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Re: [boost] "SuperC"
by Phil Bouchard 19 Aug '08

19 Aug '08

"David Abrahams" <dave(a)boostpro.com> wrote in message news:877iae4oeq.fsf@mcbain.luannocracy.com... [...] >> Let's put it this way. All new "unordered" and multiset containers could >> easily be implemented as: >> 1) superc1st<double, list, vector> s1; >> 2) superc2nd<string, double, map, vector> s2; >> 3) superc2nd<string, double, map, map> s3; > > Sounds reminiscent of boost::graph::adjacency_list. It's a n-th dimensional container as opposed to adjacent_list. All in all we will benefit from: - "unordered" when list is part of the container. Ex.: superc<char, _map<char>, _list> s; - multisets or unordered multisets. Ex.: superc<employee, _map<string>, _map<string>, _map<double>, _map<double>, list> s; - the vector O(1) access when fragmentation is minimal - accessing sorted nodes (using map) but still adjacent in memory (vector). Ex.: superc<char, _map<char>, _vector> s = (_node<_map<char>, _vector> []) {'T', 'h', 'i', 's', ' ', 'i', 's', ' ', 'a', ' ', 't', 'e', 's', 't', '.'}; - interchanging vector iterators to map iterators. Ex.: superc<char, _map<char>, _vector> s; superc<char, _map<char>, _vector>::iterator i = s[10]; // if new _vector<>::operator [] returns: _node<> & s.find(i, s.end()); // O(log n) find from within a range of iterators only - STL code reuse - easy implementation - easy to use -Phil

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[fsm review] Terminal emulator example
by Phil Endecott 19 Aug '08

