#include <windows.h>

#include "DiskSpace.h"

typedef BOOL (* diskEx) (LPCTSTR root, PULARGE_INTEGER a, PULARGE_INTEGER B, PULARGE_INTEGER C);

DiskSpace::DiskSpace(const char *rootName)
{
	char 	rootPath[128];
	DWORD totalClusters;
	OSVERSIONINFO osVerInfo;

  // copy the rootname to our own path
	strcpy(rootPath, rootName);

  // get some guide to the os version
	osVerInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
	GetVersionEx(&osVerInfo);

  // if get disk free space fails then note fatal initialisation error
	if (!GetDiskFreeSpace(rootName, &sectorsPerCluster, &bytesPerSector,
												&freeClusters, &totalClusters))
	{ this->initialised = FALSE;
    return;
	}

	// call the advanced form of getDiskSpace if we have access to it; this
  // will cope with 2Gb+ partitions correctly 
	if (osVerInfo.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS &&
			LOWORD(osVerInfo.dwBuildNumber) > 1000 ||
      TRUE)
	{ HMODULE module;
		FARPROC proc;
		ULARGE_INTEGER freeBytes, freeToCaller, totalBytes;

		module	= LoadLibrary("KERNEL32.DLL");
		proc 		= GetProcAddress(module, "GetDiskFreeSpaceEx");
		if (proc == NULL)
		{	this->initialised = TRUE;
			return;
		}
		(* ((diskEx) proc))(rootPath, &freeBytes, &freeToCaller, &totalBytes);
		// Get free clusters - use the ULARGE_INTEGER variables to get the
		// result and avoid overflow problems
		//freeBytes = freeBytes / sectorsPerCluster; //(sectorsPerCluster * bytesPerSector);
		//freeClusters = totalBytes;
	}
  this->initialised = TRUE;
	return;
}

BOOL DiskSpace::initialisedOk()
{	return this->initialised;
}

unsigned double DiskSpace::totalFreeSpace()
{ 	return this->freeClusters * (((double) (this->sectorsPerCluster * this->bytesPerSector)) / (double) (1024));
}

int DiskSpace::fileClusters(int fileSize)
{	int sectors, clusters;

	sectors	= (fileSize + this->bytesPerSector - 1) / this->bytesPerSector;
	clusters	= (sectors + this->sectorsPerCluster - 1) / this->sectorsPerCluster;
	return clusters;
}

int DiskSpace::fileSpace(int fileSize)
{	return this->fileClusters(fileSize) * this->bytesPerSector * this->sectorsPerCluster;
}