March 2010 - Boost - lists.preview.boost.org

[range] strings
by Domagoj Saric 09 Mar '10

09 Mar '10

Currently, the following assertion: char const test_string[] = "a test string"; assert( test_string == boost::as_literal( test_string ) ); fails while the following one: assert( test_string == boost::as_literal( test_string ).advance_end( 1 ) ); passes because the left-hand side parameter of operator== is implicitly converted to a boost::iterator_range<> object which _includes_ the trailing zero (because it is treated as any other array) while the boost::iterator_range<> returned by boost::as_literal<>() _excludes_ the trailing zero... I 'know' that there is no 'happy' solution for this because the status quo is 'consistent' across all types but it, on the other hand, creates problems (or unexpected results), like the one outlined above, when strings, char pointers and literals are used...For this reason I would prefer more the other 'less than happy' solution that would treat strings in a special way (by never including the trailing zero)... Another problem is that the conversion, implict or otherwise, from a char container/range whose iterators are not plain char pointers (e.g. std::strings in 'secure STL' implementations) does not work (does not compile). My last post in the [program_options] thread offers a 'fix'. Yet another problem is that the as_literal<>() template function does not use the fact that it was passed an array to implicitly/directly deduce the length but it still calls std::strlen(). The make_range() function it calls for that: make_range( T* const r, bool ) { return iterator_range<T*>( r, r + length(r) ); } is also duplicated by: inline const char* str_end( const char* s, const char* ) { return s + strlen( s ); } ... Yes, some will object that the 'desired' direct deduction of length would be broken for 'typical' local buffers that are not completely filled (if there is no clear way of distinguishing them from literals): void foo() { char buf[ 256 ] = "a small string"; as_literal( buf ).size() == std::strlen( buf ); // in status quo as_literal( buf ).size() == _countof( buf ) - 1; // as proposed } but that could then also be said for the current implict conversion from such a "char buf[ 256 ]" into a boost::iterator_range<char const*>... I'd vote that this be handled with a runtime assertion that if a plain char array is passed it must be 'completely filled' (i.e. strlen( buf ) == _countof( buf ) ) otherwise the range must be explicitly constructed (iterator_range<char const *>( buf, buf + actual length )... Additionaly the above mentioned implementations of make_range() and str_end() add two extra instructions (substraction and addition) because they use strlen() that works with 'indexes'/size which then have to be converted to pointers... Additionaly#2 the boost::range_detail::is_char_ptr() function in as_literal.hpp is a runtime function when it seems it could be a metafunction... -- "What Huxley teaches is that in the age of advanced technology, spiritual devastation is more likely to come from an enemy with a smiling face than from one whose countenance exudes suspicion and hate." Neil Postman

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Syntax colouring for Notepad++
by Paul A. Bristow 09 Mar '10

09 Mar '10

Does anyone have or know of a user defined language plugin for Notepad++ to provide syntax colouring for Quickbook and jamfiles (makefile is reasonable but not perfect)? (or suggestions for syntax colouring other text editors?) Thanks Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

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[SoC] Submission Template
by Andrew Sutton 09 Mar '10

09 Mar '10

I've created a student submission template as part of the SoC application (which I'm currently working on). It's largely reconstructed from last year's template, with a couple of modifications. Can mentors from previous years and prospective mentors for this year please look over the template to see if there's any other information that might be useful? It can be found here: https://svn.boost.org/trac/boost/wiki/SoCSubmissionTemplate Thanks, Andrew Sutton andrew.n.sutton(a)gmail.com

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Re: [boost] [contract] Released Contract Programming Library on SourceForge
by Andrzej Krzemienski 09 Mar '10

