- Boost - lists.boost.org

recommend logging library?
by Neal D. Becker 22 Mar '04

22 Mar '04

I notice boost doesn't have a logging library. I have seen several floating around. Are there any recommendations?

13 24

[fsm] Finally ...
by Andreas Huber 22 Mar '04

22 Mar '04

... has boost::fsm reached a reasonably stable state. Code, examples and documentation can be found here: http://boost-sandbox.sf.net/fsm.zip The documentation can also be browsed online: http://boost-sandbox.sf.net/libs/fsm Comments, questions, etc. are most welcome. Andreas Huber

1 0

[filesystem] relative_to
by John Torjo 22 Mar '04

22 Mar '04

Dear boosters, I noticed that currently there's no way to get the relative path of path A related to path B. What I mean is, given two **complete** paths, to get the relative path of one related to the other. To give a real example, I have an application that starts in directory initial_path(). I have several dialogs that allow the user to browse for files. My requirement is, after the user browses for a file, to internally ALWAYS store the path relative to initial_path(). Since there's no way to do this currently, I created my own function. Do you think it could be a useful addition to filesystem library? // converts the given path, making it relative to the src path // // precondition: dest & src are both complete path relative_to( const path & dest, const path & src) { // both paths should be complete assert( dest.is_complete() && src.is_complete() ); path::iterator dest_begin = dest.begin(), dest_end = dest.end(); path::iterator src_begin = src.begin(), src_end = src.end(); path result; #if defined(BOOST_WINDOWS) //#if defined(WIN32) if ( dest.root_name() != src.root_name() ) { // paths are on different drives (like, "c:/test/t.txt" and "d:/home") return dest; } if ( src_begin != src_end) ++src_begin; if ( dest_begin != dest_end) ++dest_begin; #endif // ignore directories that are same while ( (src_begin != src_end) && (dest_begin != dest_end)) { if ( *src_begin != *dest_begin) break; ++src_begin, ++dest_begin; } // now, we begin to relativize while ( src_begin != src_end) { result /= ".."; ++src_begin; } while ( dest_begin != dest_end) { result /= *dest_begin; ++dest_begin; } return result; } void test_relative_to( const std::string & dest, const std::string & src) { std::string result = relative_to( dest, src).string(); std::cout << "Testing path '" << dest << "',\n" " relative to '" << src << "'\n" " result : '" << result << "'\n" << std::endl; } int main(int argc, char* argv[]) { path::default_name_check( &native); test_relative_to( "c:/temp/test/inner/i2/file.txt", "c:/temp/test"); test_relative_to( "c:/temp/test/inner/i2/file.txt", "c:/temp/test/other"); test_relative_to( "c:/temp/test/inner/i2/file.txt", "c:/temp"); test_relative_to( "c:/temp/test/inner/i2/file.txt", "c:/temp/test"); test_relative_to( "c:/temp/test", "c:/temp/test"); test_relative_to( "c:/temp/test/inner/i2/file.txt", "d:/temp/test"); test_relative_to( "c:/temp/test", "d:/temp/test"); test_relative_to( "c:/other/test/inner/i2/file.txt", "c:/temp/test"); test_relative_to( "c:/other/test/inner/i2/file.txt", "c:/oth/test/other"); test_relative_to( "c:/other/test/inner/i2/file.txt", "c:/temp"); test_relative_to( "c:/other/test/inner/i2/file.txt", "c:/other/test"); return 0; } Best, John

