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[GSoC] Distinct check, hash and block cipher library ?
by Pierre Talbot 03 Apr '11

03 Apr '11

Hello everyone. My name is Pierre Talbot and I'm a Belgian student who'd like to work with the Boost community in the context of GSoC, and if it's possible I hope much more. I'm also (note the "also") interested in the checks and hashes projects. I tried to code an interface of the checks and hashes projects and actually I thought we could split this project into two distinct projects. Actually, the checks and the hashes are different in many ways. Indeed I though we could address them : the check project : - Control redundancy check : CRC 16/32/64 - Checksums : Fletcher, Adler, Luhn, and Verhoeff algorithm - Credit card checks : VISA, Mastercard, AMEX, ... - International number : ISBN, ISSN, EAN, IBAN, ... the hash project : - MD family : MD5, MD6 (optionnal). - SHA-1 and SHA-2 family : SHA-224, SHA-256, SHA-384, SHA-512 - SHA-3 as Black or Groslt,... - Tiger - RIPEMD family (RIPEMD-128, RIPEMD-160, RIPEMD-256) - RadioGatun - Very Smooth Hashing (VSH) - Optionnal(?) : Non cryptographic hash function Why so many different algorithms ? I think the users need a larger range of hashing functions. Some hashes are quicker, lighter or more resistant to collision. Others are better for the micro-controllers, and some systems use other hashes than SHA-1 or MD5. Why split one project into two distinct ones? Because I think that in the GSoC context, these two projects are too much work for a single person to provide a complete documentation. Indeed if you think it's impossible to split it, I think that the hashes should be limited to the SHA-1/2 and MD5 algorithms (because there are the most widespread). Furthermore, the documentation of the hash project should be even more complete if we want to provide details about the speed/ usage of an algorithm. I also want to discuss the possibility of building a Block Cypher Algorithm Library. Firstly I would like "to share a plan of a library" : - The three 128 bits algorithms recognized by ISO : AES (Rijndael), Camellia, and SEED. - Two very powerful algorithms : Blowfish (currently resistant to cryptanalysis) and Twofish (finalist to the AES contest). - Serpent (finalist to the AES contest). - The old DES and Triple-DES algorithms I read about the timing attacks on this kind of algorithms. In the first place, I think we could ignore those attacks because the attackers need to know details about the server configuration (processor, amount of RAM, ...). They also need to know the precise time of each algorithm's instruction in the processor. So this attack needs to be carried out in a "local context" and not on the internet. (Considering that packets have a variable latency). It's for these reasons that I think these attacks are highly theoretical. I think we should improve this library later. What do you think about all of this ? Thank you very much for reading me. Pierre Talbot.

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[config] Purpose of compiler identification macros
by Edward Diener 03 Apr '11

03 Apr '11

In select_compiler_config.h there are a number of compiler identification macros of the form BOOST_CXX_SOMECOMPILER. I can find nowhere in boost where these are being used. What is the purpose of these macros ?

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Re: [boost] GSoC idea - interval trees, ITL tie in
by Brestin Seby 03 Apr '11

03 Apr '11

>> Phil Endecott wrote: >>> Andrew Sutton wrote: >>>>> While reading Boost documentation, and reviews on XInt, I though >>>>> about the possibility of implementing for Boost some new data >>>>> structures that are not yet implemented not even in STL like >>>>> interval trees, binary indexed trees. >>> >>>> These seem like interesting data structures, but I'm not sure that >>>> there's a large demand for them. >>> >>> Brestin, please have a look at the reviews for Joachim Faulhaber's >>> Interval library. Andrew is right that there is not much demand for >>> interval trees. Personally I would still like to have them, though. >> >> Joachim could mentor the GSOC project and the interval tree could >> be an enhancement to his library rather than a new boost library. >> It might be best to reduce the scope to the single data structure. >Hi Sebastian, >interval_tree is still on my todo list for Boost.ICL and didn't make >it to materialize as real code yet. So an implementation would be a >welcome contribution, that is also expected by some boosters ;) I >haven't been active as GSoc mentor yet but it would obviously make >sense. Thank you for your replies. This helps me a lot on writing my proposal. By the way could I add more than one idea to the proposal?

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[testsystem] broken?
by Joachim Faulhaber 03 Apr '11

03 Apr '11

It looks like the tests on boost/trunk and release branch stopped to be updated since Thu, 31 Mar 2011 20:23:30. Is someone able to do anything about it? Regards, Joachim -- Interval Container Library [Boost.Icl] http://www.joachim-faulhaber.de

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GSoC idea - interval trees, binary indexed trees, permutation
by Brestin Seby 02 Apr '11

02 Apr '11

Hello, my name is Sebastian Brestin. I am a student from Romania. While reading Boost documentation, and reviews on XInt, I though about the possibility of implementing for Boost some new data structures that are not yet implemented not even in STL like interval trees, binary indexed trees. I also have an other idea about implementing (Boost:Permutation) a Permutation Class that allows operations on permutations. What do you think?

