. What do you think? Is there any hope for subbitset in boost? Best wishes Andreas Klein.

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which Operating Systems should be supported?
by Oliver Kowalke 19 Nov '08

19 Nov '08

Hello, I'd like to know which operating systems should be take into account if a new library gets contributed? Should only the newest version of the os be considered (I think not - at least on Windows). - Windows - Linux (kernel version + glibc version) - xBSD (FreeBSD, NetBSD, OpenBSD, DragonFly, .... MAC OS?) - HP/UX - Solaris, OpenSolaris (is there a difference beside the second is open source?) - AIX - what about this systems (maybe no futher activly developed): - IRIX - Tru64 special purpose os: - QNX regards, Oliver -- Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer

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boost and vendor's TR1 implementations
by Sergey Sadovnikov 19 Nov '08

19 Nov '08

Hello All, Today there is at least two implementations of TR1 library extensions shipped with compilers. I mean VS 2008 SP1 and gcc 4.3.x STL. Because of boost has it's own implementation of TR1 there is some problems with migrating code to this compilers. For example: 1. There is many ambiguous names if both boost and std::tr1 exposed into global namespace. 2. boost::transform_iterator knows nothing about std::tr1::bind shipped with VS2008 compiler. I think what first problem is very serious. I sure what there is a lot of code what exposed 'boost' namespace into global scope. Some of boost test cases has such directives (tests for 'function', 'tokenizer', 'string algo' libraries for example). When developers will start to expose 'std::tr1' namespace into global scope they will be encountered many problems with compilation. I think what it will be good idea to hide boost implementation of TR1 classes when this classes shipped with compiler. For example: //... #ifdef _HAS_TR1 #include <memory> namespace boost { using std::tr1::shared_ptr; //... other usings } #else // rest of the shared_ptr.hpp #endif -- Best Regards, Sergey mailto:flex_ferrum@artberg.ru

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namespace noncopyable_
by Kenneth Laskoski 19 Nov '08

19 Nov '08

Why is this nested namespace noncopyable_ necessary? The comment "// protection from unintended ADL" seems greek to me. Can someone please enlighten me and point out a practical consequence of simply defining "namespace boost { class noncopyable {...}; }" Thanks, Kenneth

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[constrained_value] New version
by Robert Kawulak 19 Nov '08

19 Nov '08

Hi all, I've updated the Boost Constrained Value library (which is likely to be reviewed soon) -- the list of changes is below: - added unconstrained -- a new constrained alias to replace it in release mode if constraint-checking is not needed and efficiency is a concern, - added Examples section to the documentation, - other minor corrections and improvements in the documentation, - using BOOST_THROW_EXCEPTION instead of boost::throw_exception() (requires Boost version 1.37.0), - fixed one place to make a better use of EBO. As usually, the code and documentation can be downloaded here: http://rk.go.pl/f/constrained_value.zip The documentation is also available online here: http://rk.go.pl/r/constrained_value Best regards, Robert Kawulak -=##############=- "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein

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Boost C++ Libraries page meaning
by vicente.botet 18 Nov '08

18 Nov '08

Hi, What is the expected behavior of the Name First Release STD Proposal STD::TR1 Header Only Use Automatic Linking Key in the page http://www.boost.org/doc/libs/? Thanks, Vicente

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[thread]when thread_resource_error is thrown?
by vicente.botet 18 Nov '08

18 Nov '08

Hi, the documentation states that the a lot of functions throwing in the Thread library throw thread_resource_error. I have do a grep on new allocation and I get Vicente@viboes1 ~/SVN/boost/thread $ grep -r "new " * detail/thread.hpp: std::auto_ptr<thread> new_thread(new thread(thread func)); pthread/thread_heap_alloc.hpp: return new T(); pthread/thread_heap_alloc.hpp: return new T(static_cast<A1&&>(a1)); pthread/thread_heap_alloc.hpp: return new T(static_cast<A1&&>(a1),sta tic_cast<A2&&>(a2)); pthread/thread_heap_alloc.hpp: return new T(static_cast<A1&&>(a1),sta tic_cast<A2&&>(a2), pthread/thread_heap_alloc.hpp: return new T(static_cast<A1&&>(a1),sta tic_cast<A2&&>(a2), pthread/thread_heap_alloc.hpp: return new T(a1); pthread/thread_heap_alloc.hpp: return new T(a1,a2); pthread/thread_heap_alloc.hpp: return new T(a1,a2,a3); pthread/thread_heap_alloc.hpp: return new T(a1,a2,a3,a4); thread_specific_shared_ptr.hpp:// We don't need any more a new class thread that inherits from boost::thread, thread_specific_shared_ptr.hpp: tss_ptr = new tss_type(* this); win32/condition_variable.hpp: entry_ptr new_entry(new list_en try(wake_sem)); win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(); win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(st atic_cast<A1&&>(a1)); win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(st atic_cast<A1&&>(a1),static_cast<A2&&>(a2)); win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(st atic_cast<A1&&>(a1),static_cast<A2&&>(a2), win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(st atic_cast<A1&&>(a1),static_cast<A2&&>(a2), win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(a1 ); win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(a1 ,a2); win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(a1 ,a2,a3); win32/thread_heap_alloc.hpp: T* const data=new (heap_memory) T(a1 ,a2,a3,a4); Where the std::bad_alloc exception is catched? Vicente