09 Mar '10

> I have released on SourceForge a library that implements Contract > Programming (a.k.a. Design by Contract(TM) ) for C++. I am considering > to submit this library to Boost (as Boost.Contract). > > Comments? Hi, As I already said, I am very glad that we can see a good Contract library for C++. I have not used it yet, but I base my first opinion on the documentation; the topics it mentions (sub-contracting, disabling contract checking within contract checks, the "oldof"), and references, proves that you have thoroughly investigated the subject. This is first such library for C++ that I am aware of. I am almost sure I will not use it in my work, in production code. I have trouble convincing my colleagues to use templates, as they are not used to "non-Java" syntax, and they find it suspicious. I am not sure how I would be able to convince anyone to writing: (class)(copyable)(myvector)(inherit)(pushable<T>)(public)(void)(push_back)( (const T&)(element) ) I am not even convinced myself. The IntelliSense will go mad. I understand the constraints you are under, but still... Perhaps if you do require this syntax, you should offer something more in exchange than only contract checking: hooks for IntelliSense, meta-data of contract-checked functions that the user can use like other type traits, etc... On the other hand, I believe the library is a very important step to introducing contract checking into C++ standard. Contracts were labeled as "No active interest today, but open to resubmit in future". Having gained a practical experience with C++ contracts, both implementability and usage, may be a good argument for reconsidering the proposal. C++ is so particular a language that the experience from Eiffel, which is mainly an OO language, usually would not apply; for instance, I could define equality as: bool operator==( MyType const& lhs, MyType const& rhs postcondition( result ) { result == !( lhs != rhs ); }; bool operator!= MyType const& lhs, MyType const& rhs ) postcondition( result ) { result == !( lhs == rhs ); }; or: bool operator==( MyType const& lhs, MyType const& rhs ); template< typename T > bool operator!=( T const& a, T const& b ) { return !(a == b); } // no post-condition required Which solution should I prefer? For an another example, if I am a defensive programmer, should I write: int compute_area() const postcondition( ans ) { ans > 0; }; or: unsigned int compute_area() const postcondition( ans ) { ans != 0; }; or: PositiveInteger compute_area() const; // compile-time checking - even better Similarly, for loop variants, I would be interested to know how it can or cannot or need not be used in more c++ specific loops: for( auto v : setOfValues ) { process(v); } How do I define a variant? Or is a variant needed? Perhaps the sole usage of "for each" guarantees termination? Or this one: std::ofsteam file("input.txt"); std::string text; while( file >> text ) { process(text); } Regards, &rzej

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Re: [boost] [gil] External header files.
by Daniel James 09 Mar '10

09 Mar '10

On 1 March 2010 18:54, Enrique Nieloud <enieloud(a)gertrudisgraphics.com> wrote: > > I just wanted to report that the following two links are broken: > > boost/gil/extension/numeric/sampler.hpp > boost/gil/extension/numeric/resample.hpp > > > In the file: > http://www.boost.org/doc/libs/1_42_0/libs/gil/example/resize.cpp That's a pain. The html file is generated automatically from the source file, which states that it's including files that don't come with boost. It'd be better if they weren't expected to be in the boost file system. Daniel

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[asio] Generating docs from trunk drops reference links
by Mateusz Loskot 09 Mar '10

09 Mar '10

Hi, I'm generating HTML docs for Boost.Asio from sources in SVN trunk (r60372) and I've noticed that all elements in Core -> Free Functions section of the Reference are not linked (Core, second column from left) So, all the links in this box point to HTML docs root directory file:///home/mloskot/dev/boost/_svn/trunk/libs/asio/doc/html/ However, the docs on website for Asio in Boost 1.42 does look correct: http://www.boost.org/doc/libs/1_42_0/doc/html/boost_asio/reference.html While generating, Boostbook (or Quickbook) does report this problem as follows: Error: no ID for constraint linkend: boost_asio.reference.read. Error: no ID for constraint linkend: boost_asio.reference.write. ... I'm generating the docs by executing sequence of two commands: mloskot@dog:~/dev/boost/_svn/trunk/libs/asio/doc$ perl doxy2qbk.pl mloskot@dog:~/dev/boost/_svn/trunk/libs/asio/doc$ bjam --v2 I attached boost-asio-docs-gen-log.txt.zip with .txt file which contains complete output of these two commands. I'm working on Linux Ubuntu 9.10 (64-bit) with the tools of versions: $ doxygen --version 1.6.1 $ bjam --version Boost.Build V2 (Milestone 12) Boost.Jam 03.1.18 $ quickbook --version Quickbook Version 1.5 Am I doing anything wrong or missing any step or Asio docs generator has changed after 1.42? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org

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Re: [boost] [Review] ITL review starts today, February 18th
by Brian Wood 08 Mar '10

08 Mar '10

Joachim Faulhaber writes: >2010/3/7 Brian Wood <woodbrian77(a)gmail.com>: >> I was being blunt in order to let you know where I stand. >> I think the ITL is an interesting library and we may add >> marshalling support for it at some point. ? My suggestion >> is to not use the exact same class names in your library >> as are already used in the standard library. ? With the >> Boost::Intrusive library there is some of that as well. >> However, he has a class called ?rbtree that is an >> alternative to intrusive::(set and multiset). ?That rbtree >> class I support while for the time being I don't support >> the intrusive set or multiset. ? ?I'm not familiar enough >> with your library to know if an itl_rbtree class would be >> workable, but mention it just in case. > > Why not just support the class templates with the names that you like > and just ignoring the rest? I may do that. I was hoping to hear your thoughts on the itl_rbtree idea. Brian Wood http://webEbenezer.net (651) 251-9384

