Re: [Boost-bugs] [Boost C++ Libraries] #1976: Inverse function for complete

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #1976: Inverse function for complete
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2008-08-22 00:56:15

#1976: Inverse function for complete
--------------------------------------+-------------------------------------
  Reporter:  me22.ca+boost_at_[hidden]  |       Owner:  bemandawes
      Type:  Feature Requests         |      Status:  new       
 Milestone:  Boost 1.36.0             |   Component:  filesystem
   Version:  Boost 1.35.0             |    Severity:  Problem   
Resolution:                           |    Keywords:            
--------------------------------------+-------------------------------------

Comment(by anonymous):

 Here's a naive implementation (that doesn't handle symlinks and isn't well
 tested):
 {{{
 #include <boost/filesystem.hpp>

 boost::filesystem::path
 naive_uncomplete(boost::filesystem::path const path,
 boost::filesystem::path const base) {
     if (path.has_root_path()){
         if (path.root_path() != base.root_path()) {
             return path;
         } else {
             return naive_uncomplete(path.relative_path(),
 base.relative_path());
         }
     } else {
         if (base.has_root_path()) {
             throw "cannot uncomplete a path relative path from a rooted
 base";
         } else {
             typedef boost::filesystem::path::const_iterator path_iterator;
             path_iterator path_it = path.begin();
             path_iterator base_it = base.begin();
             while ( path_it != path.end() && base_it != base.end() ) {
                 if (*path_it != *base_it) break;
                 ++path_it; ++base_it;
             }
             boost::filesystem::path result;
             for (; base_it != base.end(); ++base_it) {
                 result /= "..";
             }
             for (; path_it != path.end(); ++path_it) {
                 result /= *path_it;
             }
             return result;
         }
     }
 }
 }}}

-- 
Ticket URL: <http://svn.boost.org/trac/boost/ticket/1976#comment:2>
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