2 2

Using Serialization for binary marshalling
by Matthew Vogt 22 Mar '04

22 Mar '04

Is anyone else interested in using Robert Ramey's serialization library for the purpose of marshalling data into pre-determined binary formats? This is not related to serialization in a general sense, but employing the syntax and underlying fundamentals of the library, to a somewhat related purpose. This is a test program demonstrating what I'm doing - I'm interested to know if anyone else is doing anything similar... Matt test.cpp: ------------------------------------------------------------------ #include <sstream> #include <cassert> #include "marshall.hpp" #include "network_oarchive.hpp" #include "network_iarchive.hpp" class test { struct subobject; // Basic fixed-size primitives uint8_t a; uint16_t b; uint32_t c; uint64_t d; // String data that must be serialized to a pre-determined length marshall::fixed_length<std::string, 20> e; marshall::fixed_length<std::wstring, 10> f; // String data that must be serialized with a prepended length // (whose size is itself predetermined) marshall::variable_length<std::string, uint8_t> g; marshall::variable_length<std::wstring, uint8_t> h; // Arbitrary data that must be serialized to a pre-determined length marshall::fixed_length<std::vector<uint16_t>, 5> i; marshall::fixed_length<std::vector<subobject>, 2> j; // Arbitrary data that must be serialized with a prepended length // (whose size is itself predetermined) marshall::variable_length<std::vector<uint16_t>, uint32_t> k; marshall::variable_length<std::vector<char>, uint32_t> l; // A sub-object of arbitrary complexity struct subobject { subobject(void) : a(0), b(0) {} subobject(uint32_t x, uint32_t y) : a(x), b(y) {} bool operator== (const subobject& other) const { return (a == other.a && b == other.b); } private: uint32_t a; uint32_t b; friend class boost::serialization::access; template <class Archive> void serialize(Archive& archive, const unsigned version) { archive & a & b; } }; friend class boost::serialization::access; template <class Archive> void serialize(Archive& archive, const unsigned version) { archive & a & b & c & d & e & f & g & h & i & j & k & l; } public: test(void) : a(0x01), b(0x0203), c(0x04050607), d(0x08090a0b0c0d0e0f), e("abcdefg"), g("xyz") { f[0] = 'A'; f[1] = 'B'; f[2] = 'C'; h.push_back('w'); i[0] = 255; i[1] = 254; i[2] = 253; j[0] = subobject(99, 100); k.push_back(1); k.push_back(2); k.push_back(3); l.push_back('l'); } test(bool) {} // Don't initialize everything bool operator== (const test& other) const { return (a == other.a && b == other.b && c == other.c && d == other.d && e == other.e && f == other.f && g == other.g && h == other.h && i == other.i && j == other.j && k == other.k && l == other.l); } }; int main(int, char**) { test t1; // Serialize object to binary format, in network byte order std::ostringstream oss; boost::archive::network_oarchive oa(oss); oa << t1; // Create uninitialized object test t2(false); // De-serialize object from binary format, in network byte order std::istringstream iss(oss.str()); boost::archive::network_iarchive ia(iss); ia >> t2; assert(t1 == t2); return 0; } This produces the following binary output: ------------------------------- 0000000 |01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 61 |a |b |c |d |e 0000020 |62 63 64 65 66 67 00 00 00 00 00 00 00 00 00 00 | 0000040 |00 00 00 00 00 00 41 00 00 00 42 00 00 00 43 00 | | f 0000060 |00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | 0000100 |00 00 00 00 00 00 00 00 00 00 00 03 78 79 7a 01 | |g |h 0000120 |00 00 00 77 00 ff 00 fe 00 fd 00 00 00 00 00 00 | |i |j 0000140 |00 63 00 00 00 64 00 00 00 00 00 00 00 00 00 00 | |k 0000160 |00 03 00 01 00 02 00 03 00 00 00 01 6c | |l

