Re: [Boost-users] filesystem statistics

21 Jun 2005


      On 6/21/05, remi.chateauneu@gmx.de  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  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 
#else
#include  // I don't want winsock.h included ever
#include 
#endif
#include 

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;
}