19 Aug '08

Dear All, Here's another FSM example which I hope is a bit less trivial than the last one. It's for the escape sequence handling in a terminal emulator. If you're curious you can see the real code here: http://svn.anyterm.org/anyterm/trunk/common/Terminal.cc The terminal emulator has to understand: - Normal characters like 'A' that write themselves on the screen at the current cursor position. - Normal control characters like tab, carriage return etc. A peculiar feature is that these characters can occur within escape sequences, where they have their normal effect. - Escape sequences, which consist of ESC followed by one character (normally a letter) and have effects like clearing the screen. - "CSI sequences", which perform more complex operations that may require parameters (e.g. scroll lines N to M up). They have the form ESC [ n1 ; n2 ; n3 ; ... X where the final letter X determines the operation and the number of numeric parameters is variable. So the state machine needs to track whether it is in an escape sequence, in a CSI sequence, or in "normal operation". The transitions are as follows: Current state | Condition | Next state ------------------------------------------------ Normal | ESC | ESC ESC | end of sequence | Normal ESC | [ | CSI ESC | char 26 | Normal CSI | end of sequence | Normal CSI | char 26 | Normal Character 26 explicitly abandons any escape sequence that is in progress. A terminal emulator should behave sensibly when it receives invalid input. One reasonable behaviour on receiving an invalid character is to ignore the preceding incomplete input and to treat the new character as if it had been received in normal mode; or, we could ignore the preceding incomplete input AND the new character and switch to normal mode. The following transitions do something along those lines: Normal | char 26 | Normal ESC | ESC | ESC ESC | invalid sequence | Normal CSI | ESC | ESC CSI | invalid sequence | Normal One thing that we don't want to do is to throw an exception when we get invalid input. My (stripped-down) ad-hoc implementation of this follows: class Terminal { screen_t screen; // basically a 2D array, with some features // for efficient scrolling int cursor_col, cursor_row; int params[MAX_PARAMS]; int nparams; enum state_t { normal, esc, csi }; state_t state; Terminal(): cursor_col(0), cursor_row(0), state(normal) {} void carriage_return() { cursor_col = 0; } void cursor_line_up() { cursor_row--; } void csi_CUU() { cursor_row -= params[0]; } // Lots more functions like those omitted. void write_normal_char(char c) { if (cursor_col>=cols) { cursor_col = 0; cursor_line_down(); } screen(cursor_row,cursor_col) = c; cursor_col++; } void process_char(char c) { // Control chars like tab, newline etc. work even inside // escape sequences: if (c <= 31) { switch (c) { .... case 13: carriage_return(); break; .... case 26: // This code abandons any escape sequence that is in progress state = normal; break; case 27: // Escape state = esc; break; .... } } else { switch (state) { case normal: write_normal_char(c); break; case esc: switch (c) { .... case 'M': cursor_line_up(); state=normal; break; .... case '[': state=csi; nparams=0; break; default: state=normal; break; } break; case csi: if (isdigit(c)) { if (nparams==0) { nparams=1; params[0]=0; } params[nparams-1] = params[nparams-1]*10 + (c-'0'); } else if (c==';') { if (nparams>=MAX_PARAMS) { return; } nparams++; params[nparams-1] = 0; } else { switch (c) { .... case 'A': csi_CUU(); break; .... } state = normal; } } } } }; OK, so let's try to implement that with the proposed library. As before, I haven't tried to compile any of this code: struct Normal; struct Esc; struct CSI; typedef mpl::vector<Normal,Esc,CSI>::type StateList; struct Common { screen_t screen; // BTW, how can I access this from outside? int cursor_col, cursor_row; void carriage_return() { cursor_col = 0; } void handle_control_chars(char c) { switch (c) { .... case 13: carriage_return(); break; .... case 26: // This code abandons any escape sequence that is in progress this->switch_to<Normal>(); break; case 27: // Escape this->switch_to<Esc>(); break; .... } } }; template <typename StateT> struct TermState: fsm::state<StateT,StateList>, virtual Common { // I think I need some using declarations here. Or do they have to be in each of // the derived classes? } struct Normal: TermState<Normal> { void write_normal_char(char c) { if (cursor_col>=cols) { cursor_col = 0; cursor_line_down(); } screen(cursor_row,cursor_col) = c; cursor_col++; } void on_process(const char& c) { if (c<=31) { handle_control_char(c); } else { write_normal_char(c); } } }; struct Esc: TermState<Esc> { void cursor_line_up() { cursor_row--; } void on_process(const char& c) { if (c<=31) { handle_control_char(c); } else { switch (c) { .... case 'M': cursor_line_up(); switch_to<Normal>(); break; .... case '[': switch_to<CSI>(); break; default: switch_to<Normal>(); break; } } } }; struct CSI: TermState<CSI> { int params[MAX_PARAMS]; int nparams; void on_enter() { nparams=0; // doing this here is nice } void csi_CUU() { cursor_row -= params[0]; } void on_process(const char& c) { if (c<=31) { handle_control_char(c); } else { if (isdigit(c)) { if (nparams==0) { nparams=1; params[0]=0; } params[nparams-1] = params[nparams-1]*10 + (c-'0'); } else if (c==';') { if (nparams>=MAX_PARAMS) { return; } nparams++; params[nparams-1] = 0; } else { switch (c) { .... case 'A': csi_CUU(); break; .... } switch_to<Normal>(); } } } }; My view is that the ad-hoc version of the code is sufficiently readable and efficient for my needs, and that the Boost.FSM version does not improve on it. What do other people think? Am I choosing bad examples? If so, please can someone post an example that does demonstrate the library's advantages? (Maybe off-topic, but if any Spirit or Expressive experts would like to show how their libraries would deal with this problem I'd be interested to see that.) Regards, Phil.

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FSM Review Announcement
by Martin Vuille 19 Aug '08

19 Aug '08

The formal review for Andrey Semashev's Finite State Machines (FSM) library is scheduled for August 11th to 20th. Quoting from the documentation: "The main goals of the library are: * Simplicity. It should be very simple to create state machine using this library. * Performance. The state machine infrastructure should not be very time and memory-consuming in order to be applicable in more use cases. * Extensibility. A developer may want to add more states to the existing state machine, and this addition should be relatively safe since it shouldn't interfere with the existing states. The developer should also be able to specify additional transitions and events for the machine with minimum modifications to the existing code." "The following compilers are known to have problems or most likely will have ones: * Microsoft Visual C++ 6.0 and 7.0. Most probably will fail to compile due to lack of partial template specialization support. * Borland C++ Builder 5.5.1 (free version). Fails to compile due to lack of partial template specialization and in-class using declarations support. Some other minor problems also have been noticed. Newer versions of the compiler have not been tested. * OpenWatcom 1.5. Fails to compile due to problems with Boost.MPL code. Newer versions of the compiler have not been tested. * SunPro C++ Compiler 5.5 for Solaris (SPARC). Most likely will show problems with function overload resolution. Newer versions of the compiler have not been tested." The current submission is available from the sandbox vault at http://tinyurl.com/yjozfn (or http://www.boostpro.com/vault/index.php?action=downloadfile&filename=FSM.zip &directory=&PHPSESSID=48493076c1ea60ae316f7b60f15b9ed1, if you prefer.) MV