3 4

BOOST_PP_COMMA, LPAREN,RPAREN delay eval?
by Larry Evans 22 Mar '04

22 Mar '04

I've looked at some of the uses of these, but can't figure out how to do the following. Using boost/preprocessor macros, I want to generate code something like: #include <boost/mpl/vector.hpp> #include <boost/mpl/at.hpp> using namespace boost::mpl; struct source { target my_target ; template<typename VecOfTypes> source ( VecOfTypes const& , at_c<VecOfTypes,0>::type a0 ) : my_target ( a0 ) {} template<typename VecOfTypes> source ( VecOfTypes const& , at_c<VecOfTypes,0>::type a0 , at_c<VecOfTypes,1>::type a1 ) : my_target ( a0 , a1 ) {} }; and use it as follows: typedef vector<int,float> int_float_typelist; source s0(int_float_typelist(),0); source s1(int_float_typelist(),0,2.5); I was planning on defining a macro, PP_CTOR_FORWARDER_OVERLOAD, to be used as: struct source { BOOST_PP_REPEAT(2,PP_CTOR_FORWARDER_OVERLOAD,(source, my_target)) }; However, I also would like to use it where instead of my_target(a0,a1), there might be super_type(new target(a0,a1)), in which case the tuple that was the last arg to BOOST_PP_REPEAT would contain left and right parens. However, when I tried: BOOST_PP_REPEAT( 2, PP_CTOR_FORWARDER_OVERLOAD, (source,auto_ptr<target> BOOST_PP_LPAREN() new target, BOOST_PP_RPAREN() )) I get: /usr/local/gcc-3.4-20040225/bin/g++ -ggdb -c -Wall -MMD -O0 -ggdb -E -I/home/evansl/prog_dev/boost-root.ln/boost_dev -I/home/evansl/prog_dev/boost-root.ln pp_ctor_forwarder.cpp |indent -st pp_ctor_forwarder.cpp:4:1: macro "BOOST_PP_TUPLE_ELEM_4_0" requires 4 arguments, but only 2 given pp_ctor_forwarder.cpp:4:1: macro "BOOST_PP_TUPLE_ELEM_4_1" requires 4 arguments, but only 2 given pp_ctor_forwarder.cpp:4:1: macro "BOOST_PP_TUPLE_ELEM_4_2" requires 4 arguments, but only 2 given pp_ctor_forwarder.cpp:4:1: macro "BOOST_PP_TUPLE_ELEM_4_0" requires 4 arguments, but only 2 given pp_ctor_forwarder.cpp:4:1: macro "BOOST_PP_TUPLE_ELEM_4_1" requires 4 arguments, but only 2 given pp_ctor_forwarder.cpp:4:1: macro "BOOST_PP_TUPLE_ELEM_4_2" requires 4 arguments, but only 2 given # 1 "pp_ctor_forwarder.cpp" How can I cause the delay in evaluation of BOOST_PP_RPAREN and LPAREN to avoid these errors? Here is my current macro def: #include "boost/preprocessor/enum_params.hpp" #include "boost/preprocessor/inc.hpp" #include "boost/preprocessor/punctuation/comma_if.hpp" #include "boost/preprocessor/tuple/elem.hpp" #define PP_CTOR_FORWARDER_PARAM(z,n,_) \ BOOST_PP_COMMA_IF(n) at_c<VecOfTypes,n>::type BOOST_PP_CAT(a,n) #define PP_CTOR_FORWARDER_OVERLOAD(z,n,data) \ template< typename VecOfTypes > \ BOOST_PP_TUPLE_ELEM(4,0,data) \ ( VecOfTypes const& \ , BOOST_PP_REPEAT(BOOST_PP_INC(n), PP_CTOR_FORWARDER_PARAM, BOOST_PP_EMPTY) \ ) \ : BOOST_PP_TUPLE_ELEM(4,1,data) \ BOOST_PP_ENUM_PARAMS(BOOST_PP_INC(n), a ) \ BOOST_PP_TUPLE_ELEM(4,2,data) \ {} TIA.

2 3

[BGL] transpose_graph documentation.
by Cromwell Enage 21 Mar '04

21 Mar '04

Accodring to <http://www.boost.org/libs/graph/doc/transpose_graph.html> the graph that will hold the transposition is supposed to have no edges in it and to have the same number of vertices as the input graph. However, looking through the source code in <boost/graph/copy.hpp>, which the algorithm uses, I see as many vertices being added to the output graph as there are in the input graph. Does this mean that the output graph is actually supposed to have no vertices to begin with? In the attached program, if the #if condition is set to 1, the program does as the documentation currently suggests, but the output is wrong. With the #if condition left at 0, the program gives the correct output. What's the verdict? Cromwell Enage __________________________________ Do you Yahoo!? Yahoo! Mail SpamGuard - Read only the mail you want. http://antispam.yahoo.com/tools

