rossi.fstools.fs.reiserfs
Class FBlock

java.lang.Object
  rossi.fstools.fs.reiserfs.FBlock

All Implemented Interfaces:

DiskStructure

Direct Known Subclasses:

InternalNode, LeafNode

public class FBlock

extends java.lang.Object

implements DiskStructure

Representation of a formated block. This is one of 2 types, either an InternalNode or a LeafNode. This base class handles the block header.

Both InternalNode and Leaf node have a common header which is represented here.

  On disk the block header looks like this:

        31        24        16       8       0
        --------------------------------------
  0000  |        Level     |  Num Items      |
        --------------------------------------
  0004  |     Free Space   |  Reserved       |
        --------------------------------------
  0008  |            Right Key               |
        --------------------------------------
  000C  |            Right Key               |
        --------------------------------------
  0010  |            Right Key               |
        --------------------------------------
  0014  |            Right Key               |
        --------------------------------------
 












Field Summary




protected  int
blocknum



           



protected  int
freeSpace



           



protected  int
level



           



protected  int
numItems



           



protected  FBlock
parent



           



protected  int
reserved



           



protected  Key
rightKey



           



protected  ReiserSuperBlock
sb



           


 



Constructor Summary
FBlock(ReiserSuperBlock sb,
       int blocknum)



          Create a new formated block.
 



Method Summary




static FBlock
createFromBuffer(ReiserSuperBlock sb,
                 int blocknum,
                 byte[] buffer,
                 int blkoffset)



          Create a formatted block instance.



 int
getBlockHeaderSize()



          Get the size of the header for this formatted block.



 int
getBlockNum()



           



 int
getDataSize()



          Get size of this structure.



 int
getFreeSpace()



          Get the amount of free space within this block.



 int
getLevel()



          Get the level of this block in the B+tree.



 int
getNumItems()



          Get the number of items or keys within this block.



 FBlock
getParent()



          Get the parent of this block.



 int
getReserved()



           



 Key
getRightKey()



          Get the right most (hightest in sort order) key contained within this block.



 ReiserSuperBlock
getSuperBlock()



          Get the superblock for this filesystem.



 void
loadFromBuffer(byte[] buffer,
               int offset)



          Load this structure from disk.



 void
setFreeSpace(int aFreeSpace)



           



 void
setLevel(int aLevel)



           



 void
setNumItems(int aNumItems)



           



 void
setParent(FBlock aParent)



          Set the parent of this block.



 void
setReserved(int aReserved)



           



 void
setRightKey(Key aRightKey)



           


 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 





Field Detail



level
protected int level







numItems
protected int numItems







freeSpace
protected int freeSpace







reserved
protected int reserved







rightKey
protected Key rightKey







sb
protected ReiserSuperBlock sb







blocknum
protected int blocknum







parent
protected FBlock parent








Constructor Detail



FBlock
public FBlock(ReiserSuperBlock sb,
              int blocknum)

Create a new formated block.

Parameters:
sb - a ReiserSuperBlock
blocknum - a int




Method Detail



getBlockHeaderSize
public int getBlockHeaderSize()

Get the size of the header for this formatted block.






Returns:
block header size.





getDataSize
public int getDataSize()

Get size of this structure.


Specified by:
getDataSize in interface DiskStructure



Returns:
size
See Also:
DiskStructure.getDataSize()





getSuperBlock
public ReiserSuperBlock getSuperBlock()

Get the superblock for this filesystem.






Returns:
superblock





getBlockNum
public int getBlockNum()











getParent
public FBlock getParent()

Get the parent of this block.  This is to allow walking back up the tree.






Returns:
parent block.





setParent
public void setParent(FBlock aParent)

Set the parent of this block.  This is to allow walking back up the tree.











getLevel
public int getLevel()

Get the level of this block in the B+tree.  A level of 1 indicates a Leaf block.  
 Greater than one indicates a node block.  A level of zero indicates a free block.






Returns:
level.





setLevel
public void setLevel(int aLevel)











getNumItems
public int getNumItems()

Get the number of items or keys within this block.  Leaf blocks contain items,
 node blocks contain keys.






Returns:
int
See Also:
LeafNode, 
InternalNode





setNumItems
public void setNumItems(int aNumItems)











getFreeSpace
public int getFreeSpace()

Get the amount of free space within this block.






Returns:
number of bytes of free space.





setFreeSpace
public void setFreeSpace(int aFreeSpace)











getReserved
public int getReserved()











setReserved
public void setReserved(int aReserved)











getRightKey
public Key getRightKey()

Get the right most (hightest in sort order) key contained within this block.







Returns:
the rightmost Key





setRightKey
public void setRightKey(Key aRightKey)











createFromBuffer
public static FBlock createFromBuffer(ReiserSuperBlock sb,
                                      int blocknum,
                                      byte[] buffer,
                                      int blkoffset)
                               throws FsException

Create a formatted block instance.  This is a factory method that reads the supplied
 buffer and creates the appropriate subclass.





Parameters:
sb - a ReiserSuperBlock for this filesystem
blocknum - block number of the block to be processed.
buffer - a byte[] buffer containing the block
blkoffset - a int offset into the buffer to the start of the block
Returns:
FBlock subclass -- either an InternalNode or LeafNode
Throws:
FsException





loadFromBuffer
public void loadFromBuffer(byte[] buffer,
                           int offset)
                    throws FsException

Load this structure from disk.


Specified by:
loadFromBuffer in interface DiskStructure


Parameters:
buffer - a byte[] containing data to be read in populating the object
offset - a int indicating the offset within the buffer to start parsing.
Throws:
FsException - if a parse error occurs
See Also:
DiskStructure.loadFromBuffer(byte[], int)