Package com.github.mjdev.libaums.driver

Class ByteBlockDevice

java.lang.Object

com.github.mjdev.libaums.driver.ByteBlockDevice

All Implemented Interfaces:

BlockDeviceDriver

Direct Known Subclasses:

Partition

public class ByteBlockDevice
extends java.lang.Object
implements BlockDeviceDriver

Simple class which wraps around an existing BlockDeviceDriver to enable byte addressing of content. Uses byte offsets instead of device oddsets in write(long, ByteBuffer) and read(long, ByteBuffer). Uses BlockDeviceDriver.getBlockSize() to calculate device offsets.

Constructor Summary

Constructors

Constructor	Description
ByteBlockDevice(BlockDeviceDriver targetBlockDevice)
ByteBlockDevice(BlockDeviceDriver targetBlockDevice, int logicalOffsetToAdd)

Method Summary

Modifier and Type	Method	Description
int	getBlockSize()	Returns the block size of the block device.
void	init()	Initializes the block device for further use.
void	read(long byteOffset, java.nio.ByteBuffer dest)	Reads from the block device at a certain offset into the given buffer.
void	write(long byteOffset, java.nio.ByteBuffer src)	Writes to the block device at a certain offset from the given buffer.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ByteBlockDevice

public ByteBlockDevice(BlockDeviceDriver targetBlockDevice,
                       int logicalOffsetToAdd)

ByteBlockDevice

public ByteBlockDevice(BlockDeviceDriver targetBlockDevice)

Method Detail

init

public void init()
          throws java.io.IOException

Description copied from interface: BlockDeviceDriver

Initializes the block device for further use. This method should be called before doing anything else on the block device.

Specified by:

init in interface BlockDeviceDriver

Throws:

java.io.IOException - If initializing fails

read

public void read(long byteOffset,
                 java.nio.ByteBuffer dest)
          throws java.io.IOException

Description copied from interface: BlockDeviceDriver

Reads from the block device at a certain offset into the given buffer. The amount of bytes to be read are determined by Buffer.remaining().

The deviceOffset can either be the amount of bytes or a logical block addressing using the block size. To get the bytes in the last case you have to multiply the lba with the block size (offset * BlockDeviceDriver.getBlockSize()).

Specified by:

read in interface BlockDeviceDriver

Parameters:

byteOffset - The offset where the reading should begin.

dest - The buffer where the data should be read into.

Throws:

java.io.IOException - If reading fails.

write

public void write(long byteOffset,
                  java.nio.ByteBuffer src)
           throws java.io.IOException

Description copied from interface: BlockDeviceDriver

Writes to the block device at a certain offset from the given buffer. The amount of bytes to be written are determined by Buffer.remaining().

The deviceOffset can either be the amount of bytes or a logical block addressing using the block size. To get the bytes in the last case you have to multiply the lba with the block size (offset * BlockDeviceDriver.getBlockSize()).

Specified by:

write in interface BlockDeviceDriver

Parameters:

byteOffset - The offset where the writing should begin.

src - The buffer with the data to be transferred.

Throws:

java.io.IOException - If writing fails.

getBlockSize

public int getBlockSize()

Description copied from interface: BlockDeviceDriver

Returns the block size of the block device. Every block device can only read and store bytes in a specific block with a certain size.

That means that it is only possible to read or write hole blocks!

Specified by:

getBlockSize in interface BlockDeviceDriver

Returns:

The block size in bytes, mostly 512 bytes.