From 376455169208576167 X-Google-Thread: f78e5,b262f0559808d68d X-Google-Attributes: gidf78e5,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news3.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local02.nntp.dca.giganews.com!nntp.speakeasy.net!news.speakeasy.net.POSTED!not-for-mail NNTP-Posting-Date: Thu, 14 Sep 2006 16:40:24 -0500 Return-Path: X-Authentication-Warning: mulga.csse.unimelb.edu.au: fjh set sender to devnull@stump.algebra.com using -f X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Original-To: std-c++@mailman.ucar.edu Delivered-To: std-c++@mailman.ucar.edu From: derek@antiquark.com Newsgroups: comp.std.c++ Subject: Re: typed_index_wrapper Organization: http://groups.google.com Message-ID: <1158268062.498188.92720@d34g2000cwd.googlegroups.com> References: <1158187421.369321.48370@m73g2000cwd.googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Complaints-To: groups-abuse@google.com User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20050922 Fedora/1.7.12-1.3.1,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: d34g2000cwd.googlegroups.com; posting-host=206.45.72.49; posting-account=7FQ00RMAAAB94nG8vVqxnuNVHkXuKSF_JQPy3MdXsIgAWnuyOJmNcQ X-Virus-Scanned: amavisd-new at ucar.edu X-Virus-Scanned: amavisd-new at csse.unimelb.edu.au Approved: Fergus Henderson , moderator of comp.std.c++ X-Virus-Scanned: amavisd-new at csse.unimelb.edu.au Date: Thu, 14 Sep 2006 16:34:46 CST Lines: 164 NNTP-Posting-Host: 65.182.171.162 X-Trace: sv3-jmjTHrxbCx1XEJGF+i8nQHK7nCGY+eiXm4AbX4PwVGLPxteQSJBAfA6qdWkFsf48AVNxjmqjIeRc8yV!VaYOe0Bdg8p7LPsEXbYXHrmC3tuoou+Pnj7sGyViVTFhmJQe1c0M7d9U2G0ng2HxafM+pFZjBrI3!w+/82b6vZPd4HSe8Okvn1ziVw8CCqyacDhwaRne0VA== X-Complaints-To: abuse@speakeasy.net X-DMCA-Complaints-To: abuse@speakeasy.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.32 Xref: g2news2.google.com comp.std.c++:3790 Dave Harris wrote: > Ideally there would only be one wrapper, not a set of them. As with > std::stack. Here's an attempt at a wrapper. I think that to be done properly, various wrappers would be needed for the various containers, mainly due to difference in constructors. The wrapper class takes two parameters: the container type, and the indexing type. EG, typed_index_wrapper < vector, EFoo > myvec. The code below shows how this adapter can be used for std::vector, std::deque and boost::array. The boost::array causes a compiler error for aggregate initialization though. Other containers, such as bitset, valarray, stack and string, are problematic for reasons mentioned near the bottom. Derek ===== #include #include #include #include #include #include template class typed_index_wrapper : public Container { public: typedef typename Container::reference reference; typedef typename Container::const_reference const_reference; typedef IndexType index_type; typedef typename Container::size_type size_type; typedef typename Container::value_type value_type; typedef Container base_type; reference operator[](const index_type& index) { return Container::operator[](size_type(index)); } const_reference operator[](const index_type& index) const { return Container::operator[](size_type(index)); } reference at(const index_type& index) { return Container::at(size_type(index)); } const_reference at(const index_type& index) const { return Container::at(size_type(index)); } typed_index_wrapper() :Container() {} typed_index_wrapper(size_t n) :Container(n) {} typed_index_wrapper(size_t n, value_type v) :Container(n, v) {} template typed_index_wrapper(InIt _begin, InIt _end) :Container(_begin, _end) {} }; enum EFoo { a = 0, b, c }; enum EBar { x = 0, y, z }; #define PRINT(a) std::cout << #a << ": " << (a) << std::endl int main() { std::string s("hello"); // The following containers are demonstrated below: // std::vector // boost::array // std::deque typed_index_wrapper < std::vector, EFoo > v1(11); typed_index_wrapper < std::vector, EFoo > v2(22, 33); typed_index_wrapper < std::vector, EFoo > v3(v1); typed_index_wrapper < std::vector, EFoo > v4(s.begin(), s.end()); PRINT(v1.size()); PRINT(v2.size()); PRINT(v3.size()); std::cout << std::endl; PRINT(v1.at(a)); PRINT(v2[a]); PRINT(v3[a]); PRINT(v4.at(a)); std::cout << std::endl; PRINT( v1 == v2 ); PRINT( v1 == v3 ); v1 = v4; std::cout << std::endl; typed_index_wrapper< boost::array, EBar > a1; // a1[0] = 111; // compiler error // a1[a] = 111; // compiler error a1[x] = 111; a1.at(x) = 111; PRINT(a1.size()); PRINT(a1.at(EBar(0))); PRINT(a1.at(x)); // Aggregate initialize won't work for boost::array. Message is // error: `a2' must be initialized by constructor, not by `{...} //typed_index_wrapper< boost::array, EFoo > a2 = {444,555,666}; typed_index_wrapper< std::deque, unsigned char> d1(1000, 0); d1.clear(); for(int i = 0 ; i < 1000 ; i ++ )d1.push_back(i); PRINT(d1.at(257)); // index will roll over because it's uchar, should print '1' // std::bitset will cause problems due to different ctors, and member functions // returning a bitset. // // std::valarray will cause problems due to different ctors, and indexing functions // that take a slice or gslice. // // std::stack doesn't provide indexed access functions. // // std::string has different ctors, and just doesn't seem applicable to typed indexing. } --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]