2 1

[Filesystem] Relational operators
by Martin 21 Mar '04

21 Mar '04

I have used the filesystem library for some time now and I am really happy with it. In the CVS I noticed that it recently added relational operators and an "equivalent" function. To my surprice the relational operators are implemented in a non-portable way. It only does a lexicographical compare! In the rationale it says: "Programmers wishing to determine if two paths are "the same" must decide if that means "the same representation" or "resolve to the same actual file or directory", and choose the appropriate function accordingly." In windows the path "file.cpp" is the same as "FILE.CPP" but not in posix. So if I write portable code I need to do add a function like bool eq_path(const path& path1, const path& path2) { #if BOOST_POSIX return path1.string() == path2.string(); #else return boost::algorithm::iequals(path1.string(), path2.string()); #endif } In most of my cases the equivalent function is not an alternative since it requires that both paths can be evaluted by the filesystem, i.e. paths must exist and the parent of relative paths must be known. --------------------------------------- Another minor question: Why does the "leaf()" member function return a string and not a path?

2 1

Re: [boost] Formal Review: Indexed Set
by JOAQUIN LOPEZ MU?Z 21 Mar '04

21 Mar '04

----- Mensaje original ----- De: Jeff Garland <jeff(a)crystalclearsoftware.com> Fecha: Domingo, Marzo 21, 2004 9:02 pm Asunto: Re: [boost] Formal Review: Indexed Set [...] > > I was unable to unzip this file on Linux -- > > $ unzip indexed_set.zip > Archive: indexed_set.zip > End-of-central-directory signature not found. Either this file > is not > a zipfile, or it constitutes one disk of a multi-part archive. > In the > latter case the central directory and zipfile comment will be > found on > the last disk(s) of this archive. > ?? So weird, I've just downloaded it (in a Windows platform) and the file opens OK. I'll try to upload a tar.gz version tomorrow (I can't right now.) > Is the sandbox also up to date? It looks like there have been > recent changes > there. > Yes, it is up to date, though I prefer to refer people to the files section instead. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