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[exception] doc error
by Daryle Walker 19 Aug '08

19 Aug '08

[This is based of an unrelated post that mentioned a file in the 1.36 release branch. I just looked and the trunk also has it.] <http://svn.boost.org/svn/boost/trunk/libs/exception/doc/ enable_current_exception.html>, as of revision 47496, has an error in its beginning. It wants T to be a user-defined type so it can derived publicly from it. However, user-defined type doesn't mean class type; it also includes enums, which can't be derived from. -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT hotmail DOT com

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Can multi-index do this?
by Daryle Walker 19 Aug '08

19 Aug '08

Is it possible for Boost.Multi-index, or anything else in Boost, to make a container that is generally random-access (like vector or deque) but efficiently allows removals anywhere (like list)? -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT hotmail DOT com

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[Boost.IOStreams] Error with c++ builder 2007
by Sean Farrow 18 Aug '08

18 Aug '08

Hi: When compiling the boost trunk, I get an error that the compiler can't cast 'const mapped_file_sink' to 'const mapped_file &' the line is 474 In libs\iostreams\src\mapped_file.cpp and reads: : mapped_file(static_cast<const mapped_file&>(other)) Anyone got any clue what is happening here? Chers Sean. __________ Information from ESET NOD32 Antivirus, version of virus signature database 3365 (20080818) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

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Can't use CLR with boost so...
by Jamie Justice 18 Aug '08

18 Aug '08

I need to convert a char array to a byte array of ASCII encoded characters to send over a TCP connection, but I can't use the CLR(and therefore the System namespace) with boost. Does anyone have a solution to this? Thanks, Jamie

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[filesystem] major problem with 1.36 on OS X
by Matthias Schabel 18 Aug '08

18 Aug '08

Attempting to compile and link the following code with a default build of 1.36 on OS X 10.5.4 (Intel) // test.cpp #include <fstream> #include <iostream> #include <string> #include <vector> //#include <boost/system/error_code.hpp> //#include <boost/system/system_error.hpp> #include <boost/filesystem/operations.hpp> #include <boost/filesystem/path.hpp> int main (int argc, char * const argv[]) { boost::filesystem::create_directory("blah"); return 0; } results in a linker error, even though the method in question is defined inline in <boost/system/error_code.hpp> : Undefined symbols: "boost::system::error_code::message() const", referenced from: boost::system::system_error::what() constin ccyMBSNr.o ld: symbol(s) not found collect2: ld returned 1 exit status This is reproducible both from a clean XCode 3.0 project and from the command line : gcc test.cpp -I/usr/local/include -I .. -L/usr/local/lib - lboost_filesystem-xgcc40-mt -lboost_system-xgcc40-mt -lstdc++ Uncommenting the explicit includes doesn't help, either. This is a weird one... Matthias

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Re: [boost] Boost 1.36.0 release notice
by Beman Dawes 18 Aug '08

18 Aug '08

Joe Gottman wrote: > Beman Dawes wrote: >> Boost 1.36.0 has been released and is available from SourceForge. See >> http://sourceforge.net/projects/boost/ >> >> This release include four new libraries: >> > I just downloaded the version 1.36 and the release history is > completely blank. Grrr... One of my highest priority tasks for the next release is going to be to get a system in place that will automatically scan a release snapshot for the presence of certain files, and optionally verify size, date, and other properties. Thanks for the heads up. --Beman

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Identification library preliminary version
by joel falcou 18 Aug '08

18 Aug '08

Hello all, I've uploaded a preliminary version of my type identification library into the vault (identification-v.01.zip) It's the current implementation of my type debugging facility that provides a simple function and class to build at run-time a human readable string containing the name of its type arguments. Identification supports a simple way to register user-defined types into itself. Samples and documentation are provided. It has been tested on g++ v4+ (both linux and windows) and on MSVC 2008 with equal success. Test on other platform and compiler are welcome as well as general comments on the interface or implementation choices. Thanks in advance.

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