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[proto] [ was Re: [spirit2] Trivial parser crashes ]
by Joel de Guzman 18 Nov '08

18 Nov '08

Joel de Guzman wrote: > Joel de Guzman wrote: >> sm4 wrote: >>> Oops - seems formatting got in the way. >>> >>> Hope this is better: >> >> Ooops, I missed your reply. Its better to post spirit >> related questions to spirit's mailing list. I'm re-posting >> this there. > > Ok, this looks like a bug in handling aliases of the form: > > r1 %= r2; > > where r1 and r2 are rules with the same type. A quick > workaround is to copy the rhs rule: > > r1 %= r2.copy(); Eric, It seems to be a problem with Spirit2's usage of proto extends. Here's what's happening: 1) Rule uses proto::extends 2) Rule implements operator %= On expressions: r %= some-expression; The rule's operator%= kicks in. However, on expressions: r %= r2; // r and r2 has the same type Then proto %= kicks in leaving it as a no-op. Nothing happens. Hence, the rhs is never "auto-assigned" to the lhs. I'm not sure how to deal with this. Do you have a hint? I place the original test code here. Tracing the code, the first %= works as expected while the second and third becomes no-ops calling proto operator %=. > ----------------------------------------------------------------------------------------- > #include <boost/config/warning_disable.hpp> > #include <boost/spirit/include/qi.hpp> > #include <boost/spirit/include/phoenix_core.hpp> > #include <boost/spirit/include/phoenix_operator.hpp> > #include <boost/spirit/include/phoenix_fusion.hpp> > #include <boost/fusion/include/adapt_struct.hpp> > #include <boost/fusion/include/adapt_struct.hpp> > > #include <iostream> > #include <string> > > using namespace boost::spirit; > using namespace boost::spirit::qi; > using namespace boost::spirit::ascii; > using namespace boost::spirit::arg_names; > > namespace phoenix = boost::phoenix; > > using phoenix::at_c; > > struct key_val > { > std::string key; > std::string value; > }; > > BOOST_FUSION_ADAPT_STRUCT( > key_val, > (std::string, key) > (std::string, value) > ) > > > template <typename Iterator> > struct my_grammar : grammar<Iterator, key_val(), space_type> > { > my_grammar() : my_grammar::base_type(start) > { > quoted_string %= lexeme['"' >> +(char_ - '"') >> '"']; > key %= quoted_string; > value %= quoted_string; > > start = > key [at_c<0>(_val) = _1] > >> ':' > >> value [at_c<1>(_val) = _1] > ; > } > > rule<Iterator, std::string(), space_type> key; > rule<Iterator, std::string(), space_type> quoted_string; > rule<Iterator, std::string(), space_type> value; > > rule<Iterator, key_val(), space_type> start; > > }; > > int main() > { > typedef std::string::const_iterator citerator; > std::string str = "\"x\": \"25\" "; > > citerator iter = str.begin(); > citerator end = str.end(); > > my_grammar<citerator> my_parser; > key_val kv; > phrase_parse(iter, end, my_parser, kv, space); // ASSERTs > > return 0; > } > ----------------------------------------------------------------------------------------- Regards, -- Joel de Guzman http://www.boostpro.com http://spirit.sf.net

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[thread] thread pining (processor affinity)
by k-oli＠gmx.de 18 Nov '08

18 Nov '08

Hello Anthony, are you interessted in a function boost::this_thread::pin_to_processor( int)? I can provide code for Windows, LINUX, HP/UX , Solaris, IRIX, AIX (xBSD seams not to offer this functionality - FreeBSD 7.1 will add processor affinity). best regards, Oliver

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