Disk Class Reference

Disk class Implements Disk abstraction that enables emulation of a disk image. Used by file system to access and make changes to the disk. More...

#include <disk.h>

Public Member Functions
	Disk ()
	constructor of Disk class More...
	~Disk ()
	destructor of Disk class More...
void	open (const char *path, size_t nblocks)
	opens the disk image More...
size_t	size () const
	check size of disk More...
bool	mounted () const
	check if the disk has been mounted More...
void	mount ()
	mount the disk More...
void	unmount ()
	unmount the disk More...
void	read (int blocknum, char *data)
	read from disk More...
void	write (int blocknum, char *data)
	write to disk More...

Private Member Functions
void	sanity_check (int blocknum, char *data)
	check if the block is within valid range More...

Private Attributes
size_t	Blocks
size_t	Reads
size_t	Writes
size_t	Mounts

Detailed Description

Disk class Implements Disk abstraction that enables emulation of a disk image. Used by file system to access and make changes to the disk.

Definition at line 18 of file disk.h.

Constructor & Destructor Documentation

Disk()

Disk::Disk ( )

inline

constructor of Disk class

Number of bytes per block

Returns

an instance of Disk class

Definition at line 41 of file disk.h.

~Disk()

Disk::~Disk

(

)

destructor of Disk class

Returns

returns nothing; deletes the Disk object

Implementation details

• Check if FileDescriptor is set
• If set, print the required information and close.

Definition at line 46 of file disk.cpp.

Member Function Documentation

mount()

void Disk::mount ( )

inline

mount the disk

Returns

void function; returns nothing

Definition at line 73 of file disk.h.

Here is the caller graph for this function:

mounted()

bool Disk::mounted ( ) const

inline

check if the disk has been mounted

Returns

true if the disk has been mounted; false otherwise

Definition at line 67 of file disk.h.

Here is the caller graph for this function:

open()

void Disk::open	(	const char *	path,
		size_t	nblocks
	)

opens the disk image

Parameters

path	path to the disk image
nblocks	number of blocks in the disk image

Returns

void function; returns nothing. throws runtime_error exception on error.

Implementation details

• Open Filedescriptor
  
• Check if FileDescriptor is valid
• Allocated blocks
• Initialize the disk

Definition at line 18 of file disk.cpp.

read()

void Disk::read	(	int	blocknum,
		char *	data
	)

read from disk

Parameters

blocknum	block to read from
data	data buffer to write into

Implementation details

• sanity_check blocknum and data
• reposition read/write file offset and check validity
• read the FileDescriptor for BLOCK_SIZE
• Increment reads

Definition at line 86 of file disk.cpp.

Here is the call graph for this function:

Here is the caller graph for this function:

sanity_check()

void Disk::sanity_check ( int  blocknum, char *  data  )

private

check if the block is within valid range

Number of mounts

Parameters

blocknum	index of the block into the free block bitmap
data	data buffer

Returns

void function; returns nothing. throws invalid_argument on error

Implementation details

• reason for exit.
• Check if block num is valid or not.
  
• Check if data pointer is valid

Definition at line 61 of file disk.cpp.

Here is the caller graph for this function:

size()

size_t Disk::size ( ) const

inline

check size of disk

Returns

size of disk in terms of blocks

Definition at line 61 of file disk.h.

Here is the caller graph for this function:

unmount()

void Disk::unmount ( )

inline

unmount the disk

Returns

void function; returns nothing

Definition at line 79 of file disk.h.

write()

void Disk::write	(	int	blocknum,
		char *	data
	)

write to disk

Parameters

blocknum	block to write into
data	data buffer to read from

Implementation details

• sanity_check blocknum and data
• reposition read/write file offset and check validity
• write the BLOCK_SIZE data to the FileDescriptor
  
• increment writes

Definition at line 112 of file disk.cpp.

Here is the call graph for this function:

Here is the caller graph for this function:

Member Data Documentation

Blocks

size_t Disk::Blocks

private

File descriptor of disk image

Definition at line 21 of file disk.h.

Mounts

size_t Disk::Mounts

private

Number of writes performed

Definition at line 24 of file disk.h.

Reads

size_t Disk::Reads

private

Number of blocks in disk image

Definition at line 22 of file disk.h.

Writes

size_t Disk::Writes

private

Number of reads performed

Definition at line 23 of file disk.h.

---

The documentation for this class was generated from the following files:

• include/sfs/disk.h
• src/library/disk.cpp