Re: [Boost-users] filesystem statistics

From: Thomas Matelich (matelich_at_[hidden])
Date: 2005-06-21 15:23:04

On 6/21/05, remi.chateauneu_at_[hidden] <remi.chateauneu_at_[hidden]> wrote:
> I am, thanks in advance !
> If this implementation is not deemed to go with Boost,
> why not a new project on Sourceforge ?
> I may try to port it to Solaris, if you wish to.
> 
> 
> Thomas Matelich wrote:
> 
> >On 6/21/05, Steve Hartmann <steven_hartmann_at_[hidden]> wrote:
> >
> >
> >>Hello all,
> >>
> >>I was browsing boost to find some portable means for getting
> >>file system statistics such as file system (disk) size, free
> >>space, etc.  I kind of expected to see this in the boost
> >>filesystem library, but they don't appear to be there.
> >>Doesn't even seem to be in the "Do-list".
> >>
> >>Am I missing something?  Looking in the wrong place?
> >>
> >>
> >
> >
> >I've got an implementation (independent of FileSystem) that works on
> >windows, hp and linux (others I'm sure, but I don't use them) if
> >anyone's interested.
> >

Its really not that complicated.  just a wrapper around statfs on unix
and GetDiskFreeSpaceEx on windows.  Its not terribly long, I'll post
it (copied from a longer .cpp file, sorry if I miss an include).

#ifndef _WIN32
#include <sys/vfs.h>
#else
#include <winsock2.h> // I don't want winsock.h included ever
#include <Windows.h>
#endif
#include <boost/cstdint.hpp>

namespace 
{
        bool getDeviceStuff(std::string const& path, boost::intmax_t&
num_bytes, boost::intmax_t& available_bytes)
        {
                if(path.empty())
                {
                        //ZLOG("diskspace") << "Cannot get device info for empty directory
path" << std::endl;
                        return false;
                }
#ifndef _WIN32
                struct statfs buf;
                if(statfs(path.c_str(), &buf) < 0)
                {
                        //ZLOG("diskspace") << "statfs failed.  " << strerror(errno) << std::endl;
                        return false;
                }
                //ZLOG("diskspace") << " f_blocks=" << buf.f_blocks << " f_bsize="
<< buf.f_bsize << " f_bavail=" << buf.f_bavail << std::endl;
                num_bytes = buf.f_blocks * buf.f_bsize;
                available_bytes = buf.f_bavail * buf.f_bsize;
#else
                __int64 freebytestocaller, totalbytes, freebytes;
                if(!GetDiskFreeSpaceEx (path.c_str(), 
                                                                (PULARGE_INTEGER)&freebytestocaller, 
                                                                (PULARGE_INTEGER)&totalbytes, 
                                                                (PULARGE_INTEGER)&freebytes))
                {
         LPVOID lpMsgBuf;
         FormatMessage( 
             FORMAT_MESSAGE_ALLOCATE_BUFFER | 
             FORMAT_MESSAGE_FROM_SYSTEM | 
             FORMAT_MESSAGE_IGNORE_INSERTS,
             NULL,
             GetLastError(),
             MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
             (LPTSTR) &lpMsgBuf,
             0,
             NULL 
         );
                        //ZLOG("diskspace") << "GetDiskFreeSpaceEx failed: " <<
GetLastError() << " - " << (LPCTSTR)lpMsgBuf << std::endl;
         LocalFree( lpMsgBuf );
                        return false;
                }
                num_bytes = totalbytes;
                available_bytes = freebytestocaller;
#endif
                return true;
        }
}

double XPlat::getDeviceFreeSpace(std::string const& path)
{
        boost::intmax_t num_bytes, available_bytes;
        if(!getDeviceStuff(path, num_bytes, available_bytes))
                return -1.0;
        double retval = double(available_bytes) / (1 << 20);
        //ZLOG("diskspace") << retval << " meg free for " << path << std::endl;
        return retval;
}

double XPlat::getDeviceFreePercent(std::string const& path)
{
        boost::intmax_t num_bytes, available_bytes;
        if(!getDeviceStuff(path, num_bytes, available_bytes))
                return -1.0;
        double retval = (double(available_bytes) / num_bytes) * 100.0;
        //ZLOG("diskspace") << retval << " {(double(" << available_bytes <<
") / " << num_bytes << ") * 100.0} percent free for " << path <<
std::endl;
        return retval;
}