Is there an easier way to pop off a directory from boost::filesystem::path?
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21-08-2019 - |
Question
I have a relative path (e.g. "foo/bar/baz/quux.xml") and I want to pop a directory off so that I will have the subdirectory + file (e.g. "bar/baz/quux.xml").
You can do this with path iterators, but I was hoping there was something I was missing from the documentation or something more elegant. Below is the code that I used.
#include <boost/filesystem/path.hpp>
#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/convenience.hpp>
#include <boost/filesystem/exception.hpp>
#include <boost/assign.hpp>
boost::filesystem::path pop_directory(const boost::filesystem::path& path)
{
list<string> parts;
copy(path.begin(), path.end(), back_inserter(parts));
if (parts.size() < 2)
{
return path;
}
else
{
boost::filesystem::path pathSub;
for (list<string>::iterator it = ++parts.begin(); it != parts.end(); ++it)
{
pathSub /= *it;
}
return pathSub;
}
}
int main(int argc, char* argv)
{
list<string> test = boost::assign::list_of("foo/bar/baz/quux.xml")
("quux.xml")("foo/bar.xml")("./foo/bar.xml");
for (list<string>::iterator i = test.begin(); i != test.end(); ++i)
{
boost::filesystem::path p(*i);
cout << "Input: " << p.native_file_string() << endl;
boost::filesystem::path p2(pop_directory(p));
cout << "Subdir Path: " << p2.native_file_string() << endl;
}
}
The output is:
Input: foo/bar/baz/quux.xml
Subdir Path: bar/baz/quux.xml
Input: quux.xml
Subdir Path: quux.xml
Input: foo/bar.xml
Subdir Path: bar.xml
Input: ./foo/bar.xml
Subdir Path: foo/bar.xml
What I was hoping for was something like:
boost::filesystem::path p1(someString);
boost::filesystem::path p2(p2.pop());
If you look at some test code on codepad.org, I have tried branch_path (returns "foo/bar/baz") and relative_path (returns "foo/bar/baz/quux.xml").
Solution
Here is something that a co-worker figured out just using string::find
with boost::filesystem::slash
. I like this that it doesn't require iterate over the entire path breaking it up, but also using the path's OS-independent definition of the path separation character. Thanks Bodgan!
boost::filesystem::path pop_front_directory(const boost::filesystem::path& path)
{
string::size_type pos = path.string().find(boost::filesystem::slash<boost::filesystem::path>::value);
if (pos == string::npos)
{
return path;
}
else
{
return boost::filesystem::path(path.string().substr(pos+1));
}
}