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class Disk{
	disk_geometry dg;
	public:
	//constructors..
	virtual ~Disk();
	Disk(disk_geometry *geo,string& filename);
	Disk(unsigned int c,unsigned int h,unsigned int s,const string& filename);
	Disk(const Disk& source);
	//Interface:
	virtual unsigned long long DiskSize(){
		return dg.bps*dg.spt*dg.cph*dg.hpd;
	}
	virtual char *ReadSector(unsigned int abs_sector); //?




};

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makeDisk() {
    <do disk creation things>
   if (disk.state == Error) {
      <do disk deletion things>
      return 0;
   }
   return disk;
}

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#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>


struct sVirtualDiskHeader
{
	uint32_t BytesPerSector;
	uint32_t SectorsPerTrack;
	uint32_t TracksPerHead;
	uint32_t Heads;
	uint32_t OtherInformation;
};
class cVirtualDiskFile
{
	private:
	sVirtualDiskHeader vdh;			/// virtual disk header.
	bool diskStateUsing;				/// was this object created from a disk file?
	char *diskStateFile;
	void *data;
	uint32_t dataSize;
	public:
	cVirtualDiskFile(char *file);
	~cVirtualDiskFile();

	bool SaveStateToDisk();
};

cVirtualDiskFile::cVirtualDiskFile(char *file)
{
	int fdescriptor;
	struct stat fdstat;
	/// copy file path from potential temporary location to a managed location by us.
	diskStateFile = (char*)malloc(strlen(file));
	strcpy(diskStateFile, file);
	fdescriptor = open(diskStateFile, O_RDWR | O_CREAT, S_IRWXU | S_IRGRP);
	if(!fdescriptor)
	{
		diskStateUsing = false;
		return;
	}
	fstat(fdescriptor, &fdstat);
	if(read(fdescriptor, &vdh, sizeof(sVirtualDiskHeader)) < sizeof(sVirtualDiskHeader))
	{
		/// empty or corrupted file, just consider this a new image and error on save.
		memset(&vdh, 0, sizeof(sVirtualDiskHeader));
		close(fdescriptor);
		diskStateUsing = false;
		return;
	}
	/// could store the data size in the header..
	data = malloc(fdstat.st_size - sizeof(sVirtualDiskHeader));
	dataSize = fdstat.st_size - sizeof(sVirtualDiskHeader);
	read(fdescriptor, data, fdstat.st_size - sizeof(sVirtualDiskHeader));
	close(fdescriptor);
	diskStateUsing = true;
	return;
}

cVirtualDiskFile::~cVirtualDiskFile()
{
	/// we implied that we are using a disk file so I figure it is implied that we sync our
	/// memory state with the disk file state before deconstruction.
	if(diskStateUsing)
	{
		SaveStateToDisk();
	}
	free(data);
	if(diskStateFile)
	{
		free(diskStateFile);
	}
}

bool cVirtualDiskFile::SaveStateToDisk()
{
	int fdescriptor;
	fdescriptor = open(diskStateFile, O_RDWR | O_CREAT | O_TRUNC, S_IRWXU | S_IRGRP);
	if(!fdescriptor)
	{
		return false;
	}
	write(fdescriptor, &vdh, sizeof(sVirtualDiskHeader));
	write(fdescriptor, data, dataSize);
	close(fdescriptor);
	return true;
}

int main(int argc, char *argv[])
{
	cVirtualDiskFile vdf("test.data");
	return 0;
}