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Boost.Atomic on OSX Leopard, x86-32?
by Josh Faust 08 Mar '10

08 Mar '10

Hey all, I'm having some trouble getting Boost.Atomic working properly on OSX Leopard. After wrangling compilation (all instances of "lock" -> "lock;", and "+r" -> "+q"), I'm hitting what looks like bad generated assembly. The following code, compiled with -O2: #include <boost/atomic.hpp> #include <stdio.h> using namespace boost; int main() { signed char a1, c1; char a2, c2; { atomic<char> a(41); char c = a++; a1 = a.load(); c1 = c; } { atomic<signed char> a(41); signed char c = a++; a2 = a.load(); c2 = c; } printf("%d %d\n", a1, c1); printf("%d %d\n", a2, c2); } produces: Macintosh-2:test josh$ ./simple2 42 41 93 41 Changing the first atomic to be the same type as the second (atomic<signed char>) produces the correct output (42 41 for both). This same problem shows up with int vs. unsigned int as well (have only tested those two). The assembly that produces the correct output: LCFI2: movl $1, %ecx ^^^^^^^^^^^^^^^^ Move 1 into ecx movl %esp, %ebp LCFI3: movl %ecx, %eax ^^^^^^^^^^^^^^^^ And eax subl $72, %esp LCFI4: movl %ebx, -12(%ebp) LCFI5: movl %esi, -8(%ebp) LCFI6: movl %edi, -4(%ebp) LCFI7: call L11 "L00000000001$pb": L11: popl %ebx movb $41, -25(%ebp) lock; xaddb %al, -25(%ebp) ^^^^^^^^^^^^^^^^^ first reference after assignment to eax (through al) movzbl -25(%ebp), %edx lock; addl $0, (%esp) movb $41, -25(%ebp) lock; xaddb %cl, -25(%ebp) ^^^^^^^^^^^^^^^^^ first reference after assignment to ecx (through cl) movl %ecx, %edi movzbl -25(%ebp), %ecx movb %cl, -41(%ebp) lock; addl $0, (%esp) The assembly that produces the incorrect output (when one is atomic<char> and the other is atomic<signed char>): movl $1, %eax ^^^^^^^^^^^^^^^^^ Move 1 into eax movl %esp, %ebp LCFI3: subl $72, %esp LCFI4: movl %ebx, -12(%ebp) LCFI5: movl %esi, -8(%ebp) LCFI6: movl %edi, -4(%ebp) LCFI7: call L11 "L00000000001$pb": L11: popl %ebx movb $41, -25(%ebp) lock; xaddb %al, -25(%ebp) ^^^^^^^^^^^^^^^^^^ First reference after assignment to eax (through al) movzbl -25(%ebp), %edx lock; addl $0, (%esp) movb $41, -25(%ebp) lock; xaddb %cl, -25(%ebp) ^^^^^^^^^^^^^^^^^^ First reference to ecx (through cl), but NO ASSIGNMENT. cl is garbage? movl %ecx, %edi movzbl -25(%ebp), %ecx movb %cl, -41(%ebp) lock; addl $0, (%esp) I am by no means an assembly expert (this has been a huge learning experience in fact) but this doesn't look right. I'm on: gcc version 4.0.1 (Apple Inc. build 5493) OSX 10.5.8, Intel Core 2 Duo (2.16 GHz) Just pulled a git clone of Boost.Atomic from http://git.chaoticmind.net/boost.atomic, rev. 886a675aa982ab5875c7bc98697b2eb26c134d03 (I think... I have no experience with git, just grabbed the top guid from "git log"). building without -O2 yields correct results. Anyone with more knowledge than I have any ideas? Am I being stupid and something else is wrong? Josh

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Re: [boost] [Review] ITL review starts today, February 18th
by Brian Wood 08 Mar '10

08 Mar '10

Joachim Faulhaber writes: >2010/3/7 Brian Wood <woodbrian77(a)gmail.com>: >> Joachim Faulhaber writes: >> > >> If you stick >> with the names of some of the classes that you have today, >> at the very least, I'll put off developing marshalling support for >> the library. > >To give you a little feed back: The sentence above didn't exactly make >me feel in peace with you ;-/ But I'm open for your suggestions. I was being blunt in order to let you know where I stand. I think the ITL is an interesting library and we may add marshalling support for it at some point. My suggestion is to not use the exact same class names in your library as are already used in the standard library. With the Boost::Intrusive library there is some of that as well. However, he has a class called rbtree that is an alternative to intrusive::(set and multiset). That rbtree class I support while for the time being I don't support the intrusive set or multiset. I'm not familiar enough with your library to know if an itl_rbtree class would be workable, but mention it just in case. Regards, Brian Wood http://webEbenezer.net (651) 251-9384