1 0

Little patch for static_assert.hpp
by Gennaro Prota 21 Mar '04

21 Mar '04

Hi John, apropos gcc's -Wundef :) The attached patch allows to compile static_assert.hpp with that option turned on. While I was at it I've also changed the license reference text and removed a spurious space at the end of the line that begins with 'agurt 15/sep/02:'. Maybe BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS could be removed too (replacing it with __BORLANDC__) PS: What's 'agurt'? -- Genny. begin 644 static_assert.hpp.diff M1FEL92!D:69F97)E;F-E(')E<&]R="!G96YE<F%T960@8GD@0U-$:69F(&)Y M($-O;7!O;F5N=%-O9G1W87)E(&]N(#(P+S`S+S(P,#0@,3DN,C`-"@T*0F%S M92!F:6QE.B!#.EQ$3T-5345^,5Q!1$U)3DE^,5Q)35!/4U1^,5Q496UP7'-T M871I8U]A<W-E<G1?;W)I9U\S+FAP<`T*0V]M<&%R960@9FEL93H@1#I<0U93 M(%)E<'-<8F]O<W1<8F]O<W1<8F]O<W1<8F]O<W1<8F]O<W1<<W1A=&EC7V%S M<V5R="YH<'`-"@T*,2PU8S$L-0T*/"`O+R`@*$,I($-O<'ER:6=H="!*;VAN M($UA9&1O8VL@,C`P,"X-"CP@+R\@(%5S92P@;6]D:69I8V%T:6]N(&%N9"!D M:7-T<FEB=71I;VX@87)E('-U8FIE8W0@=&\@=&AE(`T*/"`O+R`@0F]O<W0@ M4V]F='=A<F4@3&EC96YS92P@5F5R<VEO;B`Q+C`N("A3964@86-C;VUP86YY M:6YG(&9I;&4@#0H\("\O("!,24-%3E-%7S%?,"YT>'0@;W(@8V]P>2!A="!H M='1P.B\O=W=W+F)O;W-T+F]R9R],24-%3E-%7S%?,"YT>'0I#0H\(`T*+2TM M#0H^("\O("`@("`@("`@("`@*$,I($-O<'ER:6=H="!*;VAN($UA9&1O8VL@ M,C`P,"X-"CX@+R\@1&ES=')I8G5T960@=6YD97(@=&AE($)O;W-T(%-O9G1W M87)E($QI8V5N<V4L(%9E<G-I;VX@,2XP+@T*/B`O+R`@("`H4V5E(&%C8V]M M<&%N>6EN9R!F:6QE($Q)0T5.4T5?,5\P+G1X="!O<B!C;W!Y(&%T#0H^("\O M("`@("`@("`@(&AT='`Z+R]W=W<N8F]O<W0N;W)G+TQ)0T5.4T5?,5\P+G1X M="D-"CX@+R\-"C8Q8S8Q#0H\("`@("`A0D]/4U1?5T]22T%23U5.1"A?7TU7 M15)+4U]?+"`\(#!X,S`P,RD-"BTM+0T*/B`@("`@(2AD969I;F5D(%]?35=% M4DM37U\@)B8@0D]/4U1?5T]22T%23U5.1"A?7TU715)+4U]?+"`\(#!X,S`P M,RDI#0HW-F,W-@T*/"`O+R!A9W5R="`Q-2]S97`O,#(Z(&$@<W!E8VEA;"!C M87)E(&ES(&YE961E9"!T;R!F;W)C92!);G1E;"!#*RL@:7-S=64@86X@97)R M;W(@#0HM+2T-"CX@+R\@86=U<G0@,34O<V5P+S`R.B!A('-P96-I86P@8V%R M92!I<R!N965D960@=&\@9F]R8V4@26YT96P@0RLK(&ES<W5E(&%N(&5R<F]R M#0H-"@T*/"TM+2TM+2TM+2TM+2TM+2TM+2TM+2`@16YD(&]F(')E<&]R="`@ :+2TM+2TM+2TM+2TM+2TM+2TM+2TM/@T*#0HM ` end

2 3

[utility] enable_if request
by Jonathan Turkanis 21 Mar '04

21 Mar '04

Hi, Often I use enable_if and its cousins to add functionality to code which works okay on compilers without SFINAE. So I have a lot of code which looks like this: template<typename T> #ifndef BOOST_NO_SFINAE typename enable_if<is_xxx<T>, int>::type #else int #endif f(T t); or template<typename T> void f( T t #ifndef BOOST_NO_SFINAE , typename enable_if<is_xxx<T>, int>::type* = 0 #endif ); It would be nice to have macros BOOST_ENABLE_IF_RETURN(condition, result) and BOOST_ENABLE_IF_PARAM(condition) so that the above could be written template<typename T> BOOST_ENABLE_IF_RETURN(is_xxx<T>, void) f(T); template<typename T> void f(T BOOST_ENABLE_IF_PARAM(is_xxx<T>)); (And similarly for enable_if_c, etc.) It's straightforward to write macros which work for conditions which don't need to be enclosed in parentheses; e.g.: #ifndef BOOST_NO_SFINAE # define BOOST_ENABLE_IF_RETURN(condition, result) \ typename boost::enable_if<condition, result>::type #else # define BOOST_ENABLE_IF_RETURN(condition, result) result #endif With a little more work, you can allow use such as template<typename T, typename U> BOOST_ENABLE_IF_RETURN((is_base_and_derived<T, U>), void) f(T, U); e.g. #define BOOST_ENABLE_IF_RETURN(condition, result) \ typename boost::enable_if< \ typename boost::function_traits< \ void condition \ >::arg1_type, result \ >::type Here the parentheses in the macro invocation are required. (I've found I can make the parentheses in the macro invocation optional by surrounding 'condition' in the above #define with parentheses -- 'void(condition)' -- but I'm not sure this is standard conforming. It does work on a lot of good compilers, though.) Any thoughts? Jonathan

1 0