org.h2.mvstore

Class FreeSpaceBitSet

java.lang.Object

org.h2.mvstore.FreeSpaceBitSet

public class FreeSpaceBitSet
extends java.lang.Object

A free space bit set.

Constructor Summary

Constructors

Constructor and Description
FreeSpaceBitSet(int firstFreeBlock, int blockSize) Create a new free space map.

Method Summary

Modifier and Type	Method and Description
long	allocate(int length) Allocate a number of blocks and mark them as used.
void	clear() Reset the list.
void	free(long pos, int length) Mark the space as free.
int	getFillRate() Get the fill rate of the space in percent.
long	getFirstFree() Get the position of the first free space.
long	getLastFree() Get the position of the last (infinite) free space.
boolean	isFree(long pos, int length) Check whether one of the blocks is free.
boolean	isUsed(long pos, int length) Check whether one of the blocks is in use.
void	markUsed(long pos, int length) Mark the space as in use.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

FreeSpaceBitSet

public FreeSpaceBitSet(int firstFreeBlock,
                       int blockSize)

Create a new free space map.

Parameters:

firstFreeBlock - the first free block

blockSize - the block size

Method Detail

clear

public void clear()

Reset the list.

isUsed

public boolean isUsed(long pos,
                      int length)

Check whether one of the blocks is in use.

Parameters:

pos - the position in bytes

length - the number of bytes

Returns:

true if a block is in use

isFree

public boolean isFree(long pos,
                      int length)

Check whether one of the blocks is free.

Parameters:

pos - the position in bytes

length - the number of bytes

Returns:

true if a block is free

allocate

public long allocate(int length)

Allocate a number of blocks and mark them as used.

Parameters:

length - the number of bytes to allocate

Returns:

the start position in bytes

markUsed

public void markUsed(long pos,
                     int length)

Mark the space as in use.

Parameters:

pos - the position in bytes

length - the number of bytes

free

public void free(long pos,
                 int length)

Mark the space as free.

Parameters:

pos - the position in bytes

length - the number of bytes

getFillRate

public int getFillRate()

Get the fill rate of the space in percent. The value 0 means the space is completely free, and 100 means it is completely full.

Returns:

the fill rate (0 - 100)

getFirstFree

public long getFirstFree()

Get the position of the first free space.

Returns:

the position.

getLastFree

public long getLastFree()

Get the position of the last (infinite) free space.

Returns:

the position.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object