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Re: [boost] [Boost-users] [Review] ITL review starts today, February 18th
by Joachim Faulhaber 08 Mar '10

08 Mar '10

Hi Jeff, thank you for your review of the ITL. You have been supportive in the course of the development at different points giving feed back about shortcomings and helping with code patches and useful suggestions. I am glad to hear that you are actually using the library for real world applications already. 2010/3/8 Jeff Flinn <TriumphSprint2000(a)hotmail.com>: >> Please always state in your review, whether you think the library should >> be >> accepted as a Boost library. > > Yes, I think the library (with the interface improvements brought out during > the review) should be accepted into boost. I've already successfully used > the library with it's existing interface in a commercial product. > >> - What is your evaluation of the design? > > As brought up during the course of the review period my main concerns for > the library's interface are: > > 1) the bloated size of the interval class with it's dynamic bound data > member. This is being addressed by Joachim providing an interface to allow > use of static bound interval classes. > > 2) the fat interface on the interval class. In my view the myriad of > mutators would best be replaced with free functions in terms of the > interval's extents and return a interval passing the calculated extents to > an interval constructor which enforces the interval's invariant(s). There > should also be a method to construct an interval given unordered extents > that effectively does interval(min(arg1, arg2), max(arg1, arg2)). > > 3) better integration of std and user defined data types en lieu of itl's > specific types. Joachim has agreed to improvements in this area. I think we have agreed in the various points involved. > 4) I'd also like to see std::inserter "just work" with the containers. I discovered that it does not just work, because for std::insert_iterator there is an invariant involved that expects the inserted to be a non empty element of the container, that the element is inserted into. This invariant is broken with interval containers because an interval/segment is not an element of an interval container. > I shouldn't have to expect to look for the itl specific adder to do this. This > was the most common usage my applications had for populating interval > containers using std::copy/transform from my applications existing data > structures. > >> - What is your evaluation of the implementation? > > Seems adequate. I was able to port to the portions I needed to CodeWarrior > 9.4 (from 2003?). IIRC, Joachim integrated the changes(simplifications) that > allowed itl to work in this environment. I added all the changes suggested, but I remember that important parts of the code, itl global operators in particular, still did not compile with CW. I tried to set up CW myself, but encountered too many problems and gave up :( > Performance for the scale of problems I've been dealing with were fine, but > as has been discussed scaling to larger sizes of millions of items may > require some specialized containers. I don't see this as a problem, it's > analogous to std::map and std::unordered_map. I share this view. > Hmm, It just occurs to me that for my application I could void the N^2 size > issue of a split_interval_map<int, set<> > with a non_combining_map<int, > data> that allowed me to iterate through all items that overlap with an > arbitrary interval in and ordered fashion. That's not much different from a > std::map<interval, data>, but with some more interval specific wrapping of > the upper/lower_bound/equal_range methods. > >> - What is your evaluation of the documentation? > > I was able to get up and running fairly quickly. As discussed some of the > colorful terminology got in the way rather than helping. Also I had expected > to just be able to populate with std::inserter, and had trouble finding docs > related to this. The example for copy/transform helped, but even during this > review I have trouble finding the docs for itl::adder/inserter. True, escaped my notice. Has to be added. >> - What is your evaluation of the potential usefulness of the library? > > Very, I've come across needs for this capability in 3 different jobs in 3 > very different industries. I've had domain specific solutions and was > looking to create just such a generic library when Joachim submitted his > library. That's interesting. I had the basic ideas and first implementation in 1999 / 2000 and I had the immediate impression that it should be made available to the public domain. But due to other projects and commercial copyright of the first version, I did not have the opportunity to make it open source for years. I always thought someone else would be faster than me ;) >> - Did you try to use the library? With what compiler? Did you have any >> problems? > > Yes, the library is being used in a commercial application built with > CodeWarrior 9.4 on Mac/Windows and with VC8 and XCode 3.x. The library > required some modifications to the template declarations for CodeWarrior. Is it now fully or still only partially compilable with CW? >> - How much effort did you put into your evaluation? A glance? A quick >> reading? In-depth study? > > I read through the documentation, integrated the library with production > code, dug through compilation error messages and headers on CodeWarrior to > port a portion of the library. I've profiled code using itl to understand > performance implications. > >> - Are you knowledgeable about the problem domain? > > Yes, I've designed/implemented/optimized integral open-closed Interval and > IntervalSet classes for use in previous projects. Thanks again for your review and the support that you provided for the ITL library. Cheers, Joachim

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