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Data / String Ref library
by Olaf van der Spek 02 Apr '11

02 Apr '11

Hi, A lot of functions take a const void*, size_t pair as two parameters. This is then cast to a const unsigned char* for further processing. Two parameters means you can't easily pass the result of an expression or function call. One parameter would be handier. const std::string& is also used frequently. However, this forces the caller to use (or construct) std::string, which is undesirable and unnecessary. A solution seems simple: data_ref and string_ref, which represent a pointer pair (void/unsigned char and char respectively). string_ref can replace const std::string&, data_ref can replace const void*, size_t. I think this would be a nice addition to Boost. Is there any interest in a library that solves this problem? -- Olaf

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GSoC XML
by Brestin Seby 02 Apr '11

02 Apr '11

Hello my name is Sebastian Brestin. I am a student from Romania. After another few hours of browsing through Boost's libraries I was thinking: What about implementing DOM into Boost? XML is the most used "data storage mechanism" over the internet. Yet Boost does not have it. I say: Let me code it! Let me now what do you think about it and which of my proposals would bring more utility to Boost.

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Re: [boost] [MSM] feature request stop(const event& event_)
by Christophe Henry 01 Apr '11

01 Apr '11

> Hi Christophe and all > > Now I have to put some effort to residing out code using MSM because > one of our module where we use MSM has reached it's limits and we > won't be able to compile it any more with VC9 32 bit compiler. > In our implementation we have several sub state machines (around 20 > per main state machine instance at the moment) ( nested in 4 level > deep) and over time as we extend the functionality we introduce new > sub state machines which are covering new functionality ... > > We now can not add any more new sub state machines because we can not > compile any more :(. While big improvements were made, there will always be a limit, especially with VC9. Did you try with VC10? It'd be interesting to know. > So I have decided to split the big state machines with a lot of subs > state machines to stand alone small state machine instances and use > our dispatching framework to dispatch events between them. This way I > will get small compile units. Sounds good. > I'm managed to complete a job apart form one problem I have now. > I'm not able to generally trigger the exit functions on the current > active states of a state machine when it is finished it's execution > like when a sub state machine exists to the outer state machine. If you mean in the fsm destructor, it's true. I'd be surprised though if on_exit was not called when leaving a submachine to its outer. > Is it possible to implement something like stop method on the back end > which would call exit on each region current state and than an exit of > the state machine whit an event passed as an argument. ? > > this would help me a lot and it would be similar to the start. Ah yes I remember thinking about it in the early phase of MSM. Unfortunately I don't remember why it was not done, just that I had a reason at that time. Actually I think it'd be even better to automatically call on_exit in the destructor. The start method is there only because you might not want to start a state machine immediately upon creation, but I have never had a very good feeling about it, so I'd prefer not repeating this. Is there a reason why you want a stop method or the calls of on_exit inside the destructor would suffice (provided I don't hit again the issue I mentioned above)? > other minor thing is it possible to make public this version of start > methode in the back_end ? > > template <class Event> > void start(Event const& incomingEvent) I'm not sure you'd be happy with this because on_entry is not called in this version (it's meant to be called from the outer machine, which itself calls on_entry), so you'd have to call it yourself. What are you trying to achieve? Regards, Christophe > > Br. > Richard

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Boost.Serialization issue loading 1.37 binary archive.
by Brandon Kohn 01 Apr '11

01 Apr '11

Hello, I've been using Boost.Serialization for some time, and have found a break while upgrading to 1.46.1 (from 1.37). The problem seems to be the size of the integral type which stores v. 1.37 has: BOOST_ARCHIVE_VERSION(){ return 5; } When saving to the binary_oarchive: // basic_binary_oarchive.hpp void save_override(const class_id_type & t, int){ // upto 32K classes const int_least16_t x = t.t; * this->This() << x; } 1.46.1 has: void load_override(class_id_type & t, int version){ library_version_type lvt = this->get_library_version(); if(boost::archive::library_version_type(7) < lvt){ this->detail_common_iarchive::load_override(t, version); } else if(boost::archive::library_version_type(6) < lvt){ int_least16_t x=0; * this->This() >> x; t = boost::archive::class_id_type(x); } else{ int x=0; * this->This() >> x; t = boost::archive::class_id_type(x); } } The salient point is that on the load in 1.46.1 an int is used to read the value which was stored as int_least16_t in version 5 archives. The trunk seems to have this as well. Regards, Brandon Kohn

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[gsoc] Interest in BGL v2?
by Michael Lopez 01 Apr '11

01 Apr '11

Hello all, My name is Michael and, if there is enough interest from the mailing list, I will be submitting an application for GSoC 2011 to work on the BGL v2. I have been working on a project called Origin ( http://code.google.com/p/origin/) when time permits, that houses the code that I intend to integrate into boost. The project was started by Andrew Sutton and I have taken an active role in its creation. The new library focuses on ease of use, replacement of property maps for labels, data structures with more concise and clear semantics, a new graph concept hierarchy, implementing graph algorithms to align with STL abstractions, and, finally, integrate C++0x into the BGL. I have already worked on the existing BGL back in 2009 for GSoC. While working on the BGL, I started seeing opportunities to bring the BGL more in-line with modern techniques and practices. I found that the library, though robust and quite mature, was lacking in some areas. The most unavoidable being C++0x support. The other design concern was that some of the data structures felt more like meta-programs. This is no good since a meta-program generates types that may model one of many concepts. Another feature that has been on BGL's want list is the implementation of algorithm objects. Some of the algorithm objects are already present in Origin. I realize that this is not a 3 month project. I fully understand that. However, I plan to continue maintaining this library in Origin, as I have been, until it is mature enough for a release and integration into other libraries. Hopefully there is enough interest to get this off of the ground. Please respond with your interests, questions and/or doubts. Michael Lopez

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